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Precision Pulse Amplitude Calibrator

IP.com Disclosure Number: IPCOM000095841D
Original Publication Date: 1964-Aug-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Yang, ES: AUTHOR

Abstract

The circuit generates square wave pulses having precision calibrated amplitude in response to input pulses of high or low duty cycle. The calibration accuracy is achieved through circuit parameters which are accurately maintained.

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Precision Pulse Amplitude Calibrator

The circuit generates square wave pulses having precision calibrated amplitude in response to input pulses of high or low duty cycle. The calibration accuracy is achieved through circuit parameters which are accurately maintained.

Normally, T1 is biased on and T2 is biased off. A constant current source, including T3, R7 and R8, develops a current I which passes through T1 and bypasses T2. When a negative-going square wave pulse is applied to the input of T1, the leading edge of the pulse causes T1 to be cut off and T2 to be turned on. The trailing edge of the pulse switches T1 back to conducting and T2 to nonconducting.

The input pulse can have relatively large amplitude variation from pulse to pulse without affecting the amplitude of the output pulse taken at the collector of T2. This can be shown from a consideration of the collector voltages of T1 and T2 which are as follows: Vc(2) = alpha(2) R(2) Vc(1) (100-X%) over alpha(1) R(1) where alpha equals current gain, R equals collector resistance, Vc equals peak- to-peak collector voltage and X equals the duty cycle. The subscript assigned to each parameter represents the designated transistor T1 or T2.

In the equation, alpha and R are constants which can be accurately measured. Vc, the collector voltage, which is directly proportional to 1 the constant current, can be varied to achieve different output amplitudes by varying the biasing on T3. The constant current I can be acc...