Variable frequency oscillator
AssigneesMatsushita Electric Industrial Co., Ltd., Victor Company of Japan, Ltd.
InventorsYasuaki Watanabe, Yukio Okabe, Mitsuru Hayakawa, Yuichi Ikemura, Yasuhiro Fujita, Daisuke Murakami
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Abstract
A variable frequency oscillator comprises an oscillating loop and a variable phase shifter for imparting one of two different phase shifts depending upon the polarities of a DC control voltage to a signal from the oscillating loop. The phase-shifted signal has its amplitude controlled by the amplitude of the control voltage and is combined with the signal in the oscillating loop. The vector sum of the combined signals determines the phase angle of the oscillator signal and hence the frequency thereof.
Claims9
A variable frequency oscillator comprising:
- an oscillating loop including an amplifier, bandpass filter means having a passband response characteristic with the center frequency substantially equal to a free-running frequency of said oscillating loop and means having two inputs for providing vector summation of two signals applied thereto, all of which are connected in series such that the output of each is connected to an input of another;
- and
- means for shifting the phase of an input signal applied thereto such that the phase shift is variable in correspondence to a control signal applied thereto, said variable phase shifting means having an input connected to an arbitrary point of said oscillating loop and an output connected to the other input of said summation providing means.
Dependencies are inferred from the claim text.