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. 30, 2001
Filed:
Mar. 02, 1999
Masahiro Tsukahara, Kasugai, JP;
Koju Aoki, Kasugai, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A phase shifter that may be used in a quadrature modulator or an image suppression mixer. The phase shifter includes a low pass filter that receives an input signal and generates a first carrier signal. A high pass filter also receives the input signal and generates a second carrier signal. A phase difference detection circuit connected to the high and low pass filters receives the first and second carrier signals and generates a control signal based on the phase difference between the carrier signals. The control signal is fed back to at least one of the low pass filter and the high pass filter to compensate for phase errors caused by parasitic capacitance. The phase shifter has a small circuit area and is very accurate, allowing it to be used in communications devices.