1960 年 16 巻 4 号 p. 277-279
An instrument has been developed as a part of a formant-vocoder for smoothly detecting wide-range voice pitch frequencies. Speech signals from a conventional telephone are cross-modulated, low-passed, frequency-inverted, and frequency-analyzed. Analyzed signals are discriminated separately, and their DC output voltages are compared in a simple diode adder in order to select the most significant voltage which indicates the pitch frequency. The voltage-versus-frequency characteristic is closely linear, and the response time is comparatively small. The temperature characteristic, however, is not satisfactorily good yet.