The Test-Board redesign plan

 

 

Replace the 30 Megasample per second, 10-bit  ADC dropped from the Analog Devices list of current products with a 40 Megasample per second product with similar precision.
Remove some short circuits inadvertently left in the original layout
Add the PC-104+ connector to make accessible to the FPGA more interrupt lines in the bus interface.
Add board level support for interrupting power supplied to the twisted pair.
Relocate oscillator and PLL components to reduce noise induction into the communications circuits.
Install support for easy change-over from local clock to distributed clock.
Install input for distributed clock which will have high immunity to noise and not cause ground loops.
Install support circuitry for the One Pulse-Per-Second signal from the GPS clock which is used to time synchronize test boards. 
Install limiting amplifiers where clipping and recovery time are a problem for the signals.
Install more robust blow-out protection for communications DAC.
Resolve component interference problems associated with stacking boards.
Relocate RJ-45 connector on the same edge as the twisted pair input and service connections.