Out in Front: April 11, 1996

PC-based waveform generator converts 80M samples/sec

Gage Applied Sciences' CompuGen 1100 differs from typical PC-based waveform-generator boards in several ways, the most obvious of which is speed. The board converts 80M samples/sec (100M with a degraded S/N ratio) and produces an analog output that, with a 50-ohm load, is flat within 0.1 dB to 5 MHz and within 1 dB from 5 to 10 MHz. Settling time to 1% of full scale of final value is 10 nsec for a 2V step. Resolution is 12 bits. Whether PC-based or box-level, most waveform generators with such speed offer only 8-bit resolution. Because the output data rate is so much faster than the ISA bus, the board stores 512k waveform samples (standard) and 8M samples (maximum) in onboard RAM.

Another feature rare in PC-based waveform generators is programmable gain. You can select among six full-scale ranges—±100, 200, and 500 mV and ±1, 2, and 5V. The board also features programmable offset to ±100% of full-scale with 8-bit resolution. The 1100's output withstands sustained short circuits to ground and to 140V-ac rms or ±200V dc. Memory-looping capability allows as many as 16 million iterations, and output modes include single step, retriggerable single shot, N outputs, and continuous.

The $4995 board comes with Windows-based software that lets you create your own waveforms without writing any code. You can cut and paste from a waveform library, describe waveforms with equations, or use waveforms you've captured with the vendor's CompuScope cards. You can use eight of the boards in one PC to create multichannel waveforms.

—by Dan Strassberg

Gage Applied Sciences Inc, South Burlington, VT. (800) 567-4243.