| 摘要 |
<p>A frequency synthesizer has at least one signal synthesizer II, III, IV driven by a basic signal 1 composed of an 8 kHz signal and of its odd harmonic frequencies for producing pilot frequency signals 36,38,40 (of 84,08 kHz, 84,14 kHz and 104,08 kHz) and corresponding carrier frequency signals at 37,39,41 which are each 12.08 kHz less than the associated pilot frequency signal, an auxiliary synthesizer I deriving the difference frequency at 42 (12.08 kHz) from the basic signal, this being used (at 12, 17,29) to derive the pilot signal from the carrier. In the signal synthesizer II, a filter circuit such as 14, 16 is used to produce the carrier frequency signal, and a synthesizing circuit comprising a modulator 12, in which the basic signal and the carrier frequency signal are combined, a band pass filter 13 and an amplifier 15, is used to obtain the required pilot frequency signal. <IMAGE></p> |
