| 摘要 |
PURPOSE:To enable adaptive control of a delay time to the center frequency variance of a reception signal, by making variable the delay time of a delay element. CONSTITUTION:The modulation wave input signal 8 is divided into 3, which are respectively input to a shift register 1, multipliers 2 and 3. The modulation signals 9 and 10 delayed for a given time with the shift register 1 are respectively fed to another input terminal of multipliers 2 and 3. The output 11 of the multiplier 2 is input to a low pass filter 4 to obtain the delayed detection output 13. The phase error detection circuit between the signals 8 and 10 consists of a part of shift register 1 and circuits 3 and 5, and the output 12 of the multiplier 3 is an output 14 rejecting the AC component with the low pass filter 5, and the control voltage output 15 with a suitale level can be obtained at the delay time control circuit 6 from the output 14. This output 15 controls the voltage controlled oscillator 7 so that normal delay detection output can be obtained even if the frequency variance of modulation wave input 8 is present, the clock rate of the transfer clock output 16 is changed and the shift register is driven with the output 16, allowing to suitably control the delay time. |
