Circuitry for biasing a MEMS transducer and associated signal processing circuitry. A reference voltage generator is configured to generate a reference voltage at a reference voltage node. Control circuitry generates a drive signal to control a first current source which is operable to supply a current to the reference voltage generator in response to the drive signal. A switched DC-DC converter, such as a charge pump has a voltage input connected to the reference voltage node and a voltage output for providing a bias voltage for the MEMS transducer. The DC-DC converter cyclically switches in a sequence of states including at least a first state where a first converter capacitance is disconnected from the voltage input followed by a second state where the first converter capacitance is connected to the voltage input. A second current source is operable to supply a bias current in response to a voltage at a bias control node. Switch control circuitry is configured to cyclically open and close a switch connected between the drive node and the bias control node, such that the switch is open during a time window that includes the time at which the switched DC-DC converter switches from the first state to the second state.

1. Field of the Invention
This application relates to biasing circuitry for MEMS transducers, in particular to biasing circuitry comprising a reference circuit such as a bandgap reference circuit and a DC-DC converter such as a charge pump.
2. Description of the Related Art
MEMS transducers such as MEMS capacitive transducers, for instance MEMS microphones, typically comprise two plates which are movable with respect to one another, for example a fixed plate and a moveable membrane. A stimulus, such as an acoustic pressure wave in the case of a microphone, can vary the distance between the plates of the MEMS transducer resulting in a capacitance that varies in accordance with the stimulus. In use a bias voltage is typically applied across the varying capacitance to provide a consequently varying electrical signal voltage or charge which can be measured. For MEMS transducers the overall capacitance of the transducer is small, typically of the order of 1 pf or so, and the change in capacitance is typically less than 1%. Thus a sensitive low-noise preamplifier is required to buffer the measured signal, i.e. the signal from the transducer.
MEMS microphone transducers are typically designed to require a bias voltage of around 12V. This is larger than the power supply voltages used for amplifiers and other electronic circuitry, so the bias voltage may be generated and supplied by a suitable DC-DC converter, typically a switched DC-DC converter such as a charge pump.
FIG. 1 illustrates an example of a typical arrangement of pre-amplifier circuitry for a MEMS sensor 100. A first terminal of MEMS transducer 101 is arranged to receive a bias voltage VCP, typically 12V or so, from a charge pump 102. An amplifier 103 has an input connected to the other terminal of the MEMS transducer. This terminal is also connected to a high-value (typically of the order of 10 Gohm or greater) bias resistance RG 104 to bias this terminal to ground without shorting out the audio band signal. The bias resistance 104 may often be implemented in the form of polysilicon diodes.
The charge pump 102 is arranged to generate the required relatively high bias voltage VCP from a lower voltage input. Typically the charge pump 102 generates a bias voltage VCP which is equal to a multiple of the voltage applied to its input. It will be appreciated therefore that were the charge pump input connected directly to the voltage supply for an integrated circuit, then the bias voltage across the transducer would vary with the applied supply voltage. Also any noise on the supply would be similarly multiplied and couple via the MEMS capacitance into the amplifier 103 and would be indistinguishable from any acoustically generated signals. Thus the voltage input for the charge pump 102 is preferably a supply-independent voltage VR. Typically this reference voltage VR is generated by a reference generator circuit 105 which will typically include a bandgap voltage reference generator. As will be understood by one skilled in the art a bandgap voltage reference generator can generate a reference voltage that is independent of variations of the supply voltage and which is also substantially temperature stable.
The power supply rejection of the amplifier circuit is also important to avoid coupling of supply noise into the signal path, so preferably the amplifier 103 is supplied with a supply-independent reference current, i.e. bias current IB, which also advantageously allows the supply current to be optimised without having to allow extra margin for the tolerance in supply voltage. Conveniently the reference voltage VR and the bias current IB are both supplied from the same reference generator circuit 105.
FIG. 2 illustrates one example of bandgap reference generation circuitry 105. To provide the bandgap reference voltage VBG, bipolar transistors Q1 and Q2 are configured to run at different current densities J1, J2, giving rise to a difference in their base-emitter voltages, Vbe, equal to (kT/q)·ln(J2/J1). Control circuitry 201 equalises the voltages at nodes A and B, resulting in this temperature-proportional voltage being imposed across a resistor R1, which thus passes a current IPTAT which is proportional to temperature. The equality is possible for only one non-zero current IPTAT through node A and the corresponding current through node B, which the control circuitry establishes by controlling at least one current source 202 to deliver a current IXA. This current is supply-independent, and thus may be mirrored to provide a supply-independent output current IXB for use by the amplifier circuit 103.
The base-emitter voltage Vbe of Q2 (or Q1) has a physically determined negative temperature coefficient of magnitude about 2 mV/K. The circuit is configured so that the negative temperature dependence of the transistor base-emitter voltage Vbe at least partially offsets a positive temperature coefficient due to the temperature-proportional current flowing through appropriate resistances. In other words, through choice of an appropriate resistive scaling factor Rx and current IPTAT, an output voltage VBG=Vbe+Rx·IPTAT is provided with a zero (or at least smaller) net temperature coefficient.
Such a bandgap reference circuit 105 thus provides a supply independent current and a supply independent voltage VBG that is relatively temperature stable. It is not typically possible however to use such a reference voltage VBG directly as an input to a charge pump as the charging current pulses drawn by the charge pump cannot be supplied without disturbing the operation of the bandgap reference circuit 105. Typically therefore the reference voltage VBG which is produced by the bandgap reference voltage generator 105 may be buffered by a suitable voltage buffer and this buffered reference voltage VBBG is provided as the input voltage to the charge pump.
In MEMS sensor applications however there are often pressures on the cost and size of the sensor circuitry and thus it would be desirable to be able to reduce the size of the sensor circuitry where possible.
Such MEMS sensors are also often used in battery powered device where power consumption is always a concern, especially in the case of MEMS microphones which may be used for relatively long periods of time, for instance to allow for input of voice commands. Thus, the supply current for a pre-amplifier circuit for a MEMS microphone is an important consideration and should be kept as low as possible.
Embodiments of the present invention therefore provide biasing circuitry for MEMS transducers that address at least some of the issues mentioned above.


A resin barrier device for connection in a vacuum line, for use in resin infusion during composite manufacture, includes a housing having an inlet port for connection to a resin source and an outlet port for connection to a vacuum source. A flow path extends between the inlet and outlet ports. A gas-permeable membrane is disposed across the flow path to prevent resin from flowing to the vacuum pump. A gasket supports the membrane and is adapted to prevent resin leakage. A method of infusing a preform with a resin also is provided.

Composite materials are formed from a reinforcement component and a matrix component, which combine to provide the composite material with properties that are an improvement over either of the components alone.
The reinforcement component is typically a fabric material. For example, carbon fibre fabric is formed by carbonizing a synthetic polymer fabric material and may be provided in the form of woven fabric, non-woven fabric or may consist of unidirectional fibres. Similar composites may be formed using alternative fabrics, such as fibreglass or synthetic polymers (e.g. aramid), or combinations of fabrics.
Multiple plies of fabric are laid up on a mould and the dry "pre-form" is then impregnated with a resin, using a resin infusion method (such as resin transfer moulding, vacuum assisted resin transfer moulding or resin transfer infusion), and the resin then cures to form a reinforcing polymer matrix. For example, in resin transfer infusion (RTI), the dry preform is sealed in a cavity defined between a flexible vacuum "foil" (sometimes called a vacuum bag) and a mould surface. The cavity is then evacuated and liquid resin flowed into the volume under the action of the resulting pressure differential.
In order to ensure that the composite component is of acceptable quality, it is essential that all air and volatiles are removed from the preform before and during the infusion process.
The applied vacuum is therefore maintained throughout the infusion process, so that the preform is as evenly infused as possible and porosity defects are minimised.
During resin infusion, particularly when performed at elevated temperature or within an autoclave, resin must be prevented from flowing out of the cavity and into costly vacuum pumps.
It has been proposed, for example in US 201310069286 of Heim et al., to place a semi-permeable membrane within the vacuum cavity between the pre-form and the vacuum film, to which vacuum port(s) are installed. Particularly for complex or large components, it can be challenging to evenly apply the membrane, and folds or leaks can result in material "bridging" or other component imperfections. Whilst it is possible in principle to place a membrane over smaller regions of the preform to mitigate such issues, it can be challenging or impossible in practice to position these such that the resin "fronts" arrive at the vacuum ports at generally the same time, so that the entire preform is infused.
One approach is to place a "catch pot" between the vacuum cavity and the vacuum pump. Since multiple vacuum ports are needed for large components, this approach can be time consuming to set up, result in significant wastage of resin and vacuum tubing upstream of the catch pot. Additionally, in a closed cell such as an autoclave, it is not possible to control the resin outflow and hence the fibre volume fraction of the component.
Another approach is to place a resin trap or barrier device in each individual vacuum line, closer to the vacuum ports. While this can reduce tubing wastage, additional costs and time are associated with the set up and post infusion cleaning of each individual trap.
Resin traps themselves can also present problems. Since they are typically based on a float valve, they can malfunction if incorrectly orientated. When combined with elevated temperatures and pressures of an autoclave, float based resin barrier devices can also be prone to leakage around the float Resin traps and resin barrier devices can also result in undesirable flow restrictions.
There remains a need to address one or more of the foregoing problems encountered during resin transfer infusion.

Resin barrier device, gasket and method for infusing a preform


Systems and methods may include a lift drone and a carrier drone to convey a payload. The lift drone may vertically lift the payload, alone or with the carrier drone, to a transfer location. The carrier drone may receive control of the payload at the transfer location, such as by receiving physical transfer of the payload, taking over conveyance of the payload from the lift drone, or the like. The lift drone may remain coupled with the payload or the carrier drone or may decouple after transfer.

Drones are increasingly being used to carry packages, such as for delivery to homes and businesses. Challenges for package delivery often include limitations on cargo weight due to lift capability limits of a drone as well as fuel requirements. A drone based package delivery is also limited in delivery distance due to battery life of the drone. In some circumstances, a drone may be optimized for travel distance but unable to perform a vertical lift, requiring a runway instead.


A probe for testing an electrical device under test. The probe has at least two outer layers and a core layer that is highly conductive. The core layer is disposed between the outer layers.

1. Field of the Invention
This invention relates to electrical probes for automated circuit and device testing.
2. Description of Related Art
In the field of electronic circuitry testing, scrubbing and contact force is an important factor in establishing a low resistance electrical contact between a probe tip and the test contact. During scrubbing, an eventual insulating oxide layer is removed in the interface between the contact tip and the test contact. Scrubbing is a microscopic shear movement of the probe tip along the test contact surface while a certain pressure is exerted from the probe tip onto the test contact. As size and pitch of test contacts decrease, it becomes increasingly difficult to tune the scrub motion irrespective of friction influences in the tip/contact interface. Also, as the integrated circuit (IC) manufacturers incorporate designs with IC pads and bumps placed over chip's active circuitry it becomes important that the scrub of the probe does not cause damage to the underlying circuitry. The size of the window of acceptable probe operation therefore, is restrained from one side by the contact resistance requirements calling for a sizable scrub, smaller scrub size required by smaller targets that need to be probed as pitches decrease, and smaller scrub (including depth) to avoid damage to the underlying circuitry.
The new generation of IC chips has pads that are placed over active circuitry in order to maximize use of the real estate. These types of chips are commonly referred in the industry as chips with "low-K dielectric". The low-K dielectric refers to the fragile polymer-based insulator now placed between the pads and the underlying circuits for electrical purposes. It is not acceptable to damage the low-K dielectric during probing operations either.
Well known buckling beam probes have been utilized to provide a combined resilient deflection and scrubbing. In order for a buckling beam probe to operate properly with a well defined scrub motion it needs to be rigidly held on its peripheral shaft and additionally guided close to the contact tip. This makes the buckling beam probe's assembly increasingly challenging with ever decreasing scale. Therefore, there exists a need for a probe that may be easily assembled in large numbers and small scale while providing a well definable scrub motion. The present invention addresses this need.
The contact resistance issue has also been addressed by probes having separate parts for scrubbing and for making electrical contact. For example, US 2004/0239352 considers dual probes having a contact probe and a separate scrub probe, where the scrub probe moves in such a way as to clean the part of the contact pad that will end up under the contact probe during test. In some cases (e.g., copper deposition manufacturing), circuit fabrication processes provide contact pads which are covered with a protective dielectric film (e.g., a silicon dioxide film). U.S. Pat. No. 6,727,719 considers a probe having an inner contact needle and an outer hard layer, where the hard outer layer is adapted for penetrating such a protective film.
An important consequence of decreasing probe and contact pad dimensions is that the current density at the probe-pad contact increases. This increased current density also raises issues which have not come up before in connection with large probes on large pads. More specifically, the current density can be high enough to form micro-welds between the probe and the pad due to local heating. Breaking these micro-welds as the probe is removed from the contact pad can lead to degradation of the probe tip (e.g., by accumulation of non-conductive material), thereby reducing probe reliability and/or lifetime.
Testing of electrical devices and circuits has been an important component of electronic manufacturing processes for some time. Such testing typically entails probing a circuit with a fixture including multiple flexible probes, each probe making electrical contact to a contact pad on the circuit chip. Various practical issues that have arisen in this context have been addressed in the prior art, especially in connection with providing reliable, low-resistance electrical contact.
Electrical contact between the probe and the contact pad can also be hampered by the presence of non-conductive material on the pad and/or the probe (e.g., a thin oxide film). Accordingly, considerable attention has been devoted to details of how the tip of the probe moves relative to the contact pad in order to improve the resulting electrical connection. This relative motion is usually referred to as a scrub motion. For example, U.S. Pat. No. 5,923,178 considers a probe having a shape which provides a scrub motion which is primarily a rocking motion without appreciable sliding. U.S. Pat. No. 5,952,843 considers a probe having a canted tip portion to facilitate penetration of the passivation layer. U.S. Pat. No. 6,529,021 considers a probe arrangement where the probe tip can be made to move in a reciprocating manner to reduce contact resistance.
As circuit manufacturing technology continues to evolve to smaller critical dimensions, new practical issues relating to probing tend to arise which are not fully addressed by prior art approaches. For example, the decreasing size of contact pads as critical dimensions are reduced leads to increasingly demanding requirements on the ability to precisely control the probe scrub motion. Excessive scrub motion can cause loss of electrical contact, if the probe moves off the contact pad.
Accordingly, it would be an advance in the art to provide greater control of probe scrub motion.


A solar control plastic glazing, comprising a plastic matrix having a plurality of metal particles homogeneously dispersed therein, is prepared by depositing a thin metal film onto the surface of a plastic sheet, heating the plastic sheet above its "softening temperature, deforming the sheet to cause the metal film to disintegrate into metal particles, and mixing the metal particles and plastic to form a composite.

It is generally known that high optical quality, transparent plastic sheets having enhanced solar control properties may be used alone or in combination with other materials, e.g., glass, to prepare solar load reducing automotive and architectural glazings. A particularly useful combination comprises well-known asymmetrical laminated glazings, wherein a plastic sheet having enhanced solar control properties is laminated to a monolithic or multi-layered glass and/or plastic support. Such a combination would impart weight reduction and safety properties to an automotive or architectural glazing, in comparison to the all-glass construction of conventional glazings.
Enhanced solar control glazings are currently used in several areas where one objective is to manage internal heat loads, by reflecting a portion of the solar spectrum which causes heating (i.e., infrared radiation) while maximizing transmission of the visible light portion of the solar spectrum. Such technology has been employed, for example, in commercial and residential glazings, and more recently in automotive glazings.
It is also known that the solar control properties of glazings may be enhanced by conventional coating techniques such as, for example, vacuum deposition or plasma-enhanced chemical vapor deposition, wherein metal or dielectric films are placed on the surface of the glazing. For example, transparent dielectric layers of fluorine-doped tin oxide or indium oxide, or very thin noble metal films of gold, silver, copper, and the like, or multi-layered structures comprising these dielectrics and metal films, may be deposited on plastic glazings by such methods. However, it is difficult to prepare metal or dielectric coatings which are uniform across the surface of the glazing by the aforesaid conventional deposition techniques. Due to the difficulties of maintaining uniform consistency, delivery, and distribution of the reactive precursors which form the desired coating at the surface of the glazing substrate, the ultimately produced metal and/or dielectric layer or layers generally exhibit a visually mottled appearance and iridescent patterns.
A publication by R. H. Doremus entitled "Optical Properties of Small Gold Particles", "Journal of Chemical Physics," 40, 2389 (1964), discloses the homogeneous incorporation of gold particles into glass to provide infrared energy reflection while maintaining visible light transmittance. The disclosed method for producing the uniform, homogeneous distribution of gold particles involves adding a gold chloride salt and ceric oxide nucleating agent to a soda-alumina-silica glass melt, irradiating the formed glass with ultraviolet energy, and thereafter heating the glass to a temperature from 400.degree. C. to 630.degree. C. to cause the gold particles to grow homogeneously throughout the glass matrix. Such a structure does not exhibit a mottled appearance or iridescent pattern, as does a glass substrate coated with a thin gold film by the conventional deposition techniques disclosed hereinabove. However, the disclosed structure, having the gold particles dispersed therein, does display infrared reflectance and visible light transmittance comparable to a glass substrate having an adhered gold film. Clearly, the disclosed technique can not be used to form gold particles within a plastic substrate.
It would be desirable to prepare a plastic having uniform infrared reflectance and visual light transmittance, which could be used alone or in association with other transparent materials, to produce enhanced solar control automotive and architectural glazings free from mottling and iridescent patterns.


A valve drive apparatus comprises a pair of valve trains, each having a rocker arm and a hydraulic lash adjuster, arranged symmetrically with respect to a center axis of each cylinder of a double overhead camshaft engine. Either one of the pair of valve trains that has a rocker arm leverage greater than a rocker arm leverage of the other of the pair of valve trains is adapted and designed so as to have a structural rigidity higher than the structural rigidity of the other.

A typical type of valve drive apparatus used for a double overhead camshaft engine has a pair of valve trains for one cylinder of the engine. The pair of valve trains, having the same structural elements, are symmetrically arranged in a V-formation with a predetermined relative angle with respect to a center axis of the cylinder. Although camshafts for timely, or sequentially, opening and closing valves through the valve trains are driven mechanically or geometrically in the same direction, they are driven dynamically in the opposite directions with respect to rocker arms. That is, because the geometric relative arrangement of the rocker arm with respect to the direction of rotation of the camshaft is opposite between the pair of valve trains and because leverage of the rocker arm changes with the rotation of camlobe, characteristic curves representing the changes of leverage of the rocker arms are symmetrical with respect to rotated angles of the camlobe. Accordingly, at a moment immediately before the valve closes, the leverage of either one of the rocker arms is larger than that of the other.
As is well known in the art, unusual vibration of the valve train is one of the primary factors that adversely affects an engine and tends to prevent satisfactory operation at high speeds. That is, when a harmonic component, having a low frequency, of a valve lift curve of a valve becomes close to a natural frequency of the valve train as engine speed increases, the natural frequency of the valve train becomes too high, so that the valve train causes unusual vibration, such as jumping or bounding. In order to raise a critical engine speed at which the engine causes unusual vibration, it si absolutely necessary to increase the natural frequency of the valve train. Both an equivalent rigidity of valve train, which depends greatly on the leverage of rocker arm, and an equivalent mass of the valve are the primary factors in determining the natural frequency of the valve train. Since the equivalent rigidity of valve train becomes higher as the leverage of the rocker arm becomes smaller, the use of a small leverage rocker arm is favorable and preferred in order to allow the engine to increase the critical engine speed in a satisfactory manner. Additional details may be obtained by reference to a book entitled, "Automobile Engineering Handbook: IV," pages 1-52, published by Automobile Technology Association.

Valve drive apparatus for double overhead camshaft engine


In embodiments of the present invention, a biodegradable/biodegradable polymer film may be used as a scaffold for tissue engineering scaffolds for engineering organized organs, such as vascular grafts, for example. In one embodiment, an ultraviolet (UV) resin made from a diacrylated biodegradable oligomer is molded into a flexible scaffold having cavities and/or channels. Channel/cavity size may be on the order of micrometers and/or nanometers, and thus the walls may have high aspect ratios. Smooth muscle cells may be deposited in the channels and because of the high aspect ratios, the cells may align along the channels/cavities as confluence is reached.

1. Field
Embodiments of the present invention relate to tissue engineering scaffolds and, in particular, to three-dimensional (3D) tissue engineering scaffolds.
2. Discussion of Related Art
In biomedical applications such as tissue engineering, cells grown on a flat surface cannot be used for tissue engineered thick organ constructs since they cannot grow well on top of each other. Scaffolding can be used to provide a three-dimensional (3D) surface, however currently available scaffolding is limited in that some, such as porous scaffolding, for example, cannot be easily used for co-culture and cell positioning for these co-cultures. Porous scaffolds also cannot be used for cells requiring contact guidance. As a result of the limitations of currently available scaffolding the ability to mimic the in vivo micro-environment of tissue cells may be hindered.

Micro-structured and nano-structured surfaces on biodegradable polymers


The present invention is directed to a delivery vector for transferring a small peptide coding sequence to a cell for expression of the small peptide coding sequence within the cell. The delivery vector comprises a secretory signal sequence; a sequence encoding a carrier protein operatively associated with the secretory signal sequence; a sequence encoding a cleavage site operatively associated with the sequence encoding a carrier protein; and a sequence encoding a small peptide operatively associated with the sequence encoding a cleavage site.

Bioactive small peptides, either occurring naturally or produced synthetically, have gained increasing interest as research tools and as pharmacological drugs in recent years. In particular, these bioactive small peptides may play key roles in various physiological, as well as pathological processes, and thus are promising targets for therapeutic interventions for many pathological conditions. Further, bioactive small peptides have gained use as agonists and/or antagonists of various biological processes with enhanced target affinity and specificity compared to conventional agents. For example, numerous small peptides have been developed that target pathological processes, such as cancer, tumor-specific angiogenesis, and pathogenic apoptosis in neurodegenerative disorders. Despite these advances, the use of small peptides as mainstream drug candidates has been hampered by their low bioavailability (due primarily to small peptides' poor permeability across the cell membrane); short half-life in cells (due primarily to the small peptides' susceptibility to cellular proteases for degradation); and immune responses triggered by repeated administration (due to the nature of the small peptide).
One strategy that has been developed to overcome these problems of exogenous administration of small peptides is to produce the small peptide intracellularly by using high-expression vectors to generate sufficient levels of the therapeutic small peptides in the cell/tissue of interest. However, expressing small peptides in mammalian cells has been challenging due to some of the same reasons that have hampered the use of small peptides as mainstream drug candidates. In spite of these problems, many researchers have employed different expression systems to express the small peptide as part of a fusion peptide with scaffold proteins or other reporter proteins, such as green fluorescent protein (GFP). This strategy may be useful for peptides that maintain their biological activity and function after fusion, but useless for many small peptides that are only active in their free peptide forms.

Small angiotensin peptide expression system in mammalian cells

University of Florida Research Foundation, Incorporated


A modified method of playing Baccarat is provided in which the conventional 5% commission charged by the gaming establishment on winning Bank hand wagers is eliminated. Preselected combinations of Bank and Player hands which would have been winning Bank hands under the conventional manner of play of Baccarat are treated as "push" or "bar" hands. The preselected combinations are chosen so that the gaming establishment maintains its desired percentage advantage over the bettor. In another embodiment, changes are made to the "third card draw rules" so that the Player's hand and the Bank's hand operate under the same criteria for whether a third card is or is not dealt to each respective hand. Separate mechanical or electrical devices can also be used to establish that a particular round of play of Baccarat would be a Bank hand "bar" round. Additionally, extra side wagers are added to the game. The bettor may make an additional wager that the hand will end in a tie, or that the "bar" hand will occur, or that a four card natural situation will occur or other additional combinations may occur during the play of the game. Appropriate odds are selected for each of these side bets. Additionally, one or more NO VALUE cards can be added to the standard deck of cards used in Baccarat. The NO VALUE card signals that if the Bank would normally have won that round, the Bank is barred from winning that round.

Baccarat is one of the many live table games played in casinos or gaming establishments. Baccarat uses a standard deck of 52 playing cards and is usually dealt from a shoe having multiple decks that have been shuffled together prior to the beginning of play.
The object of the game of Baccarat is for the bettor to successfully wager on whether the Bank's hand or the Player's hand is going to win. The bettor receives even money for his wager if he selects the winning hand and loses his wager if he selects the losing hand. Because of the rules of play of Baccarat, the Bank's hand has a slightly higher chance of winning than does the Player's hand. Therefore, if the bettor wagers on the Bank's hand, the bettor must pay to the gaming establishment a commission (typically, 5%) of the amount the bettor wins. No commission is paid if the bettor successfully wagers on the Player's hand.
As used in this specification, the term "Conventional Manner of Play of Baccarat" is as follows:
A multiple number of decks of standard playing cards, 52 in number, are used; typically eight decks are shuffled together and placed in a shoe from which the cards are dealt during the play of the game.
Each bettor makes a wager on whether the Bank's hand or the Player's hand will win. After all wagers are made, two cards are dealt from the shoe to the Bank position and two cards are dealt from the shoe to the Player position on the table layout. The cards are turned face up and the value of the Bank hand the Player hand is determined.
Aces count one; Kings, Queens, Jacks and Tens count zero and the other cards count their respective face value. The suits (Spades, Hearts, Diamonds and Clubs) have no meaning in Baccarat.
The highest hand value in Baccarat is nine. All hand values range from a low of zero to a high of nine. If when the cards are added together, the total of the hand exceeds nine, then the hand value is determined by subtracting ten from the total of the hand. For example, a seven and a eight total fifteen, but the hand value is five. An Ace and a nine total ten, but the hand value is zero.
A two card total of eight or nine is called a "natural"; a two card total of zero is called a "baccarat". As will be explained below, in certain situations in the play of the game, a third card will be dealt. The value of this third card is added to the total of the first two cards and a new hand value is established. Again, if the new hand total exceeds nine, the hand value is determined by subtracting ten from, the total of the hand.
Prior to the deal, each bettor can make one of three wagers: 1) that the Bank hand will win; 2) that the Player hand will win; or 3) that the Bank hand and the Player hand will tie. Wagering locations are provided on the Baccarat table layout. Whichever of the Bank hand or the Player hand is closest to a total on nine is the winner.
All winning Bank hand wagers are paid off at odds of one-to-one and the house charges a five percent (5%) commission (also known as the vigorish or the "vig") on the amount won by the bettor. For example, if a bettor wagers $100 on the Bank hand and the Bank hand wins, the bettor wins $100 and is charged a $5 "vig" on the amount that the bettor won. The bettor is not charged any "vig" on the amount of his wager.
All winning Player hand wagers are paid off at odds of one-to-one and the bettor is not charged any "vig" on the amount of his winnings or his wager. Winning wagers on the Tie hand bet are paid off at odds of nine-to-one or eight-to-one (depending on the gaming establishment) and the bettor is not charged any "vig" on the amount of his winnings or his wager. If a Tie hand occurs, all wagers on the Bank hand and all wagers on the Player hand are "pushes" and the amount wagered is returned to the bettor.
A typical Baccarat table layout is an oval with positions for the casino dealers along one side of the oval and usually twelve bettor locations, six at each end of the oval. The bettor locations are numbered one through twelve and each bettor location has an area designated for a wager on the Bank hand and an area designated for a wager on the Player hand. Locations are provided on the table layout where the cards comprising the Bank hand and the cards comprising the Player hand can be displayed. Also in the approximate center of the table layout are twelve "vig" boxes numbered one through twelve in which the casino dealers keep track of any commissions or vigorish owed to the gaming establishment by each player.
The play of Baccarat typically uses three casino dealers to operate the game. The casino dealers jointly participate in the shuffling of the eight decks of cards. After the shuffle is completed, one of the participants is asked to cut the decks using a plastic cut card. The dealer then separates and restacks the cards from the point of the cut and a participant then inserts the plastic cut card no less than fifteen cards from the end of the stacked decks and the entire stacked decks are placed into a shoe from which the cards are dealt during the play of the game. When the inserted plastic cut card appears during play, the hand in progress is completed and that round of play then ends. The cards are reshuffled to prepare for the next round of Baccarat.
At the beginning of a round of play and after the decks have been placed in the shoe, the dealer deals the first card from the shoe and turns it face up on the Baccarat table. The value of this card determines how many additional cards are removed or "burned" from the shoe before the actual play commences.
In conventional Baccarat, the bettors deal the cards used in the game. Initially, one of the casino dealers (called the "Caller") passes the shoe to the bettor sitting in seat number "1" at the Baccarat table. After all wagers have been made, the Caller tells the bettor with the shoe to begin the deal. The bettor deals a first card to the Caller, a first card to himself, a second card to the Caller and a second card to himself. All cards are dealt face down. The two cards given to the Caller represent the Player hand and the two cards kept by the bettor who is dealing the cards represent the Bank hand.
The Caller then allows one of the other bettors to turn up or "face" the Player's hand. Traditionally, this honor is given to the bettor who has made the largest wager. The bettor "faces" the two cards of the Player's hand and tosses them to the Caller. The Caller places these two cards face up in the table location designated for the "Player Hand" and the Caller announces the point total of the Player hand.
The bettor who has the shoe then "faces" the Bank hand and tosses these two cards to the Caller. The Caller places these two cards face up in the table location designated for the "Bank Hand" and the Caller announces the point total of the Bank hand.
Depending on the point total of the Player's hand and the Dealer's hand, one more card may be dealt to either the Player's hand, the Dealer's hand or both. The rules for determining whether a third card is dealt are fixed rules, there is no discretion for either the Player's hand or the Dealer's hand on whether a third card is dealt.
If either the Player hand or the Dealer hand has a point total of eight or nine on the first two cards, no third card is dealt to either hand and the hand with the highest point total is the winner (or the hand is a Tie, as the case may be). If neither the Player hand or the Dealer hand has a point total of eight or nine, then there is a possibility of a third card draw.
The third card draw rules are as follows:
Rule #1: If the initial two card Player hand has a point total of 0, 1, 2, 3, 4 or 5, the Player hand draws a third card. If the initial two card Player hand has a point total of 6 or 7, the Player hand stands and does not receive a third card. PA1 Rule #2: If the Player hand stands and does not draw a third card, then the Bank hand follows Rule #1. In other words, if the Player hand has a point total of 6 or 7, the Bank hand draws a third card on a point total of 0, 1, 2, 3, 4 or 5 and the Bank hand stands on a point total of 6 or 7. PA1 Rule #3: If the Player hand draws a third card, the Bank hand must draw or stand as follows:
______________________________________ Bank hand Bank hand DRAWS Bank hand STANDS two card when the Player's when the Player's point total hand third card is: hand third card is: ______________________________________ 0, 1 or 2 Bank always draws 3 0, 1, 2, 3, 4, 5, 6, 7 or 9 8 4 2, 3, 4, 5, 6 or 7 0, 1, 8 or 9 5 4, 5, 6 or 7 0, 1, 2, 3, 8 or 9 6 6 or 7 0, 1, 2, 3, 4, 5, 8 or 9 7 Bank always stands ______________________________________
All third card draw determinations are automatically made by the Caller who is skilled in the game of Baccarat.
The complete winning hand rules and the third card draw rules of conventional Baccarat are set out graphically in Table 1. as follows:
TABLE 1 ______________________________________ BACCARAT RULES--- ______________________________________ PLAYER HAVING TWO CARD TOTAL OF ______________________________________ 1-2-3-4-5-10 DRAWS A CARD 6-7 STANDS 8-9 TURNS CARDS OVER ______________________________________ BANKER HAVING DRAWS WHEN DOES NOT DRAW TWO GIVING OR WHEN GIVING OR CARD PLAYER'S PLAYER'S THIRD TOTAL THIRD CARD CARD DRAW OF DRAW IS AN IS AN ______________________________________ 0, 1, 2 ALWAYS DRAWS 3 1-2-3-4-5-6-7-9-10 8 4 2-3-4-5-6-7 1-8-9-10 5 4-5-6-7 1-2-3-8-9-10 6 6-7 1-2-3-4-5-8-9-10 7 STANDS 8-9 TURNS CARDS OVER ______________________________________
When the rules of Baccarat require a third card for the player hand, the Caller will request a "card for the Player." After the Player hand is completed, the Bank is completed in the same fashion. The Caller then declares which hand has the highest point total and declares that hand the winner (or the Caller declares a Tie hand as the case may be).
The bettor who is acting as the dealer continues to hold the deal until the Player hand wins. As soon as the Player hand wins, the shoe passes counterclockwise around the Baccarat table to the next bettor so that each bettor has the opportunity to deal the cards. Each bettor holds the shoe and continues to deal until the Player hand wins and then the shoe is passed to the next bettor. Any bettor may decline to deal the cards. The fact that one of the bettors is physically dealing the cards has no affect on the outcome of the game because the rules for drawing and standing do not allow any discretion on the part of the participants.
At the end of each hand, winning wagers are paid and losing wagers are collected by the house. Any "vig" due to the house is marked in the "vig" boxes in the center of the table layout. Gaming chips are used to represent the amount of money owed by each bettor to the house for the "vig". In order not to slow down the game, the "vig" is not actually collected from each bettor until the end of the round determined by all of the cards in the shoe being dealt down to the plastic cut card, usually approximately eighty hands.
The mathematical analysis of the game reveals that the 5% "vig" is what gives the house its advantage and allows the gaming establishment to make a profit from providing the Baccarat game to the bettors. Because the rules for standing and drawing third cards are automatic, the mathematical analysis shows that the Bank hand will win 45.8% of the hands, the Player hand will win 44.6% of the hands and the Tie hand will occur 9.6% of the hands. If the Tie hands are disregarded because they do not affect any Player or Bank wagers, it is then determined that the Bank hand will win 50.7% of the time and the Player hand will win 49.3% of the time.
Because the Bank hand wins more than 50% of the hands (disregarding the Tie hands that do not affect any Player or Bank wagers), if a bettor always bet on the Bank hand, the bettor would have an advantage over the gaming establishment. By charging a 5% "vig" on all Bank hand wins, the gaming establishment compensates for the percentage of winning Bank hands being slightly over 50%.
After figuring in the 5% "vig" that must be paid by bettors on winning Bank hands, the gaming establishment has a 1.23% advantage over the bettor when the bettor wagers on the Player hand and the gaming establishment has a 1.06% advantage over the bettor when the bettor wagers on the Bank hand. The Tie hand wager gives the gaming establishment a 4.88% advantage over the bettor when the payoff odds are nine-to-one and a 14.1% advantage over the bettor when the payoff odds are eight-to-one.
One of the detriments of the conventional manner of play of Baccarat is the necessity for calculating, recording and collecting this 5% "vig" on all winning Bank hand wagers. Many people are reluctant to sit down and participate because they do not understand the "vig" and why they should have to pay a 5% commission on winning Bank hand wagers. They may consider this unfair and something extra for the gaming establishment.
The gaming establishments also suffer disadvantages from the 5% commission. The determination of the 5% amount is done visually by a casino dealer and is subject to casino dealer error and disputes with the bettors over the amount of the "vig". The reconciliation and collection of the "vig" at the end of each shoe can result in delays of the beginning of the next round of play. If a bettor loses all of his money ("taps out") during a round of the game, the gaming establishment may have difficulty collecting the unpaid "vig" that has accrued to that bettor during that round of the game. It has been estimated that as much as twenty percent of the accrued "vig" goes uncollected. Because the house margin on Baccarat is so small, uncollected "vig" can seriously impact the profitability of a Baccarat table or the entire Baccarat pit, if more than one table is in play.
Another detriment of the conventional manner of play of Baccarat is the complexity of the "third card" draw rules. These complicated rules deter new bettors from participating in the play of Baccarat.
From the perspective of the gaming establishment, the play of a round of Baccarat should take a predictable length of time. An average of eighty hands are possible per each round of a shoe of eight decks of cards. During the play of each hand, the Player hand and the Dealer hand are dealt. According to the rules of Baccarat, each Player hand and Dealer hand may receive a third card. Winning wagers are paid and losing wagers are collected. The "vig" must be determined and recorded for each winning Bank hand wager. Because approximately half of the time the Bank hand will be the winning hand, it can be very time consuming toward the end of each shoe to record and accrue the amount of the "vig". Anything that slows down the actual play of the game results in decreased revenues to the gaming establishment.
There is a need in the gaming industry to increase the amount of revenue being generated by Baccarat tables over a given period of time without simply requiring the bettor to increase the amount of his wager.
It is an object of the present invention to provide a modified method of play of conventional Baccarat that increases the number of hands that can be dealt and played in a given length of time.
It is a further object of the present invention to provide a modified method of play of conventional Baccarat that eliminates the need for the gaming establishment to collect a commission or vigorish during the play of the game.
It is a further object of the present invention to provide a modified method of play of conventional Baccarat that simplifies the "third card draw rules" thus mitigating the possibility that dealer errors will occur in determining when and when not to deal a third card to either the Player or the Bank. Also new players will not have any difficulty understanding the "third card draw rules".
It is a further object of the present invention to provide a modified method of play of conventional Baccarat that permits additional wagering opportunities during the play of the game without slowing the game down.
It is a feature of the present invention to eliminate the collection of a commission or vigorish on each winning Bank hand or on any winning wager made during the play of Baccarat.
It is a further feature of the present invention to provide that certain card combinations that would have been winning hands in conventional Baccarat are now simply push hands for which the bettor only receives his original wager back.
It is a further feature of the present invention to provide that the "third card draw rules" are the same for the both the Player's hand and the Bank's hand. This simplifies the game and mitigates against the Dealer making mistakes during the play of a hand of Baccarat. Also new players will not have any difficulty understanding the "third card draw rules".
It is a further feature of the present invention to provide additional betting opportunities so that the bettor may wager that certain card combinations will occur during the play of a hand of Baccarat.
It is an advantage of the present invention that revenues to the gaming establishment will increase because more hands of the game can be played in a given length of time.
It is a further advantage of the present invention that the elimination of the commission or vigorish on the winning Bank hand wager will eliminate casino dealer errors and patron disputes regarding the amount of the vigorish and that revenue will not be lost when a player taps out without paying the accrued vigorish.
It is a further advantage that the simplified "third card draw rules" will speed up the play of a hand of Baccarat, will increase revenues generated for the gaming establishment, will encourage participation by new bettors and will cut down on the number of wrongly dealt hands.
It is a further advantage of the present invention that, by permitting additional wagers to be made that certain card combinations will appear during the play of each hand, the activity at the game of Baccarat will be increased resulting in additional revenues to the gaming establishment. The bettor will also receive additional opportunities to win during the play of the game.
Other objects, features and advantages of the present invention will become apparent from a consideration of the following detailed description.


An improved reed valve mechanism having a cushioned reed valve seat is disclosed. The present invention provides a smooth resilient insert which is attached around ports in a reed cage and projects beyond the reed cage surface on which the reed valve members seat. The benefits of conventional rubber coated reed cages are supplied without the expenses inherent in previous construction methods. Various mechanical mounting means are disclosed for ease in construction and improved reed valve performance.

1. Field of the Invention
The present invention is directed to reed valve mechanisms for use in controlling fluid intake into and/or through fluid passages in internal combustion engines and in other fluid passages. More particularly, the present invention provides improved apparatus and method for constructing such reed mechanisms.
2. Background of the Prior Art
Presently it is common to employ various valve mechanisms to control air or air and fuel intake into and through internal combustion engines. The most widespread use of such valves today is a flexible "reed valve" which covers a port in a reed cage. The reed valve is attached at one of its ends to a base of the reed cage, allowing its unattached opposite end covering the port to be lifted away from the port. By orienting the reed cage in a downstream direction in the engine's air intake passage, when a negative pressure is present in the engine, the reed valve is flexed away from the reed cage port ant fluid is permitted to be drawn into the engine; when draw from the engine ceases, the reed valve shuts upon the port and fluid flow ceases.
The use of such reed valves is now standard on most crankcase compression two-stroke cycle engines both to control fluid intake and fluid transfer from the crankcase to the combustion chamber. Examples of such mechanisms are disclosed in applicant's U.S. Pat. Nos. 3,905,340, 3,905,341 and 4,051,820. More recently, similar reed valves have been utilized to improve engine performance in a variety of other applications, including in four-stroke cycle engines.
With the widespread use of reed valves, including metal and fiber composites, there has been considerable interest in finding ways to improve reed valve life and performance. One technique to improve reed valve life is to coat the reed cage with an elastomer, such as rubber or plastic, to provide a cushioned seat for the reed valve to strike on each cycle of the engine. In internal combustion engines, the use of such a cushioned seat is considered crucial to achieve adequate reed valve life from most conventional reed valves.
The conventional process for creating a cushioned reed valve seat is time consuming and expensive. Currently reed cage manufacturers must first arrange to have a recess provided in the reed cage surrounding each port in the reed cage. This is accomplished either by casting the reed cages with the recess or by machining the recess into the cage once the cage has been constructed. Once the recess is provided, the reed cage is then subjected to a complex coating process.
To coat the reed cage with rubber, generally two dies are furnished, one adapted to surround the outside of the recessed portion of the reed cage and the other inserted on the inside of the reed cage to prevent rubber from leaking into the interior of the reed cage. These dies must be carefully proportioned to assure exact fit and minimal leakage during rubber casting. Once the dies are in place, liquid rubber is injected under pressure into openings in the dies to fill the recessed portion of the reed cage.
After the rubber coating is applied, the rubber coating must then be planed or machined down to provide a smooth valve seat surrounding each port. If machining is not performed exactly or if too little rubber has been provided (e.g. as the result of air pockets), an uneven surface may be created which will lessen engine performance and may cause premature wear and deterioration of the reed valves.
Another come-on problem emerges if the dies do not exactly fit the reed cage. In these instances, the rubber will spread well beyond the recessed portion of the reed cage and require additional machining work for preparation of the valve cage. Evidence of such rubber leakage is commonalty seen on production reed cage units.
The entire procedure is extremely exacting and very expensive, costing on the order of approximately $14.00 per valve for low volume production and no less than approximately $3.00 per valve for very high volume production. These costs severely restrict the use of rubber coated valve seats to only higher cost applications, making it unrealistic to coat inexpensive reed cages such as reed plates in air compressors.
The molding process itself also tends to limit the type of valves which may be rubber coated. Reed cage designs which do not readily permit the insertion of a die or machining equipment into the interior of the reed cage, such as the aeroform reed cage disclosed in applicant's U.S. Pat. No. 4,879,976, cannot be rubber coated using this process without employing even more precise dies. Although it is possible to rubber coat these units by using a die which only mounts on the outside of the cage and includes projections which exactly fit within each port in the reed cage to prevent leakage into the interior of the reed cage, this process has design tolerances which are so demanding that full production quantities are not: practicable.
In response to the restrictions and high costs of this procedure, a number of other solutions have been implemented. In U.S. Pat. No. 4,696,263, applicant disclosed that the reed valves themselves may be rubber coated to improve life and performance. It has been found that reed valves constructed using this technique will perform as well or better against an uncushioned reed cage as conventional reed valves will perform against a rubber coated reed cage. However, if these rubber coated valves are combined with a properly constructed rubber coated reed cage, exceptional reed valve life can be expected.
Other procedures which have been implemented to avoid premature reed valve failure include techniques for improving flow through the reed cage itself, such as is disclosed in applicant's U.S. Pat. No. 4,879,976, and various modifications to basic reed valve design to limit stresses on the reed petals, such as is disclosed in applicant's U.S. Pat. No. 5,036,806. Despite the successes with these strategies, a cushioned reed cage remains highly desirable for maximum reed valve life.
Various attempts to create a less expensive cushioned reed cage also have been explored over the years. A number of patents have apparently described applying an independent layer of elastomer directly to a reed cage in order to cushion the reed valve. In U.S. Pat. No. 3,286,728 to Stephenson, issued Nov. 22, 1966, it is suggested to apply a layer of elastomer alone to a single face of a reed cage in order to create a cushioned reed valve seat. The precise method of attachment of the elastomer is not addressed in this patent. U.S. Pat. No. 4,633,825 to Flaig, issued Jan. 6, 1987, similarly teaches that a single layer of elastomer alone may be applied to each face of a non-recessed reed cage to provide a cushioned reed seat. A grommet is employed no assist in holding the elastomer layer in place on the distal end and the reed valve mounting hardware is used to hold the reed valve members and the elastomer in place on the base end.
In a somewhat different application, U.S. Pat. No. 4,082,295 to Bainard, issued Apr. 4, 1978, shows use of a reed valve to control fluid flow between crankcase chambers of a multiple cylinder two-stroke cycle engine and an elastomer seal attached to the reed valve seat to seal against the crankshaft. In that patent it is suggested to employ a rubber coating on a metal substrate as a non-recessed reed valve seat, with a mounting bolt passing through a reed valve and the reed valve seat to hold the entire unit together. Although it is not shown, that patent also suggests employing a similar non-recessed, rubber coated metal reed valve seat in other reed valve construction, such as that shown in the Stephenson patent.
Although the apparatus disclosed in the above patents may function adequately, further significant improvements are believed possible in reed cage construction. First, although a number of the above patents suggest avoiding a recessed reed cage, a recessed reed cage is believed to be important for proper reed valve performance. Second, none of the above patents is believed to provide a fully adequate method of mounting a separate elastomer layer to the reed cage. Among the probable problems are: the fragile nature of a non-reinforced elastomer layer; and insufficient and/or overly complicated methods of mounting the elastomer layer.
Accordingly, it is a primary object of the present invention to provide a method of construction of a reed valve mechanism for use in an internal combustion engine which supplies a cushioned reed valve seat at minimal manufacturing cost and effort.
It is a further object of the present invention to provide such a reed valve mechanism with a smooth and even valve seat without the need for machining of the cushioned surface.
It is an additional object of the present invention to provide such a reed valve mechanism which optimizes reed valve life and performance by reducing stresses on the reed valve members while assuring proper reed valve operation.
It is another object of the present invention to provide such a reed valve mechanism which is easily and efficiently constructed, with minimal expense and complication.
It is yet another object of the present invention to provide such a reed valve mechanism which may be easily implemented with other advances in reed valve technology to deliver even greater performance and reed valve life.
A still further object of the present invention is to provide a cushioning member for reed valves which may taper uniformly upward from the base of the valve cage to the apex thereof to allow more uniform seating of the reed valves.
These and other objects of the present invention will become evident from review of the following specification.


A closed-loop STTD system extended from an open-loop STTD system adopting four antennas transmission diversity technique and its signal transmitting method are disclosed. The signal transmitting method in a closed-loop space-time transmit diversity (STTD) system having a plurality of transmission antennas, includes: space-time coding symbols to be transmitted; classifying the coded symbols to certain groups; and multiplying different weight values to each transmission symbol group and transmitting them.

1. Field of the Invention
The present invention relates to a mobile (radio or wireless) communication system and, more particularly, to a signal transmitting and receiving method in a closed-loop space-time transmit diversity (STTD) system having a plurality of transmission antennas.
2. Description of the Background Art
In general, in a mobile (radio or wireless) communication system, when data is transmitted at high speeds, the phase of a received signal is distorted due to a fading phenomenon (i.e., signal weakening) generated on a wireless channel. Fading reduces the amplitude of a received signal from a few decibels (dB) to scores of dB. Thus, if the distorted phase of the received signal is not compensated during data demodulation at the receiving end, information errors occur in the received data, and the quality of the overall mobile communication service is undesirably degraded.
Thus, in order to transmit data at high speeds without degradation of service quality, various types of signal transmission diversity techniques are employed,. An example is disclosed in, S. M. Alamouti, "A Simple Transmit Diversity Technique for Wireless Communications", IEEE Journal on Select Areas in Communications, Vol. 16, No. 8, pp. 1451-1458, October 1998. Also, additional background information can be found in 3GPP, "Physical Channels and Mapping of Transport Channels onto Physical Channels (FDD)", TS 25,211, V4.3.0, December 2001.
Transmission diversity techniques are generally classified into time diversity and space diversity. Time diversity, which uses interleaving and coding to overcome the fading, is commonly used for a Doppler spread channel. However, time diversity is not suitable for use in a low speed Doppler spread channel.
Space diversity is used for channels with a small delay spread (such as a so-called "indoor channel" used for indoor environments) and channels with a low speed Doppler spread (such as a so-called "pedestrian channel" used for pedestrians). Space diversity is a transmission diversity technique using two or more transmission/reception antennas. That is, upon transmitting the same signal through two transmission antennas, if the receiving end determines that the size of the signal transmitted through one antenna has been undesirably reduced due to fading (i.e., signal weakening), the signal transmitted through the other antenna is selected and received by the receiving end.
Space diversity is further classified into a reception antenna diversity (using multiple reception antennas), and a transmission antenna diversity (using multiple transmission antennas). For transmission antenna diversity, an algorithm used for receiving downlink signals and obtaining a diversity gain can be roughly divided into an open-loop mode and a closed-loop mode.
The third-generation partnership project (3GPP) currently employs a space-time transmit diversity (STTD) technique, which is a type of open-loop mode transmission antenna diversity. The STTD is a technique for obtaining a diversity gain through space-time coding, which is based upon the channel coding technique commonly applied on a time axis framework, but being extended into a spatial domain. Namely, the STTD is used to obtain a space diversity gain as well as a time diversity gain by performing coding among the symbols transmitted respectively through each antenna when two transmission antennas are used.
The STTD can be applied to every type of downlink physical channel, except a synchronization channel used in WCDMA. Open-loop STTD is advantageous in that it causes no detrimental changes in radio communication performance due to varying data transmission speeds, because a feedback signal is not necessary.
The general operation principles of the STTD technique for performing coding among the data symbols transmitted through two antennas will now be described.
The STTD encoding for two antennas and a transmission order based on time are shown in Table 1.
TABLE 1Time (t)Time (t + T)Antenna 1s1s2 Antenna 2−s2*s1*wherein, 's' is a data symbol, and 'T' is a data symbol period.
Referring to Table 1, the symbols (s1,s2) to be transmitted are encoded by an STTD encoder and then respectively sent to the two transmission antennas (antennas 1 and 2) in time consecutive order. That is, for antenna 1, symbol s1 is sent at time t, and symbol s2 is sent at a later time, t+T. For antenna 2, symbol −s2* is sent at time t, and symbol s1* is sent at a later time, t+T.
In other words, the STTD encoder outputs s1 and s2 to transmission antenna 1 as they are (i.e., without any further changes thereto after encoding), but the STTD encoder converts the symbols s1 and s2 into −s2* and s1*, respectively, and then outputs them to antenna 2. Here, "*" indicates a conjugate. The symbols (s1, s2, −s2*, s1*) sent to the transmission antennas are then transmitted to a receiving end via a multipath manner.
Assuming that the data symbols transmitted through each transmission antenna pass through respectively different independent channels, and assuming that there are no variations in the channel at time (t) and at time (t+T), the received signals (r1 and r2) at the receiving end can be defined by equations (1):r1=r(t)=h1s1−h2s2*+n1r2=t(t+T)=h1s2+h2s1*+n2  (1)wherein h1(=α1ejβ1) and h2(=α2ejβ2) represent the channels (e.g., are channel responses) between one transmission antenna (either antenna 1 or antenna 2) and the reception antenna, respectively, while n1 and n2 are noise factors referred to as an "additive white Gaussian noise" (AWGN), which is a complex Gaussian noise. Also β1 and β2 are phases of fading channels h1 and h2, respectively. Additionally α1 and α2 are amplitudes of fading channels h1 and h2, respectively
Each channel (h1 and h2) can be estimated by using a pilot signal transmitted from each transmission antenna. Also, if the received signals (r1 and r2) are combined together in a manner shown in equations (2) below, the resulting output values (estimate (or deduced) symbols (ŝ1,ŝ2)) are equivalent to the output values obtained when using a maximum ratio combining (MRC) method of reception diversity, and thus the received symbols can be properly deduced (estimated).ŝ1=h1*r1+h2r2*=(α12+α22)s1+h1*n1+h2n2*ŝ2=h1*r2−h2r1*=(α12+α22)s2+h1n2*+h2*n1  (2)1) Related Art 4-Antenna Open-Loop STTD System
FIG. 1 is a drawing illustrating an open-loop STTD transmitting end using four antennas in the related art.
As shown in FIG. 1, the 4-antenna open-loop STTD transmitting end includes an STTD encoder 10 for performing space-time coding on data symbols to be transmitted; first multipliers 11 and 12 for multiplying certain gain factors (χ and ξ) to the data symbols outputted from the STTD encoder 10; second multipliers 13 and 14 for multiplying certain phase rotations (θ1 and θ2) to the outputs of the first multipliers 11 and 12; and four transmission antennas (A1-A4) for transmitting the outputs of each multiplier 11 through 14.
As shown in FIG. 1, upon receiving original data symbols to be transmitted, the STTD encoder 10 performs encoding and generates first data symbols (s1, s2, s3 and s4). The STTD encoder 10 then sends the first data symbols as they are (i.e., without any further changes thereto after encoding) for further processing and ultimately to the antennas A1 and A2.
On the other hand, the STTD encoder 10 performs encoding and processing to generate second data symbols (−s2*, s1*, −s4* and s3*). Here, the processing includes converting the first data symbols (s1, s2, s3 and s4) into conjugate data symbols (−s2*, s1*, −s4* and s3*), respectively. Thereafter, the second data symbols (−s2*, s1*, −s4* and s3*) are output for further processing and ultimately sent to the antennas A3 and A4. Here, '*' signifies a conjugate.
The first data symbols (s1, s2, s3 and s4) outputted from the STTD encoder 10 are multiplied by a predetermined gain (χ) in the multiplier 11, and delayed by a predetermined phase (θ1) in the multiplier 13. Meanwhile, the second data symbols (−s2*, s1, −s4* and s3*) outputted from the STTD encoder 10 are multiplied by a predetermined gain (ξ) in the multiplier 12, and then delayed by a predetermined phase (θ2) in the multiplier 14. Accordingly, the transmission antennas (A2 and A4) transmit the first data symbols with phase differences of θ1 and θ2, respectively, compared to the second data symbols transmitted by transmission antennas A1 and A3. Here, the gains (χ and ξ) are each assumed to be '1' merely to simplify calculations,
Accordingly, signals containing data symbols transmitted through each transmission antenna (A1˜A4) for each symbol duration (T) can be expressed by equation (3):
                              [                                                                      A                                      1                                                                                A                                      2                                                                                A                                                            3                      1                                                                                A                  4                                                              ]                =                  [                                                                      s                  1                                                                              s                  2                                                                              s                  3                                                                              s                  4                                                                                ⅇ                                          j                                                                                θ1                                                                                s                    1                                                                                ⅇ                                          j                                                                                θ1                                                                                s                    2                                                                                ⅇ                                          j                                                                                θ1                                                                                s                    3                                                                                ⅇ                                          j                                                                                θ1                                                                                s                    4                                                                                -                                      s                    2                    *                                                                                s                  1                  *                                                                              -                                      s                    4                    *                                                                                s                  3                  *                                                                                -                                          ⅇ                                              j                                                                                θ2                                                                                s                    2                    *                                                                                ⅇ                                          j                                                                                θ2                                                                                s                    1                    *                                                                                -                                          ⅇ                                              j                                                                                θ2                                                                                s                    4                    *                                                                                ⅇ                                          j                                                                                θ2                                                                                s                    3                    *                                                                                ]                                    (        3        )
The signal received during four symbol durations (4T) at the receiving end having one reception antenna can be expressed as equations (4):r1=(h1+h2ejθ1)s1−(h3+h4ejθ2)s2*+n1r2=(h1+h2ejθ1)s2+(h3+h4ejθ2)s1*+n2r3=(h1+h2ejθ1)s3−(h3+h4ejθ2)s4*+n3r4=(h1+h2ejθ1)s4+(h3+h4ejθ2)s3*+n4  (4)
If h1+h2ejθ1 and h3+h4ejθ2 are substituted by 'a' and 'b', respectively, the signals received during the four symbol durations can be simplified to equations (5):r1=as1−bs2*+n1r2=as2+bs1*+n2r3=as3−bs4*+n3r4=as4+bs3*+n4  (5)
Using equations (5), the original data symbols transmitted from the transmitting end can be deduced at the receiving end (i.e., can calculate an estimate of the original data symbols) by using equations (6):ŝ1=a*r1+br2*=(a2+b2)s1+a*n1+bn2*ŝ2=a*r2−br1*=(a2+b2)s2+a*n2−bn1*ŝ3=a*r3+br4*=(a2+b2)s3+a*n3+bn4*ŝ4=a*r4−br3*=(a2+b2)s4+a*n4−bn'*  (6)
The conventional 4-antenna open-loop STRD transmission method explained above shows an excellent performance when a terminal moves at a high speed, i.e., a fast-moving terminal (e.g., the user is in a moving vehicle), but the performance is degraded if the terminal moves at a low speed, i.e., a slow-moving terminal (e.g., the user is walking).
Here, the terms "high speed" and "low speed" are relative expressions, but may be defined as required by the radio communication environment. For example, a threshold speed for a moving terminal may be set to be 10 km/h (kilometers per hour). So, any movement at or over this threshold speed would be considered as "high," while any speed below the threshold would be considered as "low." That is, if the terminal is slow-moving, severe fading (i.e., signal weakening) may occur on the transmission path (e.g., a channel) of a specific transmission antenna used for the slow-moving terminal. Thus, If a transmission signal is lost due to severe fading at a specific antenna, transmission power must be undesirably further consumed to re-transmit the signal to the terminal.
Therefore, if the terminal moves at a low speed, a closed-loop STTD transmission method that employs feedback is preferably used to maximize the gain of the transmission antenna diversity. In other words, by using closed-loop STTD for slow-moving terminals, a better performance (e.g., signal connectivity) than that of the open-loop STTD transmission method can be obtained, because the closed-loop STTD transmission method uses the reception information of each antenna provided from the terminal (i.e., feedback is provided). Thus, by using both the open-loop and closed-loop STTD techniques, optimal performance (e.g., signal connectivity) can be obtained whether the terminal is fast moving or slow moving.
2) Related Art 2-antenna Closed-loop STTD System
FIG. 2 is a drawing illustrating a 2-antenna closed-loop STTD system using two transmission antennas in accordance with the related art. As shown in FIG. 2, the 2-antenna closed-loop STTD system includes a STTD transmitting end having two transmission antennas (Tx1, Tx2) and a STTD receiving end having one reception antenna (Rx).
The STTD transmitting end can include: an STTD encoder 20 for performing space-time coding on data symbols to be transmitted; multipliers 21 and 22 for multiplying predetermined weight values w1 and w2 to the data symbols outputted from the STTD encoder 20; and two transmission antennas Tx1 and Tx2 for respectively transmitting the outputs of the multipliers 21 and 22.
The STTD receiving end can include: one receiving antenna (Rx1); a STTD decoder 23 for performing space-time decoding on a signal received via the receiving antenna (Rx1); a cross-interference conversion unit 24 for processing output signals (d1, d2) of the STTD decoder 23 to generate estimate symbols (ŝ1, ŝ2); and a weight calculator 25 for calculating the weight values (w1, w2) and feeding back the information to the STTD sending end.
The signal transmission method in the related art 2-antenna closed-loop STTD system will now be described.
Upon receiving original data symbols to be transmitted, the STTD encoder 20 in the transmitting end performs encoding and generates first data symbols (s1, s2), which are sent for further processing and ultimately to the first antenna Tx1.
On the other hand, the STTD encoder 20 performs encoding and processing to generate second data symbols (−s2*, s1*). Here, the processing includes converting the first data symbols (s1,s2) into conjugate data symbols (−s2*, s1*), respectively. Thereafter, the second data symbols (−s2*, s1*) are sent for further processing and ultimately to the second antenna Tx2. Here, '*' signifies a conjugate.
The first data symbols (s1, s2) outputted from the STTD encoder 20 are multiplied by the weight value (w1) in the multiplier 21 and then sent to the first antenna Tx1, while the second data symbols (−s2*, s1*) are multiplied by the weight value (w2) in the multiplier 22 and then sent to the second antenna Tx2.
At the STTD receiving end having one reception antenna, the signals received during two symbol durations (2T) can be expressed as equations (7):r1=w1h1s1−w2h2s2*+n1r2=w1h1s2+w2h2s1*+n2  (7)wherein h1(=αejβ1) and h2(=α2ejβ2 ) indicate the channels (i.e., channel responses) between the transmission antennas Tx1 and Tx2, and the reception antenna Rx, respectively, while n1 and n2 indicate an additive white Gaussian Noise (AWGN).
The STTD decoder 23 of the STTD receiving end performs space-time decoding on the received signals (r1, r2) received through the reception antenna Rx, and then generates and outputs decoded signals (d1,d2) expressed as equations (8):d1=h1*r1+h2r2*=(w1|h1|2+w2|h2|2)s1+(w1−w2)h1*h2s2*+(h1*n1+h2n2*)d2=h1*r2−h2r1*=(w1|h1|2+w2|h2|2)s2+(w2−w1)h1*h2s1*+h1*n2−h2n1*)  (8)Assuming that (w1|h1|2+w2|h2|2)=A, (w1−w2)h1*h2=B, (h1*n1+h2n2*)=C1 and (h1*n2−h2n1*)=C2, the above equations (8) can be simplified to equations (9):d1=AS1+BS2*+C1d2=AS2−BS1*+C2  (9)
The cross interference conversion unit 24 processes the decoded signals (d1,d2) outputted from the STTD decoder 23, and generates estimate symbols (ŝ1,ŝ2) that estimate (deduce) the original symbols transmitted by the transmitting end. That is, in order for the receiving end to estimate (deduce) the original symbols, the cross interference conversion unit 24 performs signal processing by using equations (10):ŝ1=A*d1−Bd*2=(|A|2+|B|2)s1+(A*C1−BC2*)ŝ2=A*d2+Bd1*=(|A|2+−B|2)s2+(A*C2+BC1*)  (10)
Meanwhile, the weight calculator 25 calculates the weight values (w1, w2) from the received signals (r1, r2) received via the reception antenna (Rx1), and feeds back the weight values (w1, w2) to the multipliers 21 and 22 of the STTD transmitting end. Here, the weight calculator 25 calculates a weight vector that maximizes the value A in the equation, (w1|h1|2+w2|h2|2)=A. The reason for doing so is because, as shown in equations (10), the value A has the greatest influence in determining the "power of each symbol," that is, the transmission power required to transmit each data symbol. Namely, based upon the characteristics of w12+w22=1 and dA/dw2=0, the weight calculator 25 calculates each weight value (w1, w2) as shown in equations (11):
                                          w            1                    =                                                                                      h                  1                                                            2                                                                                                                          h                      1                                                                            4                                +                                                                                                h                      2                                                                            4                                                                    ,                              w            2                    =                                                                                      h                  2                                                            2                                                                                                                          h                      1                                                                            4                                +                                                                                                h                      2                                                                            4                                                                                (        11        )
Referring to the above, the present inventors have recognized a problem in the related art method. Namely, the weight values calculated by the weight calculator 25 have not been induced from an optimal weight vector that maximizes the estimated symbol transmission power. In other words, in order to maximize the transmission power of symbols (ŝ1,ŝ2) that are estimated (deduced) at the receiving end, a weight vector that maximizes |A|2+|B|2 should be preferably calculated, in principle. However, because the related art weight calculation method generates weight values by inducing a weight vector that only maximizes A (and not |A|2+|B|2), the related art has shortcomings in that the transmission power of the symbols (ŝ1,ŝ2) estimated at the receiving end cannot be maximized.
By employing transmission antenna diversity when two or more transmission antennas are used, not only is a diversity gain obtained by the multiple-antenna transmission unit, but also a signal-to-noise ratio gain is also obtained. Thus, the signal-to-noise ratio gain increases proportionally to the number of transmission antennas used.
As shown in FIG. 2, current UMTS systems generally employ transmission diversity techniques for two transmission antenna systems. However, this method is restricted to situations where there is an STTD receiving end that performs transmission diversity for two transmission antennas Thus, the STTD receiving end operating under the current standards applicable to two transmission antenna systems would not operate properly if more than two transmission antennas are to be used.
In other words, the related art 2-antenna open-loop STTD system and method (e.g., FIG. 2) cannot be directly applied to closed-loop STTD systems employing more than two transmission antennas. For example, if four transmission antennas are to be used while still employing the related art method for transmitting signals with two antennas, the structures of the STTD transmitting end and the STTD receiving end of the closed-loop STTD system need to be changed, and the transmitting/receiving methods also need to be changed.
Similarly, the related art 4-antenna open-loop STTD technique (e.g., FIG. 1) cannot be applied to a 4-antenna closed-loop STTD technique, or at least there would be many difficulties in attempting to make such application.
Therefore, the present invention provides a structure and method for a closed-loop STTD being designed to be suitable for performing transmission antenna diversity when multiple (e.g., two or more) transmission antennas are employed.
The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.

Space-time transmit diversity (STTD) for multiple antennas in radio communications


An authoring system on a mobile device (or other type of device) may help a user to author a message based on context available on the device. Context data comes to exist on the device in some manner. For example, the context may contain the results of a search that a user has performed on the device. A message may be proposed based on the search query and/or the result—e.g., if a user searches for “Edinburgh,” the authoring system may propose the message “Username likes Edinburgh” or “Username is learning about Edinburgh.” The authoring system may allow the user to change the message and/or to add additional content and/or links to the message. The user may then to send the message over some channel such as e-mail, a social network, a microblogging site, etc.

Messages and other text content are normally composed on a computer using a keyboard. A traditional computer has a QWERTY keyboard with mechanically movable keys, which allows a user to enter text by typing. As it has become possible to put more computing power into a smaller device, many functions that were traditionally performed on desktop and laptop computers are now being performed on smaller devices such as handheld computers, phones, music players, and tablet devices.
While it is possible to miniaturize components such as a processor, memory, disk, and network interface, one component that cannot easily be miniaturized beyond a certain point is a physical keyboard that is large enough to be used comfortably by human hands. Small devices often have mechanisms for text input, such as an on-screen keyboard operated through a touch screen, a tiny keyboard designed to be operated by thumbs (as on some smart phones devices), double- or triple-duty keys that each represent two or three letters of the alphabet (as on basic wireless phones), or handwriting recognitions systems. However, these mechanisms normally do not provide the ease of a full-size keyboard when it comes to composing text content.
When a person uses a device (small or large), there various contextual clues that may be available and that might help the user compose the message without having to enter the message from scratch. However, existing systems generally are not designed to make use of these clues.


A copolymer of an .alpha.-olefin with an alkenyl aromatic hydrocarbon having a structure in which tertiary carbon atoms are mutually separated by two methylene groups in the skeleton of the copolymer, a process for producing said copolymer with a specific catalyst and a molded article of said copolymer, and the copolymer and molded article thereof are transparent, excellent in elastic recoverability, flexibility, mechanical strength and scratch resistance.

1. Field of the Invention
The present invention relates to a copolymer suitable for a stretch film and a wrap film in particular, a process for producing said copolymer, and a molded article of said copolymer.
2. Description of the Related Arts
In general, an elastic recoverability, transparency and mechanical strength found in a polyvinyl chloride are required for a copolymer to be used as a stretch film, a shrink film or a wrap film. However, the polyvinyl chloride comes in question concerning environmental pollution because of the possibility of generation of harmful substances in incineration. Various kind of polymers are presently considered as a replacement for the polyvinyl chloride, but it is a status quo that none of them being satisfactory from the viewpoints of viscoelastic properties and transparency has been obtained.
Since copolymerization of an .alpha.-olefin represented by propylene with an alkenyl aromatic hydrocarbon represented by styrene was carried out using a Solvay type titanium trichloride catalyst, studies using various solid catalysts have been carried out. For example, polymerization processes which use a solid catalyst using titanium tetrachloride and an electron donor are disclosed in Japanese Patent Publication (Kokai) Nos. 60-26011 and 4-318006. However, in both of those processes, the polymerization activity is low and a homopolymer is formed as a by-product. Further, the obtained copolymer has a low amount of copolymerized styrene and possesses some crystallinity, and is not adequate from the viewpoints of elastic recoverability, flexibility and transparency.
Japanese Patent Publication (Kokai) No. 8-269134 discloses a process for producing a copolymer of propylene with styrene which has syndiotactic propylene sequences using a so-called homogeneous Ziegler-Natta catalyst which uses a specific transition metal compound and an organoaluminum compound. However, the copolymer obtained by the process, has also a low styrene content and a crystallinity, and is insufficient from the viewpoints of elastic recoverability, flexibility and transparency.

Copolymer, process for production thereof, and molded article thereof


A method for manufacturing a piezoelectric element includes a process for forming a first conductive layer, a process for forming a piezoelectric layer having a region serving as an active region, a process for forming a second conductive layer, which overlaps with the region, a process for forming a third conductive layer, which overlaps with the region, on the second conductive layer, a process for forming an opening portion that divides the third conductive layer into a first portion and a second portion, a process for forming a resist layer that covers the opening portion and a peripheral portion at the side of the opening portion of the first portion and the second portion; a process for etching the third conductive layer to form a first conductive portion and a second conductive portion, and a process for etching the second conductive layer to form a third conductive portion.

1. Technical Field
The present invention relates to a method for manufacturing a piezoelectric element and a method for manufacturing a liquid ejection head.
2. Related Art
For example, a liquid ejection head having a piezoelectric element is known as a liquid ejection head, such as an ink jet printer for ejecting liquid droplets, such as ink. Such a liquid ejection head can change the pressure in a pressure chamber formed under the piezoelectric element by displacing the piezoelectric element by a driving signal or the like, for example, and can eject liquid droplets, such as ink, supplied into the pressure chamber from a nozzle opening.
In such a liquid ejection head, there is one having a structure in which a piezoelectric layer is covered with an upper electrode for the purpose of protecting the piezoelectric layer of a piezoelectric element vulnerable to external factors, such as humidity (JP-A-2005-88441). Such a piezoelectric element has an active region in which the piezoelectric layer is sandwiched between a lower electrode and an upper electrode and generally the active region has a shape of extending in a specific direction in plan view. In such a piezoelectric element, the displacement amount of the piezoelectric element becomes excessively large in the end portion in the longitudinal direction of the active region. As a result, cracks are generated in the piezoelectric layer of the piezoelectric element to reduce the reliability in some cases.
Therefore, a method for manufacturing a piezoelectric element that can highly accurately and simply manufacturing a piezoelectric element having high reliability capable of suppressing the generation of cracks has been desired.

Method for manufacturing piezoelectric element and method for manufacturing liquid ejection head


A communications network system capable of reducing the time from the occurrence of a trouble to the rebuilding of the system and a rebuilding method thereof. In a communications network system which comprises a plurality of node devices (10-1 to 10-4) distributed at a plurality of positions and transmission lines (1a, 1b) for connecting the plurality of node devices, one of the plurality of node devices is set as a master station (10-1) to operate the system, when the master station has a trouble, the individual node device makes an inquiry to the other node devices, and a node device which has confirmed that no other node device has a higher priority than itself becomes a substitute master station to take the place of the troubled master station to continue the operation of the system.

Such a type of communications network system conventionally known is based on an STM (synchronous transfer mode).
FIG. 10 is a block diagram showing a conventional communications network based on STM (synchronous transfer mode). The communications network system of FIG. 10 has four node devices 1-1 to 1-4 connected through optical transmission lines 1a, 1b and the node device 1-1 determined as a master station.
The node device 1-1 as the master station is connected to an operation management device 2-1 which collects information on operation conditions of the node devices 1-1 to 1-4 and the optical transmission lines 1a, 1b and displays the collected results on, for example, a screen.
The node device 1-1 as the master station in the configuration shown in FIG. 10 is shown in detail in the block diagram of FIG. 11.
In FIG. 11, the node device 1-1 as the master station comprises an optical transmission line interface 3 connected to the optical transmission lines 1a, 1b, a frame generation part 4 which generates a transmission frame and circulates it through the respective node devices, a frame termination part 5 which examines a transmission frame having come back through the respective node devices, a control part 6 which is connected to the operation management device 2-1 to control comprehensively the entire operation of the node device 1-1, and an interface part 7 connected to an external interface.
In the above-described communications network system based on STM (synchronous transfer mode), the respective node devices 1-1 to 1-4 must synchronize at intervals of, for example, 125 .mu.S; then as shown in FIG. 11, the node device 1-1 as the master station needs the frame generation part 4 to generate a transmission frame at intervals of 125 .mu.S and circulate it through the respective node devices. Besides, the node device 1-1 as the master station needs the frame termination part 5 in order to examine the transmission frame having come back through the respective node devices and to transmit it again at intervals of 125 .mu.S.
To improve reliability of the system, it is necessary to have a substitute master station, for example, the node device 1-3 shown in FIG. 10, which can take the place of the node device 1-1 as the master station in case that the node device 1-1 as the master station has a trouble. And, the node device 1-3 to be a substitute master station also needs to have the frame generation part and the frame termination part. In this case, the node device 1-3 to be the substitute master station is connected to an operation management device 2-2 same as the operation management device 2-1.
In the configurations shown in FIG. 10 and FIG. 11, if there were a trouble in the optical transmission lines 1a, 1b or the optical transmission line interfaces of the respective node devices 1-1 to 1-4, it is detected by a neighboring node device, and information on the trouble is put on the transmission frame, which is circulating through the respective node devices, to inform the node device 1-3 to be the substitute master station of the trouble.
The node device 1-3 to be the substitute master station having received the information on the trouble puts information for instructing to change the transmission lines or to loop back on the transmission frame circulating through the respective node devices, and the respective node devices having received the information perform processing according to the information.
Thus, if a conventional communications network system based on STM (synchronous transfer mode) had a trouble, the node device 1-3 to be a new master station operates to reconfigure the network having the trouble, but there is a disadvantage that it takes a long time from the occurrence of a trouble to the rebuilding of the system.
And, if the node device 1-3 to be the master station had a trouble, it cannot generate a transmission frame or mark its own number in the transmission frame whenever the transmission frame is generated. In such a case, a plurality of other substitute master stations detect the situation, mark their own numbers in the transmission frame to generate respective transmission frames, and circulate such transmission frames. Upon receiving such transmission frames, the other substitute master stations, if their own numbers (priority) are larger than those of the other substitute master stations, abandon the received transmission frames but if smaller than them, pass on them as they are. And, when the substitute master station receives the returned transmission frame having its own number marked, this substitute master station becomes a new master station.
As described above, the conventional communications network system based on STM (synchronous transfer mode) circulates the transmission frames to decide a master station. Therefore, it takes a long time to decide a new master station after the occurrence of a trouble in the master station, resulting in a drawback of taking a long time to reconfigure the system.

Communication network system and rebuilding method thereof