| 摘要 |
<p>The voice testing device which determines the volume and frequency range of the voice, includes a sound generator which generates a frequency selected from a range of frequencies to give an acoustic signal. The person being tested speaks or sings into a microphone which passes the voice signals to the Y-input of a coordinate writer which receives at X-input an acoustic signal forming a control signal, and gives an indication of the amplitude of the voice signals. A switching system connects the X-input either with the sound generator or a control voltage corresponding to the voice signals. The selector system includes two sets of push buttons. One set is for selecting one note from the C major scale and the second set is for selecting an octave from a range of five octaves.</p> |
