| 摘要 |
<p>The fixed frequency oscillator, which is conventionally used to provide a reference signal to a mixer (26), is replaced by a derivative circuit (40). This samples a part of the transmitted signals and spreads them in frequency according to a first type of binary sequence. The received signals, provided by a distant transmitter that transmits signals which are spread in frequency according to binary sequences of a second type, are changed in frequency (26), amplified (28) and frequency demodulated (30). The frequency spread is then removed in a circuit (32) with the aid of binary sequences of the second type. This then allows discrimination of the useful binary signals provided by the distant transmitter with the aid of a digital demodulator (42).</p> |
