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:
Jul. 28, 1987
Filed:
Dec. 13, 1985
Otmar Kappeler, Neuenburg, DE;
Deutsche ITT Industries GmbH, Freiburg, DE;
Abstract
A generator circuit according to the invention generates two 90.degree. phase-shifted frequency-variable sinusoidal signals by mixing the output signal of a fixed-frequency oscillator and of a continuously variable oscillator with the aid of two multipliers operating as mixers. The fixed-frequency signal is applied to the second multiplier via a 90.degree. phase shifter. The output signal of the multipliers which contains the sum and the difference frequency of its input signals, is respectively fed to a low-pass filter or to a band-pass filter, which suppresses the sum frequency or the difference frequency respectively. By the 90.degree. phase shifter, the sinusoidal signal is phase-shifted with respect to the sinusoidal signal by exactly 90.degree.. During the continuous variation process, the signal as applied to the 90.degree. phase shifter remains stable in its frequency, whereas the output signal of the continuously variable oscillator as fed directly to the two multipliers, is changed in its frequency.