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. 09, 1978
Filed:
Jun. 03, 1977
Bortolo M Pradal, Pittsburgh, PA (US);
Paul L Buess, Pittsburgh, PA (US);
RCA Corporation, New York, NY (US);
Abstract
A direct FM modulator includes an oscillator comprising a current conducting device providing amplification to sustain oscillations and a frequency determining circuit connected thereto for controlling the frequency of oscillation. The frequency determining circuit includes a piezoelectric element in series with a voltage variable capacitance and an adjustable capacitance coupled across this series combination. The capacitance of the voltage variable capacitance is changed by a modulating voltage to provide frequency deviation about the center frequency of oscillation. A frequency linearization of the crystal oscillator is provided by a selected value of capacitance coupled across the varactor and the capacitance value of the adjustable capacitance such that the frequency deviation vs. voltage is maximum at the initial reference bias voltage and is symmetrical about this reference bias.