A dual-channel signal averager for spontaneous signals

This signal averager has been developed for spontaneous transients of tension and of aequorin bioluminescence in skinned cardiac cells. The signal with the largest signal-to-noise ratio (generally the tension transient) is entered in Channel 1 and triggers the system. Then the averager will unmask the signal entered in Channel 2 if it was buried in the noise during the direct recording. This signal averager uses an inexpensive microcomputer and a program written in Assembly Language. To facilitate its use, the averager is remotely controlled by a potentiometer for the adjustment of the threshold voltage above which the signal in Channel 1 will be collected and by three push buttons for starting the data collection, for averaging and displaying the results, and for resetting the system. The display is purely analog on the recorder, including averaged signals and interval for the signals in both channels together with a graphical representation of the standard deviations and of the number of observations. This signal averager could be used for any preparations developing spontaneous signals with variable intervals, provided that at least one of the synchronous signals has a large enough signal-to-noise ratio to trigger the system.