| 摘要 |
1278568 Radio signalling CIT COMPAGNIE INDUSTRIELLE DES TELECOMMUNICATIONS 5 Oct 1970 [3 Oct 1969] 47162/70 Heading H4L An arrangement for controlling the transmitted power of a transmitter-receiver (for example to minimize consumed power or reduce the chance of detection) comprises an attenuator in the drive to the power circuit controlled in accordance with received pilot-tone signals representing the signal strength at a remote location. As described each of a pair of transmitter-receivers in mutual communication has, as shown, an attentuator 16 (between modulator 14 and RF power amplifier 17) which is controlled by pilot-tones F 1 , F 2 ... in for example the band 200-300 Hz. One of these tones is generated at the remote location by a circuit 30 responsive to received signal strength and controlling oscillators in a unit 19. The circuit 30 contains a number of threshold circuits S 1 ... S n whose outputs are supplied to a logic circuit 31. The received tones are filtered in unit 26 and control via a logic circuit 27 a digital-toanalog arrangement for providing a control voltage for varicap diodes in the attenuator 16. Fig. 3 (not shown) illustrates the circuit in more detail, particularly the logic circuits 27 and 31. |
