Concertola and Midi
By Robbie Rhodes
The contact bounce is easily filtered with a simple resistor and capacitor (RC) filter before the signal goes into the CMOS commutator circuit. The signal level preceding the filter network must be limited to twice the threshold voltage of the CMOS device. In this way no timing distortion will be introduced. Since the fall-time of the pouch and bleed combination is around 20 milliseconds, the RC time constant can be about the same without affecting the data.
Richard Tonnesen is the expert on these matters -- his pneumatic reader has been in use almost 15 years!
-- Robbie Rhodes
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(Message sent Wed 29 Nov 1995, 07:48:04 GMT, from time zone GMT-0800.) |
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