Icom IC-M700PRO Servise Manual

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Icom IC-M700PRO Servise Manual Manual pdf 11 page image

3 - 63-3-3 2ND LO AND REFERENCE OSCILLATORCIRCUITSThe reference oscillator (X3001) generates 30.0 MHz fre-quency used for the both DDS ICs as a system clock andfor the LO output. The oscillated signal is doubled at thedriver (Q3002) and picked up the 60 MHz frequency atthe resonator circuit (L3004, L3005). The 60 MHz signal isapplied to the MAIN unit as a 2nd LO signal.3-3-4 BFO CIRCUITThe DDS IC (IC3002) generates a 10-bit digital signalusing the 30 MHz system clock. The digital signal is con-verted to an analog wave signal at the D/A converter (R3120–R3139). The analog wave is passed through the low-passfilter (L3037, L3038, C3154–C3158), and is then appliedto the MAIN unit as the BFO signal. The PA unit separategrounding from the other units to obtain floating.1101116171820212223242526272830313233343536Input port for the CPU reset signal.When receiving a “LOW” pulse, theCPU is reset.Data input port from the sub CPU inthe FRONT unit.Data output port to the sub CPU inthe FRONT unit.Input port to the sub CPU in theFRONT unit.Outputs low power control signal for60 W power.Outputs low power control signal for20 W power.Input port for the CW keying.High: When key is closed.Outputs a “SEND” control signal forthe ACC (1) and ACC (2) sockets.Outputs a “SEND” control signal forT8 and R8 voltage line control.Low : For transmit.Outputs an alarm control signal toactivate the 2-tone emergency alarmencoder.High : Alarm ON.Outputs a tone switching signal for the2-tone emergency alarm encoder.High : High tone.Outputs a clock signal for theEEPROM (IC134).Data bus line for the EEPROM(IC134).Outputs a serial signal for theEEPROM (IC135).Data bus line for the EEPROM(IC135).Input port for the S-meter indication.Input port for the RF-meter indication.Input port for the antenna currentmeter indication for [EUR] version.The ANTC signal can be receivedwhen an optional AT-130E is con-nected.Input port for the squelch detectedsignal.High : When squelch is open.Input port for the transmit/receiveswitching signal.Input port for the scan control signalfrom the ACC (1) socket.Outputs RF gain control signal to theAGC circuit.3-4 PORT ALLOCATIONSCPU (MAIN unit; IC132)RESRXDOTXDONSENPOC2POC1CWINASENCSENALMSALMCSCLSDASOSDARSMMFORANTCSQLSTRCSCASRFGPin Port Descriptionnumber name