Just for an update. I changed the values of the voltage divider for the monitoring circuit. Decreased the current by a factor of about four. My monitored voltage surge on the signal conditioner output caused by LED jump dropped from 200mvpp, to 20mvpp. And duplicated it on two other units...
Sounds like NAV/MAR, don't remember Army paying that much attention to things as such. I worked Navy Helicopters for 20 years. I used to have my ASEMICAP login to their resources. The biggest problem with what I'm batteling is, I didn't design it. I'm trying to debug someone elses H/W design...
The electronics are in enclosures, and depending on the application, may be as close as 15ft. We do see external noise from variable speed motors, CB's etc and try to mitigate those as much as possible. When we setup the transmit/receive pair the pulsed field is nulled. What we are actually...
VE1BILL, thanks for the quick look. And yes I shouldn't see any affect with the dc, however reality does intrude:). What I'm curious about is with the minor ripple from the SMPS sources sitting atop the reference voltage. Could these be setting up a small magnetic field that when current is...
I'm still working through some of the transmit refinement for our antenna design. I've had a chance to actually see what is being measured by using a Tektronix Spectrum Analyzer. Definitely an eye opener. Now comes another interesting question about our antenna system. If you check my...
Ouch, trying to keep costs down, don't have a lot of funding for the R&D department ;-) hence the raw calculator work :-D But you're right that would definitely make it easier to check the antennas out.
I was looking at something similar. Those will definitely help with the transmit coils. The receive section is a little harder because of the dual coil setup. i.e.
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C C
C...
The detection uses timing pulses to enable the "look" for the magnetic decay, so the receive section is turned off during the primary pulse and the kickback pulse. The timing is critical to the detection system. Although it would be nice to increase the number of turns at a rate that is...
I had a chance to peruse the non-foster filters, It looks like it might work, however as noted the frequency is definitely below most of the designs presented.
The reason for the original question is the documentation for the original antenna designs were incomplete. I.e. It's more of a trial...
That sounds like it might help. Currently we "tune" each receive antenna using a resistor network to balance the incoming signal. Active wouldn't be a bad option, and I can always change the input hardware to accomidate for that.
My biggest frustration though is the varying widths of the conveyors means the number of turns changes to keep the current down and not drive the circuits into overload. When we wind and antenna, we pre-pour check it to make sure it will terminate correctly and also to ensure the current is...
We have some more sensitive designs that use a box around the transmit and receive antennas, but they are operating around 10-14kHz. The conveyors are variable width. The reason I am looking is the antenna designs were created around 40 years ago, but nothing has been done to improve them with...
We manufacture Metal Detectors for Industrial applications. I.e. metal traveling down a conveyor belt. We send out a 50us pulse that has a sharp rise and drop from the inductive effect from the wire wrap antenna. Our antennas are 16ga copper and 22ga copper. The transmit antenna has about 17...
I'm looking for ideas or references that will help me design multi loop coil antennas for 1380Hz to 5000Hz range. The system is a transmit and receive system that puts out a bipolar pulse, and measures the Eddy current decay off of a piece of metal that passes between the antennas. I'm looking...
