Posted by Reg
on 9/15/2009, 9:20 am, in reply to "Just curious, is this the Pulse Devil patent?"
75.70.158.108
Hi Frank,
Nope, the PD uses a different concept for its design. If you can find a schematic of the PPD1, that was the initial basis or concept for the PD foundation. The PPD1 was an Eric Foster design for a discriminating PI. It worked on a mineral free beach but suffered because of ground mineralization much like the old TR's. So, in bad ground the disc feature didn't work well.
So, the trick was to be able to minimize the effects of the ground signal and the PPD1 should work much better on land also.
Now, can that be done? Yep, I am sure it can.
Why do I say that? Well, the VLF motion detector is simply very similar to the old VLF/TR but with both the TR disc and VLF all metal signals run through filters to minimize the ground signal. So, the VLF motion detector simply uses a modified VLF/TR fundamental design.
Now, using a somewhat similar concept on the PPD1 and you would have a motion disc PI.
The Pulse Devil samples multiple times with some like a typical PI and other samples taken during the actual transmit pulse. The two signals are then used to develop the disc feature.
The original PPD1 also sampled both during the off time and during the transmit pulse to accomplish its disc feature.
BTW, the PPD1 used the old Garrett coaxial coil housing and had two receive coils, I believe.
Reg
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