Reports until 16:01, Thursday 05 September 2024
H1 ISC
naoki.aritomi@LIGO.ORG - posted 16:01, Thursday 05 September 2024 (79938)
PI ETMY output filter change

This is a request from Vlad a long time ago. 

In 73697, Vlad changed the bandpass filter in H1:SUS-ETMX_PI_UPCONV_UC3_SIG to steeply cut off the lower sideband (80kHz-300Hz) for 80.3 kHz PI. The new filters are FM1 and 2 (80to81kHz_a and 80to81kHz_b).

Vlad asked me to implement a similar filter for other PIs. I changed the bandpass filter in H1:SUS-ETMY_PI_UPCONV_UC7_SIG for 10.4kHz PI. The new filters are FM4 and 5 (10to11kHz_a and 10to11kHz_b) and old filter is FM1.

The first and second attachments show the new and old bandpass filters. The new filter has -144dB gain for lower sideband (10kHz-430Hz), while the old filter has -40dB gain. The SDF is accepted.

Images attached to this report