sddsnaff at fixed frequency

[wguo]

Hi Michael,

Is it possible to add one input for sddsnaff such that it analyzes data at the input frequency?
The problem arises when I apply naff to the turn-by-turn data of all the BPMs in the ring. In principle the main frequency should be the same for different BPMs; however, a small spread comes out and results in a large phase deviation when the number of turns becomes large.

Weiming

[michael_borland]

Weiming,

Is the ideal to process N signals together and force the use of the same frequency for all of them?

--Michael

[wguo]

Yes. Sddsnaff gives slightly different frequencies for N signals. It is critical if the phase is a concern.
I could do a simple FFT myself since the frequency is given, however, I trust sddsnaff to be more reliable in case there is only a small number of turns.

Weiming