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:
May. 13, 2003
Filed:
May. 29, 2001
Shunsuke Hirano, Yokohama, JP;
Ryoichi Yamada, Yokosuka, JP;
Yasunori Miyahara, Ayase, JP;
Yukio Hiraoka, Nishinomiya, JP;
Hisashi Adachi, Minoo, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A frequency synthesizer is provided with a prescaler and a counter which output a signal having a frequency generated by frequency-dividing an output signal of a VCO a reference frequency divider for frequency-dividing a frequency of a reference signal of a reference signal source a frequency adjusting meas operated in such that a frequency error between the output signal of the counter and the output signal of the reference frequency divider is detected, and in response to this detection result, such a signal is outputted by which either a capacitor value or an inductor value employed in a resonant circuit of the VCO is switched; and also a bias control means for applying an arbitrary voltage V to a control voltage terminal of the VCO so as to bring an output signal of a charge pump into a high impedance state when the frequency adjusting means is operated. Since the resonant frequency of the resonant circuit is changed in response to an actual oscillation frequency of the VCO the frequency synthesizer can be phase-locked at a desirable frequency. Also, since the VCO can be manufactured in the IC form, the compact VCO can be made in low cost.