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:
Nov. 22, 1994
Filed:
Oct. 01, 1993
Kazuya Yamamoto, Itami, JP;
Kousei Maemura, Itami, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A quadrature modulator includes a 0.degree./90.degree. phase shifter including only resistors, capacitors, and transistors that separates an input carrier wave into two carrier waves having a phase difference of 90.degree. from each other by differentiating and integrating. The quadrature modulator includes amplitude compensating circuits for converting the two carrier waves from sinusoidal waveforms to rectangular waveforms having predetermined amplitudes. The amplitude compensating circuits are inserted between the phase shifter and double-balanced mixers. The phase shifter consists of circuit elements appropriate for circuit integration and produces a high degree of orthogonality in its output signals as a function of variations in the characteristic values of the circuit elements. Complementary carriers having precise orthogonality as well as superior balance are input to double-balanced mixers. Accordingly, a superior modulation wave having fewer spurious components is obtained easily with simplified circuit integration.