Apparatus for digitizing noisy time duration signals which prevents adverse effects of contact bounce

Claim 1

Apparatus for processing noisy time duration signals which have stable portions represented by a first voltage level and may have transient portions adjacent their leading and trailing edges in which the voltage fluctuates between said first level and a reference level, the apparatus including a. converting means 18, 19, 21 connected to receive said noisy signals and transduce each into digital form, the converting means requiring for each signal a control pulse which is synchronized to the trailing edge of the signal; b. a one-shot multivibrator 35 which receives said noisy signals and produces an output pulse whose width is greater than said transient portions whenever a signal changes from the first level to the reference level; and c. a gated one-shot multivibrator e.g., 11 having first and second input connections 23, 24 coupled to receive the output of the multivibrator 35 and said time duration signals, respectively, and serving to produce said control pulse at an output connection 25 only when the trailing edge of said multivibrator output pulse is received at a time when the time duration signal is at its reference level.