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CIRCUIT DESCRTPTION 1) Receiver System 1. Front End The signal from the antenna is passed through a low-pass filter and input to the voltage step up circuit consisting Of L14. The signal from L14 is led to the gate of Q1. D19 is the diode limiter circuit against the excessive input power of more than 20dBm.
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2) Transmitter System 1. Modulation Circuit 3) PLL Circuit The microphone amplifier IC1 (IDC, LPF) consists of two operational amplifi- ers. The signal from the microphone is led to pre-emphasis circuit consisting of C36 and R47 and then to the limiter circuit. The limiter circuit uses the saturation of the OP amplifier.
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4) Terminal Function of Microprocessor Port No. I/O Logic PinName Description SEG19 LCDSegment19 Output SEG20 LCDSegment20 Output SEG21 LCDSegment21 Output SEG22 LCDSegment22 Output SEG23 LCDSegment23 Output AnalogGround 0V Vref Reference Voltage Input 5V CPU Power Supply hnput 5V 1750_ ToneBurstOutput 10 O Clock BEEP BeepToneOutput...
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Port No. I/O Logic PinName Description 40 I/O Clock Data Output for EEPROM 41 O Clock Clock Output 42 O Clock DataOutput 43 O Clock Strobe Output for PLL IC 44 O Clock Strobe Output for CTCSS IC I Active Low SFT Shift Key Input I Active High SD Signal Detection Input...
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ADJUSTMENT 11. Distortion Meter 1) Required Test Equipment 1. Digital Multimeter Measurable frequency 1kHz Voltage range: FS= 18V or so Input level: Up to 40dB Input resistance: 1M ohm or more Distortion level: 1% - l00% 2. Regulated Power Supply 12.
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2) Adjustment for DR130 SSG Mod:1KHz +/-3.5KHz/DEV SP terminal is connected to 8ohm dummy load. RX speaker output level is 50 to 100mW 1. Power supply voltage is 13.8V. Power switch is off. 2. Turn the squelch and volume knobs counterclockwise. 3.
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TX Adjustment Condition Measurement Adjustment Specification/ Item Test equipmen Unit Terminal Unit Parts Method Remarks VR1: max Power:High PTT: ON High Power Frequency:145.00MHz Power:High +/- 1.0W PTT: ON Power Meter Back Main Below 10.5A Frequency:130.00MHz Above 5W Power:High Check (T.E.EZ) PTT: ON Frequency:174.00MHz Above 5W...