| 摘要 |
<p>The transmitter (2) emits a carrier at frequency F1 for a short duration and then switches to carrier frequency F2 for another short period. Transmission is then stopped for a further period equal to the sum of the first two periods, then the routine is repeated. The local oscillator (6) in the receiver (4) oscillates at frequency F2 while F1 is being received and at F1 while F2 is being received in order to avoid interference between the two frequencies.</p> |
