The 45.1 MHz signal passes through a crystal filter for adjacent-channel selectivity, then enters the IF IC. Here, it is mixed down to a second IF of 450 kHz, passed through a ceramic filter, and demodulated into raw audio. Transmitter Circuitry (TX)
The tuner software prompts the radio to transmit at multiple frequencies across its range. Adjust the softpot values for both high-power and low-power settings to meet legal and operational targets (e.g., 25W low, 45W high), ensuring the current draw stays within safe limits. Modulation Balance and Limit
The 45.1 MHz signal passes through a crystal filter for adjacent-channel selectivity, then enters the IF IC. Here, it is mixed down to a second IF of 450 kHz, passed through a ceramic filter, and demodulated into raw audio. Transmitter Circuitry (TX)
The tuner software prompts the radio to transmit at multiple frequencies across its range. Adjust the softpot values for both high-power and low-power settings to meet legal and operational targets (e.g., 25W low, 45W high), ensuring the current draw stays within safe limits. Modulation Balance and Limit motorola gm3688 service manual exclusive
