Combined display of video image with superimposed analogue waveforms for clinical applications.

An instrument is described which has been developed for use in any clinical investigation where a video image and analogue data are simultaneously acquired and where synchronous viewing of the data is important, both at the time of the study, and at subsequent review. Up to eight analogue signals can be superimposed on the video image, appearing as coloured waveforms scrolling from the right. The output is available in a PAL encoded form suitable for video recording in colour. Resolution is 256 (vertical) by 512 (horizontal) with a maximum sample rate of over 15 kHz. Additional features are: a graticule for calibration, a facility to display alphanumeric characters, and an option for automated uninterrupted viewing of the visual image. The system has been used in urodynamic investigations, for overnight studies of sleep disorders, and for electrophysiological studies during open heart surgery.