Patent ID: 7161437

Claim:
A voltage controlled oscillator for outputting a signal whose frequency changes in accordance with a value of a control signal, wherein: the oscillator has an even number of, at least four, amplifiers; each amplifier is a non-differential input type and has a first input and a second input and a single-ended output, a gain from the first input to its output and that from the second input to its output both having a negative value, and a signal propagation delay time from the first input to its output and that from the second input to its output changing in accordance with a value of the control signal; each of the first inputs of the amplifiers is connected to one of the outputs of another one of the amplifiers so that they may be formed in a ring; and each of the second inputs of the amplifiers is connected to one of the outputs of such one of the amplifiers as to be distant by an even number of stages therefrom.