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Peak Sensing Circuit

IP.com Disclosure Number: IPCOM000094974D
Original Publication Date: 1965-Jul-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

McCullough, JW: AUTHOR

Abstract

Peak sensing circuit 10 detects only peak or major pulses in a train of pulses which are surrounded by spurious noise pulses. The discrimination level is not constant but changes with each peak pulse. By this arrangement, spurious pulses which are larger than some of the peak pulses can be discriminated against if the peak pulse which directly precedes the large spurious pulse is of a higher amplitude.

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Peak Sensing Circuit

Peak sensing circuit 10 detects only peak or major pulses in a train of pulses which are surrounded by spurious noise pulses. The discrimination level is not constant but changes with each peak pulse. By this arrangement, spurious pulses which are larger than some of the peak pulses can be discriminated against if the peak pulse which directly precedes the large spurious pulse is of a higher amplitude.

Positive pulses applied to input terminal 15 charge capacitor C through transistor T1 causing Schmitt trigger 20 to fire. As the trailing edge of the pulse falls away, T1 becomes reverse biased, thus resetting trigger 20.

The diode coupled, input bias circuit consisting of diodes D1, D2, D3, resistors R1 and R2 is decoupled by D1 when the input pulse is positive going. If a pulse peak suddenly increases, such as the increase from the peak of pulse 2 to the peak of pulse 3, T1 saturates allowing C to charge quickly to the new peak voltage level.

Thus, pulse 3-1 is discriminated and 20 does not fire even though pulse 3-1 is larger in amplitude than pulse 2. This is because the larger capacitor voltage established by pulse 3 is not overcome. As the trailing edge of a peak pulse falls below the triggering level, D1 becomes forward biased. Such provides a relatively long time constant discharge path to permit detection of a peak pulse which is somewhat smaller than the preceding one, such as pulse 5.

If there are no input pulses, T1 is biased in its...