Patent attributes
A communication apparatus includes a phase-locked loop circuit which receives a first signal having a frequency and converts it into an output signal having a transmission frequency and includes a current output type phase comparator which converts a phase difference between the first signal and a second signal into a current signal, a low pass filter which filters the current signal of the current output type phase comparator to produce an output signal a voltage controlled oscillator which produces an output signal having a transmission frequency corresponding to the output signal of the low pass filter the output signal of the voltage controlled oscillator constituting the output signal of the phase-locked loop circuit, a frequency converter which frequency-converts the output signal of the voltage controlled oscillator to produce the second signal, and a current source which supplies a current to an input of the low pass filter.
