Oscillator controlling apparatus

Abstract

An oscillation controlling apparatus has a digitally-controlled oscillator configured to output an oscillating signal with an oscillation frequency according to an oscillator adjustment signal, and include a variable current source which supplies operation current based on an operation current control signal, a phase difference calculating unit configured to calculate a phase difference between the oscillating signal and a reference signal to output a phase difference signal, a filter configured to smooth a difference between a phase instruction signal setting the oscillation frequency of the digitally-controlled oscillator and the phase difference signal to output the oscillator adjustment signal, and a controlling unit configured to obtain the oscillator adjustment signal, output the operation current control signal so as to vary a value of the operation current, extract the value of the operation current at which the oscillator adjustment signal becomes the maximum value, and output the operation current control signal so that the operation current supplied by the variable current source becomes the extracted value.

Dependencies are inferred from the claim text.