Method and apparatus for use in temporal analysis of waveforms
First Claim
1. Apparatus for indicating when a waveform satisfies selected conditions, comprising:
- first and second comparator means for comparing the instantaneous value of the waveform with first and second reference values, respectively,means for adjusting the first and second reference values,means for generating a gating signal when the instantaneous value of the waveform has attained both a first predetermined relationship with the first reference value and a second predetermined relationship with the second reference value,clock means for providing an indication of time,latch means for holding the value of the clock means at the instant the first predetermined relationship is satisfied, andgate means for passing the contents of the latch means to output when the gating signal is generated.
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Abstract
In single fibre electromyography it is useful to be able to measure intervals between waveforms (obtained from needle electrodes inserted into muscle fibres) reaching certain levels. A circuit is described, which is of general application, and which allows such intervals to be measured. First and second comparators which have adjustable reference levels receive an incoming waveform and, by means of polarity select circuits, provide outputs only when the reference levels are passed by waveform portions changing in selected respective directions. The time at which the first comparator is satisfied is available from a counter 33 but it is only passed to a computer interface when the second comparator has also been satisfied. Enable circuits prevent an output to the computer unless the comparators are satisfied within selectable time intervals.
228 Citations
10 Claims
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1. Apparatus for indicating when a waveform satisfies selected conditions, comprising:
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first and second comparator means for comparing the instantaneous value of the waveform with first and second reference values, respectively, means for adjusting the first and second reference values, means for generating a gating signal when the instantaneous value of the waveform has attained both a first predetermined relationship with the first reference value and a second predetermined relationship with the second reference value, clock means for providing an indication of time, latch means for holding the value of the clock means at the instant the first predetermined relationship is satisfied, and gate means for passing the contents of the latch means to output when the gating signal is generated. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of providing an indication when a waveform satisfies selected conditions, comprising the steps of:
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setting first and second reference values, comparing the instantaneous value of the waveform with the first and second reference values respectively, generating a gating signal when the instantaneous value of the waveform has attained both a first predetermined relationship with the first reference value and a second predetermined relationship with the second reference value, storing a value representing elapsed time at the instant the first predetermined relationship is satisfied, and passing the stored time value to output when the gating signal is generated. - View Dependent Claims (9, 10)
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Specification