BB60c not a true 14 bit A/d

When looking at the IQ spectrum in zero mode, the noise floor is much higher than one would expect with a 14 bit A/D. At 100kHz RBW it is only -70dbc. This makes it equivalent to only a 6 bit A/D. I suspect its the dithering that is doing this. Any way to turn it off if its the cause? Otherwise I would like an explanation.

A 14bit A/D should have around 84 db snr. Running at 40 Msps, the resultant noise floor should be -160 dbc/hz. I am measuring -120 dbc/hz.

[Andrew]

(Edited as a follow up on this topic after conversations with the customer)

One of the weaknesses of the BB60C is the low Dynamic Range/SNR. It is the result of amplification in the RF section to reduce residual signals.

Depending on your settings we would expect a maximum ~48dB SNR in a given IF band. (measuring SNR at 40MS/s IQ) It may be less in some configurations (as you mentioned, band zero).

The SM200A would be our recommended receiver if you needed better performance in this regard.

Thank you for your patience Jonathan. It was nice talking to you. Let us know if you have follow up questions/comments.

Regards,
Andrew

• This reply was modified 6 years, 10 months ago by Andrew.
• This reply was modified 6 years, 10 months ago by Andrew.
• This reply was modified 6 years, 10 months ago by Andrew.

if SM200A can produce a lite version, just narrow the frequency from 230MHz to 6GHz, I think the price also will drop more, we will consider to buy it for the developing.

Hi testpoint,

Thanks for the feedback. We have discussed something like this a few times here at Signal Hound but at this point we don’t have any definite plans to work on this. Maybe in the future.

If you have any additional comments or questions, let me know.
Andrew

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