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:
Aug. 10, 2004
Filed:
Jul. 10, 2003
Hung Chang Lin, Silver Spring, MD (US);
Maryland Semiconductor, Inc., Clarksburg, MD (US);
Abstract
A BJT operating as a mixer has its collector biased at the knee of the I vs V characteristic. A local oscillator voltage is applied to the base and an RF signal voltage is applied to the collector through a singled-ended emitter follower. The nonlinear curvature at the knee produces a beat frequency current. The base of the emitter follower can be fed from a current mirror or through an ohmic resistor. This mixer requires less supply voltage, and results in more conversion gain and less feed-through of the RF input signal than the Gilbert multiplier. Alternatively, the RF voltage can be applied to the gate and the local oscillator voltage can be applied to the drain. Sometimes, it is more desirable to invert the collector and the emitter, or to connect a normal transistor and an inverted transistor in parallel to optimize conversion gain.