peter_hawk
Newbie level 4
integrator output
Dear all:
I am now desinging a 2nd-order sigma delta modulator.
The architecture is gain=0.5 in both Integrator. ( Boser / Wooley 1988)
I use simulink to run simulation. (SDT Tool
by S. Brigati Ver.(0.1) 08/04/98)
Input: 0.5 sinewave
Quantizer: +1 / -1
Opamp saturation voltage in Integrator: +1.35 / -1.35 <== ?
This is Ideal 2nd-Order SDM Simulink
This is the ideal Integrator with opamp saturation voltage
This is the PSD of Ideal 2nd-Order SDM
(input=0.5, opamp saturation voltage=1.35)
First Integrator output ( have some data >1 and <-1)
If I modify the opamp saturation voltage from 1.35 to 1 (quantizer output +1/-1)
The PSD is very poor
PSD of 2nd-Order SDM with OPAMP Saturation Amplitude=1
The output of 1st Integrator ouput is saturation at +1 / -1
Can anyone give me some suggestions?
Dear all:
I am now desinging a 2nd-order sigma delta modulator.
The architecture is gain=0.5 in both Integrator. ( Boser / Wooley 1988)
I use simulink to run simulation. (SDT Tool
by S. Brigati Ver.(0.1) 08/04/98)
Input: 0.5 sinewave
Quantizer: +1 / -1
Opamp saturation voltage in Integrator: +1.35 / -1.35 <== ?
This is Ideal 2nd-Order SDM Simulink
This is the ideal Integrator with opamp saturation voltage
This is the PSD of Ideal 2nd-Order SDM
(input=0.5, opamp saturation voltage=1.35)
First Integrator output ( have some data >1 and <-1)
If I modify the opamp saturation voltage from 1.35 to 1 (quantizer output +1/-1)
The PSD is very poor
PSD of 2nd-Order SDM with OPAMP Saturation Amplitude=1
The output of 1st Integrator ouput is saturation at +1 / -1
Can anyone give me some suggestions?