Kenwood TS-950S Service Manual

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TS-950S/SDCIRCUIT DESCRIPTIONparator locking the VCO9. Divide ratio data N9 isprovided by the digital unit. Division ratios are changedin CW, AM, and FM modes so that the VCOQ fre-quency is shifted as required.The output from PLL9 is applied to pin 10 of MIX5.Here it is mixed with the output from PLL4, and passesthrough a low-pass filter to produce a 10-MHz (9.92-MHz in CW mode) signal. One output from PLL® isdivided by 100 by IC12 (M54459L) to generate a 100-kHz (99.2-kHz in CW mode) signal. The signal passesthrough buffer amplifier Q11 (2SC2712) and is appliedto the signal unit as the main CAR.The other output is applied to pin 2 of IC11(SN16913P) of MiX8. MIX8 combines it with the 10-MHz reference signal. The signal passes thru a low-pass filter and is then converted to the 80450 kHz AFTsignal used by AF VBT in the CW mode. It then passesthrough buffer amplifier Q10 (2SC2712) and is appliedto the AF unit.+ Marker signal and AFSK signalThe 1-MHz signal generated by the reference oscil-lator circuit of the CAR unit is applied to the MKRmodule and divided in half internally; the 500-kHz har-monic signal is then applied to the RF unit wheneverthe calibration (CAL) switch is turned on.The 1-MHz signal is applied to programmable di-vider IC16 (MC14569BCP). The divides ratio of IC16 isinterlocked with the mark/space condition of the RTTYkey jack, and switched between 235/218. The actualshift width is controlled by the decoder output from1C17 (TC4556BP) and the SFT moduie according to theSEL data provided by the digita! unit.The output from IC16 is applied to IC15 (TC4013BP)and divided in half to make a duty ratio of 50%. Thisoutput is connected to the microphone amplifier circuitof the signal unit through the A.LPF of Q19 (2SA1162)to become the AFSK modulation signal. 1C16 opera-tion is halted in modes other than FSK mode, resultingin no AFSK signal.Item Rating9.285MHz+50kHz or more at 9.285MHz458 or more at 8.83MHz (~455kHz}45dB or more at 9.74MHz (+455kHz}40d8 or more at 10.715MHz (+1430kHz}Nominal center frequency3dB attenuation bandwidthGuaranteed attenyation |Insertion loss 6d8 or lessFormula = 20-log (#42)Ripple 1.0c0B or less (within 3dB band)Input and output impedance | 330QVoltage capacity 50V DC (1 minute}Table 2 Ceramic filter (L72-0350-05) (CAR unit CF1)item RatingCenter frequency (fo} Within 10.700MHz + 50kHz{The center frequency must be the center of the 3dB band)3dB attenuation bandwidth With in 150 + 40kHz20dB attenuation bandwidth | 380kHz or lessInsertion loss With in 8.0dBFormula = 20-log (Se)Ripple (within 3dB band) 1.0d8 or lessSpurious attenuation (9 to 12MHz) ! 38dB or moreVoltage capacity (between pins} 50V DC (1 minute)Input and output impedance | 330QTable 3 Ceramic filter (L72-0369-05) (CAR unit CF2)Receiver Circuit Configuration(Refertoblock diagram on page 265, 266 and 267.)The incoming receive signal from the antenna ispassed through the transmit/receive selector circuit onthe filter unit (X51-3060-XX). The signal is routed tothe RX ANT OUT (RCA jack) on the rear panel, and isapplied to the RF unit (X44-3100-00) ANT terminalthrough the rear cable. This signal is applied to thereceiver bandpass filter through the RF attenuator (0 to30 dB selectable) via relays K1 and K2 and the low-pass filter (30 MHz). The bandpass filter divides thereceiver frequency range (up to 30 MHz) into 15 bands.The appropriate section is automatically selected byRX bandpass filter control data (RBO, 1, 2, 3} that issupplied from the digital unit (X46-3050-XX).RX frequency (MH2} RX BPF DataRBS RB2 RBI RBO0.0~ 05 1 Qa 0 1O5~ 1.6 Q 1 0 016~ 3.0 Q a 1 13.0~ 4.0 0 1 1 04.0~ 7.0 0 1 1 17O~ 75 1 ie) ie) 07.5 ~ 10.0 0 1 0 110.0 ~ 10.5 1 1 1 010.5 ~ 14.0 1 0 1 014.0 ~ 14.5 0 0 90 014.5 ~ 18.0 1 0 1 118.0 ~ 21.0 oe ee 0 021.0~ 21.5 Q 0 90 121.5 ~ 24.5 iho 0 124.5 ~ 30.0 0 0 1 0Table 4 RX BPF selection dataThe signal from the bandpass filter passes throughthe RF AGC circuit cornposed of PIN diodes D37 andD38 (MI204). It is then amplified by the RF amplifiersQ5 (2SK125-5) and Q6 (2SK520). (When AIP is on, thesignal is directed to RF buffer amplifier Q4 (2SK125)with unity gain, not to RF amplifiers Q5 and Q6.) Theamplified signal is separated by L70 for use in the main 14and sub channets.