An analog data acquisition board for the Macintosh II.

Area of Science:

• Computer Engineering
• Electrical Engineering
• Scientific Instrumentation

Background:

• Existing Macintosh II data acquisition boards lack simultaneous multi-channel sampling and are relatively slow.
• There is a need for faster, more capable data acquisition hardware for scientific applications on the Macintosh II platform.

Purpose of the Study:

• To design and develop a high-speed Analog-to-Digital (A/D) board for the Macintosh II.
• To enable simultaneous multi-channel data acquisition with improved speed and resolution.

Main Methods:

• Designed a single-slot A/D board utilizing 38 integrated circuits for the Macintosh II's 32-bit NuBus.
• Implemented simultaneous sampling of up to eight channels with a sampling period ranging from 1 microsecond to 1.6777215 seconds.
• Achieved a total conversion and acquisition time of 1 microsecond (500 ns A/D conversion + 500 ns track-and-hold/multiplexer time).

Main Results:

• The board provides 12-bit resolution for signals between +/- 2.5 volts.
• For eight channels, the maximum Nyquist frequency is 62.5 KHz.
• Single-channel data acquisition supports frequencies up to 500 KHz, and dual-channel comparisons up to 250 KHz.

Conclusions:

• The developed A/D board offers a significant advancement for scientific data acquisition on the Macintosh II.
• It addresses the limitations of existing boards by providing simultaneous multi-channel sampling at high speeds.
• The board enhances the Macintosh II's utility as a powerful machine for scientific data acquisition and processing.