Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Delta Sigma Modulation SNR - Bit Resolution

Status
Not open for further replies.
T

tom.73545

Newbie level 5
Joined
Mar 31, 2009
Messages
10
Helped
2
Reputation
4
Reaction score
2
Trophy points
1,283
Activity points
1,337
Hi all...

I have problems to determine the SNR and the bit resolution from a Delta Sigma Modulation. I have now a 1st order delta sigma modulation and if I look at the bit-stream at the output of the delta-sigma, I am quite confuse how we can know from this bit-stream the SNR as well as the resolution. I have searched many literatures but most of them just easily mention the formula to calculate. But in practical way, how can we get this information from the bit-stream only?

Thanks in advance for your help and support.
 

To calculate SNR and resolution you must plot the output signal's FFT. The SNR is the ratio between the output signal amplitude and the noise floor amplitude. From the SNR you can calculte the resolution SNR (dB) = 6.02*n + 1.761 where "n" is the number of bits
 

Thanks for your reply.

Yes I know about this formula... I have attached a screen shot from the result I got from the FFT calculation from the bit-stream.

The clock I used for the DS is 100kHz and the signal input is sinus with f= 1khz.
For the FFT calculation I used: Fsampling 200kHz and number of points is 4096. The result is like shown in the figure attached.

I am quite confused because the noise floor is not like a stable value.

Thanks once again for your time and help.
 

Attachments

  • FFT_SNR.JPG
    FFT_SNR.JPG
    95.7 KB · Views: 127

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top