| 摘要 |
PURPOSE:To reduce the time required for circuit adjustment by using a loop filter in common for a phase locked loop system and an AFC loop system and using the, loop filter so as to adjust the frequency characteristic. CONSTITUTION:An output of a phase detector 9 is fed to an input of an adder 10 and an output of a DC amplifier 16 is added hereto via a switch 17 simultaneously and the sum enters a loop filter 11. The input is fed to an amplifier 25 via a resistor 28 in the filter 11 shown in figure. An output signal from the adder 10 is inputted to the filter 11, in which the signal is converted into a signal having a waveform with a preset response characteristic, and the resulting signal is outputted to a VCO 12 as a voltage control signal. The AFC loop common use phase locked loop acquisition circuit is formed by the AFC loop comprising the circuit consisting of a band pass filter 13, an amplitude limiter 14, a frequency discriminator 15, a DC amplifier 16 and a switch 17 and the phase locked loop acquisition circuit comprising the adder 10 and the filter 11. |
