Signal processing electronics for multiple electronic and optical measurements on cells

Processing electronics for flow cytometry applications requiring simultaneous or sequential analysis of multiple electrical and optically sensed signals has been developed. A maximum of six analog signals are input to the processor. A measurement mode selector determines what signals are to be analyzed and the initial timing sequence of sense gates for acquiring signal crest values. Processor signal-triggering and sense gate time delays are selectable. Logic coincidence-anticoincidence circuits determine constraints on incoming signals. Gated peak-sense and hold signals are routed to computer interface electronics for digitizing and are then displayed as frequency distribution histograms using an LSI-11 computer. Signals also are processed as single parameters, ratios, and gated single parameters for output to a multichannel pulse-height analyzer and cell sorting electronics. The functional features of the processor are described along with examples illustrating simultaneous and sequential analysis of cultured cells stained with fluorescent dyes.