FREQUENCY CONTROL CIRCUIT

摘要

PURPOSE:To realize the reduction in the circuit scale and in the power consumption with a simple frequency control circuit used for frequency synchronization for a carrier signal recovered by a phase demodulator demodulating a phase modulation wave. CONSTITUTION:In the frequency control circuit provided with a frequency error detection means 10 detecting a frequency error of a carrier signal reproduced from a reception signal and outputting a frequency error signal and with an integration means 20 accumulating the frequency error signals and outputting the result as a frequency control signal, the frequency error detection means 10 is provided with a phase detection means 11 receiving 2 series of orthogonal sine wave signal and cosine wave signal in a carrier signal, applying inversion of a sign of the sine wave signal and addition of an offset in response to the combination of the signs of each signal, converting the result into a signal having a non-negative and non-positive consecutive gradient in response to the phase of the carrier signal and outputting the result as a phase detection signal and with a difference processing means 12 taking a difference between the phase detection signals and converting the difference into a frequency error signal.