Hi As temperature shifts up and down, the phase will change. If you have something with bandwidth measured in KHz, it’s a good bet it’s going to have a change dimensioned as tens if not hundreds of microseconds. That probably going to get you multiple cycles at 10 MHz over maybe a thousand seconds. One cycle is 0.1 ppm …..
Yes there is a lot of handwaving in all that. There (obviously) are a lot of ways to make a filter. You can be at various points in the passband of the filter. It can have a lot of poles or not quite so many. Your room may swing a lot and do it quickly or you may live in a cave deep in a mountain. KHz could mean 1 KHz or it could mean 200 KHz ….. If you are doing something that ultimately gets back to time (this is Time Nuts …) the drift from a narrow filter will probably bug you. Bob > On Jul 18, 2019, at 4:07 AM, Hal Murray <[email protected]> wrote: > > > [email protected] said: >> The thing to avoid is a lot of bandpass filters. They will be temperature >> sensitive and “modulate” the output as temperature changes. > > What does "modulate" mean in that context? Are you talking about minor phase > shifts which would be very very low frequency phase modulation or is there > something more complicated going on? > > > -- > These are my opinions. I hate spam. > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
