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# Gain Switching Circuit

IP.com Disclosure Number: IPCOM000091265D
Original Publication Date: 1967-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 25K

IBM

Shen, MN: AUTHOR

## Abstract

This circuit is a gain switching circuit which is independent of its load. With transistor T1 conducting V Out = ›1-(1/n)| x IR where n is the total number of resistors R(1)...R(n), I is the input current from a modulated current source, and R is the resistance of R(1)...R(n). If T1 is then turned off and transistor T2 turned on, then V Out = ›I-(2/n)| x IR. Furthermore, as each transistor T1...Tn is turned on in sequence and the previously conducting transistor is turned off, the gain is reduced by a factor of 1/n. Furthermore, the staircase signal can be developed from the envelope of the output by switching transistors T1...Tn on and off sequentially in the order of decreasing numerical value assigned to them in the drawing.

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Gain Switching Circuit

This circuit is a gain switching circuit which is independent of its load. With transistor T1 conducting V Out = >1-(1/n)| x IR where n is the total number of resistors R(1)...R(n), I is the input current from a modulated current source, and R is the resistance of R(1)...R(n). If T1 is then turned off and transistor T2 turned on, then V Out = >I-(2/n)| x IR. Furthermore, as each transistor T1...Tn is turned on in sequence and the previously conducting transistor is turned off, the gain is reduced by a factor of 1/n. Furthermore, the staircase signal can be developed from the envelope of the output by switching transistors T1...Tn on and off sequentially in the order of decreasing numerical value assigned to them in the drawing.

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