CASPR

I'm looking for working knowledge on a CASPR system. The manual is not forthcoming on what I'd like to learn about its operation. Is there anyone with knowledge on the setup parameters for this system who can answer a few questions?

Thanks for any help,
Mike

Can you give me a little more information on the system. What kind of EMC System do you have (Conducted Immunity, ESD, EFT, etc). I have not heard of CASPR but I will ask my colleagues.

Cody,
CASPR is a virtual chamber program; it masks the ambients in the open and allows you a graph of the EUT signals.
It is for Radiated Emissions testing.
Mike

This is a reply from the EMC list:

If this is the same CASPR system I used about 8 years ago it is comprised of 8 port device that antennas/probes were attached and software running on a computer that also controlled the 8 port device.

It had two modes of operation, ambient cancelation and source localization, modes were selected in software.

For the ambient cancelation to work that measurement antenna and cancelation antenna had to be some distance apart. If I remember right it was something on the order of 10m.

I always thought the manufacture of that system did a disservice to the source localization capabilities by not promoting it more. Once you were used to the system it was one of the fastest debugging tools around.

Here is another reply from the EMC list:

We took a test ride many years ago. Interesting concept, difficult to implement. The hardware was setup at a distance. It basically assumed near equal distribution of ambient fields which were then subtracted from actual readings of EUT on an OATS. The results being just what you wanted to measure in the first place.

One More Post Perhaps the most informative:

The hardware referred to is the CASSPER correlation analyzer by Scientific Applications & Research Associates, Inc.

The hardware used the principle of correlation analysis, analyzing the phase correlation between multiple (minimum 2) test channels. The correlation determination between channels requires a significant data processing effort per data and time point. On the state-of-the-art hardware available at the time the data processing was really too slow for any real-time work, causing a horrible screen refresh rate in most cases, but it was great for source finding during bench debugging with some patience. Later hardware and software upgrades solved some of the processing speed issue, I’m told, but the evaluation unit I had was too slow for the type of work I was doing.

It was discontinued in 2008 (www.sara.com/EM/cassper/index.html). Maintenance was available through CASSPER(_at_)sara.com into 2009 according to that page.