Circuit for a flash stroboscope for examining vocal chord functions

US4807291A · kind A · utility

Assignee

• RICHARD WOLF GMBH · DE

Inventors

• Reiner Hoffmann · Mühlacker, DE
• Peter Jaggy · Rain, DE

Key dates

• Filing date: Oct 10, 1986
• Grant date: Feb 21, 1989
• Expiry date: Oct 10, 2006

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61B1/2673
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

A circuit for a flash stroboscope for examining vocal chord functions has a number of band-pass filters connected in parallel which have different cut-off frequencies. The acoustic signal generated by the vocal chords is fed to the inputs of these filters as an electrical signal after conversion in an electro-acoustic transducer. The output signal or fundamental wave signal allowed to pass by filter with a fundamental frequency of interest for the examination is supplied to a lamp circuit, which activates a flash lamp by trigger pulses generated from the fundamental wave. The band-pass filters are scanned automatically and successively to determine the presence of an output signal having the fundamental frequency of interest. The scanning operation is stopped upon detection of an output signal of this frequency at one of the filter outputs, so that the output of this filter can be connectd to the lamp circuit. The scanning operation is repeated cyclically so that the circuit can always be updated to the existing condition in the event of possible changes of the fundamental wave frequency.