Radiant energy – Photocells; circuits and apparatus – Photocell controlled circuit
Patent
1998-10-30
2000-11-07
Allen, Stephone B.
Radiant energy
Photocells; circuits and apparatus
Photocell controlled circuit
356445, G01N 2100
Patent
active
061440248
ABSTRACT:
An optical densitometer includes a receiver adapted to produce an electrical output voltage characteristic of an optical density to be measured. A voltage-controlled oscillator produces a periodic signal having an output waveform with a frequency and period characteristic of the output voltage of the receiver. A counter produces a digital value corresponding to the output waveform of the periodic signal produced by the oscillator; and a converter produces a digital optical density signal from the digital value. The counter is adapted to produce its digital value corresponding to the frequency or period of the periodic signal produced by the oscillator. The counter may include a portion adapted to produce a digital value corresponding to the frequency of the periodic signal produced by the oscillator; and a portion adapted to produce its digital value corresponding to the period of the periodic signal produced by the oscillator.
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Allen Stephone B.
Kessler Lawrence P.
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