Compatible multiplex closed-circuit television and analog data recording.

An economical system is described for multichannel recording of analog signals on a videotape recorder. The instrument digitizes each analog signal at a rate of 60 Hz and is suitable for continuous recording of low-frequency phenomena commonly monitored in microcirculatory studies. The system provides complete synchronization with real-time video information on the same black and white videotape recorder without interference with the normal picture.