Browse Prior Art Database

AC Cross Over Detection

IP.com Disclosure Number: IPCOM000096831D
Original Publication Date: 1963-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Lasker, RJ: AUTHOR [+2]

Abstract

The circuit effects cross-over detection of an AC signal, i. e., passage through zero. It consists of input clipper and buffer stage 10, amplifying stage 11 and pulse generator 12.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

AC Cross Over Detection

The circuit effects cross-over detection of an AC signal, i. e., passage through zero. It consists of input clipper and buffer stage 10, amplifying stage 11 and pulse generator 12.

An AC signal fed into the Input is clipped in stage 10 and amplified to a prescribed level by cascaded amplifiers 13 and 14. The amplified signal is then applied to the base of transistor 15. This is biased to conduction and, in turn, biases tunnel diode 16 to one of its operating states. Change of polarity of the input signal, passage through a crossover, effects changed current flow through transistor 15. Concomitant switching of diode 16 to its second operating state occurs. the resulting voltage variation across diode 16 is amplified by transistor 17 to provide the desired output pulse.

On succeeding change of polarity at the input in a different direction, diode 16 is reset to its first operating state and the transistor 17 is shut off.

The circuit detects differences in phase angle between a pair of sinusoidal signals to within an accuracy of plus or minus one minute of arc, where the indicating output pulses can have a rise time of as small as 25 nanoseconds.

1

Page 2 of 2

2

[This page contains 3 pictures or other non-text objects]