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:
Oct. 08, 1996
Filed:
Jun. 06, 1994
Kunitoshi Yonekura, Tokyo, JP;
Masahiro Matai, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
In a radio receiver a PLL oscillator generates a phase locked oscillation signal with a controllable frequency and a frequency multiplier multiplies the controllable frequency with a controllable factor into a local oscillation frequency to provide a local oscillation signal for mixing into an IF signal with a radio signal reaching the receiver, the IF signal is monitored to raise the controllable frequency and to reduce the controllable factor when a spurious signal coexists with the radio signal. This coexistence is detected by monitoring a level difference between the IF signal and an output signal of an IF filter. Preferably, the oscillator comprises in a PLL two VCO's for generating phase locked oscillation signals of higher and lower oscillation frequencies, such as 260 and 65 MHz, and a controllable prescaler supplied with high and low voltage signals when the VCO's are put in operation at the higher and the lower oscillation frequencies. Concurrently, the controllable factor is controlled to factors of unity and four.