Acquisition and analysis of fast single channel kinetic data on an apple IIe microcomputer

Abstract

We describe a method for acquisition and analysis of single channel kinetic data, that uses a ubiquitous microcomputer, the Apple IIe (and is thus cheap), and is yet sensitive and powerful (analysis of up to 6000 events per run of the program; event detection only limited by the amplifier bandwidth). For data acquisition, the original record is converted into an idealized record of open and closed times, using half amplitude threshold analysis or a two-cursor window discriminator. A Time Interval Meter (TIM) has been developed that measures the durations of the TTL-signal from the window discriminator and stores up to 256 intervals in a FIFO-buffer. Each cycle of the TIM is completed within 1 γs. The, largely Pascal, software reads the intervals from the FIFO-buffer and stores them in the main memory of the microcomputer (cycle time 70 γs). The package is completed with Pascal programs for statistical analysis, including histogram construction of open and closed times, non-linear fit of up to 3 exponentials and correlation analysis.