Patent ID: 6972632
Filing Date: 2005-12-06
Classification: H03J

Abstract:
1. A frequency control apparatus comprising: a frequency converter for receiving a signal of a first frequency modulated with a symbol representing digital information and for mixing the received signal with a second frequency different from the first frequency to convert the first frequency to a third frequency lower than the first frequency; an oscillator for oscillating the second frequency, said oscillator being controlled to generate the second frequency in response to a control signal generated on a basis of an output of said frequency converter; a data converter for restoring the symbol supplied from said frequency converter in conformity with modulation by which the symbol is modulated to output restored data; a phase error operator for measuring the restored data to obtain an in-phase component and a quadrature component to the in-phase component, and using the components obtained to calculate a first phase error and a second phase error for the received signal; an adder for summing the first and second phase errors; a first multiplier for multiplying an output of said adder with a first coefficient; and an integrator for integrating results of said first multiplier to generate the control signal.