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. 23, 1991
Filed:
Mar. 28, 1990
Jean-Francois Debroux, Saint Etienne de St Geoirs, FR;
Thomson Composants Militaires et Spatiaux, Courbevoie, FR;
Abstract
Disclosed is an amplifier circuit with gain controlled by a current or a voltage. It is sought to obtain a linear gain as a function of the set value current or voltage, whereas amplifiers with controlled gain usually have a non-linear variation of the gain as a function of gain control voltage. According to the invention, there is proposed an amplifier circuit with the particular feature of having two identical amplifiers with controlled gain: one receives the signal to be amplified and gives an amplified output signal; the other receives a reference voltage or current and gives an output which is compared with a signal with a set value of variation in gain. The result of the comparison is used to automatically control the gain of the second amplifier to adjust its output to a desired value. The first amplifier receives the same automatic control signal as the second one. The second amplifier has its output automatically linked to a set value while, at the same time, having a fixed voltage or current as an input signal. It therefore has a known gain proportionate to the set value. Finally, the first amplifier, which is identical to the second one and receives the same gain control signal, thus has a gain proportionate to the set value, in accordance with what was desired.