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:
May. 02, 1995
Filed:
Oct. 07, 1993
Christian Nystrom, Sollentuna, SE;
Charles Persico, Sunnyvale, CA (US);
Other;
Abstract
A compact local oscillator network for use in a quadrature modulator and/or demodulator is presented. Single side band circuitry is configured to produce quadrature signals with a high degree of accuracy such that two equal amplitude signals are generated having a precise 90.degree. phase difference. The network accuracy is substantially not affected by phase or amplitude imbalances within or introduced into the network. For example, the network may include: a first quadrature circuit for dividing a first input signal into a first in-phase signal and a first quadrature signal 90.degree. out of phase; a second quadrature circuit for dividing a second input signal into a second in-phase signal and a second quadrature signal 90.degree. out of phase; a first mixer for mixing said first in-phase signal and said second in-phase signal; a second mixer for mixing said first quadrature signal and said second quadrature signal; a third mixer for mixing said first quadrature signal and said second in-phase signal; a fourth mixer for mixing said first in-phase signal and said second quadrature signal; a first combiner for combining the outputs of said first and second mixers into a first combiner for combining the outputs of said first and second mixers into a first local oscillator output signal; and a second combiner for combining the outputs of said third and fourth mixers into a second local oscillator output signal.