title: An analog data acquisition board for the Macintosh II.
abstract: The Macintosh II has the hardware to make a good scientific data acquisition and data processing machine. The data acquisition boards currently available do not sample multiple channels simultaneously. They are also relatively slow. We have designed a fast Analog-to-Digital Board for the Macintosh II that samples eight channels at once. This board acquires data with sampling periods from 1 microsecond to 1.6777215 seconds in increments of 100 nanoseconds. Any jitter is due to the stability of the clock which is about one part per billion. The actual analog-to-digital conversion time is 500 nanoseconds with another 500 nanoseconds taken up by the track-and-hold amplifier acquisition time and the multiplexer setting time. The board samples as many as eight channels, giving 12-bit resolution for signals between plus and minus 2.5 volts. For eight channels the maximum Nyquist frequency is 62.5 KHz. The board will acquire single-channel data that has frequencies up to 500 KHz. Simultaneous comparisons of two channels can be made for signals that have a highest frequency component of 250 KHz. Thirty-eight integrated circuits were used on a single-slot board that connects to the Macintosh II's 32-bit NuBus.
authors.forename: R J
authors.initials: RJ
authors.lastname: Morgan
authors.forename: T P
authors.initials: TP
authors.lastname: Karnowka
authors.forename: T N
authors.initials: TN
authors.lastname: Solie
mesh_terms: D000703:Analog-Digital Conversion; D000818:Animals; D004285:Dogs; D004386:Duodenum / Q000502:physiology; D008838:Microcomputers; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D012984:Software; D013270:Stomach / Q000502:physiology