Kenwood TK-5810 Service Manual

Also see for FleetSync TK-5810(H): Instruction manual Specifications Service manual Instruction manual

TK-5810 (BG) /5810H (BG)24Fig. 2 Front-end RF amplifier and 1st local1st IF49.95MHzRX terminal (CN200)450~520MHz (K)400~470MHz (K2)1st Local OSC400.05~470.05MHz (K)350.05~420.05MHz (K2)VCTUNEVCOD204,D205,D206,D207RF AMPQ200Local AMPQ203BPFL207,L208,L209,L210LPFLNA1st MIXERIC200CIRCUIT DESCRIPTION1. OverviewThis transceiver is a UHF/FM/P25 transceiver designedto operate in the frequency range of 450 to 520MHz (K) or400 to 470MHz (K2).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 and sec-ond 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 local oscil-lator output to produce the 450kHz second IF. This signal isdetected 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 thenamplifi ed and fed to the antenna.Fig. 1 Frequency configuration3. Receiver System3-1. Front-end RF AmplifierThe receive signal from the RX terminal (CN200) of theTX-RX unit (X57-727) is amplified by a transistor (Q200) andpasses through the band-pass filter (L207, L208, L209 andL210) to remove unwanted signal.The signal passing through the band-pass filter goes intothe 1st mixer.These band-pass fi lters are tuned to a desired frequencyby variable capacitance diode (D204, D205, D206 and D207).A tuning voltage corresponding to the desired signal isapplied to each variable capacitance diode to tune to the re-ceive frequency.3-2. 1st LocalThe 1st mixer uses double balanced mixer (IC200).The receive signal passing through the band-pass filter(L207, L208, L209 and L210) and the 1st local signal gener-ated by the VCO, are mixed by the 1st mixer (IC200) to pro-duce a 1st IF signal (49.95MHz) (Lower heterodyne).ANTTX/RX: 450~520MHz (K)TX/RX: 400~470MHz (K2)400.05~470.05MHz(K)350.05~420.05MHz(K2)PAAMPTXAMPMICAMPVCXO16.8MHz50.4MHzx3ANTSWRFAMP1st MIX49.95MHzMCF SPMICCF450kHzMIXIF AMPPLLVCOASICA/DD/ADSPAFAMP450~520MHz (K)400~470MHz (K2)