Computer-generated spectrogram displays for on-line speech research

A program to generate and display spectrograms on a computer-controlled scanned-display television monitor is described. The program features computation of power spectra for selected time segments with the aid of the fast Fourier transform algorithm, four-level intensity quantization controlled by a threshold under operator control, and flicker-free scanned display of the generated data. The computer-generated spectrograms suffer from intensity and spatial resolution limitations relative to conventional spectrograms. However, their rapid generation and flicker-free display makes their use appropriate in a man-computer interactive environment to complement aural evaluation of digitally synthesized or processed speech signals.