Jennie W, Sina K, Jim W,

Summary: Yesterday we had a check through the SPI model just to make sure we have turned on everything and that all is working well, we got as far as ascertaining that no light was making it to the PDs on the ISIJ and K benches and also did some other checks on the LO aand longitudinal IFO paths.

Couple of things we discovered/checked:

• Checked LO using dtt (the 4kHz signal is too fast to show up on ndscope as a sine wave and looks sawtooth) and it looks good. Attached are the various channel we checked starting with the common analogue sin and cosine shown with the first two arrows on the left in the LO screen. The phase of the common path phase rotator should be set to 0 so the signal should be unchanged at the next set of arrows in this picture. We checked those in dtt also here and they lie under the first two traces.
• The phase rotators in the sine and cosine paths should also be set to 0 and leave the next two arrowed channels unchanged, which they do except from the amplitude which is intentionally different (see next point).
• We decided to set the oscillator input gain to 1 in the digital oscillator (this was previously 1000) and put this gain in the output conditioning blocks (by switching off mV2V filter) which get sent as analogue signals to the double mixer. This large number is chosen specifically as the amplitude of signal neede to drive the double mixer so we feel it makes more sense to put it here.
• Some of the display channels in the medm LO screen are too low sampling frequency to display the 4kHz signal. We changed the displayed output channels H1:SPI-H23_LO_ANA_SIN_OUTMON, H1:SPI-H23_LO_ANA_CLK_OUTMON and H1:SPI-H23_LO_ANA_COS_OUTMON from the SIN and COS blocks to read the _OUTPUT channel instead.
• We will also add in some cdsfilt modules at the output of the digital oscillator module H1:SPI-H23_LO_SRC in order to get fast output channels on the medm. This requires model changes so we will implement when a DAQ restart does not interfere with cornber commissioning efforts.
• We corrected the screen SPI_CUST_IFO_DEMOD as it was displaying the phase channel for the wrong cdsPhase part (H1:SPI-H23_LO_ANA_COMROT) instead of (H1:SPI-H23_IFO_{MEAS,REF}_{A,B}_DEMOD_PHASE).

NB: We found out today that the shutter controller for our laser pick-off was not connected - Jim and Fil have now solved this (alog #91467).