Browse Prior Art Database

Pulse Detector

IP.com Disclosure Number: IPCOM000081032D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Cole, TG: AUTHOR

Abstract

The circuit shown is a receiver or pulse shaper having the characteristics of a Schmitt trigger, whilst being implemented in four-phase logic. It has moreover an adjustable hysteresis. Shown below the circuit diagram is a symbolic representation of the receiver which will be used to illustrate its operation.

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Pulse Detector

The circuit shown is a receiver or pulse shaper having the characteristics of a Schmitt trigger, whilst being implemented in four-phase logic. It has moreover an adjustable hysteresis. Shown below the circuit diagram is a symbolic representation of the receiver which will be used to illustrate its operation.

The switch numbers in the symbolic representation correspond to device numbers in the circuit diagram so that S6 and S7 close during phase A, S1 and S8 during phase B, S4 and S5 during phases C and D, and S66 and S77 during phase D.

Capacitors COUT, CG6, CG7 and CNOUT are the node capacitances associated with the names indicated. Capacitors CGD66 and CGD77 are the gate-to-drain capacitances of devices 66 and 77.

The sequence starts at phase A when switches S6 and S7 close discharging CG6 and CG7. Nodes OUT and NOUT maintain a differential voltage of VLOGIC, one node being at zero volts.

For the case when hysteresis is of interest EIN can be considered equal to VREY. Hence, during phase B when S1 and S8 close, nodes OUT and NOUT are charged to the same potential. The differential voltage previously hold between OUT and NOUT is transferred - attenuated by the capacitor divider action of CGD66 and CG6 (and clearly CGD77 and CG7) - to nodes G6 and G7.

The differential voltage between nodes G6 and G7 at the end of phase B is given by Delta VG6 - G7 = VLOGIC X CGD66 over CGD66 CG6.

During phase C switches S4 and S5 close; equalizing the potential bet...