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Phase Shift Amplifier

IP.com Disclosure Number: IPCOM000098758D
Original Publication Date: 1959-Dec-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

French, WK: AUTHOR

Abstract

Passive elements and a voltage variable capacitor C are arranged to form a high gain amplifier. With no input signal E(1) the alternating voltage V from generator 1 and the alternating voltage V + 0 from generator 2 are balanced at the junction 3 by suitable adjustment of the bias 4 so that the output signal E(0) is zero. Isolation of the input from the generated voltage V is provided for by the twin T network TTN which is tuned to the frequency of V.

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Phase Shift Amplifier

Passive elements and a voltage variable capacitor C are arranged to form a high gain amplifier. With no input signal E(1) the alternating voltage V from generator 1 and the alternating voltage V + 0 from generator 2 are balanced at the junction 3 by suitable adjustment of the bias 4 so that the output signal E(0) is zero. Isolation of the input from the generated voltage V is provided for by the twin T network TTN which is tuned to the frequency of V.

The voltage across the primary of the transformer T is directly controlled by the capacitance of C which, in turn, varies in magnitude according to the value of an applied input signal E(I). A small change in voltage of the signal E(I) in one direction results in an unequal phase condition at the junction 3 and the development of a large alternating voltage across the transformer T. A phase sensitive demodulator PSD, which includes diodes D(1) and D(2), provides detection of the developed voltage.

A change in the signal E(1) in the opposite direction results in a voltage across the transformer which is 180 degrees out of phase with respect to that developed in the first instance.

The amplifier has positive or negative gain depending on how the secondary of the transformer is connected to the PSD.

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