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:
Jan. 11, 1994
Filed:
Oct. 08, 1992
Jean-Francois Debroux, St Etienne de St Geoirs, FR;
Thomson Composants Militaires et Spatiaux, Courbevoie, FR;
Abstract
The invention relates to an amplifying circuit with controlled gain, the gain of which is an exponential function of a gain control voltage. The circuit includes two identical amplifiers A1 and A2, the first constituting the basic amplifying cell of the circuit (input Ie, output Is), and the second receiving a reference signal (Iref). The output from the second amplifier, which is the product of the input Iref times the gain G, serves as input to a feedback control loop for the gain G of the amplifiers. This loop receives a set point voltage Vc with a view to establishing a gain G which is an exponential function of Vc. A large-gain differential amplifier AD constitutes the core of this loop: the differential voltage between its inputs tends to be held at zero by the feedback control loop. According to the invention, an element (FTL) with logarithmic transfer function is inserted into the loop between the output of the second amplifier A2 and the input of the large-gain differential amplifier AD.