Accession Number : ADD017371

Title :   Pre-Amplifier With Multi-Stage Feedback.

Descriptive Note : Patent Filed 22 Mar 94, patented 6 Dec 94,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Hagerty, James D

Report Date : 06 Dec 1994

Pagination or Media Count : 7

Abstract : A circuit for amplifying an input signal comprises an operational amplifier, a dual operational amplifier, and a buffering operational amplifier all cascaded in the aforementioned order. The first operational amplifier amplifies the input signal with minimum noise degradation, is set up as a non-inverting amplifier stage, and has a local negative feedback loop comprising a resistor and capacitor in parallel. The dual operational amplifier has two amplifying devices. One device forms a second amplifying stage which increases the gail of the pre-amplified input signal and has a local negative feedback loop comprising a resistor. The other device is a third operational amplifier which combines with the buffering operational amplifier to form an amplifying and buffering stage. The third operational amplifier connects in series to the output of the second amplifying stage. The buffering operational amplifier connects in series to the output of the third operational amplifier and buffers the amplified signal at this output. The amplifying and buffering stage has a two-stage feedback loop comprising a resistor connected between the output of the buffering operational amplifier and the inventing input of the third operational amplifier. A four-stage feedback loop includes a resistor and capacitOr in parallel and connects between the output of the buffering operational amplifier and the inverting input of the first operational amplifier.

Descriptors :   *OPERATIONAL AMPLIFIERS, BUFFERS, INPUT, OUTPUT, PREAMPLIFIERS, DEGRADATION, FEEDBACK, SIGNALS, NOISE, AMPLIFICATION, LOOPS, STAGING, DUAL CHANNEL, RESISTORS

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE