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:
Apr. 27, 1999
Filed:
Feb. 06, 1997
Hidenori Maruyama, Tokyo, JP;
NEC Corporation, , JP;
Abstract
In a radio transmitter-receiver, a single frequency conversion method is used at a side of transmission and a double frequency conversion method is used at a side of reception. The frequency for transmission is identical with that of reception. A common oscillator of an oscillation frequency f1 is used for a local frequency for transmission/reception-first frequency conversion. A reception second local frequency signal and a transmitter intermediate frequency signal are generated by independent oscillators with oscillation frequencies 2f2 and 2f3 respectively. These oscillators generate two times the frequency of the conventional example thereof, thus providing the signals with frequency of 1/2 times the frequency-division by the frequency dividers for the reception side second frequency converter and transmission side intermediate frequency converters respectively. The output signals of these two oscillators are mixed in the frequency converter before the output signals are divided into 1/2-times the frequency thereof by the frequency divider, thus generating a base band signal of �2f2+2f3!/2 (in which '+' means mixing of signals) with the same frequency as that of the second local frequency signal. In this constitution, during reception of the signals, it allows the operation of the frequency divider for a transmitter intermediate frequency signal to halt temporarily. For this reason, since interference to the intermediate frequency band at the reception side vanishes therefrom, it becomes unnecessary to shield the reception side and the transmission side from each other.