Overclocking to 128 MHz
When Justin used a 128 MHz clock for the ADC I simply thought that it was not possible. I based this to the FX3014 specs that state the upper limit of GPIFII to 100MHz. He was right and this kind of overclocking is possible, maybe because we don't use the FX3 in an extended temperature range or maybe because the GIPIFII state machine we use is simple. The transfer rate of the USB stream raises to 128 Msps with 16 bit samples i.e. 256 MBs. This requires a quite fast PC and it may raise some more problems in the transfer. Nevertheless it runs on my PC (I7-3770) and offers another advantage other than wider bandwidth. Howard Su noticed that the noise level when running in 128M mode decreases by some 3dB while the signals remain with the same amplitude. What's happening is that we have a 3dB decimation gain as explained in https://www.analog.com/en/ technical-articles/analog- tips-decimation-for-adcs.html : " ... The SNR calculation of a...