| 摘要 |
The voiced sounds produced by a diver breathing a helium oxygen mixture are stored as incremental charges on individual ones of a bank of condensers. The condensers are sequentially, and for discrete intervals of time, connected to the input by a series of switches sequentially closed by operation of a storage counter. A first oscillator, which may be variable, controls the rate of operation of the storage control counter. A series of output switches are successively closed to connect successive condensers to an output circuit. The output switches are successively closed by the operation of a readout counter which is in turn controlled by the output of a second oscillator operated at a fixed frequency which is less than the frequency of the first oscillator. In the free-running mode, i.e., in the absence of a glottal wave, both storage and readout counters are reset by the last count of the readout counter. The imposition of a glottal wave on the input, however, operates to reset both storage and readout counters regardless of how far a count has progressed. Formant frequencies are thus reduced in proportion to the ratio of the oscillator frequencies while glottal frequencies are unchanged. |
