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:
Feb. 23, 1999
Filed:
May. 12, 1997
Alexander Fairgrieve, Menlo Park, CA (US);
Elantec Semiconductor, Inc., Milpitas, CA (US);
Abstract
A variable frequency oscillator providing a constant amplitude with variations in frequency. The variable frequency oscillator includes: an oscillator having an input connected for receiving a current I.sub.1, and outputs for providing complementary signals having a frequency varying in proportion to the current I.sub.1 ; first and second transistors, each having a base connected to a respective one of the oscillator outputs; current supply circuitry having a first output connected to the input of the oscillator for providing the current I.sub.1, and a second output connected to the emitters of the first and second transistors for providing a current I.sub.3, the current I.sub.3 varying in proportion to the current I.sub.1, without varying significantly due to changes in the oscillator frequency; and first and second output amplifiers, each having an input connected to the collector of a respective one of the first and second transistors, and an output for providing a signal which varies in proportion to the current I.sub.3 and varies inversely proportion to the oscillator frequency. With such circuitry, variations in amplitude of signals driving the output amplifiers due to changes in oscillator frequency will cancel inverse variations in amplitude of signals at the outputs of the output amplifiers due to the changes in the oscillator frequency.