Kenwood TS-950S Service Manual

Also see for TS-950S Digital: Instruction manual Instruction manual Instruction manual Instruction manual Service manual

TS-950S/SDCIRCUITDESCRIPTION- Reference data1) Butterworth characteristicThe ratio of input voltage V1 and output voltage V2 isgiven by the equation (1).v2 |Pecan Sem ramerr erro eaeetre (1)Vil V1 +l/fcysV2N1 becomes (1) when f < fe and decreases whenf> fc. As the figure below shows, this functions as alow-pass filter with fc as a boarder. This is called theButterworth characteristic and is representative of fil-ter characteristics. The fc is called a cutoff frequency.ifc fLow-pass characteristic2) Tchebycheff characteristicA Butterworth characteristic has a flat response inthe passband, but can have a sharp cutoff when thepassband contains ripple. A characteristic that con-tains an equal ripple in the passband is called aTchebycheff characteristic. The maximum cutoff canbe obtained with respect to the ripple in the givenpassband. The amplitude of a five-degree Tchebycheffcharacteristic having 1 dB of ripple in the band isshown in the figure below.-30= ~40a= -s0= 608090 |-100 eee Seoa {|or 02030405 3 2Amplitudeoffive-degreeTchebycheffcharacteristic3)Simultaneous TchebycheffcharacteristicAllamplitudesof the characteristicsdescribed abovedecreasewhenattenuation decreases.Atthat time,the transfer functionisrepresented bythe reciprocalofapolynomial expression.Whenthenumeratorofthe transferfunctionisalsorepresentedbyapolyno-mialexpressionandtransmissionZeropointsare settosomeattenuationbands,aneven sharpercutoff canbeobtained.Acharacteristicthatcontains equalrippleinthepassbandandattenuationbandiscalledasimultaneousTchebycheffcaracteristic.Thesharpestcut-offcharacteristiccanbeobtainedwithrespecttothegivendegree,allowablerippleinthepassband,andminimumattenuationintheattenuationband.Thefive-degreeamplitudecharacteristicwhentherippleinthepassbandis1dBandminimumattenuation,asintheattenuationbandisapproximately50dBasshownbelow.\T|(dB)80oeCejsoe]O10203040512°9346510QAmplitudeofsimultaneous Tchebycheffcharacteristic4) Nyquist bandWhen a signa! is sampled using sampling frequencyts in accordance with the sampling theorem, sampledsigna! f (t) can be reproduced by interpolating a sampledsignal if its band is 1/2 fs. A band of 1/2 fs is called theNyquist band.5) Transition band characteristicThis indicates the situationinwhichthebandtran-sits from passband to stopband.6) IIR LPF (IR fitter)Thisissuitableformanufacturingafilterhavingasharpcutoff.Thisfiltercanbedesignedbyconvertingthe transfer functionof ananalogfilter.7) FIR filterThis filter has a perfectly linear phase, stable opera-tion, and improved singal-to-noise ratio (SNR).8) Decimation filterThis filter is used to decimate data when a signal isconverted to a low sampling frequency.9) Interpolation filterThis filter is used to interpolate data when a signal isconverted to a high sampling frequency. 63