Pipeline ADc Modeling in Simulink

[suhas_shiv]

simulink pipeline

Hi all,

I have gone thru some papers on pipeline ADC modeling in simulink. Some papers have used a Matlab Function box(with their own code I guess) for sub-ADC and sub-DAC. I wanted to know what kind of function could describe those blocks? Are there any ADC/DAC blocks readily available in Simulink or would I have to write a function/code to represent them? If I have to write a code, could anyone give me a hint/idea as to how to proceed.

Any response is greatly appreciated. Thanks.

Suhas

 

[matchasm]

adc modeling

It's quite nasty, because you probably want to model comparator offset using some Gaussian distribution and all comparisons must be done by hand.

That means, you need to construct a comparator routine that makes a certain output based on some wiring scheme from the comparator codes. I suggest making the output DAC ideal, because modeling mismatch is reaaalllyyy time-consuming.

A last suggestion: try writing the routine in MEX; it will save tremendous amounts of sim time.

 

[icx]

digital to analog simulink

what's the MEX?

 

[sankudey]

mex simulink

You first model your system from top level to sub blocks...it would contain...comparators....S/H...m-DAC...dig correction blocks etc....now just write the routines for each of them....this routine basically contain the IP-OP relation-ship of the blocks (in voltage domain)....just like C-prog....

Once this is done you call them in proper manner....I guess this will do the job....

I once did it in MATLAB...not in simulaink....thus with simple math functions it was done....

now you can give some variable for the offset/error in reference/S/H or m-dac....just put them mathimatecally.....you will be getting it....

I can give you one more reference......although this is not related to modeling in simulink...but discusses about pipeline ADC in good manner....

may help you....

Digital techniques for improving the accuracy of data converters
Un-Ku Moon; Temes, G.C.; Steensgaard, J.;
Communications Magazine, IEEE
Volume 37, Issue 10, Oct. 1999 Page(s):136 - 143
Digital Object Identifier 10.1109/35.795604

Summary: This article provides a tutorial overview of some previously developed methods for enhancing the accuracy and linearity of data converters (analog-to-digital as well as digital-to-analog) by introducing auxiliary digital circuitry which calibrates, c.....


gd luck...
sankudey

 

[matchasm]

pipe line matlab application

what's the MEX?

I guess MEX is short for Matlab EXtension and it lets you put C code into your Matlab code through a library interface. It saved me hours during my own pipeline sim programming. This is what the Help says:


Introducing MEX-Files

You can call your own C or Fortran subroutines from MATLAB as if they were built-in functions. MATLAB callable C and Fortran programs are referred to as MEX-files. MEX-files are dynamically linked subroutines that the MATLAB interpreter can automatically load and execute.

MEX-files have several applications: Large pre-existing C and Fortran programs can be called from MATLAB without having to be rewritten as M-files. Bottleneck computations (usually for-loops) that do not run fast enough in MATLAB can be recoded in C or Fortran for efficiency.

MEX-files are not appropriate for all applications. MATLAB is a high-productivity system whose specialty is eliminating time-consuming, low-level programming in compiled languages like Fortran or C. In general, most programming should be done in MATLAB. Don't use the MEX facility unless your application requires it.

 

[Syukri]

pipeline adc simulink

The role of the sub-DAC is to supply the gain stage with the analog voltage level
that represents the quantized portion of the input sample. Given is the circuit by Alma-Bukic of implementing the sub_DAC.

On the other hand....sub-ADC is the component so call one bit ADC or usually known as comparator.