Browse Prior Art Database

Velocity Transducer

IP.com Disclosure Number: IPCOM000053132D
Original Publication Date: 1981-Sep-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

DiGirolamo, A: AUTHOR [+2]

Abstract

Many machines use emitter wheels or grating strips to sense velocity or position or both. The output from these devices is a digital pulse stream with a period dependent upon the machine velocity (pulse train A). Often the velocity is desired in an analog, rather than digital, form. In the past this has been accomplished with smoothing circuits, sophisticated multiple moving discs, or transducers requiring mini-computers. All of these have disadvantages, such as low accuracy, time delay, or high complexity.

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Velocity Transducer

Many machines use emitter wheels or grating strips to sense velocity or position or both. The output from these devices is a digital pulse stream with a period dependent upon the machine velocity (pulse train A). Often the velocity is desired in an analog, rather than digital, form. In the past this has been accomplished with smoothing circuits, sophisticated multiple moving discs, or transducers requiring mini-computers. All of these have disadvantages, such as low accuracy, time delay, or high complexity.

The disclosed concept employs a triggering of a ramp wave at the trailing and/or the leading edges of emitter pulses (pulse train B). The value of the ramp wave may be held at each trigger pulse (signals C and D). This ramp and hold may be accomplished either digitally or in an analog form. The voltage waveform B is proportional to the pulse period t. However, velocity is proportional to 1/t, so a divide must be accomplished. By employing a divide function module (available off the shelf) which has signal D as the divisor and a constant as the dividend, the output from this module will be proportional to the frequency of pulses or machine velocity. The output then may be updated at each trigger (waveform B), affording minimum time delay.

It should be recognized that the divide function may also be accomplished using a logarithmic converter, inverter, and anti logarithmic converter. This type of design has the following advantages: wide dyna...