OSCILLATOR, FREQUENCY MULTIPLIER, AND TESTING APPARATUS

摘要

An oscillator for producing an oscillation signal of a desired frequency, comprising a reference oscillation part for producing reference signals of a predetermined frequency; a plurality of first variable delay circuits connected in cascade for receiving the reference signals to sequentially delay, by substantially the same delay amount, and output the received reference signals; a phase comparison part for comparing the phases of the reference signals produced by the reference oscillation part with the phases of the delayed signals outputted from the last stage of the plurality of first variable delay circuits; a delay amount control part for controlling the delay amount of the plurality of first variable delay circuits such that the phases of the reference signals are substantially equal to the phases of the delayed signals outputted from the last stage of the plurality of first variable delay circuits; and a frequency addition circuit for performing a logic arithmetic processing of input signals to be inputted to the respective ones of the first variable delay circuits, thereby producing an oscillation signal as obtained by combining the edges of the input signals.