Kenwood TK-5310 K4 Service Manual

Also see for TK-5310: Specifications Instruction manual Specifications Instruction manual

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TK-531016CIRCUIT DESCRIPTION1. OverviewThis transceiver is a UHF/FM/P25 portable transceiverdesigned to operate in the frequency range of 450 to520MHz (K, K2, K3) or 380 to 470MHz (K4, K5, K6).The unit consists of receiver, transmitter, phase-lockedloop (PLL) frequency synthesizer, base band parts, powersupply, and control circuits.2. Frequency ConfigurationThe receiver is a double-conversion superheterodyneusing first intermediate frequency (IF) of 49.95MHz andsecond IF of 450kHz. Incoming signals from the antenna aremixed with the local signal from the PLL circuit to producethe first IF of 49.95MHz.This is then mixed with the 50.4MHz second localoscillator output to produce the 450kHz second IF. Thissignal is detected to give the demodulated signal in the DSP.The transmit signal frequency is generated by the PLLVCO, and modulated by the signal from the DSP. It is thenamplified and fed to the antenna.3. Receiver System3-1. Front-end RF AmplifierThe signal is passed through an antenna matching coil,where the high-frequency components are amplified by aMOS FET(Q301). The signals are then fed into band-passfilter that uses varactor diode tuning to reject unwantedsignal components, and is fed to the 1st mixer.3-2. 1st MixerThe 1st mixer uses the GaAs IC (IC302). The 1st mixermixes the signal with the 1st local oscillator frequency fromthe VCO, and converts it to the 1st IF (49.95MHz).The signal then passes through monolithic crystal filter(XF300) to remove unnecessary nearby frequencycomponents. The signal from the MCF is used as the 1st IFsignal.3-3. IF AmplifierThe 1st IF signal is amplified by the IF amplifier (Q302) andfed into the FM IC (IC304). The IF signal is then mixed withthe 2nd local oscillator frequency of 50.4MHz to generate theFig. 1 Frequency configurationANTTX/RX : 450~520MHz(K, K2, K3)TX/RX : 380~470MHz(K4, K5, K6)ANTSWRFAMPPAAMPTXAMP1st MIX MCFVCXO49.95MHzCF450kHzMIXIF AMPAFAMPSP16.8MHz50.4MHzx3400.05~470.05MHz(K, K2, K3)330.05~420.05MHz(K4, K5, K6)450~520MHz(K, K2, K3)380~470MHz(K4, K5, K6)PLLVCOFPGAA/DD/ADSPMICAMPMIC2nd IF of 450KHz. The 450KHz signal is then passed througha ceramic filter (CF300) and fed back into IC304 for additionalamplification.3-4. Wide/ Narrow/ P25 Switching CircuitNarrow and Wide and P25 settings can be made for eachchannel by switching the ceramic filters CF303 (Wide),CF302 (Narrow), CF301 (P25).The Wide and Narrow and P25 data is output from pin51(WN) and pin52 (VN) of CPU (IC5).When a Wide data (VN : low level, WN : high level) isreceived, the 450KHz signal is passed through a ceramic filter(CF303). When a Narrow data (VN : low level, WN : low level)is received, the 450KHz signal is passed through a ceramicfilter (CF302). When a P25 data (VN : high level, WN : highlevel) is received, the 450KHz signal is passed through aceramic filter (CF301).If the 450kHz signal is a FM signal(Wide, Narrow), thesignal is detected by a ceramic discriminator (CD300). AFsignal is fed to CODEC(IC454), the AF level is adjusted and itis output from 15pin of IC454. Q304 turns on/off with theWide/Narrow data and the IC304 detector output level ischanged to maintain a constant output level during Wide orNarrow signals.If the 450kHz signal is an P25 signal, the signal is preparedby the buffer amplifier (IC308) and fed to FPGA (IC457). TheP25 signal is A/D-converted by the FPGA and DSP (IC8), andis performed P25 demodulation.The AF signal is output from 15pin of CODEC (IC454).1st Local OSCBPF BPF 1stLNA MIXERQ301TUNE2IC302MCFXF30049.95MHzIF AMPQ302Q3032nd Local OSCFM ICIC304TriplerX3CF300TUNE1X30016.8MHzVCXOWN WNVNVNCF303CF302CF301P25NarrowWideIC303 IC305IC306 IC307CF30016.8MHzVCXOX300x3Q30350.4MHz49.95MHz450kHzIC304FM ICDETP25CDCD300AFVN WNLH HL HLWideNarrowP25FilterFig. 2 Receiver sectionFig. 3 Wide/Narrow/P25 switching circuit