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:
Jan. 10, 1989
Filed:
Aug. 24, 1987
Koyo Kegasa, Hyogo, JP;
Takafumi Murai, Hyogo, JP;
Osamu Yamanaka, Hyogo, JP;
Takeshi Fujii, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A PLL frequency synthesizer comprises a voltage controlled oscillator which oscillates in response to a frequency signal corresponding to a control signal to be input and which outputs the frequency signal as an output of said PLL frequency synthesizer; a multiplier means for multiplying a reference frequency signal to be input; a mixer for mixing the frequency signal which is output from the voltage controlled oscillator and the multiplied reference frequency signal which is output from the multiplier, and for outputting a frequency signal representative of a difference therebetween; a variable frequency divider for dividing the difference frequency signal at a variable dividing ratio; a fixed frequency divider for dividing the reference frequency signal at a predetermined dividing ratio; a frequency phase comparator for detecting a phase difference between an output signal from the variable frequency divider and an output signal from the fixed frequency divider and for outputting a phase difference signal therebetween; a filter for removing high frequency components of the phase difference signal which is supplied as the control signal to the voltage controlled oscillator; and a device for switching the polarity of the phase difference signal. An output frequency of the voltage controlled oscillator can be switched to either a frequency higher than or a frequency lower than the frequency which is H (H is a positive integer) times as high as the output frequency of the multiplier, or the output frequency of the voltage controlled oscillator can be switched to either a frequency higher than the frequency which is H times as high as the output frequency of the multiplier or a frequency lower than the frequency which is (H+1) times as high as the output frequency of the multiplier.