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:
Sep. 08, 1998
Filed:
Dec. 22, 1995
Kenneth Wilson Clayton, Plano, TX (US);
Robert Rudolf Rotzoll, Allen, TX (US);
Microtune, Inc., Plano, TX (US);
Abstract
The system and method for switching a radio frequency (RF) signal between mixers can provide a large automatic gain control (AGC) range while maintaining low noise levels by using a switching circuit to select between at least two mixers that are switched between a common load using reverse biasing. To turn off a specific mixer, RF inputs to that mixer are reverse biased, which shuts off the current to the load. The full AGC of the switching circuit is approximately the sum of the AGC of each mixer. Each mixer has a limited AGC range, which limits the amount of current swing needed for the full AGC of the switching circuit. By dividing the switching circuit between two or more mixers, the transistor devices in each mixer may be sized appropriately with respect to the current levels being used in each mixer. For instance, in a mixer designed specifically for low noise applications, the transistor devices can be very large. For a mixer that is designed to tolerate more noise, the transistor devices may be smaller, which allows more precise tailoring of the ft of the particular mixer. These two mixers may be coupled together in the system and method of switching an RF signal between mixers to obtain the individual benefits of each mixer.