Browse Prior Art Database

Pulser

IP.com Disclosure Number: IPCOM000074938D
Original Publication Date: 1971-Jul-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Buhler, OR: AUTHOR

Abstract

The illustrated circuit having high-noise immunity for use in an industrial environment provides a digital clock at twice line frequency F. The line signal F is full-wave rectified at 10. Neon tube NE2 is repeatedly fired by the high-amplitude rectified signal. Current flows through voltage divider 11 switching transistor 12 to current conduction. As NE2 ionizes and deionizes, output rectangular signal 14 is generated at frequency 2F. Because of differences in the ionization and deionization voltages, as well as line voltage variations, output signal 14 is asymmetrical. To make signal 14 symmetrical, a bistable multivibrator could be added to output terminal 16.

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Pulser

The illustrated circuit having high-noise immunity for use in an industrial environment provides a digital clock at twice line frequency F. The line signal F is full-wave rectified at 10. Neon tube NE2 is repeatedly fired by the high-amplitude rectified signal. Current flows through voltage divider 11 switching transistor 12 to current conduction. As NE2 ionizes and deionizes, output rectangular signal 14 is generated at frequency 2F. Because of differences in the ionization and deionization voltages, as well as line voltage variations, output signal 14 is asymmetrical. To make signal 14 symmetrical, a bistable multivibrator could be added to output terminal 16.

For a 1-to-1 frequency relationship, a half-wave rectifier is substituted for full- wave rectifier 10. A bridge-rectifier could be substituted for the transformer-diode rectifier 10.

Noise immunity is provided by both NE2 and capacitor 17. Because of the finite ionization and deionization time of NE2, high-frequency noise on line F is isolated. Further, the voltage hysteresis of NE2 (about 30 volts) between the firing and extinguishing voltages provides low-frequency noise immunity. Variations in noise on the line may cause NE2 to fire early or extinguish late. Such variations in the output signal appear as phase shifts, but do not introduce extraneous signal cycles. High-frequency noise that may be capacitively coupled through NE2 is filtered by capacitor 17.

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