Robert wrote:
One "off the shelf" or more likely out of the junk box option is to use the filter components from a 10Mb/s ethernet card. They work quite well but might introduce some temperature related phase shifts.
As others have pointed out here in the past, to minimize phase and amplitude shifts with temperature changes, you would like the phase and amplitude responses to be changing as gradually as possible in the vicinity of the oscillator frequency. However, this is not the case with a bandbass filter centered on the oscillator frequency or a low-pass filter with a cutoff near the oscillator frequency.
If the undesired output components are harmonics, you can reduce the first few with traps (i.e., notch filters). This may be all you need (for example, if the harmonics were generated by a buffer amp with simple nonlinearities). Even if there is an extended harmonic series, as may be the case with the 5680A, it will allow you to filter the higher harmonics using a low-pass filter with relaxed specifications (higher cutoff frequency, fewer poles, and/or better damping), thus preserving gentle phase and amplitude response at the oscillator frequency.
Best regards, Charles _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
