Browse Prior Art Database

Multipurpose High Resolution One-Track Tachometer

IP.com Disclosure Number: IPCOM000044151D
Original Publication Date: 1984-Nov-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Promis, GG: AUTHOR [+2]

Abstract

This article describes a circuit and means for generating a synchronization pulse and unique timing signals with a one-track digital tachometer providing evenly spaced signals. The circuit also provides high tachometer resolution. The figure shows a block diagram of the circuit. A single track tachometer 10 is attached to the motor 11 (or any other rotating device whose speed and/or position is to be monitored). The pulses on this digital tachometer are uniformly spaced with the exception that a modified pulse is provided once per revolution for synchronization. The modified pulse can be an additional pulse or a missing pulse that can be detected because of the abrupt change in relative pulse timing.

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Multipurpose High Resolution One-Track Tachometer

This article describes a circuit and means for generating a synchronization pulse and unique timing signals with a one-track digital tachometer providing evenly spaced signals. The circuit also provides high tachometer resolution. The figure shows a block diagram of the circuit. A single track tachometer 10 is attached to the motor 11 (or any other rotating device whose speed and/or position is to be monitored). The pulses on this digital tachometer are uniformly spaced with the exception that a modified pulse is provided once per revolution for synchronization. The modified pulse can be an additional pulse or a missing pulse that can be detected because of the abrupt change in relative pulse timing. The output signals of the tachometer can be provided by a photo detector 12, but in any event is fed into a phase detector 13 that is part of a phase-locked loop. The output of the phase detector is filtered and frequency-compensated and is used to control a voltage-controlled oscillator 14 which is outputting approximately 1 MHz. The output of the voltage-controlled oscillator is frequency divided by a binary counter 15 and fed back to the second input to the phase detector. By this means the output of the voltage controlled oscillator is maintained at a frequency that is a direct multiple of the drum tachometer frequency. The use of a phase-locked loop greatly increases the resolution and positional accuracy of a ta...