| 摘要 |
PURPOSE:To detect anomaly of phase synchronization with a high precision, by frequency-converting an error signal voltage and by detecting that difference between this converted frequency and a frequency set previously is a prescribed value or more, in the phase synchronization detecting circuit using the phase oscillator of a transmitter. CONSTITUTION:At a normal time, output (c) of loop amplifier 5 (an error voltage signal corresponding to phase difference between reference input signal (a) from buffer amplifier 1 and output signal (b) from voltage variable oscillator 3) is frequency-converted by voltage frequency converter 8 and is input to preset counter 10 through switching circuit 9 and is stored previously. Next, switching circuit 9 is switched to the counter 13 side to count ouput (d), and the output of counter 13 is compared with the stored value by digital comparator 11; and if their difference is a prescribed value or more, sweep oscillator 6 is operated through OR circuit 12 to stop the operation of output multiplier 4. |
