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Thu Mar 13 02:52:06 2008, Lisa, Configuration, LSC, Locking with 3f
Thu Jul 24 01:04:01 2008, rob, Configuration, LSC, IFR2023A (aka MARCONI) settings
Thu Jul 24 01:04:01 2008
In reply to:
IFR2023A (aka MARCONI) settings
P.S.: We made a test by changing the frequency of the local oscillator by a little bit and then coming back to the original value. We observed that the phase of the signal can change, so every time this frequency is moved the 3f demod phase need to be retuned.
We discovered this little tidbit in March, and remembered it tonight. Basically we found that whenever you change the frequency on one of these signal generators (and maybe any other setting as well), the phase of the signal can change (it's probably just the sign, but still...), meaning that you when you return settings to their intial value, not everything is exactly as it once was. For most applications, this doesn't matter. For us, where we use one Marconi to demodulate the product of two other Marconis, it means we can easily cause a great deal of grief for ourselves, as the demod phase for the double demod signals can appear to change.
Programmatically, what this means is that
every time you touch a Marconi you must elog it
Especially if you change a setting and then put it back.