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:
Mar. 31, 1998
Filed:
Nov. 15, 1996
Shigeru Kagawa, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
The invention provides a quadrature demodulator which removes unnecessary higher harmonic signals included in a demodulation output without giving rise to increase in number of externally connected parts and increase in current consumption. The quadrature demodulator includes a first double differential circuit to which a modulated signal and a first local signal are inputted, a first emitter follower circuit for effecting impedance conversion, a second double differential circuit to which the modulated signal and a second local signal having a phase shifted by 90-degrees from the first local signal are inputted, and a second emitter follower circuit connected to a pair of outputs of the second double differential circuit for effecting impedance conversion. The quadrature demodulator further includes a CR circuit including a resistor and a capacitor connected to each of the outputs of the first and second double differential circuits such that an active filter is formed from the CR circuit and a corresponding one of the first and second emitter follower circuits.