Accession Number : ADD008014

Title :   Balanced Impedance Coupler.

Descriptive Note : Patent Application,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Previti,Frank R

Report Date : 04 Nov 1980

Pagination or Media Count : 13

Abstract : A balanced preamplifier is disclosed for impedance-coupling an audio signal source, such as a microphone, to a differential amplifier. In one embodiment, the preamplifier comprises a first stage wherein a pair of complementary bipolar transistors are connected in a common-base configuration and coupled to a low-impedance microphone so that the microphone signal is applied to the respective emitters of the transistors and transformed to an appropriately higher impedance level at the respective collectors thereof with common-mode passage of external and internal noise. A second stage including a complementary pair of bipolar transistors in a common-emitter configuration is coupled to the first stage for greater power and voltage amplification requirements. In a second embodiment, the preamplifier comprises a pair of complementary field-effect transistors (FET) connected in a series common-drain configuration and coupled to a high-impedance microphone so that the microphone signal is applied to the respective gates of the FETs and transformed to an appropriately lower impedance level at the respective sources thereof with common-mode passage of noise. (Author)

Descriptors :   *Patent applications, *Preamplifiers, *Transistor amplifiers, *Bipolar transistors, Field effect transistors, Coupling(Interaction), Requirements, Impedance, Amplifiers, Intervals, External, Voltage, Noise

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE