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. 03, 1990
Filed:
May. 05, 1988
Marc H Popek, Indian Harbour Beach, FL (US);
Pat O Bentley, Palm Bay, FL (US);
Harris Corporation, Melbourne, FL (US);
Abstract
An amplitude modulation apparatus for achieving an extremely deep extinction ratio (in excess of -90 dBc) at nanosecond rise times required by an SAW device comprises the cascaded combination of a controlled switching device (GaAsFET), capable of providing a medium degree (40 dB) of attenuation at nanosecond switching rates, and a double balanced mixer, both multiplier input ports of which are coupled to receive split outputs from the GaAsFET switch. Because of the nonlinearity of the transfer function of the mixer when driven by the same RF carrier input at both multiplier ports, the output of the mixer is in excess of -90 dBc. In an SAW-based signal processing system, the output of the mixer is coupled to RF drive input of the SAW device. With the throughput functionality of the GaAsFET switch being precisely controlled to supply an integral number of half RF carrier frequency cycles to the double balanced mixer, the resultant waveform that is applied to the SAW device drive input from the mixer contains no energy at the RF carrier that could otherwise introduce unwanted Fresnel distortion.