Recent upgrades to the MOTRAN atmospheric radiation code improve the accuracy of its radiance predictions, especially in the presence of clouds and thick aerosols, and for multiple scattering in regions of strong molecular line absorption. MODTRAN3.5 features a generalized specification of cloud properties, while research version MODTRAN4 implements a Correlated-k (CK) approach for more accurate calculation of multiply scattered radiance. Comparisons to cloud measurements demonstrate the viability of the CK approach. The impact of these upgrades on predictions for AVIRIS viewing scenarios is discussed for both clear and clouded skies; the CK approach provides refined predictions for AVIRIS nadir and near-nadir viewing.

The present invention relates generally to systems which calculate the effects of the atmosphere on the transmission of radio and optical beams, and more specifically to a moderate resolution propagation model (and system) of the earth's atmosphere. This model can be used for predicting atmospheric transmittance and background radiance from 0 to 50,000 cm.sup.-1 at a resolution of 2 cm.sup.-1.
The interest in atmospheric transmittance and background radiance along with the associated subject of astronomical refraction goes back to Laplace. With the advent of large telescopes and phase array radar systems, this interest has become ubiquitous, since the output signals of these systems experience attenuation due to atmospheric particles, water vapor and other gases along the viewing path.
The transmittance and radiance along a path through the atmosphere depend upon the total amount and the distribution of the absorbing and scattering species as well as the variation of pressure and temperature along the path. The integrated amount of absorber or scatterer along a path is known by various names, including "column density," "equivalent absorber amount," and "air mass." While the term "air mass" applies specifically to the total amount of gas along the path, it will be used here to refer loosely to the integrated amounts for all the different species relative to the amount for a vertical path.
The task of ascertaining atmospheric transmittance and atmospheric background radiance is alleviated, to some extent by the systems disclosed in the following U.S. Patents, the disclosures of which are incorporated herein by reference:
U.S. Pat. No. 5,315,513 issued to Abreu et al; PA1 U.S. Pat. No. 5,075,856 issued to Kneizys et al; PA1 U.S. Pat. No. 4,611,929 issued to Holyer; PA1 U.S. Pat. No. 4,661,907 issued to Arnone et al; and PA1 U.S. Pat. No. 4,521,861 issued to Logan et al.
The last three references disclose alternative atmospheric model systems. The first two patents are for the MODTRAN and LOWTRAN models that are improved by this invention. The closest reference is the Abreu et al patent, which uses an earlier model that lack the specific features specified below.
Perhaps the most significant of the above-cited references are the Kneizys and Abreu patents, which were filed for the LOWTRAN 7 and MODTRAN models of the atmosphere, which are discussed below. The Holyer reference discloses a satellite method for measuring sea surface temperature which utilizes LOWTRAN 5, which is a predecessor of the present invention.
In February of 1980, the Phillips Laboratory of Hanscom Air Force Base, Massachusetts developed LOWTRAN5, a Fortran computer code designed to calculate atmospheric transmittance and radiance for a given atmospheric path at low spectral resolution. The details of LOWTRAN 5 are described in a technical report by F. Kneizys et al entitled "Atmospheric Transmittance/Radiance; Computer Code LOWTRAN 5, AFGL-TR-80-0067," the disclosure of which is incorporated herein by reference. This report is available from the National Technical Information Service where it is identified as document number ADA088215.
In LOWTRAN 5, 6 and 7, the atmosphere is modeled as a set of spherically symmetric shells with discrete boundaries. The temperature, pressure, and absorber (gas and aerosol) densities are specified at the layer boundaries. Between boundaries, the temperature profile is assumed linear while the pressure and densities are assumed to follow exponential profiles.
LOWTRAN 6 was developed and described in August 1983 in a technical report entitled "Atmospheric Transmittance/Radiance; Computer Code LOWTRAN 6, AFGL-TR-83-0187," the disclosure of which is incorporated herein by reference. This report is available from the National Technical Information Service, where it is identified as document number ADA137796.
LOWTRAN 6 was an improvement over the previous model LOWTRAN 5, which assumed that the index of refraction was constant between layer boundaries. LOWTRAN 6 assumes a continuous profile for the refractive index, with an exponential profile between layer boundaries. It is more accurate than the previous models and works for all paths.
The LOWTRAN 7 model and computer code calculates atmospheric transmittance and background radiance for a given atmospheric path at low spectral resolution. This version is an extension and update of the current code, LOWTRAN 6 (and its predecessors LOWTRAN 5, LOWTRAN 4, LOWTRAN 3 and LOWTRAN 2). All the options and capabilities of the LOWTRAN 6 code have been retained, but additional refinements have been added, as described below.
The LOWTRAN 7 code calculates atmospheric transmittance, atmospheric background radiance, single scattered solar and lunar radiance, direct solar irradiance, and multiple scattered solar and thermal radiance. The spectral resolution of the model is 20 cm.sup.-1 (full width at half-maximum) in steps of 5 cm.sup.-1 from 0 to 50,000 cm.sup.-1 (0.2 um to infinity). A single parameter band model is used for molecular line absorption and the effects of molecular continuum-type absorption; molecular scattering, aerosol and hydrometer absorption and scattering are included. Refraction and earth curvature are considered in the calculation of the atmospheric slant path and attenuation amounts along the path. Representative atmospheric, aerosol, cloud, and rain models are provided in the code with options to replace them with user-provided theoretical or measured values.
But now LOWTRAN 7 has been displaced by its progeny--MODTRAN--with a current combined (AF and ONTAR) distribution to over 1000 users. The basic advantages of MODTRAN center on the improved spectral resolution and compatibility with HITRAN in its most recent issue ('92 and '95 for MODTRAN2 and 3, respectively). The most important generic message, however, is that most cases, all LOWTRAN versions should be replaced by MODTRAN.
Because MODTRAN3 is now undergoing external release in mid-1995 (alone with its ONTAR PC version), its advantages are restated here. The primary changes from older versions include: (1) a new solar irradiance, at 1 cm.sup.-1 resolution (first suggested by B.-C. Gao and developed by R. Kurucz); (2) an alternate multiple scattering algorithm based on DISORT (3) parameter statement control over the total number of atmospheric layers, facilitating user control over the degree of accuracy in replicating atmospheric structure (4) new IP and UV temperature dependent cross sections and (5) improved band model and radiance algorithms, developed and validated against LBL calculations. Subsequent modifications will be made to MODTRAN as they become available. For instance, a new measurement-based solar irradiance (from Shuttle measurements from the 1992 ATLAS campaign, expected in 1995) will be provided, along with the existing options.
Coupled with all previous descriptions of MODTRAN capabilities, MODTRAN3 calculations are demonstrating a breadth of unique applications. In a series of papers, led by the work of J.-M. Theriault, preliminary use of MODTRAN for analysis of moderate resolution interferometer data has been established. These papers did not advocate using MODTRAN alone as the forward radiance algorithm, but, rather, showed that MODTRAN could be employed to obtain the large derivative matrices used in physical inversion algorithms. Because these matrix elements are calculated from determining the sensitivity of small single layer perturbations of each detectable species upon the full path radiance, the near equivalence of the individual matrix elements to those derived analytically from LBL codes was unexpected.
This set of studies did not recommend that the iterative least squares minimization test of forward calculation vs. measurement employ MODTRAN. That recommendation can only be made after careful analyses of the impact of spectral resolution (and its accuracy) on vertical resolution and instrument signal to noise and other error sources. Such studies are currently being undertaken.
A direct outgrowth of the sensitivity of the matrix elements was the suggestion that the MODTRAN layer-specific optical properties (effective optical depth and transmittance/radiance differentials; that is, those quantities derived from differences and ratios of adjacent full path BM calculations) were essentially equivalent to the LBL direct layer calculations. Given the near linearity of this sensitivity, MODTRAN became a candidate for flux-divergence and energy deposition calculations.
The WMO InterComparison of Radiation Codes used in Climate Models (ICRCCM) had already established the basis for evaluation of LBL codes, so MODTRAN was tested against these evaluations. Initial work by L. Kimball, L. Bernstein, and colleagues has now confirmed that with appropriate modifications (an improved radiance algorithm, implemented in MODTRAN3, and introduction of the mathematics to reduce spherical geometry to the "flat earth" approximation of ICRCCM), the IR spectrally integrated (0-3000 cm.sup.-1) cooling rates for H.sub.2 O, CO.sub.2, and O.sub.3 fall within the range of the LBL codes participating in the initial studies.
For two specific examples of a newer ICRCCM comparison (R. Ellingson, private communication) for MODTRAN3 and FASCODE; the measurements are from the AERI, a well-calibrated, surface-based interferometer developed by the Univ. of Wisconsin. In each case the results have been degraded to 10 cm.sup.-1 resolution and subsequently compared to the ICRCCM standard radiative transfer model: LBLRTM. While the statistics appear to slightly favor FASCODE over LBLRTM, in general (and for the 4 ICRCCM cases), LBLRTM and FASCODE are relatively indistinguishable, although the DOE-funded effort has made much progress in both computational efficiency and upgraded spectral sampling (resulting in improvements to better than 1%, not distinguishable on this scale. This agreement is not unreasonable in that both codes have a common lineage. The important aspect is that these two line-by-line codes (and the next generation, FASE) share the best agreement with the ICRCCM measurement set, approximately 2-3% mean difference and 4-6% rms difference (with values beyond 2400 cm.sup.-1 dropped because of extremely low S/N). The comparable statistics for MODTRAN are approximately twice as large, 5-10% mean and 6-12% rms. The difference in the statistical errors between MODTRAN and the line-by-line codes can also be seen in any direct comparison of their calculations, whether in transmittance or radiance; MODTRAN residuals are usually within a few percent of exact calculations, and every attempt is being made to reduce this magnitude.
Another recent example of validation of both FASCODE and MODTRAN also employs a Univ. of Wisconsin measurement set derived from their airborne instrument: HIS. A small spectral range (2000-2700 cm.sup.-1) of a measurement was taken from the NASA ER-2 over the Eastern Pacific. This spectral band has been chosen because it demonstrates the overlap in the thermal and solar Planck functions. The residual between measurement and FASCODE longward of 2400 cm.sup.-1 is due to reflected solar contributions. Putting in a minimum surface albedo of 0.05 and employing the MODTRAN solar capability reduces this residual between measurement and model almost completely. The virtue of having a single model with full thermal and solar radiation fields is quite apparent.
Given this success and general agreement with the LBL spectral cooling rate distributions for H.sub.2 O calculated by Clough et al., a more general energy deposition study has been undertaken. Again, the "flat earth" assumption has been maintained but otherwise a preliminary version of MODTRAN3 (missing only the new solar irradiance and the DISORT algorithm) was used for all calculations. The code was run from 0 to 50,000 cm.sup.-1 in two modes: (1) radiance with single scattering (which includes both thermal and solar sources), and (2) direct solar irradiance. A typical pair of up- and down-welling radiances for the full path at 15 km, might be measured from an aircraft flying at the tropical tropopause. The direct solar contribution is omitted and the assumed surface albedo is 0.1. Similar radiance calculations were done for 4 quadrature angles at each of 60 layer boundaries to approximate the 2.pi. fluxes while the approximations for daily averaged solar insolation were based upon a single solar incidence angle weighted for day of year (120) and latitude (tropical, 15N). An actual energy budget as determined from measurement, would also be the end result of complex sets of integrated data and spectral syntheses, no single instrument being able to provide the spectrally appropriate up- and down-welling contributions over the entire spectral range. Of course, this preliminary demonstration can only begin to provide estimates of sensitivities, even when validating data are available.
Characterization of surface properties from AVIRIS measurements is hampered by atmospheric attenuation and path radiances. MODTRAN, the Air Force PL/Geophysics Directorate moderate spectral resolution (2 cm.sup.-1) background radiance and transmission model, is often used to account for the atmospherics in AVIRIS measurements. It rapidly predicts the molecular and aerosol/cloud emissive and scattered contributions to observed radiances along with the atmospheric attenuation. MODTRAN has been extensively validated against both measurements and the high spectral resolution FASCODE model.
In view of the foregoing discussion, it is apparent that there remains an ongoing need to obtain refined estimates of atmospheric transmittance and background radiance, and that state-of-the-art methods are literally adapted for use almost as fast as they are developed by users that include the United States Air Force and other DOD agencies. The present invention is intended to satisfy that need.

System and method for modelling moderate resolution atmospheric propagation

The United States of America as represented by the Secretary of the Air Force


A computing system includes a digital signal processor, a storage medium for storing parameter tables, a central processing unit coupled to the digital signal processor and the storage medium, and a shared memory coupled to the digital signal processor and the central processing unit. The digital signal processor stores a data request in the shared memory and issues a request command to the central processing unit when access to the parameter tables is desired. Upon receipt of the request command, the central processing unit reads the data request in the shared memory, accesses the storage medium for retrieving requested data that corresponds to the data request, stores the requested data in the shared memory, and issues a response command to the digital signal processor. The digital signal processor retrieves the requested data from the shared memory upon receipt of the response command from the central processing unit.

1. Field of the Invention
The invention relates to a computing system, more particularly to a method for enabling a digital signal processor in a computing system to access parameter tables through a central processing unit.
2. Description of the Related Art
A central processing unit (CPU) is responsible for peripheral components control, logic operations, arithmetic operations, instructions decoding and execution, etc., and is the control center of a computer system. Since the main function of the central processing unit is peripheral components control, the central processing unit is suitable for performing only simple arithmetic operations like addition and subtraction, and is not suitable for performing complex mathematical computations or logic operations. When the central processing unit is instructed to perform the complex mathematical computations or logic operations, poor operating efficiency (i.e., low computational speed or even inoperability) will occur. A digital signal processor (DSP) is specially designed for performing complex arithmetic computations involving addition, subtraction, multiplication and division, and complex logic operations in a low power but highly efficient manner. Therefore, a central processing unit usually operates in combination with a digital signal processor for improving digital computation efficiency in a system, such as a digital versatile disc (DVD) player, or a mobile phone, etc.
FIG. 1 illustrates a conventional system 1 that incorporates a digital signal processor (DSP) 11. The DSP 11 is electrically connected to an external input/output (I/O) interface 13 and a memory unit 12. The memory unit 12 includes a read-only memory (ROM) 121 and a random access memory (RAM) 122, and stores program code and data for the operations of the DSP 11. In general, the digital computations performed by the DSP 11 involve algorithms that require the use of parameter tables. For example, in voice recognition applications, parameter tables are needed for judgment after analytical computation of sound. Moreover, in the formula Y=aX^2+bX+c, where X is an input signal, Y is an output signal, and a, b and c are parameters, the number of possible results could be quite enormous in view of the possible combinations of the parameters (a, b, c). For example, assuming that a, b, c are 4-bit data, the possible combinations can amount to 16*16*16≈4000. Parameter tables formed from the possible parameter combinations can be stored in the ROM 121 beforehand such that, when needed by the DSP 11, the relevant data can be retrieved from the memory unit 12 through appropriate addressing. This method of memory access is called direct addressing and can be completed in one computing cycle. The external I/O interface 13 is electrically connected to an external circuit. Thus, the DSP 11 can be used for digital computations in order to improve the system computing efficiency.
At present, the data width of the DSP 11 is widely designed as 16 bits. The addressable space of the DSP 11 is thus limited to 64 KB (216=64 KB). If the size of the parameter tables is more than 64 KB, the parameter tables cannot be stored in the memory unit 12. In practice, limitations on the size of the parameter tables may be even more restricted, because the addressable space must include the ROM 121, the RAM 122 and a memory map for the external I/O interface 13. Therefore, the size of the addressable space allocated for the parameter tables is actually less than 64 KB. Moreover, the system 1 of FIG. 1 is usually designed as a single packaged chip. In view of cost and size considerations, the capacity of the memory unit 12 is usually only around 2 KB. Since the memory unit 12 has space reserved for storing program code and other data, it is evidently impractical for parameter tables having sizes greater than 1 KB to be stored in the memory unit 12 for data access by the DSP 11 using the conventional direct addressing method.
In many applications, such as digital signal processing in voice recognition, image processing, mobile phone communications and video signal interfacing, etc., the size of parameter tables is generally larger than 64 KB. Thus, the parameter tables cannot be stored in the memory unit 12. Therefore, the system 1 must be configured to cooperate with an external memory having slower access speed (such as flash memory or dynamic random access memory). The external memory configuration is shown in FIG. 2. As illustrated, the external I/O interface 13′ of a system 1′ that is identical in structure to the system 1 of FIG. 1 is coupled to an external memory 21 which has the parameter tables stored therein. The external I/O interface 13′ relies upon indirect addressing to access data from the external memory 21.
The following are some of the drawbacks associated with the conventional configuration of FIG. 2:
1. Additional external circuits are needed. Because the external memory 21 is accessed by indirect addressing, there is a need to provide an address register 22 for temporary storage of the address of requested data, a data register 23 for temporary storage of data retrieved from the external memory 21, and an access control circuit 24 (for example, a direct memory access (DMA) controller) so that data corresponding to the address in the address register 22 may be retrieved from the external memory 21 and stored in the data register 23 for subsequent use by the DSP 11′ in the system 1′, thereby resulting in increased components costs.
2. Computing time is increased. When the DSP 11′ accesses the parameter tables through the external circuits 22, 23 and 24, an address is first written into the address register 22, and the access control circuit 24 then retrieves the requested data from the external memory 21 in accordance with the address in the address register 22 and stores the requested data in the data register 23 for subsequent access by the DSP 11′ through the external I/O interface 13′. Therefore, instead of directly accessing data from an internal memory unit 12 as done by the DSP 11 in the aforesaid system 1 of FIG. 1, extra steps are required for reading data through the external circuits 22, 23 and 24 such that data reading cannot be completed in one computing cycle. Moreover, when the DSP 11′ issues a request for data, the DSP 11′ cannot proceed with other operations until the requested data is provided thereto. Therefore, the computing time is increased, and the computing efficiency and speed of the DSP 11′ are decreased.
The data width of a commercially available central processor unit is 32 bits, thus resulting in an addressable space of as high as 4 gigabytes (232≈4*106). The capacity of a computer memory (for example, flash memories, dynamic random access memories, etc.) used with a central processing unit can also be enormous. Together, the central processing unit and the computer memory will have adequate addressable space and memory capacity for parameter table utilization. Since a central processing unit has an inherent memory access function and is used in combination with a digital signal processor, if a method for enabling the digital signal processor in a computing system to access parameter tables through the central processing unit is provided, the aforesaid drawbacks can be overcome.

Computing system, and method for enabling a digital signal processor to access parameter tables through a central processing unit


The present invention relates to a video processing method and apparatus capable of performing a proper video process corresponding to various color systems. A decoder extracts color information from a received video signal including vertical synchronous information for a vertical scanning frequency of a picture, color information of the picture, and frequency information corresponding to the color information. A frequency evaluator evaluates the received vertical scanning frequency and the received frequency of the video signal color information on the basis of the vertical synchronous information and the frequency information of the color information. A controller controls the decoder to extract the color information on the basis of the frequency of the color information when the received vertical scanning frequency and the received frequency of the color information evaluated by the frequency evaluator are identical with predetermined vertical scanning frequency and the predetermined frequencies of the corresponding color information.

1. Field of the Invention
The present invention relates to a video processing method and apparatus. More particularly, the present invention relates to a video processing method and apparatus capable of performing a proper video process corresponding to multiple color systems.
2. Description of the Related Art
A video display apparatus, such as a television (TV), receives a video signal corresponding to an image transmitted from such sources as a digital TV broadcast and cable TV broadcast. A video display apparatus can also receive a video signal from various video devices such as a video cassette recorder (VCR) and a digital versatile disc (DVD) player. Further, video display apparatuses can process received video signals and display images accordingly.
A video processing apparatus includes a tuner to set a channel that a user wants to view. The tuner selects/receives a signal corresponding to a frequency assigned to the set channel, in other words the tuned channel. Also, the video processing apparatus includes a decoder which decodes signals corresponding to information about picture and sound, among others, from the received video signal. Since the signal selected and decoded by the video processing apparatus is based on international standards, the video processing apparatus is configured to process the signal on the basis of such international standards. The international standards include those standards such as national television system committee (NTSC), phase alternating line (PAL), Sequential couleur a memoire (SECAM), among others. Thus, the video processing apparatus is set to decode a signal according to at least one of the international standards.
For example, in the case of an NTSC-M standard, the field frequency is 59.72 Hz, the line frequency is 15.734266 KHz, and the color subcarrier frequency is 3.579545 MHz. Therefore, in a video processing apparatus receiving a signal based on the NTSC-M standard, when the received signal has a field frequency of 59.52 Hz, the decoding process is performed with the line frequency and the color subcarrier frequency established as preset 15.734266 KHz and 3.579545 MHz, respectively. Further, in the video processing apparatus receiving a signal based on a PAL-B/G/I standard, the decoding process is performed with a field frequency, line frequency and color subcarrier frequency established as 50 Hz, 15.625 KHz and 4.4336187 MHz, respectively. Thus, a conventional video processing apparatus identifies the field frequency of the received signal, then performs the decoding process on the basis of the preset line frequency and preset color subcarrier frequency corresponding to the identified field frequency.
Users often want a video processing apparatus to properly process signals based on a number of standards. For example, the video processing apparatus may be connected to a DVD player, a game system, or the like, and receive a signal therefrom and output a video signal and an audio signal. However, when the signal outputted from the DVD player, the game system, or the like, is not the same as the signal standard that the corresponding video processing apparatus is configured to accommodate, the video processing apparatus cannot provide proper video and audio signals.
For example, when a signal outputted from a game system is based on the NTSC-N standard, the signal has a field frequency of 50 Hz, but its line frequency and color subcarrier frequency are 15.625 KHz and 3.579545 MHz, respectively. Because the field frequency of the video processing apparatus receiving an NTSC-M standard signal is set to 60 Hz, the video processing apparatus cannot properly decode the signal outputted from such a video device. Meanwhile, in the case where the video processing apparatus is set to receive a PAL-B/G/I standard signal, the video processing apparatus determines that the input signal is based on the PAL-B/G/I standard because the input signal has a field frequency of 50 Hz. Thus, the video processing apparatus for the PAL-B/G/I standard tries to apply the decoding process to the input signal by regarding the corresponding line frequency and corresponding color subcarrier frequency as 15.625 KHz and 4.4336187 MHz, respectively. However, the real color subcarrier frequency of the input signal is not compatible with the preset color subcarrier frequency of the video processing apparatus. Thus, the video processing apparatus cannot correctly extract color information from the input signal and as a result incompletely displays the image.


An image sensing apparatus includes a sensing device for receiving a light signal, performing a photoelectric conversion and storing information, and a control device for changing the saturation level of the electric charge storable by the sensing device. The saturation level of the electric charge is changed by the control device so as to be comparatively small in an earlier part of a unit-light storage interval which forms one picture, and larger in a latter part of the interval.

This invention relates to an image sensing apparatus for photographing a subject, by way of example, more particularly, to an image sensing apparatus having a tone control function preferrable for use in compensating for backlighting or the like.
When photographing a subject using a video camera or the like in a backlighted situation where illumination is intense, the tones contained in one picture (or frame) cover a wide range.
Since an image sensing apparatus using a solid-state image sensor as employed in a video camera or the like does not have enough dynamic range for converting all of these tones into video signals, clipping occurs above and below the brightness level. This is a phenomenon in which the subjects appears too bright and devoid of color or too dark, even black. Specifically, the tones of extremely bright portions and extremely dark portions cannot be expressed in one picture.
In the case of backlighted photography, the main subject becomes shadowed and appears very dark in comparison with the brightness of the background, and blackening of the subject occurs.
A conventional countermeasure to prevent the foregoing is to use a technique, referred to as backlighting control (BLC), through which a backlighting correction is performed by increasing the amount of exposure. A backlighting correction based upon this conventional technique will be described in detail with reference to the drawings.
First, the operation of BLC in an exposure adjusting mechanism using an iris will be described with reference to FIG. 1, which is a block diagram illustrating the construction of a backlighting correction circuit.
As shown in FIG. 1, light rays from a subject enter via an optical lens 10, the amount of light is limited by an iris 11, and an image is formed on an image sensor 12. A signal resulting from a photoelectric conversion and conforming to the state of the formed image is outputted by the image sensor 12 and converted into a video signal by a signal processing circuit 13, which delivers the video signal as an output.
The video signal is supplied also to an AE circuit 14, which generates an iris control signal conforming to the video signal. Upon receiving the iris control signal from the AE circuit 14 via an adder 15, a driver 16 generates a drive signal which drives an ig meter 17, whereby automatic adjustment of the amount of light by the iris is realized.
In the above-described approach for automatically adjusting the amount of light, the common practice is to make the adjustment in dependence upon the integrated value of the video-signal luminance level in one picture, and therefore emphasis is placed solely upon the average brightness of the entirety of one picture. As a consequence, in the case of backlighted photography, the adjustment of the amount of light incident upon the image sensor is carried out in dependence upon the background, which is extremely bright. The result is that the main subject becomes too dark, as a result of which the blackening phenomenon occurs.
In such a case, it is necessary for the photographer to issue a backlighting correction command to turn on the BLC function In the arrangement of FIG. 1, a BLC switch 19 is turned on (closed), whereby a correction signal generating circuit 18 supplies the driver 16 with a signal for widening the opening of the diaphragm. This signal arrives via the adder 15. As a result, the driver 16 drives the ig meter 17 in the opening direction to increase the amount of light incident upon the image sensor 12, whereby the backlighting correction is achieved.
By thus closing the BLC switch 19 to carry out the backlighting correction through this conventional technique, the image is changed from the BLC-OFF state (the state prior to the backlighting correction), shown in FIG. 2(a), to the BLC-ON state (the state after the backlighting correction), shown in FIG. 2(b). As will be appreciated from FIGS. 2(a) and (b), the background shows up well in the BLC-OFF state, but the subject is darkened and does not show up very well. By contrast, the tones of the subject are expressed and appear excellently in the BLC-ON state.
However, in the conventional image sensing apparatus described above, performing the backlighting correction increases the amount of light received by the image sensor, thereby causing the main subject to show up well, but the background appears washed out and cannot be made to appear. This may be understood from FIG. 2(b).
In other words, with the backlighting correction by the conventional technique, clipping occurs at a high or low level owing to the limitation upon the dynamic range of the image sensor, so that it is not possible to pick up the images of both the main subject and background well.

Image sensing apparatus having tone control function


A signal processing circuit (10) for a fiber optic sensor (12) includes a d.c. block (14) coupled to the fiber optic sensor (12) for removing d.c. components from the fiber optic sensor output signal, and a low pass filter (16) coupled to the d.c. block (14) for reducing noise in the fiber optic sensor output signal and generate a filtered signal. A comparator (18) is coupled to the low pass filter (16) and generates a squared signal indicative of zero crossings in the filtered signal. A lock-in amplifier or synchronous demodulator (20) is coupled to the comparator (18) and generates an output signal indicative of a phase shift in the two light waves propagating in the fiber optic sensor (12).

A number of fiber optic sensors being commercially produced or currently under development are based on the sinusoidally modulated fiber optic interferometer. These include fiber gyroscopes, current sensors, flow sensors, and acoustic sensors. An example of a fiber optic interferometric sensor is described in U.S. Pat. No. 5,644,397, titled Fiber Optic Interferometer Circuit and Magnetic Field Sensor, and issued to Blake on Jul. 1, 1997, hereby incorporated by reference. For example, the fiber gyroscope detects rotation as a phase shift induced in the light waves due to the Sagnac effect. In current and magnetic field sensors, the phase shift in the light waves may be induced by the Faraday effect.
A common method for extracting the desired information from the sensor output is to use an "open loop" signal processing technique. Although "closed loop" signal processing techniques are known to yield superior performance over open loop techniques, the open loop techniques have the advantage of requiring only a single frequency modulator rather than the wide bandwidth modulator required in the closed loop technique.
The output from a sinusoidally modulated interferometric sensor, I.sub.out, can be represented by: ##EQU1## where .omega. is the bias modulation frequency, .phi..sub.R is the phase shift to be measured, .phi..sub.m is the modulation depth, and .theta. is a phase delay uncertainty between the modulation drive signal and the output signal. The most widely used method for determining .phi..sub.R is to synchronously detect the first harmonic component of I.sub.out. The resulting signal is I.sub.o J.sub.1 (.phi..sub.m) cos .theta. sin .phi..sub.R. In order to determine .phi..sub.R from this signal, it is necessary to either measure or stabilize the other three variables, I.sub.o, .phi..sub.m, and .theta.. Consequently, open loop signal processing schemes commonly contain four basic circuits for determining these four parameters. Three of these circuits are synchronous demodulators for the measurement of three different harmonic levels in the output signal, and the fourth circuit is a zero-crossing or level-crossing circuit for determining .theta.. Stable high Q filters are needed for each of the synchronous demodulators and ratioing circuits are needed for comparing the various harmonic levels. In practice, a complete demodulation circuit of this type requires well over a hundred individual electronic components and is quite expensive. Therefore, it is desirable to simplify the demodulation circuitry.

Open loop signal processing circuit and method for a fiber optic interferometric sensor


Peak detection is conducted by converting a continuous waveform into discrete samples. The discrete samples are evaluated to identify three points near a peak of the continuous waveform. After the three points near the peak are identified, they are stored in a discrete domain data structure which is used in conjunction with a table generated from a continuous transformation function in order to identify an accurate peak amplitude and time.

1. Field of the Invention
The present invention is directed to precise waveform peak detection, and is more particularly directed to an apparatus and methodology which efficiently provides high accuracy peak amplitude and time identification for a wide bandwidth.
2. Description of Related Art
Analog peak detectors generally fall into two categories; very accurate with a narrow bandwidth or inaccurate with a wide bandwidth. At low frequencies (e.g., audio), it is possible to use operational amplifiers to build precision peak detectors. These configurations can be very accurate, but fall prey to narrow bandwidth limitations. Other analog designs have much wider bandwidths (up to a few MHz), but fall prey to inaccuracies that are due to non-linear gain functions which limit useful operation to a small amplitude range. Furthermore, their use is generally acceptable only when errors of several percent can be tolerated.
The alternate approach to analog peak detection is through digital analysis of waveforms. This involves the use of an analog-to-digital converter (ADC) that digitizes an input signal with an evaluation of the resulting discrete values conducted in order to identify signal peaks and their corresponding characteristics (i.e., amplitude and time of occurrence). One particular method consists of very high speed ADC sampling and subsequent digital magnitude comparisons. While this is a straightforward approach, typically the sample rate of an ADC is not fast enough to guarantee that a data point is taken at the exact time of the signal peak. Instead, a sample on either side of the peak is identified as the true peak, thereby resulting in a reported peak value which is somewhat smaller than the actual value.
For high frequency input signals, e.g. several MHZ, it is also difficult to obtain an ADC sample rate that is sufficient to provide high precision identification. For a simple sine wave input, the minimum required sample rate that provides an accuracy of 0.01% is 223 times the input frequency. Currently, the fastest single twelve bit ADC chip has a maximum sample rate of approximately 40 million samples per second (MSPS), which would limit the input frequency to 400 kHz if the sample error is to be less than 0.05%, or 4.0 MHZ for an error no larger than 1.0%.
It is possible to increase the effective sampling rate of an ADC by incorporating an interpolation circuit. With an interpolation circuit, additional samples are provided between the measured points. However, the drawback is that the input bandwidth must be limited to avoid inducing errors into the interpolated values.
Faster sampling rates may also be obtained by using ten bit, eight bit, or six bit ADCs. However, the accuracy is then limited by the resolution of the ADC. Generally, the nominal input signal is scaled to approximately two-thirds of full scale. At this input sampling rate, the error due to ADC quantization is 0.073% for a twelve bit ADC, 0.293% for a ten bit ADC, 1. 172% for an eight bit ADC, and 4.688% for a six bit ADC. Therefore, current ADC technology provides peak detection that is limited to low frequencies (less than about 1 MHZ) if good accuracy (better than about 0.5%) is required. Furthermore, at high sample rates, it is difficult to design a digital magnitude comparator which will adequately examine the ADC output for peak identification. In addition, this method provides a peak time which is only known to within one ADC sample interval, which is not accurate enough for some applications.
An additional ADC peak determination methodology consists of utilizing an ADC that is triggered to measure only at the input signal peaks. This method has the problem of generating an appropriate trigger signal. It is not possible to generate a trigger at the time of the peak, but rather a trigger is presented which is delayed by a fixed amount of time after the peak has occurred. This is due to the process selecting a peak based upon a detected decrease in amplitude. Therefore, the analog signal must be delayed without distortion and the delay must exactly equal the delay in the trigger circuit. However, it is very difficult to build a wide band analog delay which does not distort the input signal. In addition, it is also very difficult to match the delays of the trigger circuit and the analog delay.
The trigger circuit must detect the time of the peak with great accuracy. The delay from the input signal peak to the trigger output must also be very stable. Timing variation in the trigger circuit causes significant error in the recorded peak value. If a desired amplitude accuracy of 0.05% is desired, the differences in the time delay of the analog delay element and the trigger channel must be 5.03.times.10.sup.-3 the input period. For example, with a one MHZ sine wave input, a timing accuracy of .+-.7.1 nanoseconds is required to maintain an amplitude accuracy of 0.1%. Furthermore, to determine the timing of the peaks requires additional circuitry (i.e., a digital time interval analyzer which measures the timing of a trigger output).
Based upon the foregoing, it is an object of the present invention to provide peak detection which has a high degree of accuracy for a wide bandwidth. Furthermore, it is an object of the present invention to provide the accurate and wide bandwidth peak detection using an apparatus and methodology which is relatively inexpensive to implement.


The invention relates to a method for the continuous synthesis of monoalkyl-hydrazines with a functionalized alkyl group. The inventive method is characterized in that it comprises a step consisting in demixing a solution containing the synthesized monoalkyl-hydrazine, by reacting an anhydrous amine with monochloramine, in an organic phase and an aqueous phase with the addition of anhydrous sodium hydroxide. The invention can be used to obtain perfect selectivity in relation to monoalkyl-hydrazine without the presence of the di- and tri-substituted forms thereof. According to the invention, the staffing amine which has not reacted is collected and reused directly without any additional treatment.

Within the context of the present invention, "monoalkylhydrazine" is understood to mean any hydrazine of formula NH2—NH—R in which R represents a functionalized alkyl group, that is to say, comprising at least one function chosen from the group consisting of a carbon-carbon (the case of allylhydrazine) or carbon-nitrogen unsaturation, a hydroxyl group (the case of 2-hydroxyethylhydrazine), an alkoxy group (the case of 2-methoxyethylhydrazine) or phenoxy group (the case of Ph—O—CH2—CH2—NH—NH2), a carboxylic acid group, a tertiary amine function (the case of (Me)2N—CH2—CH2—NH—NH2) or a phenyl group (the case of Ph-CH2—NH—NH2).
The monoalkylhydrazines, in particular allylhydrazine, are compounds frequently used as intermediates in the manufacture of medicines.
At present, the only methods of synthesis described in the scientific literature call upon hydrazine hydrate (N2H4) and the nitrosamines. In the particular case of the synthesis of allylhydrazine, the first method consists of gradually adding 1.28 moles of allyl bromide to 8.96 moles of hydrazine monohydrate, which corresponds to a molar ratio of 7. During the addition, the temperature must be maintained below 40° C. The reaction mixture is then heated under reflux at 70° C. for one hour. After extraction with ether and distillation, a mixture consisting of 57% monoallylhydrazine (CH2═CHCH2NHNH2), 11% diallylhydrazine ((CH2═CHCH2)2NNH2) and triallylhydrazine is obtained. The implementation of a higher ratio decreases the quantity of the monoallylhydrazine to the benefit of the diallylhydrazine (34.6% yield in (CH2═CHCH2)2NNH2). The difficulties of allylation are at the level of the non-selectivity and the separation of the allylhydrazine in mono-, di- and tri-allylhydrazine/water/N2H4 mixtures (Loffe B. V et al., Zh. Org. Khim (1967) 3(6), 938-8). A series of patents (JP 93-256100; JP 93-261194; JP 7118218; JP 7112963) have been filed which call upon various methods to yield a compound of high purity.
A second method for the synthesis of allylhydrazine consists of a low-temperature (5° C.) nitrosation of allylhydrazine followed by a chemical hydrogenation (LiAlH4) of the nitrosated derivative (1-nitrosoallylamine) in an etherated medium. The yield of the reaction does not exceed 42%. However, the product arising from the first step must be handled with much precaution because of its toxicity (it is a highly carcinogenic compound), which poses problems for its industrial production. Moreover, the use of LiAlH4 requires the absence of trace amounts of water, watertight reactors and anhydrous solvents (diethyl ether), the effect of which is to increase the risks of igniting the reaction mixture.
Moreover, it is recognized that the so-called "Raschig" reaction can be called upon for the preparation of the various hydrazines, which consists of synthesizing the monochloramine by the reaction of ammonia with a sodium hypochlorite solution and reacting the monochloramine thus formed with an amine to obtain the corresponding hydrazine. This method is rather difficult to implement because it requires two distinct-steps, the first carried out at a low temperature for the synthesis of the monochloramine and the second carried out at a high temperature, in which the synthesis of the hydrazine is carried out. In addition, the monochloramine must be in the presence of a sufficient excess of amine in the intermediate solutions so as to avoid secondary degradation reactions, and subsequently the method always requires very large quantities of the solutions to be-treated. However, this method cannot be applied to the preparation of all alkylhydrazines and especially not for the preparation of mono-substituted alkylhydrazines. Moreover, treatment of the synthesis solutions requires the extraction of water and then amine, which requires costly operations.

Method for the continuous synthesis of monoalkyl-hydrazines with a functionalized alkyl group

Centre National de la Recherche Scientifique (CNRS)


A versatile waste disposal apparatus for separating and disposing the liquid waste from vacuum cleaning of soiled carpets. The air, liquid and accumulated dirt in a mixture from a conventional vacuum cleaner are separated in one large tank, and the filtered liquid is passed on either to an integrated or non-integrated smaller tank with cutoff, air venting, and pump controls. The filtered liquid is ultimately passed on to a wastewater system so that the tanks are empty after use. The waste disposal apparatus can be integrated with a dwelling's central vacuuming system and operated on house current. The apparatus can be installed in a vehicle and powered by the vehicle's battery.

1. Field of the Invention
The present invention relates to an automatic continuous carpet cleaning waste water disposal apparatus, for either commercial use by professional carpet cleaners or homeowners with a central vacuum system. A large capacity primary tank collects the waste liquid and air continuously from a cleaning wand during the cleaning of soiled carpets, separates the liquid from the gas, and filters both materials. Then the filtered liquid is passed to a smaller capacity secondary tank, wherein the liquid is continuously disposed by a pump to a wastewater drain. The secondary tank is equipped with an automatic slide valve for closing off the flow from the primary tank when the secondary tank is overloaded. The secondary tank has an air vent and a float with a cutoff switch for stopping the pump when the liquid level has reached a minimum level. The two tanks can be integrated and used in the home or separated with the large tank outside the home in a vehicle. The versatile system can be operated on 12 V. D.C. (vehicle) or 115 V. A.C. (dwelling).
2. Description of Related Art
The following related art describes various machinery and modes of operation in disposing of liquid waste. However, there is a failure to recognize the versatility of a disposal apparatus that can be either operated in situ or in part outside the building being cleaned. The related art fails to describe a relatively maintenance free apparatus which requires only periodic washing out of the tanks. The advantage of leaving a job site with emptied tanks in the vehicle or cleaning apparatus is not seen in most of the related art.
The related art of interest will be discussed in the order of perceived relevance to the present invention.
U.S. Pat. No. 4,800,612 issued on Jan. 31, 1989, to Edward R. Valentine describes a vacuum power booster with automatic waste liquid discharge for a carpet cleaning water vacuum extraction apparatus. The dirty waste liquid from the vacuum pickup wand is conducted by vacuum to a mobile second waste liquid storage tank adjacent to the pickup wand for filtering and expulsion of air by an overhead vacuum pulling motor. The liquid level in the second tank is maintained either automatically by the positions of the inlet and outlet ports or a float and switch device to open an outlet valve when the liquid level is high. The filtered liquid is conducted to the first tank located outside the building in a vehicle and back directly to the cleaning wand. No volume capacities of either tank are disclosed. The first tank is housed with a cleaning solution storage tank from which the cleaning solution is apparently added to the recycled liquid. Other monitors on the first tank are gauges for fluid flow and pressure. Also, air is exhausted to the atmosphere from the first tank. It is clear that only two separated liquid tanks are contemplated with recycling of the cleaning liquid in the system. Therefore, this reference is distinguished by not discharging the filtered but dirty fluid into a sewer system and the requirement of two vacuum sources.
U.S. Pat. No. 3,942,217 issued on Mar. 9, 1976, to Jack A. Bates describes a carpet cleaning machine comprising a wet vacuum pickup wand, a main collector tank integrated within the cleaning fluid reservoir on a cart and an auxiliary collecting tank on a separate stand/cart for separation of the residue. The upright barrel-shaped auxiliary collecting tank receives the dirty cleaning fluid from the wand, and recycles the fluid when the fluid level reaches the top of the tank to the main collector tank. When the collected sediment reaches the top of the auxiliary collecting tank, the tube from the wand is connected to the main collector tank and the dirty liquid is recycled and collects in the main collector tank. Power for liquid flow and vacuum pull is supplied by a motor driving a pump and a blower on the cart. This system requires the two collecting tanks to move with the cleaning wand, whereas the present invention utilizes stationary collection tanks.
U.S. Pat. No. 4,823,428 issued on Apr. 25, 1989, to Conrad Sevigny describes a waste liquid disposal apparatus for an industrial floor cleaning system with detergents. The collection tank has an overhead vacuum pump which vacuums waste water from the cleaning machine for disposal into a tank. When the waste water reaches a predetermined level as determined by a set of three electrodes and a control unit, the tank on the toilet bowl empties automatically into a toilet. An additional apparatus supplies the detergent to the water coming from a water tap, which is pumped under pressure to the mobile floor cleaning unit. This reference is distinguished (1) by having only one collection tank, (2) requiring the use of the toilet bowl or a permanent fixture to a water plug drain for disposal of the detergent containing waste water, and (3) requiring the use of the detergent-mixing apparatus.
U.S. Pat. No. 4,226,000 issued on Oct. 7, 1980, to Herbert Tribolet describes a wet and dry vacuum cleaning system using hot water from a tap. A vacuum motor in a wheeled canister pulls a vacuum through a first dirty water tank and the cleaning wand. Apparently, enough vacuum is applied to suck a supply of cleaning water from a second tank in the sink and connected to the water tap. The first tank can be placed on top of and combined with the wheeled vacuum pulling canister. The collected dirty water is not filtered but disposed of when the first dirty water tank is full. The reference is further distinguished by its requirement of a hot water faucet.
U.S. Pat. No. 5,618,410 issued on Apr. 8, 1997, to George M. Wallace et al. describes an automatically draining vacuum apparatus for a dry vacuum apparatus of a dental aspirator. The apparatus requires a float to partially block a vacuum port to create a second vacuum force which is less than the first vacuum force to allow the fluid to drain to restore the first vacuum force. The apparatus is distinguished by its multiple walled structure and reliance on a specific use for dental aspiration.
German Patent Application No. DE 3,739,731 A1 published on Jun. 15, 1989, for Peter Worwag describes a spray extraction carpet cleaning apparatus using electric motors in the cover of the wheeled cleaning fluid canister to drive the pump for application of cleaning fluid, and in the cover of wheeled dirty liquid canister to drive the suction pump for subsequent removal and recycle of the soiled liquid. As best understood, there is no filtration of the sediment from the dirty liquid. In fact, the perforated collection head in the dirty liquid tank rests on the bottom where the sediment is expected to settle. The reference provides for the interchangeability of the covers with its apparatus to be utilized on only one canister, and the wheeled canisters would not be capable of holding a large volume of dirty liquid in the primary tank.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.

Automatic carpet cleaning waste water disposal apparatus


A system and method for forming a polymeric molding. A mold component includes a transmissive portion for passing curing energy such as UV light into the mold cavity. A masking collar is engaged around the transmissive portion to block curing energy from exposing and curing polymeric material outside of the region underlying the transmissive portion.

Contact lenses, intra-ocular lenses, surgical implants, and a variety of other items are manufactured by casting a dose of uncured prepolymer in a mold and curing the prepolymer. For example, U.S. Pat. No. 5,508,317, which is hereby incorporated herein by reference, discloses materials and manufacturing processes suitable for producing polymeric contact lenses and other items. One manner of curing the polymeric material in the mold is to include a photo-initiator in the material, which initiates crosslinking upon exposure to light of an appropriate wavelength. By casting the material in a mold that transmits light, polymeric crosslinking may be initiated through the mold.
For example, it is known to cast lenses between glass or quartz molds shaped to the intended dimensions of the lens. Polymeric crosslinking is initiated by exposure to ultraviolet (UV) light (i.e., electromagnetic radiation having wavelength from about 4 nanometers to about 380 nanometers) through the quartz molds. A chromium mask is applied to the quartz mold to block passage of light through portions of the mold where crosslinking is not desired, the transition between masked and unmasked portions of the mold defining an edge of the lens. A collimator or aperture in the sleeve or bushing housing the quartz mold collimates the UV light to more precisely define the lens shape. Cured lenses can be inspected in the molds by illumination with infrared light.
The manufacture of quartz molds and the application of a chromium mask to molds, however, has proven to be relatively expensive and time consuming. In addition, the provision of an aperture in the sleeve housing of a mold and the use of a chromium mask has been found to permit an undesirable degree of light spreading and reflection during the curing step, potentially resulting in curing under masked portions of the mold and the production of out-of-tolerance items.
Thus, it can be seen that needs exist for an improved system and method for curing polymeric moldings. It is to the provision of improved systems and methods meeting this and other needs that the present invention is primarily directed.

This patent is subject to a terminal disclaimer.

System and method for curing polymeric moldings having a masking collar


A method, article of manufacture, and apparatus for identifying defects and resolutions is discussed. Computer systems may be grouped into clusters, and their health may be determined based on these groupings. System optimizations or defect solutions may be distributed to systems in unhealthy clusters, bringing them into a healthy cluster.

In our data driven world, computer systems are becoming increasingly complex. In an effort to keep mission critical systems online, it is necessary to ensure they are optimally configured and free of defects, such as bugs. This may involve resolving issues as they arise as quickly as possible. To help resolve such issues, computer systems typically record status information in log files. These files may contain information from a single application or a system as a whole.
Log files often record information related to the operation of computer systems and/or individual applications. Often these files are text based and stored on a local computer. When an issue arises, a user may need to review gigabytes of log files containing billions of lines of information. Often the information used to debug a defect is on a single line hidden somewhere in these files.
There is a need, therefore, for an improved method, article of manufacture, and apparatus for automating system defect and optimization discovery, and distributing solutions or optimizations to computer systems.

Automated defect and optimization discovery


A device according to the invention is suitable for scanning an information carrier with tracks around an axis. The device has means for transferring information to/from a scanning spot on the information carrier. The device has tangential displacement means for moving the scanning spot in a tangential direction and radial displacement means for moving the scanning spot in a radial direction. The device has control means for controlling the radial displacement means and radial position measurement means for generating a radial position signal (cos(9xcex2r), sin(9xcex2r)) which is a measure of the instantaneous radial position of the scanning spot. The device has a scanning mode in which the scanning spot follows a track and a displacement mode in which tracks are crossed. The device according to the invention is characterized by tangential position detection means for generating a tangential position signal (Sxcex1) which is indicative of the tangential position (xcex1) of the scanning spot. With the aid of the control means it is achieved that in the displacement mode the scanning spot is moved in a radial direction. The displacement is effected in a time interval having a radial displacement time (Tr) which is a function of the difference between a desired tangential position (xcex1e) and an instantaneous tangential position (xcex1b).

1. Technical Field
The invention relates to a device for scanning an information carrier having tracks around an axis, which device has means for transferring information from/to a scanning spot on the information carrier and has tangential displacement means for moving the scanning spot in a tangential direction and radial displacement means for moving the scanning spot in a radial direction, which device has control means for controlling the radial displacement means and has radial position measurement means for generating a radial position signal which is a measure of the instantaneous radial position of the scanning spot, which device has a scanning mode, in which the scanning spot follows a track, and a displacement mode, in which the scanning spot is moved in a radial direction and tracks are crossed.
The invention further relates to a method of operating such a device.
2. Related Art
A device of the type defined in the opening paragraph is known from U.S. Pat. No. 5,402,401. The device is suitable for reading and/or writing audio/video and/or file information from/onto a rotating information carrier such as a Compact Disc. In the scanning mode of the known device the radial error signal serves as a radial position signal. This radial position signal is used for centering the scanning spot on a track. In the displacement mode the scanning spot is moved in a radial direction in accordance with a predetermined velocity profile. On the one hand, a short duration of the displacement mode is desirable in order to obtain a short latency time between successive scanning modes and, consequently, an optimum efficiency of the information transfer. On the other hand, it is advantageous to effect the radial movement of the scanning spot comparatively slowly in order to limit the power consumption, noise production and wear in the displacement mode. A low power consumption is of particular importance for portable equipment.
It is an object of the invention to provide a device of the type defined in the opening paragraph, in which device the velocity of movement of the scanning spot can be limited without a consequent increase of the latency time. For this purpose, according to the invention, the device of the type defined in the opening paragraph is characterized in that the device further has tangential position measurement means for generating a tangential position signal which is indicative of the tangential position of the scanning spot, the control means causing the scanning spot to be moved in the radial direction in the displacement mode in a time interval with a radial displacement time which is a function of the difference between a desired tangential position and a current tangential position. This makes it possible to adapt the velocity of the movement in a radial direction to the duration of the time interval necessary to reach the desired tangential position. The invention is based on the recognition of the fact that it is not useful to move the scanning spot so rapidly that this scanning spot has already reached the desired radial position well before the desired tangential position is reached.
Since the scanning spot is moved to a desired radial position in a time interval longer than a minimum time interval, radial displacement requires less power and leads to a reduced noise production and a reduced wear. On the other hand, the rate at which information transfer from/to the information carrier is possible is not adversely affected because the radial displacement time is selected so as to allow for the difference between the desired tangential position and the current tangential position, as a result of which the desired radial and tangential positions are not reached any later than in the case that the radial movement is effected within the shortest possible length of time.
It is to be noted that from JP 07-176173 an apparatus is known in which a rotation signal which is indicative of a rotation of the information carrier is used for the correction of a counting signal. Thus, it is precluded that the rotation of an information carrier having spiral tracks leads to track counting errors.
In the device in accordance with the invention the control means provide a movement of the scanning spot over a similar radial distance in a comparatively long first radial displacement time and a comparatively short second radial displacement time for a comparatively small first difference and a comparatively large second difference in tangential positions.
In an embodiment of the device in accordance with the invention the control means include first control means for generating a signal which is indicative of the desired instantaneous position as a function of the time, second control means for generating an error signal which is indicative of a difference between the desired instantaneous position and the instantaneous position, and third control means for generating a control signal for the radial displacement means. This embodiment makes it possible to realize the radial movement within narrow tolerances within the radial movement time.
A variant of said embodiment is characterized in that the control means include fourth control means for generating a prediction signal which corresponds to an expected value of the control signal and include signal combination means for generating the control signal from the error signal and the prediction signal. This variant provides a very stable control of the radial displacement means in that only a small amplification of the error signal is necessary.
An embodiment is characterized in that the radial position measurement means have detection means coupled to the displacement means. The device may include, for example, a memory for storing a relationship between values of a detection signal generated by the detection means and numbers of tracks of the information carrier, so that it is known to which track a given value of the detection signal corresponds. Conversely, the track corresponding to a detection signal value can be calculated if the variations in track pitch are sufficiently small.
In an embodiment the radial position measurement means include track crossing counting means for generating a counting signal which is indicative of a number of tracks crossed, means for generating a tracking error signal which is indicative of the distance of the scanning spot from the nearest track, and means for generating a radial position signal from the counting signal and the tracking error signal. In this way, the radial position of the scanning spot can be determined accurately.
In the case of information carriers having continuous spiral tracks, in contradistinction to separate circular tracks, the counting signal is influenced by the rotation of the information carrier. For use with an information carrier having spiral tracks the device preferably has correction means for correcting the counting signal on the basis of the tangential position signal.
In accordance with the invention a method of operating a device for scanning an information carrier having tracks around an axis, in which method the information carrier is rotated about the axis, which method comprises a scanning mode in which information is transferred from/to a scanning spot on the information carrier and in which the scanning spot is moved along a track, and displacement mode in which the scanning spot is moved in a radial direction and in which tracks are crossed, is characterized in that in the displacement mode the scanning spot is moved in the radial direction in a time interval with a radial displacement time which is a function of the difference between a desired tangential position and a current tangential position.

Device for scanning an information carrier and method of operating such a device


Biocompatible nanoparticles 1 which entrap a bioactive substance and whose surface is positive-charge-modified are electrically adhered to a balloon portion 9 of a catheter main body 5 through a negatively charged resin layer 11, and thus a nanoparticle layer 12 is formed. After the catheter main body 5 is indwell in vivo, the nanoparticles 1 are gradually eluted from the nanoparticle layer 12 and are effectively delivered to cells.

In recent years, as lifestyles have been westernized and the population has been aging, more and more people have suffered from atherosclerotic diseases such as myocardial infarction, angina pectoris, cerebral apoplexy and peripheral vascular diseases even in our country. As a reliable treatment for such atherosclerotic diseases, percutaneous transluminal angioplasty (hereinafter referred to as "PTA"), such as percutaneous transluminal coronary angioplasty for a coronary artery of a heart, which surgically dilates a stenosis or obstruction of a blood vessel, is widely used.
PTA is a manipulative technique in which a thin tube (balloon catheter) with a balloon at its end is passed through a stenosis within a blood vessel, then the balloon at the end is inflated to dilate the stenosed blood vessel, and thus normal blood flow is restored. By doing this, the lumen of the blood vessel in an affected area is dilated, and thus the blood flow through the lumen of the blood vessel is increased. In addition to atherosclerotic diseases, PTA is also used such as in a stenosis treatment for a shunt blood vessel formed in an arm of a hemodialysis patient.
In general, the portion of a blood vessel that has been subjected to PTA is damaged such as by the detachment of endothelial cells and the injury of elastic laminas, and a vascular intima grows as a healing reaction for a vascular wall, with the result that restenosis occurs in about 30 to 40% of the stenosed areas that have been successfully dilated by PTA.
More specifically, human restenosis is considered to result primarily from an inflammatory process that occurs one to three days after PTA due to the adhesion and invasion of monocytes and the intimal thickening formation process of smooth muscle cells which grow most rapidly about forty five days after PTA. Since, when restenosis occurs, it is necessary to perform PTA again, the establishment of prophylaxis and treatment thereof is urgently required.
To meet the requirement, attempts have been widely proposed to reduce the restenosis rate by using a drug-eluting device in which an anti-inflammatory drug or a smooth muscle cell growth inhibitor is carried on the surface of a stent or balloon catheter made of a metal or high-polymer material and thereby releasing the drug locally in a site of a lumen where the device is indwelt over a long period of time. For example, in patent documents 1 and 2, there are proposed drug-eluting catheters in which the expanding portion (balloon) of the catheter is polymer coated, and a therapeutic drug such as a nucleic acid drug is incorporated into the polymer coating.
Since restenosis results primarily from smooth muscle cell growth, it is determined that it is most effective to inhibit the growth of the smooth muscle cells during a time period from the date when the growth of the smooth muscle cells is found in an intimal as a pathological finding, that is, the date when 30 days elapse after the start of a treatment to the date when the cells grow most rapidly, that is, the date when 45 days elapse. Hence, it is considered that it is most effective to design a drug-eluting catheter such that the amount of drug released peaks at least both during a period of 10 days after the start in order to inhibit an inflammatory process and during a period of 30 to 60 days in order to inhibit the growth of the smooth muscle cells and that the drug necessary to indicate its efficacy is evenly released for each period.
However, since, in the methods of patent documents 1 and 2, the polymer layer is decomposed in vivo and then the drug is released, the drug is released insufficiently in the early stage of the indwelling of the catheter, and thus it is impossible to effectively inhibit an inflammatory process occurring during a period of 1 to 3 days after the catheter is indwelt. When a hydrogel polymer is used as in patent document 1, since a water-soluble drug such as a decoy oligonucleotide is eluted in a short period of time, it is not easy to control the rate at which the drug is released.
In patent document 3, there is disclosed a drug-eluting stent (hereinafter referred to as a "DES") in which a first bioactive substance is contained in a polymer layer formed on the surface of the stent, and a biocompatible nano- or microcapsule entrapping a second bioactive substance is further contained, and thus it is possible to release the first bioactive substance in the early stage and then gradually release the second bioactive substance within the capsule. According to the method of patent document 3, a suspension of nanoparticles is sprayed or applied onto the main body of the stent or the main body of the stent is immersed in the suspension of nanoparticles, and thus the nanoparticles are adhered to the stent main body. However, with this type of method, it is difficult to uniformaly adhere a sufficient number of nanoparticles.
Here, the structure of a conventional biocompatible nanoparticle is shown in FIG. 19. The surface of the conventional biocompatible nanoparticle (hereinafter simply referred to as the "nanoparticle") 1 is coated with polyvinyl alcohol 2; a bioactive substance 3 is entrapped therewithin; and, in general, the surface is negatively charged. However, since a cell membrane in vivo is negatively charged, an electrical repulsion force disadvantageously causes the nanoparticle as shown in FIG. 19 to be poorly adhered to cells. In order for the entrapped bioactive substance to be locally and effectively incorporated into a lesion such as a stenosis, it is necessary to further enhance the movement of the nanoparticles into the cells.
Moreover, since biocompatible polymers are generally hydrophobic (liposoluble) and thus liposoluble bioactive substances alone can be entrapped into nanoparticles with high probability, it is difficult to sufficiently coat, by the method of patent document 3, the surface of the stent with a hydrophilic (water-soluble) bioactive substance such as a nucleic acid or a gene.
To overcome this problem, in patent document 4, there is disclosed a DES in which biocompatible nanoparticles whose surface is positive-charge-modified are electrically adhered to the main body of the stent, and there is also disclosed a method of manufacturing a DES by adhering the nanoparticles to the stent main body in an electrical continuous state, using electrophoresis, ultrasonic mist or the like. In patent document 5, there is disclosed a medical device having nanocapsules (nanoparticles) composed of a therapeutic drug, a magnetic or paramagnetic material and a polyelectrolyte multilayer shell, and a catheter is described therein as an example of the medical device.
Patent document 1: JP-T-H09-500561
Patent document 2: JP-T-2003-521275
Patent document 3: JP-A-2004-357986
Patent document 4: JP-A-2007-215620
Patent document 5: JP-T-2006-518736

Drug-eluting catheter and method of manufacturing the same


Fabricating a device including a Schottky diode by growing a dielectric film on a SiC substrate structure and forming an ohmic contact on the opposite surface of the substrate structure by depositing a layer of metal and annealing at a temperature above 900.degree. C. Implanting doping material in the substrate structure through spaced apart openings to form high resistivity areas and depositing a dielectric layer on the dielectric film to define a contact opening positioned between the spaced apart high resistivity areas. Annealing the implant at a temperature less than approximately 400.degree. C. to reduce reverse leakage current and depositing metal in the contact opening to form a Schottky contact.

In the fabrication of semiconductor devices, it is known that damaging the substrate in an area surrounding the gate contact with implants of electrically inactive ions affects the electrical field along the surface of the substrate and, hence, the breakdown voltage of the device. See for example, U.S. Pat. No. 5,399,883, entitled "High Voltage Silicon Carbide MESFETS and Methods of Fabricating Same", issued Mar. 11, 1995. In all of these prior art devices, the damaged area extends at least from the gate electrode to the drain electrode, and in some devices the damage region also extends to the source electrode.
It is well known in the art that guard rings and the like can be diffused into the substrates of silicon semiconductor devices (and especially silicon power devices) for purposes of terminating or separating devices on a common substrate. However, devices formed on silicon carbide (SiC) substrates cannot be terminated using diffused guard rings because of the very small diffusion coefficients of conventional dopants in SiC. Use of field plates on SiC substrates is also limited since high electric fields in the dielectric and the subsequent breakdown of the dielectric is likely to occur before avalanche breakdown of the SiC.
However, all of these prior art devices, in actual practice, have relatively large reverse leakage current and a soft-breakdown. Accordingly, it would be highly advantageous to provide a method of fabricating semiconductor devices with an improved reverse breakdown characteristics.
It is a purpose of the present invention to provide a new and improved method of fabricating semiconductor devices.
It is another purpose of the present invention to provide a new and improved method of fabricating semiconductor devices including a Schottky diode or contact.
It is still another purpose of the present invention to provide a new and improved method of fabricating semiconductor devices including a Schottky diode or contact with improved reverse breakdown characteristics.
It is yet another purpose of the present invention to provide a new and improved method of fabricating semiconductor devices including a Schottky diode or contact on silicon carbide substrates with improved reverse breakdown characteristics.
It is a further purpose of the present invention to provide new and improved semiconductor devices including Schottky diodes or contacts.
It is still a further purpose of the present invention to provide new and improved semiconductor devices including Schottky diodes or contacts with improved reverse breakdown characteristics.
It is yet a further purpose of the present invention to provide new and improved semiconductor devices including Schottky diodes or contacts on silicon carbide substrates with improved reverse breakdown characteristics.

Method of fabricating semiconductor devices and the devices


A protector for an ink cartridge container including a containing case body, an ink inlet for a recording head, a cartridge containing part into which an ink cartridge is removably insertable, and a door body capable of opening and closing an opening opposed to the ink inlet with the cartridge containing part sandwiched therebetween, the protector includes a protective cap unit including: a main body; a supporting rod protruded toward the ink inlet from the main body; a guiding funnel formed at a front edge of the supporting rod; and an elastic cap provided at an inner diametrical portion of the guiding funnel and capable of coming into close contact with the ink inlet, wherein: the protective cap unit is removable from and insertable into a containing case body; and the protective cap unit is formed as a different shape than that of the ink cartridge.

Generally, an ink-jet recording device includes a recording head provided in a carriage. The carriage reciprocatingly moves in a direction (main scanning direction) intersecting with or perpendicular to a recording medium (e.g. recording sheet) to be conveyed. The recording head ejects drops of ink, thereby recording an image on the recording medium. The ink is stored in advance in a cartridge type ink tank (e.g. ink cartridge), and is supplied from the ink cartridge to the recording head.
Generally, ink cartridges are divided broadly into so-called on-carriage types and off-carriage types depending on the arrangement.
The on-carriage type is one in which a case for removably containing an ink cartridge is provided over a carriage movable as described above, and the ink cartridge accommodated and held within the case supplies ink to a recording head.
The off-carriage type is one in which a case is provided somewhere in a housing of an ink-jet recording device except in a position over a carriage, and an ink cartridge is accommodated and held within the case. Ink is supplied from the case to a recording head through an ink supply pipe.
Normally, one of the above-described types is necessary for replacing an ink cartridge with a new one when the remaining amount of stored ink is reduced.
In either of the on-carriage type device and the off-carriage type device, an ink cartridge is first set in a case in order to carry out a print test at a factory. A non-defective ink cartridge, which has been subjected to the test, is detached from the case to remove ink within a recording head, and the recording head is filled with a preservative solution having a property similar to that of ink except in colorant or pigment at the time of factory shipment. Alternatively, ink is allowed to remain within the recording head, and all ink inlets connected to the recording head are covered with a protective cap or a dummy cartridge, which has a shape similar to that of an ink cartridge (and in which no ink is stored), instead of the ink cartridge. According to the above, leakage of a preservative solution or ink (hereinafter, simply called "liquid") from the ink inlets is prevented. Further, a nozzle face of the recording head is protected by covering the nozzle face with a nozzle cap, as disclosed in JP-A-2002-79690, JP-A-2004-230857, JP-A-2005-238857 and JP-A-2003-54000.
The device is formed so that a lock lever or an engaging part for fixing the ink cartridge to the case is utilized. Thus, an improperly disengagement of the protective cap or dummy cartridge is prevented. Further, sealing property and hermetic property for the ink inlets is maintained.


A method and a device for measuring density properies of a particle distribution, in which method a first parameter relating to the particle distribution is measured at a first measuring point (302), at least part of the flow that passed through the first measuring point is guided to the second measuring point (304), a second parameter relating to the particle distribution is measured at a second measuring point (305), and said first and second parameters relating to the particle distribution are used to determine at least one density property of the particle distribution of the original flow (306).

With tightening environmental regulations, there is an increasing need for the measurement of particle emissions. In particular, the need for measurement is present in the development of filtering methods, in the research of various combustion processes, as well as in processes for monitoring actual emissions. One significant parameter in the measurement of particle emissions is particle density. The particle density is an important factor in a variety of properties which are significant in view of the particle being carried along, including for example the settling velocity of the particle. For this reason, the particle density is significant, for example, in the health effects of the particles, such as the accumulation of the particles in the lungs.
Problems involved in the measurement of the particle density are described, for example, in the article by W. P. Kelly and P. H. McMurry, "Measurement of Particle Density by Intertial Classification of Differential Mobility Analyzer-Generated Monodisperse Aerosol" [Aerosol Science and Technology 17: 199–212, 1992]. The same article also teaches a method of prior art for the measurement of particle density by means of a DMA device (Differential Mobility Analyzer) and an impactor. FIG. 1 shows the principle of operation of this method.
In the method disclosed in the article, a flow 13a carrying a particle distribution to be analyzed is led to an apparatus 10 consisting of a DMA device 11 and an impactor 12. The flow is first led to the DMA device 11 which, by means of an electrical field, separates the particles with a narrow electrical range of mobility from the flow to a flow 13b to be led to the impactor 12. Particles whose electrical mobility is not within this narrow range are guided with flows 13c and 13d away from the measuring device 10.
By means of the DMA device, it has thus been possible to separate the monodispersive aerosol flow 13b having a given narrow electrical mobility distribution 14b, from the polydispersive aerosol flow 13a having an electrical distribution 14a and being led to the measuring device.
This monodispersive aerosol flow is then led to the impactor 12 which, in a way known as such, classifies them on the basis of their aero-dynamic diameter, collecting particles with different aerodynamic diameters on different collection plates. By measuring the collection plates, it is possible to determine the aerodynamic size distribution 15 of the particles contained in the flow 13b input in the impactor.
When both the electrical mobility diameter and the aerodynamic size distribution of the particle distribution to be analyzed are known, it is possible to compute the density of the particle distribution in the way presented in the article.
The above-presented solution of prior art involves the problem that the density can -only be determined for a narrow electrical mobility range at a time. In other words, by means of the method, the density can be computed for the monodispersive flow 13b by means of the DMA device. To determine the density distribution of the particles in the polydispersive flow 13a, this must be implemented, according to the above-presented solution of prior art, by scanning, i.e. by first determining the density in one electrical mobility range and then changing the adjustments of the DMA device in such a way that the measurement is made in another electrical mobility range. This procedure is repeated until the density has been determined in the whole range desired.
For the above-presented scanning measurement to produce reliable results, the flow 13a to be analyzed should remain unchanged during the whole measurement operation. Under real measuring conditions, there may be temporal variations in the flow to be analyzed, for which reason the above-presented solution of prior art is poorly suitable for the real-time measurement of a flow containing polydispersive particles under real conditions.

Method of measuring density properties of a particle distribution


A semiconductor device includes gate electrodes stacked to be spaced apart from each other on a substrate in a first direction, extending in a second direction, and including pad regions bent in a third direction, sacrificial insulating layers extending from the gate electrodes to be stacked alternately with the interlayer insulating layers, separation regions penetrating through the gate electrodes, extending in the second direction, and spaced apart from each other to be parallel to each other, and a through-wiring region spaced apart from the separation regions to overlap the pad regions between the separation regions adjacent to each other and including contact plugs penetrating through the pad regions. The through-wiring region includes slit regions, and each of the slit regions is disposed to penetrate through the sacrificial insulating layers on one side of a respective pad region.

The present disclosure relates to semiconductor devices, and more particularly, to semiconductor devices including a plurality of slit regions and pad regions in a memory cell region.
Semiconductor devices are typically needed to process large amounts of data while volumes thereof are gradually decreasing. Thus, it is important to increase integration density of semiconductor elements constituting semiconductor devices. Accordingly, as one method of improving the integration density of semiconductor devices, a semiconductor device having a vertical transistor structure, rather than a conventional planar transistor structure, has been proposed.


A method for audio encoding includes: analyzing an audio frame using a psychoacoustic model to obtain a corresponding masking curve and window information; transforming the audio frame according to the window information to obtain a spectrum, and dividing the spectrum into a plurality of frequency sub-bands; estimating a scale factor for each frequency sub-band; quantizing the frequency sub-bands; encoding the quantized frequency sub-bands; and packing the encoded frequency sub-bands and side information into an audio stream. Each scale factor is estimated based on a quantizable audio intensity of each frequency sub-band, which is adjusted according to a cumulative total amount of buffer space used for storing the encoded frequency sub-bands and an amount of buffer space used for storing a previously encoded audio frame, and a mean of intensities of all signals in the corresponding frequency sub-band and spectrum position of the corresponding frequency sub-band.

1. Field of the Invention
The invention relates to an apparatus and method for audio encoding, more particularly to an apparatus and method for audio encoding without performing loop computations.
2. Description of the Related Art
For conventional audio encoding methods, reference can be made to U.S. Patent Application Publication No. 20040143431. Referring to FIG. 1, in the aforesaid patent application, a conventional audio encoding system 10, which is described in the Description of the Related Art therein, includes a Modified Discrete Cosine Transform (MDCT) module 12, a psychoacoustic model 14, a quantization module 16, an encoding module 18, and a packing module 19.
A Pulse Code Modulation (PCM) sample, which is also referred to as an audio frame, is inputted into the MDCT module 12 and the psychoacoustic model 14. The psychoacoustic model 14 analyzes the PCM sample to obtain a masking curve and a window message corresponding thereto. From a range defined by the masking curve, a range of audio signals perceivable by the human ear can be observed. The human ear can perceive only audio signals the intensities of which are larger than the masking curve.
The MDCT module 12 performs MDCT on the PCM sample according to the window message transmitted from the psychoacoustic model 14 so as to obtain a plurality of transformed MDCT samples. The MDCT samples are grouped into a plurality of frequency sub-bands having non-equivalent bandwidths according to the auditory characteristics of the human ear. Each frequency sub-band has a masking threshold.
The quantization module 16 and the encoding module 18 perform a bit allocation process on each frequency sub-band repeatedly to determine an optimum scale factor and a stepsize factor. Based on the scale factor and the stepsize factor, the encoding module 18 encodes each frequency sub-band using the Huffman coding. It is noted that the encoding based on the scale factor and the stepsize factor requires all the MDCT samples in each frequency sub-band to conform to the encoding distortion standard. That is, the final encoding distortion of each MDCT sample should be lower than the masking threshold determined by the psychoacoustic model 14 within a limited number of available bits.
After encoding by the encoding module 18, all the encoded frequency sub-bands are combined via the packing module 19 for packing with corresponding side information so as to obtain a final audio stream. The side information contains information related to the encoding procedure, such as window messages, stepsize factor information, etc.
Referring to FIG. 2, the bit allocation process performed by the quantization module 16 and the encoding module 18 includes the following steps:
Step 300: Start the bit allocation process.
Step 302: Quantize disproportionately all the frequency sub-bands according to a stepsize factor of the audio frame.
Step 304: Look up in a Huffman Table to calculate the number of bits required for encoding all the MDCT samples in each frequency sub-band under a distortionless state.
Step 306: Determine whether the required number of bits is lower than the number of available bits. If yes, go to step 310. If no, go to step 308.
Step 308: Increase the value of the stepsize factor, and repeat step 302.
Step 310: De-quantize the quantized frequency sub-bands.
Step 312: Calculate the distortion of each frequency sub-band.
Step 314: Store a scale factor of each frequency sub-band and the stepsize factor of the audio frame.
Step 316: Determine whether the distortion of any frequency sub-band is higher than the masking threshold. If no, go to step 322. If yes, go to step 317.
Step 317: Determine whether there are other termination conditions, e.g., the scale factor has reached an upper limit, that have been met. If no, go to step 318. If yes, go to step 320.
Step 318: Increase the value of the scale factor.
Step 319: Amplify all the MDCT samples in the frequency sub-band according to the scale factor, and go to step 302.
Step 320: Determine whether the scale factor and the stepsize factor are optimum values. If yes, go to step 322. If no, go to step 321.
Step 321: Adopt the previously recorded optimum value, and go to step 322.
Step 322: End the bit allocation process.
The above bit allocation process primarily includes two loops. One is from step 302 to step 308, and is generally referred to as a bit rate control loop, which is used for determining the stepsize factor. The other is from step 302 to step 322, and is generally referred to as a distortion control loop, which is used for determining the scale factor. To complete one bit allocation process, it generally requires the execution of many distortion control loops, and each distortion control loop requires execution of many bit rate control loops, thereby resulting in reduced efficiency.
FIG. 3 illustrates a method proposed in the aforesaid U.S. patent publication to improve efficiency of the bit allocation process. The proposed bit allocation process includes the following steps:
Step 400: Start the bit allocation process.
Step 402: Execute a scale factor prediction method so that each frequency sub-band generates a corresponding scale factor.
Step 404: Execute a stepsize factor prediction method to generate a predicted stepsize factor of an audio frame.
Step 406: Quantize each frequency sub-band according to the predicted stepsize factor.
Step 408: Encode each quantized frequency sub-band using an encoding scheme.
Step 410: Determine whether a predetermined bit value is used most efficiently according to a determination criterion. If yes, go to step 414. If no, go to step 412.
Step 412: Adjust the value of the predicted stepsize factor, and repeat step 406.
Step 414: End the bit allocation process.
Although the process proposed in the aforesaid patent publication can simplify the number of loops, it still contains one primary loop (i.e., from steps 406 to 412). Besides, steps 402 and 404 actually further include many sub-steps. Therefore, the process proposed in the aforesaid patent publication still cannot eliminate loop computations, and cannot achieve better efficiency in audio encoding. In addition, in realizing the hardware for the audio encoding system, effective control may not be achieved due to the presence of the loop.

Adjustment of scale factors in a perceptual audio coder based on cumulative total buffer space used and mean subband intensities