Voice-operated gas lamp stroboscopes

Claim 1

A voice-operated stroboscope, comprising an acoustic transducer microphone to be supported near the mouth of a patient to be actuated by sound pressure variations caused by the larynx of the patient when producing selected sounds, an audio-frequency amplifier having an input coupled to said transducer and an output having means providinG trigger voltages for activating a trigger tube to conduct in predetermined time-lag and phase relationship to vibrations produced by the patient''s vocal chords, a normally non-conductive electrical current control trigger tube having a control grid coupled to the output of said amplifier to be triggered into a state of conduction responsive to amplified signals representing vibrations of the vocal cords, said time-lag and phase relationship being determined by the amplitude of the amplified signals applied to said trigger tube relative to its threshold trigger voltage and by the distance from the transducer microphone to the vocal chords, and a gaseous stroboscopic lamp having an anode coupled to said current control trigger tube to produce light flashes upon conduction of the latter to enable incident sounds from the vocal chords of the patient to trigger the flashes of the stroboscopic lamp substantially in synchronism with the individual audible vibrations of the patient''s vocal chords so that an observer may view or photograph such dynamic motion as though the vocal chords were nearly motionless.