Kenwood TK-3310 Service Manual

Contents

TK-331013CIRCUIT DESCRIPTION2-2. First MixerThe signal from the front end is mixed with the first localoscillator signal generated in the PLL circuit by Q406 to pro-duce a fi rst IF frequency of 38.85MHz.The resulting signal passes through the XF401 MCF tocut the adjacent spurious and provide the optimum charac-teristics, such as adjacent frequency selectivity.2-1. Front End (RF Amplifier) CircuitThe signal coming from the antenna passes through thetransmit / receive switching diode circuit (D201, D202, D203and D204) and a BPF (L418 and L419), and is then ampli-fi ed by the RF amplifi er (Q407).The resulting signal passes through a BPF (L419, L418,L491, L414 and L413) and goes to the mixer. These BPFsare adjusted by variable capacitance diodes (D408, D407,D405, D404 and D403). The input voltage to the variable ca-pacitance diodes is a regulated voltage output from the DCamplifier (IC811).Fig. 2 Receiver systemSPANTIC401IF,MIX,DETQ4061st MIXANTSWQ403x2 multiply2nd LocalX1TCXO19.2MHzAFbasebandIC812BPF1BPFQ407RF AMP XF401MCFQ405IF AMPIC815AF PABPF1 1st LocalBPFCF402 CF4012. Receiver SystemThe receiver system is shown in Figure 2.Fig. 1 Frequency configuration1. Frequency ConfigurationThe receiver utilizes double conversion. The first IF is38.85MHz and the second IF is 450kHz. The fi rst Local os-cillator is supplied from the PLL circuit.The PLL circuit in the transmitter generates the neces-sary frequencies.RX: 450~520MHz,TX: 450~500MHz: X(LMR)411.15~481.15MHz: X(LMR)450~500MHz: X(LMR)1st MIX MCF SPMICCF450kHzANTANTSWRFAMPIFSystemx2multiplyPLLVCO38.85MHz 38.4MHzTXAMPRFAMPAFAMPMICAMPAFbasebandTCXO 19.2MHzTX/RX: 476.4250~477.4125MHz: X(CB)437.5750~438.5625MHz: X(CB)476.4250~477.4125MHz: X(CB)