BFO FREQUENCY CONTROL

摘要

a signal generator that generates sine waves having a certain frequency; a signal receiver that produces continuous wave- demodulated signals when tuned to same frequency of the sine waves from a antenna within tolerance; a A/D converter that converts them to digital waves; a personal computer stage that also includes a Fast Fourier Transformer producing a spectrum of the digital signal from the A/D converter. Checking a frequency spectrum and a maximum frequency(center frequency) within desired level repeatedly, a BFO frequency is finely adjusted to demodulate the continuous wave signal automatically by the computer.