ground clock in (SMA) and out (MMCX) [v1.1 BOM change]

sinara-hw / Kasli

Kasli is a powerful FPGA carrier, capable of controlling 12 Eurocard extension modules.

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ground clock in (SMA) and out (MMCX) [v1.1 BOM change] #26

Closed jordens closed 5 years ago

jordens commented 5 years ago

I have seen a couple times that that floating shield thing is a bad idea, also on crate-internal MMCX wiring. The symptom is 400/800 kHz switcher modulation sidebands anywhere from -30 dBc to -80dBc on the urukul clock. Shorting the shield on both ends resolved it each time. This can a pure BOM change and I'd like to have it implemented on all future Kasli v1.1 builds and Kasli v2.0 as well.

R29,R30,R31,R32,R214=0R

c.f. #5 and maybe #10

hartytp commented 5 years ago

Agreed. Floating grounds can be the right thing to do in rare cases, but it's not a sensible default option.

hartytp commented 5 years ago

(I thought we agreed to do this ages ago)

jordens commented 5 years ago

We agreed. I'm just pushing to rush this into the current boards without waiting for v1.2/v2.0.

marmeladapk commented 5 years ago

a87c75c

jordens commented 5 years ago

Thanks. The v1.1.1 version you assigned is a very good idea.