Out in Front: June 6, 1996
Hewlett-Packard is aiming two new digital storage oscilloscopes (DSOs) at designers who build systems around 8-bit microcontrollers, including designers of electromechanical and medical systems. Among features that are unusual
in DSOs in this price range is a capture memory of 1M samples/channel. Most scopes with such deep memories cost more than $10,000. Both the $3495 54645A and the $4995 54645D have two analog channels with 100-MHz bandwidth and a maximum real-time sampling rate of 200M samples/sec. In addition, the 54645D includes a 16-channel logic-timing analyzer
that also captures 1M samples/channel. When you use all 16 channels, the timing analyzer's maximum capture rate is 100M samples/ sec/channel. If you use only eight channels, the capture rate and per-channel memory double.
Thanks to a multiprocessor architecture called MegaZoom, the two DSOs avoid the noticeable delay that typically occurs between changes in front-panel settings and the resulting changes in the display. A similar lag occurs when the signal changes. With the HP scopes, the delay is imperceptible. As with HP's earlier 54620 units, which perform only logic-timing analysis, the 54645D emphasizes the requirements of people who don't use a logic analyzer every day. You select trigger conditions by using a straightforward menu system. And, you can use logic patterns to trigger analog acquisitions.
Despite their deep memories, the scopes incorporate random equivalent-time sampling for repetitive waveforms. The scopes can use both single-shot and equivalent-time sampling. When the signals are repetitive, random sampling makes the effective sampling rate several times as high as the maximum 200M-sample/sec real-time rate. This feature provides better waveform detail than is possible when the scope samples rapidly changing signals at the maximum single-shot rate.
—by Dan Strassberg
Hewlett-Packard Co, Santa Clara, CA. (800) 452-4844, http://www.tmo.hp.com.