MattE, Hong, Kiwamu, Rana

We've made a temporary hookup at EY to get the in-vac, IR, TransMon QPD signals into the new fast 'h1susetmypi'. This is so that we can monitor the amplitude and frequency of the unstable opto-acoustic modes in the interferometer (0910.2716). The only cabling change we've made is to add a breakout board at the AA chassis, so things out to run as before after the EQ rings down.

Cabling Details:

The TransMon QPD cable goes into a Transimpedance/Whitening amplifier (D1001974) with Z = 1000 Ohms. Then there's a 0.4:40 pole:zero stage with a gain of 1 at DC. The output of this board then goes through a whitening chassis and then the output of that box (in the rack near the BSC) goes into the electronics room and into an ISC AA Chassis via a 9-pin dsub. We put the breakout board at the AA side of this cable. We used clip-doodles to go into a SCSI breakout board and via ribbon cable into the ADC for the h1susetmypi. This is a temporary setup to allow us to commission the model software. In this setup, since we're using the whitening filter outputs, we also get the whitening gain and amplificaiton which is used for the QPD servos. Also we do not need to use the PEM patch panels as initially planned.

The transimpedance box has a single pole at 80 kHz. The whitening filter has no poles below 80 kHz. So these should be fast enough to let us see PI modes up to 30 kHz.

We had to use some critical electrical tape to keep the BNC-clip shields from shorting with each other; take care in working near the AA side of this cabling - it may put offsets into the QPDs and disturb the lock acquisition.