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:
Sep. 07, 1999
Filed:
Jun. 20, 1997
Hideo Nakanishi, Kanagawa, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
In a direct conversion receiver with an AFC function comprising a local oscillation circuit constituted by a synthesizer, the local oscillation frequency is prevented from radiating as an interfere wave against the receiver per se so as not to reduce the reception characteristic, and it is made possible to reduce the value of the multiplication factor N of a multiplier in the synthesizer without making the frequency of a VCO per se high. Specifically, a first local oscillation signal 12 obtained by multiplying an output frequency F.sub.X of a reference crystal oscillation circuit portion 8 of a synthesizer circuit section 7 by M by a multiplier 11 is mixed with an FSK modulation signal 1 in a first mixer 4. In a second mixer 5, the thus mixed signal is further mixed with a second local oscillation signal 13 obtained by multiplying an output frequency F.sub.V of a synthesizer 9 by N by a multiplier 10. The frequencies of the first and second local oscillation signals are selected so as to establish the condition M.multidot.F.sub.X >N.multidot.F.sub.V so that the multiplication factor N of the multiplier 10 can be made small.