Noway2 wrote:
> sunny wrote:
>> On Oct 22, 10:52 pm, Tim Wescott <
[email protected]> wrote:
>>
>>> On Mon, 22 Oct 2007 09:32:33 -0700, sunilammanabrolu wrote:
>>>
>>>> I was given a project to design, simulate and synthesize a digital low
>>>> pass filter with cutoff frequency 150 Hz and stop band attenuation of
>>>> 80 db/decade
>>>
>>>> The filter i have chosen is iir Butterworth filter with order 4
>>>> I have relialized the filter using fdatool in matlab
>>>> Can any one pls help me with the vhdl code
>>>> thx in advance
>>>
>>> That's an extremely general request, in that there's a whole bunch of
>>> steps
>>> to get from a filter definition to a working implementation on an
>>> FPGA or
>>> ASIC. You really need to tell us what step isn't working for you.
>>>
>>> In the absence of other information, I would suggest that you start by
>>> writing VHDL that implements the filter in simulation, but without
>>> trying
>>> to make it synthesizable. If you're really at a loss you may want to
>>> start by getting the algorithm to work in a spreadsheet, MATLAB, C, or
>>> whatever other language you are most comfortable in, then move to VHDL.
>>>
>>> At any rate, once you get the algorithm working in VHDL in simulation,
>>> then you should be able to rewrite it as something that's sythesizeable,
>>> and start debugging (and yes, you will be doing some debugging).
>>>
>>> If you're having trouble with the first step, i.e. going from the
>>> z-domain
>>> filter to an algorithm, look about 3/4 of the way down
>>> inhttp://www.wescottdesign.com/articles/zTransform/z-transforms.htmlor
>>> in a
>>> good reference on practical DSP such as Rick Lyons' "Understanding
>>> Digital
>>> Signal Processing", in Chapter 6 where he talks about IIR filters.
>>>
>>> Good luck, and check back here when you figure out just where it is
>>> in the
>>> process that you're getting stuck.
>>>
>>> --
>>> Tim Wescott
>>> Control systems and communications
>>> consultinghttp://www.wescottdesign.com
>>>
>>> Need to learn how to apply control theory in your embedded system?
>>> "Applied Control Theory for Embedded Systems" by Tim Wescott
>>> Elsevier/Newnes,http://www.wescottdesign.com/actfes/actfes.html
>>
>>
>> Thanks Tim
>> i have generated the vhdl cofe using matlab
>> The working implementation our teacher has asked is on FPGAs
>> I dont know anything about FPGAs.He has asked me to work on Modelsim
>> thats all.
>> Can anyone pls help me ...
>>
> You aren't being clear about exactly what you need help with. Nobody
> here is going to hand you a solution to turn in. Tim's advice to you
> was correct. Start by trying to implement the filter in Matlab, then
> get it to work in some other form of code. C would likely be a good
> choice because its strucutre is in many ways similar to VHDL, though a
> spreadsheet would be a better first step to see the math.
>
> Modelsim is a VHDL simulator that will allow you to work with the VHDL
> to determine what kind of results you get without needing to worry about
> a particular FPGA. This has the advantage of allowing the full VHDL
> command set, some of which is not synthesizable to logic. If you are
> having trouble with this part then you should be looking for some
> tutorials on it. Start with something small.
>
> If you are completly over your head and none of this is making sense to
> you then most it would appear that you have taken on something that you
> aren't ready to do yet and you need to re-evaluate your courses.
>
>
Or the prof was being unrealistic in his expectations, in which case
everyone in the class* will bomb and he'll re-evaluate his assignment,
or you'll need to re-evaluate who you take your classes from.
* Except for that one irritating guy...
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html