The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 22, 1989
Filed:
Nov. 29, 1988
Kenji Matsuo, Yokohama, JP;
Ikuo Tsuchiya, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A voltage controlled oscillator comprises a phase locked loop section and a voltage controlled oscillator section. The phase locked loop section is coupled with an input signal at a reference frequency and a reference potential, and performs a signal feedback control so as to obtain a constant delay time of a first variable delay circuit contained in the phase locked loop section. The voltage controlled oscillator section controls a delay time of a second variable delay circuit in a ring oscillator by a control input voltage and an output voltage of a low-pass filter contained in the phase locked loop section, and produces a signal oscillating at a frequency as determined by the delay time. In the voltage controlled oscillator thus arranged, the output frequency is determined by controlling a delay time of the second variable delay circuit in the voltage controlled oscillator section. Since the delay time is accurately controlled by the phase locked loop section, the obtained output frequency is stable against the variance of the process parameters. Since the delay time is varied by the reference frequency of the input signal, the output frequency may be set at a desired frequency, and hence a frequency band of the oscillation frequencies may also be set appropriately.