naderi
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Hello all,
What can limit the input signal level for a delta sigma modulator?
I used an example given in the delta-sigma toolbox from Matlab and optimized a 3rd-order NTF for:
-Continuous-time with RZ DAC
-all poles at DC.
-out-of-band noise Hinf=1.7
-BW = 20kHz
-OSR = 128
-cascaded-integrator-feedback (CIFB) structure.
(fs=5.12MHz, U(1:3)=[0.1727, 0.7209, 1.4812])
After optimization and conversion to continuous-time, I tested in time-domain by the simulink. It seems that the maximum input signal level cannot be above 1/4 of U1 (coefficient of the outer feedback look shown in the figure), which is 0.043. Otherwise the modulator become unstable.
Is it possible to increase the input signal level?
I appreciate your comments.
Thanks,
What can limit the input signal level for a delta sigma modulator?
I used an example given in the delta-sigma toolbox from Matlab and optimized a 3rd-order NTF for:
-Continuous-time with RZ DAC
-all poles at DC.
-out-of-band noise Hinf=1.7
-BW = 20kHz
-OSR = 128
-cascaded-integrator-feedback (CIFB) structure.
(fs=5.12MHz, U(1:3)=[0.1727, 0.7209, 1.4812])
After optimization and conversion to continuous-time, I tested in time-domain by the simulink. It seems that the maximum input signal level cannot be above 1/4 of U1 (coefficient of the outer feedback look shown in the figure), which is 0.043. Otherwise the modulator become unstable.
Is it possible to increase the input signal level?
I appreciate your comments.
Thanks,