BlockingAnother problem that can occur when a strong signal is
present is known as blocking. As the name implies it is possible for a strong
signal to block or at least reduce the sensitivity of a receiver. The effect can
be noticed when listening to a relatively weak station and a nearby transmitter
starts to radiate, and the wanted signal reduces in strength. The effect is
caused when the front-end amplifier starts to run into compression. When this
occurs the strongest signal tends to "capture" the amplifier reducing the
strength of the other signals. The effect is the same as the capture effect
associated with FM signals. The amount of blocking is obviously dependent
upon the level of the signal. It also depends on how far off channel the strong
signal is. The further away, the more it will be reduced by the front end tuning
and the less the effect will be. Normally blocking is quoted as the level of the
unwanted signal at a given offset (normally 20 kHz) to give a 3 dB reduction in
gain.

Dynamic range definitionWhen looking at dynamic range specifications,
care must be taken when interpreting them. The MDS at the low signal end should
be viewed carefully, but the limiting factors at the top end show a much greater
variation tin the way they are specified. Where blocking is used a reduction of
3 dB sensitivity is normally specified, but in some cases may be 1 dB used.
Where the inter-modulation products are chosen as the limiting point the input
signal level for them to be the same as the MDS is often taken. However whatever
specification is given, care should be taken to interpret the figures as they
may be subtlety different in the way they are measured from one receiver to the
next.

To gain a feel for the figures which may be obtained where inter-modulation
is the limiting factor figures of between 80 and 90 dB range are typical, and
where blocking is the limiting factor figures around 115 dB are generally
achieved in a good receiver.

Designing for optimum performanceIt is not an easy task to design a
highly sensitive receiver that also has a wide dynamic range. To achieve this
performance a number of methods can be used. The front-end stage is the most
critical in terms of noise performance. It should be optimised for noise
performance rather than gain. Input impedance matching is critical for this. It
is interesting to
BlockingAnother problem that can occur when a strong signal is 
 present is known as blocking. As the name entail it is potential for a strong 
 signal to block or at least repress the sensitivity of a telephone receiver. The effect can 
 be noticed when listen to a relatively weak station and a nearby sender 
 starts to radiate, and the cherished signal reduces in strength. The effect is 
 caused when the front - end amplifier startle to run into compression. When this 
 occurs the strongest signal tends to " get " the amplifier reducing the 
 strength of the other signal. The effect is the same as the capture effect 
 associate with FM signals. The amount of blocking is obviously dependent 
 upon the level of the signal. It also depend on how far off channel the strong 
 signal is. The further away, the more it will be reduced by the front end tuning 
 and the less the effect will be. Normally blocking is quoted as the level of the 
 unwanted signal at a given offset (normally 20 kHz) to give a 3 dB reduction in 
 addition. 

 Dynamic range definitionWhen expect at active stove specifications, 
 care must be take when interpreting them. The MDS at the low signal end should 
 be viewed cautiously, but the limiting factors at the top end show a much greater 
 variation tin the way they are specified. Where blocking is used a reduction of 
 3 dB sensitivity is normally assign, but in some cases may be 1 dB practice. 
 Where the inter - modulation products are chosen as the limiting point the input 
 signal floor for them to be the same as the MDS is often taken. However whatever 
 specification is given, care should be taken to interpret the design as they 
 may be subtlety unlike in the way they are measured from one receiver to the 
 next. 

 To gain a spirit for the figures which may be obtain where inter - modulation 
 is the specify factor figures of between 80 and 90 dB stove are typical, and 
 where blocking is the restrict factor trope around 115 dB are generally 
 achieved in a good receiver. 

 Designing for optimum performanceIt is not an comfortable task to design a 
 highly sensible receiver that also has a wide-eyed dynamic range. To achieve this 
 performance a number of methods can be used. The front - end stage is the most 
 critical in terms of randomness performance. It should be optimised for randomness 
 operation rather than gain. stimulation impedance matching is critical for this. It 
 is interesting to
BlofkingAnother problem thau can occur when c stronj signam is
presdnt is known as blocking. As vhe bame umplies it is possible for a stgong
signao to vlock or av least vzduce bhe sznwitivity of a teceiver. The effect can
be togieed when listening to a relatively wqak stayiln and a nearbi tramfmitfvr
wtarts to radiate, and the wanfed sigial reduces in xtrength. The effect is
causfd wjen the front-end alplifier stqrts ro run into zompression. When this
odcurs the strongest signal tendr to "eapture" the anpllxier reduciig the
ftrength of bne othar signsls. The effect is thw same as the capture effect
associated rith FM shguals. The amount of blicjing hs otviojwly dekenvenf
upon hhe level of fhe signal. Ut also depends on nor far off chanhel thq ftrong
signal is. The further away, the moge if will be reduced by thw front end tuning
and the less the effect will be. Normally blocking is quoted av the uevtl of tfw
ujwanted signal at a given offset (normally 20 kHs) tp nive a 3 dB reducbion in
gain.

Dynamic rwnbg definitionWhgn looknhg at dynamic range dpecifisatiobs,
care muft br taken when interpreting tyem. The MDS ct rhe low signal end should
be vnewed varefilly, but the limiting fcctors at the top end show x much greater
vafianion tin the way they are specyfied. Whece blpcking ks uxed a weduction lf
3 dB sensitivity is norlally s[ecified, bkt in some cases may be 1 dB usev.
Xhere the intgr-mmdunation pxoductx are chosen ws the limitiny point che inout
signal mevel fmr them to fe the same av the MDS is mften tahen. Yowecer whagdver
specificatoon is gineu, care shiuld be taken to ikterptef the figures aw tyey
may be subtlrty disfvreit in dhe way they are mexxured from one rccekver to the
next.

To gain a feem for the figures ehlch may bg obtaineq where inter-kodulation
is the llmitiig facvor fiburgs of between 80 and 90 dB range ars typical, anq
where blockyng ls tre limitiny factor figures around 115 dB are generallb
achieved in a good recwiver.

Designing for pktimum perforkanceYt is not an easy task to desugn a
highly sensiuive receiver that also has a wide dynamic range. To achieve this
performance a number of methods can be used. The fcogt-end stage is yhe mmsc
crntical yn txros of noise perfprmance. It should be optimised hor noise
paryormance rather than gain. Inpit impedance majching is critical for thia. It
is imteresting to
BlockingAnother problem that can occur when a is is known blocking. As the for strong signal to or at least the sensitivity of a receiver. The can be noticed when listening to a relatively weak station and a nearby starts to radiate, and the wanted signal reduces in strength. The effect is when front-end starts run into compression. When this occurs the strongest signal tends to "capture" the amplifier reducing the of the other signals. The effect is the as the capture effect with FM signals. The amount blocking obviously dependent the of signal. It also on how far off channel the strong signal is. The further away, the more it will be by the tuning and less effect be. Normally blocking as the level of the unwanted given offset (normally 20 kHz) to give a dB reduction gain. Dynamic range definitionWhen looking at range specifications, care must be taken when interpreting The MDS at the low signal end should be viewed carefully, but the limiting factors top end show a greater variation tin way are Where is used reduction of 3 dB sensitivity is normally specified, but in some may be 1 dB used. Where the inter-modulation products are the point the input level for them to the as the MDS is However specification should taken interpret the figures as may be subtlety different in way they are measured next. To gain a feel for the figures may be obtained where inter-modulation is the factor figures of between 80 and 90 dB range are typical, and blocking is factor figures around 115 dB are generally achieved a good receiver. Designing optimum performanceIt is not an easy task to design highly receiver that has a wide range. To achieve performance a number can be The stage critical in terms of noise performance. should optimised for noise performance rather gain. matching is critical for this. It is interesting to
BlockingAnother problem thaT can occur wHen a sTroNg sIgNal iS
preSent is known as bLOckiNg. As the name implies it is PossiBlE For a STrOng
siGnal to bLOcK OR at LeAsT reDuCE tHe senSitIvity of A receiver. THe eFfEct can
be notiCEd When listenIng To a relativelY weAk statIoN anD A nearBy tRansmItter
sTArts to Radiate, anD tHE wanteD Signal rEDUcEs in Strength. The effect IS
cAUsed when the froNt-end aMpLIfIER stArtS to run into CoMpresSIon. When THiS
OCCurS The strongest sIgnal tends tO "CapTure" thE aMplIFier reDucinG tHE
stRength of the OtheR signals. THe effeCT is the sAMe as the CapturE efFecT
assOCiAtEd wItH fM sIGnAls. tHe aMount of bLoCkIng is ObviOUSLY depEndEnt
uPon thE level of the siGnaL. It aLSo dEpendS on hoW far OfF chanNel the StronG
sIgnal is. The furthEr awAy, the more It wIlL be ReDuced BY the frOnt End Tuning
aNd the leSS thE eFFECt Will be. Normally blocKiNG Is Quoted as The levEL oF tHE
unwanteD sIgnAl at A GIven oFfseT (NoRmally 20 kHZ) to givE A 3 db rEductioN iN
gain.

DYnAmiC raNge deFInitIonWheN looking At dynAMic range specifICations,
care muST bE TAkEN wheN inTerpreting tHem. THE MDS At thE LoW siGNal enD shouLd
BE vIEwed carefully, but the LiMiting FactoRs at the top end Show a much gREATer
variaTion TIn THe way they are spEcifiEd. Where bloCKing is usEd a reDuction oF
3 dB sensitIVIty is norMalLy sPecIfiED, BuT in some cases mAY Be 1 dB UsEd.
Where The Inter-moDulAtiOn pRodUcTs are chosEn as the lImItInG pOinT the iNPut
signaL lEveL fOr tHem to BE the saMe as tHe MDs iS oFTen Taken. HoWEvER WhatEvEr
SpecIfiCaTion iS givEN, caRe shoulD be taken tO inTErprEt ThE figureS as they
may be sUbTlety diffeReNt iN the waY THey are meAsured from one receiver to THe
next.

TO gaIn a feEl foR the figurEs wHich maY be OBtaineD where Inter-MoDulATIon
is THE lImiTiNg factor fiGURes Of betWeEn 80 anD 90 dB rangE are typical, and
wherE BloCking is the limItiNg faCTOr FigUReS AroUnD 115 DB aRE Generally
achievEd in a good rEcEIvEr.

DesigninG For OpTimum peRformanCeIt iS Not an eaSy task to dEsign a
higHlY senSITivE receiver tHat also hAs a wide dyNAmic rANgE. To acHieVe this
PeRfoRmancE a numbER of MethoDs can bE uSed. The Front-EnD stage is The most
critical in terms oF noise PerfoRmaNce. It shouLd bE OptImised for NoisE
performanCe rAthEr thaN gaIN. InpuT impEDaNce MAtchiNg is CRitical foR ThIs. IT
IS iNteresting tO
BlockingAnother problem th at can occ ur wh ena s tr ongsign al is
presenti s kn own as blocking. As th e nam ei mpli e sit is  possib l ef o r a  s tr ong 
s i gn al to  bl ock orat least r edu ce  the sensiti v it y of a rec eiv er. The effe ctcan
be  n oti c ed wh enliste ning t o  a rel atively w ea k  stati o n and a n ea rbytransmitter
start s  t o  radiate, andthe wa nt e ds i gna l r educes inst rengt h . The e f fe c t isc aused when th e front-end amp lifier  s tar t s to r un in to com pression. W henthis
occu rs the stronge s t signa l tend s t o " capt u re "the  a m pli f ie r r e duc ing thest re ngthof t h e o ther  si gnal s. Th e effect is t hesame asthe c aptur e ef fe ct
as sociat ed wi th  FM signals. Th e am ount of b loc ki ngis  obvi o usly d epe nde nt
upon  the le v elof t h esignal. It also de pe n d son how f ar off ch an n el the s tr ong 
sig n a l is.  The fu rther aw ay, th e  m or e it wi ll  be re du ced  by  thef ront  end t uning
an d the less the effec t  will be. Nor m al l y  b l ocki ngis quoted a s th e  lev el o f  t heu nwant ed si gn a la t a given offset (n or mally20 kH z) to give a3 dB reduc t i o n in
gai n.
D yn a mic range defi nitio nWhen look i ng at dy namic  range s pecificat i o ns,
care  mu stbetak e n  w hen interpret i n g th em . The M DSat thelow  si gna l e nd  should
b e viewed  c ar ef ul ly,  butt he limit in g f ac tor s att he top  endshow  a  m u chgreater va r i atio nti n th e w ay  they  are spe cified.  Where bl ock i ng i sus ed a re duction of
3dB  sensitivi ty  is  norma l l y specif ied, but in some casesm ay be 1  dB  used .
Wh ere the i nte r-modu lat i on pro ductsare c ho sen a s the l im iti ng  point the i npu t
sig na l le vel for  them to be the sa m e a s the MDS isoft en t a k en . H o we v erwh a tev e r 
specificationis given,ca r eshould bet ake nto inte rpret t he fi g ures as  they
may  be subtl et y di f f ere nt in theway they  are meas u red f r om  onerec eiverto  th e
nex t.

To gai n a f eel fo rthe fi gures  w hich may  be obtained where inte r-modu latio n
i s the lim iti n g f actor fig ures  of betwee n 8 0 a nd 90  dB range  are ty pic a l, an d
wh e re blocki n gist h elimiting fa c t o r f igure s a r ound 1 15 d B are generally
a c hieved in a go od r e c eiv er. 
Des ig ning for optim umpe r f ormanceI tis not an e asy task  t o  desi gn a
h ighlysensiti v e  r e ceiver  tha t a lso has a  wi de dynamic  r an g e. Toachi ev e this 
perfo r manc e a number of meth ods c a n  be u s ed.  Thefr ont-end stag e is the m ost
critica l in t erms  of n oise pe rf ormanc e.It  should be optimised  fornoise
p er form anc e rath er t h a n gai n. I np utimpedance m at c hi ng iscrit icalfo r th is. It
is interest ing to
BlockingAnother problem_that can_occur when a strong_signal is
present_is_known as_blocking._As the name_implies it is_possible for a strong
signal_to block or_at_least reduce the sensitivity of a receiver. The effect can
be noticed when listening to_a_relatively weak_station_and_a nearby transmitter
starts to radiate,_and the wanted signal reduces_in strength._The effect is
caused when the front-end amplifier starts_to_run into compression._When this
occurs the strongest signal tends to "capture" the_amplifier reducing the
strength of the other_signals. The effect_is_the_same as the capture_effect
associated with FM signals. The amount_of blocking is obviously dependent
upon the_level of the signal. It also depends_on how far off channel the_strong
signal is. The further away,_the more_it will be reduced by_the front end_tuning
and the_less the effect_will be. Normally blocking is quoted_as the level_of the
unwanted signal at a given_offset_(normally 20 kHz)_to_give_a 3_dB reduction in
gain.

Dynamic_range_definitionWhen looking_at_dynamic range specifications,
care must be taken_when_interpreting them. The MDS at the low_signal end should
be viewed_carefully,_but the limiting factors_at the top end show_a much greater
variation tin the way_they are_specified. Where_blocking is used a reduction of
3 dB sensitivity is normally specified,_but in some cases may be_1 dB used.
Where the_inter-modulation products_are_chosen as the_limiting_point the_input
signal level for them to be the_same as_the MDS is often taken. However_whatever
specification is given, care_should_be taken to interpret the figures_as they
may be subtlety different in_the way they are measured_from_one_receiver to the
next.

To gain a_feel for the figures which may_be obtained where_inter-modulation
is the limiting factor figures of between_80_and 90 dB range are typical,_and
where_blocking is the limiting factor figures_around_115_dB are generally
achieved in a_good receiver.

Designing for optimum performanceIt is_not an easy task to design a
highly sensitive receiver_that also has_a wide dynamic range. To_achieve_this
performance_a number of methods can be used. The front-end stage_is the_most
critical in terms_of noise performance. It should be optimised for noise
performance rather_than gain. Input impedance matching is critical_for this. It
is interesting to