Tektronix TBS1052C: The FFT Frequency Plot - how can I 'fine shift' it about?

[ButchJames]

This is possibly a dumbo question, and BTW I have not had any problems with other 'digital' scopes I have: an 'old' Tektronix TDS1002, and a Siglent SDS800X series.

So regarding the TBS1052C (or TBS1000 series?) ...

In FFT mode I simply cannot get the scope to fine-shift the FFT plot along the frequency or x-axis!

The 'multipurpose' dial allows me to dial in only discrete (and rather large) increments of frequency, whether that be in fine/coarse mode. I even tried to use the
horizontal dial (as we would in the time domain), but has no affect.

Everything else appears fine on the scope, but this is bugging me. Surely Tek hasn't screwed up here?

Hoping that someone tell tell me what where I need to look!

{PS: I fully understand the Math of Fourier and in Engineering, but not Tek's way of doing things its seems}

[rvalente]

I never used the TBS1052B in FFT mode, but AFAIK the capture has only 2500 points, so Id say the FFT would be useless.

[coromonadalix]

tried on old series,  pretty much useless,  not enough points qty and memory size ... it is OLD as you say

[ButchJames]

Thanks for the replies.

This issue has nothing to do with Record Length and/or/both N ... the 'FFT size' N, the amount of computational integration terms, but the actual micro-shifting of the actual plot either to the left or right.

I shall pursue this, or even contact TEK.

Cheers guys. 

[ButchJames]

In FFT mode, this TEK TBS1052C is a bit of a strange one! 

The center line is supposed to be used to identify a frequency component, which it can, BUT we can only (seemingly?) adjust the Horizontal Center Position in discrete increments
which are equal to 1/2 of the lowest Horizontal Frequency Spacing that we can set, and this is dictated by ...

Freq Division Spacing = 10*1875/2000*(1/Tacq) for the '2000' pts record length buffer.

Tacq = acquisition time, which is 15 x Tbase/div time.

I've asked AI, and it knows SFA in the real world. 

Ironically, I may have to use 'Cursors' function to asses the spectra. What a load of BS!

It's a pity, as the scope is very nice in the time domain.

We live and learn.

[ButchJames]

The record length quoted are 1000, 2000, and 20,000 points.

But in reality, this scope sets the Sar, and so from Sa = Sar x Tacq, the buffer sizes ('record length') are then set to 937.5 (rounded no doubt), 1875, or 18750 samples.

Ironically, my old TDS1002 does the job .... no problem!

It is quite feasible that my scope has an issue?