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:
Mar. 01, 1988
Filed:
Oct. 15, 1986
Charles B Koerner, Port Murray, NJ (US);
ITT Avionics a Division of ITT Corporation, Nutley, NJ (US);
Abstract
A VSWR protection circuit employs first and second mixers whereby the first mixer receives at one input the transmitted frequency and has a local oscillator coupled to the other input to provide at its output a difference frequency. This difference frequency is applied to the input of the second mixer which also receives at another input a frequency which is the sum of an undesired EMI signal plus a residue signal due to reflection from the transmitter. The second mixer produces difference frequencies according to the output from the first mixer. The output from the second mixer is applied to a narrow bandpass filter which essentially allows the transmitted frequency to propagate. The output from the narrow band filter is then detected whereby a DC control voltage is provided and used as a gain control for the transmitting amplifier and essentially is independent of most interfering frequencies.