Noise display on 16702A with 16555D cards

[davorin]

Evenin'

I'm currently trying to capture some simple I2S waveforms coming from a Carambola2 WLAN module and a Keystone DAB+/FM module...

The waveforms look nice on a cheapo Saleae clone...though it is limited to 12Msamples/sec....
So I fired up my 16702A with 16555D cards....and oddly...as soon as I want to capture more than 1 or 2 signals...I see clock noise...

The first waveform is just a capture of the WORD and SCLK signal...
The second picture is with additional MCLK signal...

Any ideas? I always connected each pair of the pod (signal/ground) to the device...

[davorin]

Hmm...after fiddling around a bit with the pod settings the waveform looks now good....though dunno why the big difference...

Before was set to LVCMOS and now to CMOS 5V....although the signals itself are 3V3 outputs....