| 摘要 |
A control method for the carrier wave of the FM synthesizer for a radio telephone system and a corresponding circuit with a processor (16), a crystal oscillator (15) in the processor, a digital/analog converter (18) and a counter (14) and with connection to the control voltage (Vohj) of the voltage-controlled synthesizer crystal oscillator (1) and with connection to the synthesizer intermediate frequency (IF2), the voltage-controlled synthesizer crystal oscillator (1) being controlled in this circuit by locking (synchronising) to the carrier frequency (fin) of the signal transmitted by the base station and received. In the circuit, the telephone processor (16) uses the counter (14) to count periods of the receiver intermediate-frequency signal (IF2) during the constant time T and obtains as a result a particular number (M) which is subjected to digital/analog conversion, the voltage obtained being used for controlling the voltage-controlled crystal oscillator (1) of the synthesizer. In the locked state, the control number (M) does not change with different counts. <IMAGE> |
