| 摘要 |
A radio communication device modulates a received audio signal with an intermediate frequency (IF) signal before mixing with the radio frequency (RF) waveform for transmission by an antenna. A voltage controlled oscillator is utilized, which is tuned to N times the desired IF frequency. This voltage controlled oscillator is frequency modulated with the inputted audio signal to a deviation N times the desired IF source deviation. The voltage controlled oscillator is locked in a phase locked loop with a system reference frequency so that the output frequency is N times the desired IF frequency. The output of the voltage controlled oscillator is supplied to a "divide-by-N" frequency prescaler for generating a signal at precisely the right IF frequency and deviation.
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