Patent ID: 6842077
Filing Date: 2005-01-11
Classification: H03D

Abstract:
1. A voltage controlled oscillation device used in a phase locked loop circuit comprising: voltage controlled oscillation means for changing an output signal frequency in a microwave band in accordance with an input voltage of a frequency control signal; fixed-frequency oscillation means having a fixed oscillation frequency higher than that of said voltage controlled oscillation means; frequency mixing means for up-converting an output signal from said voltage controlled oscillation means to a sum frequency and difference frequency by using an output signal from said fixed-frequency oscillation means, the sum frequency and difference frequency being controlled by the input voltage of a frequency control signal; and frequency selection means for selecting and outputting one of the sum frequency and difference frequency contained in the output signal from said frequency mixing means; wherein the output of the frequency selection means is a local frequency signal of a phase locked loop circuit; wherein the voltage controlled oscillation means comprises a control voltage input terminal to which the frequency control signal is received as an input; and wherein the output signal from the voltage controlled oscillation means is connected as an input only to the frequency mixing means.