Excess loop delay in CTDS ADCs

Status
Not open for further replies.

mordak

Member level 5
Joined
Mar 8, 2013
Messages
82
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Location
Neverland
Visit site
Activity points
2,134
Hey guys,

I have a question about continuous time (CT) delta sigma modulators. As you know excess loop delay (ELD) may result in decreasing SNR or even instability. But there is a way to compensate excess loop delay in CT ADCs by adding a second loop and using Dlatch and D flip flops (attached pic). It's from a paper published by Shouli Yan :
A Continuous-Time Delta Sigma Modulator With 88-dB Dynamic Range and 1.1-MHz Signal Bandwidth
I also tried to simulate it in Simulink to see how it works. After simulation I saw that any delay generated by ADC up to 1 clock cycle could be tolerated with this technique. However, still any delay by DAC_A would result in significant SNR degradation of the whole ADC. I don't know if I made a mistake somewhere or it makes sense. Any suggestion would be appreciated.



Thanks
 

Status
Not open for further replies.

Similar threads

Cookies are required to use this site. You must accept them to continue using the site. Learn more…