Doug: As I understand the process, there isn't actually cancellation AT the OATS. They have a monitor antenna nearby, but relatively far from the EUT on the OATS. A real EUT signal should fall off considerably by the time it reaches the monitor antenna, but an ambient emission will be relatively constant at the monitor and measurement antennas. All you have to do is sample the ambient, invert it, and sum it with the measurement antenna voltage. This should delete the ambient from the measurement data. (Easy to say! All you need is enough computing power and sufficiently capable processing algorithms.)
The "cancellation" takes place as a data operation within the Cassper hardware (or it's controlling computer), and not as an energy cancellation of the propagating fields actually on the OATS site. And yes, I would also like to know more about how Cassper manages to do this. But, I also realize they can't give away their trade secrets either. Ed :-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-) Ed Price [email protected] Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis :-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-) > -----Original Message----- > From: Doug [SMTP:[email protected]] > Sent: Wednesday, March 22, 2000 11:38 PM > To: [email protected] > Subject: Re: Ambient Cancellation Device for OATS > > > Perhaps it's because I've never understood ... > > How exactly does one do ambient cancellation at an OATS? > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > To cancel your subscription, send mail to: > [email protected] > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Jim Bacher: [email protected] > Michael Garretson: [email protected] > > For policy questions, send mail to: > Richard Nute: [email protected] > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected]
