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:
Apr. 26, 1994
Filed:
Dec. 11, 1992
Lars H Mucke, San Diego, CA (US);
Nokia Mobile Phones, Ltd., , FI;
Abstract
The circuit amplifies an input RF band of signals and exhibits a signal gain in decibels that is a linear function of a logarithmic control signal input. The circuit employs a transistor having an emitter electrode connected through an inductor/resistor combination to a source of common potential. Within a limited band of RF frequencies, the resistor inductor combination appears to be a high impedance. A PIN diode is connected in shunt across the resistor/inductor combination and, in response to a control current, alters its RF resistance. A capacitor is connected across the emitter of the transistor and provides a tuning function so that, at the mid-frequency of the RF band, a resonant tuned circuit results, thereby causing a high value resistive load to appear across the PIN diode. In this manner, linear gain control is achieved by varying a DC control current through the PIN diode.