Design and fabrication of a prototype speech synthesizer

Speech synthesizing circuitry for use with hand-painted spectra is described. Photocontrolled audio oscillators are employed to obtain pure tones. Oscillation conditions are examined in a unified form for both vacuum tube and transistor circuitry. Amplitude stabilization is discussed employing a complex load. A prototype unit with six oscillators is found to have excellent frequency and amplitude stability for arbitrary audio oscillator frequencies. With additional oscillators, photo diode control of the sound intensity will provide the necessary flexibility for speech synthesis.