Tweet
Here for your fun, is the DXP format files I started laying out in an impedance matched format. The plan WAS to make the board THREE layer, with the Tx and "high" current stuff on one side, the middle layer was a ground plane and the bottom layer, the audio and filters. I don't have time anymore as I'm working on a PI IB machine based on this and a front end amp I found which gives 0.2nV Root/Hz.
The BIG problem people are missing with these PI IB designs is tht the front end MUST have LOW gain or you get a load of ground effect (YES you DO!!). A gain of around 6-10 is OK, anything more is no good. I plan to put the main high gain AFTER the synch demods along with filters and maintain a differential signal path throughout the design. I want to see just how low a signal I can see.
I've heard that nV processing is possible but to get down there, the system overall dynamic range will be over 132dB which means I'll be close to "earth noise". Biggest problem is grounding the circuit and I'm looking at a conductive handle so the user becomes the "ground" but this in itself poses all sorts of other issues which must be overcome
.
Maybe someone will take these files on an finish what I started. GOOD LUCK! Oh, BTW NO DRC has been done on what has been layed out so far as it's ALL been manual (NO AUTOROUTE)!
I've included ALL the working files too such as the large CAPS. I was planning to use Rogers PCB material for it's low dielectric and low moisture absorbtion, also screening cans and conformal coating. Just some pointers.
ENJOY.
The BIG problem people are missing with these PI IB designs is tht the front end MUST have LOW gain or you get a load of ground effect (YES you DO!!). A gain of around 6-10 is OK, anything more is no good. I plan to put the main high gain AFTER the synch demods along with filters and maintain a differential signal path throughout the design. I want to see just how low a signal I can see.
I've heard that nV processing is possible but to get down there, the system overall dynamic range will be over 132dB which means I'll be close to "earth noise". Biggest problem is grounding the circuit and I'm looking at a conductive handle so the user becomes the "ground" but this in itself poses all sorts of other issues which must be overcome
.Maybe someone will take these files on an finish what I started. GOOD LUCK! Oh, BTW NO DRC has been done on what has been layed out so far as it's ALL been manual (NO AUTOROUTE)!
I've included ALL the working files too such as the large CAPS. I was planning to use Rogers PCB material for it's low dielectric and low moisture absorbtion, also screening cans and conformal coating. Just some pointers.
ENJOY.
Comment