Scilab and DSP

Tim Wescott wrote:

> 
> So in Scilab I can write a transfer function as easy as
> 
> H = %z / (%z - 1),
> 

#include <complex>

> and I can the do Bode plots,

Export to Excel

> or multiply it by another transfer function,
> or "multiply" it (actually cascade systems) by a state-space system model.
> All this makes it very easy to do what I want to do with the package.

Entities should not be multiplied beyond necessity.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

Vladimir Vassilevsky wrote:
> 
> 
> Tim Wescott wrote:
> 
>>
>> So in Scilab I can write a transfer function as easy as
>>
>> H = %z / (%z - 1),
>>
> 
> #include <complex>

I can prototype algorithms in Scilab with about 1/10th the code and time 
spent than in C++, thanks.

> 
>> and I can the do Bode plots,
> 
> Export to Excel

Scilab does _much_ better plots than Excel, in less time.
> 
>> or multiply it by another transfer function,
>> or "multiply" it (actually cascade systems) by a state-space system 
>> model.
>> All this makes it very easy to do what I want to do with the package.
> 
> Entities should not be multiplied beyond necessity.
> 

Transfer functions shouldn't, but the state space representations stay 
numerically robust long after the transfer function representations have 
disappeared in a puff of quantization errors.

-- 

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

On 2007-11-21, Randy Yates <yates@ieee.org> wrote:
>
> Do you use the gEDA tools to do circuit card layout? I wonder if they
> have an autorouter available. I've been considering Orcad but 1) I
> don't like to spend money and 2) it won't run under linux.

gEDA/gaf (gaf = "gEDA and friends") cover the schematic capture and
simulation part of the task.  It has a symbiotic relationship with
"PCB" (formerly xpcb) which was developed independently.

PCB does have an autorouter, and I've seen it route moderately complex
boards.  The results are not "pretty", though.  There are tools to
beautify the resulting wires, but I have not experimented with them much.
There was someone complaining about a bug using the autorouter on a 16+
layer board with a 1156 BGA part in the middle.  I know we gave him a
workaround, but I don't know how the autorouting went.

I took my flex board (you can find it on my website) and ripped up the
nets, disabled power and gnd and autorouted the 130 signals (took about 2
seconds on my old 1GHz server).  It only did slightly worse than me.  I
did have to remove the flood polygons, though.  PCB is not smart about
polygons w/autorouting.

If you want to use PCB, you'll want to set up to build it from CVS
(on sourceforce) because there's some fairly active development.

-- 
Ben Jackson AD7GD
<ben@ben.com>
http://www.ben.com/

Ben Jackson wrote:

> On 2007-11-21, Randy Yates <yates@ieee.org> wrote:

>>Do you use the gEDA tools to do circuit card layout? I wonder if they
>>have an autorouter available. I've been considering Orcad but 1) I
>>don't like to spend money and 2) it won't run under linux.

> gEDA/gaf (gaf = "gEDA and friends") cover the schematic capture and
> simulation part of the task.  It has a symbiotic relationship with
> "PCB" (formerly xpcb) which was developed independently.

Has anyone tried the PCB123 tools?  It seems that they have free
design software, presumably designed for their fab system.
I have thought about using it, but not actually tried them yet.

-- glen