Microwave Human Vocal Vibration Signal Detection Based on Doppler Radar Technology

A speech radar system is presented for extracting speech information from the vocal vibration signal of a human subject. Due to the tiny glottis motion of several millimeters, a coherent homodyne demodulator with high sensitivity is developed to detect reflected radio signal, phase modulated by the vibrating vocal cords. The signal detection quality and system circuit design are described. Measurements of vowels and words, both with the speech radar system and the conventional acoustic microphone system, were conducted and compared. The essential speech information can be reliably obtained from the proposed speech radar, making it more appealing for speech applications in high background acoustic noise environment.