Forums

Serial Digital Audio filtering B.Eng Project HW help?

Started by Unknown March 25, 2005
Hi,
Thanks in advance to anyone who reads this and may offer some help.

I am an undergraduate student and I have an idea for my big Capstone
Project.  I want to create a digital audio system.  I have designed the
basic SPDIF in->upsample->DAC->analog audio out path using the many
ASICS available today.

To get a superlative grade, I want to insert a module in between the
upsampler and the DAC stage to do LPF, BPF and HPF.  The idea is that I
can then have 3 DAC stages and create a digital crossover (ie a
seperate signal to drive seperate amps for tweeter, midrange and bass
speakers).

It seems that DSP is the place to do this kind of number crunching.
Problem is, I've never used DSPs before and my university can't really
support a custom project like this one.  Can anyone suggest some HW,
software that I can buy to implement my filter module?  Basic
requirments are:

1 serial digital in (24 bit, 96Khz or 192khz)
3 serial digital out (24 bit 96khz or 192khz)
latency is OK as long as the 3 outputs are synchronized
student price (maybe up to US$200)-the achilles heel of my project!

Of course it would be nice if the hardware had specific ports to handle
the serial digital audio streams so that I wouldn't have to do
conversion in software.

Any help with hardware selection and development environment is
appreciated!

Many thanks,

John Callaghan

I'd like to incorporate something similar into an FPGA project (many
now include multiple MACs, and can be configured to do repetitive
DSP-like tasks such as filters). A MF-HF crossover can easily use FIR
filters, and keep the outputs "synchronized" (I'm playing with 200 tap
linear phase filters). But that will be more difficult for the LF-MF
crossover, especially if it's allowed to go arbitrarily low (eg 50Hz).
Also, I wonder if you could help another novice by explaining why you
need to upsample?

On 25 Mar 2005 13:49:23 -0800, jd76duke@bigpond.com.au wrote:

>Hi, >Thanks in advance to anyone who reads this and may offer some help. > >I am an undergraduate student and I have an idea for my big Capstone >Project. I want to create a digital audio system. I have designed the >basic SPDIF in->upsample->DAC->analog audio out path using the many >ASICS available today. > >To get a superlative grade, I want to insert a module in between the >upsampler and the DAC stage to do LPF, BPF and HPF. The idea is that I >can then have 3 DAC stages and create a digital crossover (ie a >seperate signal to drive seperate amps for tweeter, midrange and bass >speakers). > >It seems that DSP is the place to do this kind of number crunching. >Problem is, I've never used DSPs before and my university can't really >support a custom project like this one. Can anyone suggest some HW, >software that I can buy to implement my filter module? Basic >requirments are: > >1 serial digital in (24 bit, 96Khz or 192khz) >3 serial digital out (24 bit 96khz or 192khz) >latency is OK as long as the 3 outputs are synchronized >student price (maybe up to US$200)-the achilles heel of my project! > >Of course it would be nice if the hardware had specific ports to handle >the serial digital audio streams so that I wouldn't have to do >conversion in software. > >Any help with hardware selection and development environment is >appreciated! > >Many thanks, > >John Callaghan
Tony (remove the "_" to reply by email)
Maybe the newest kit from Danville Signal Processing fits your needs. It has 
an Altera FPGA an an Analog Devices' floating point DSP. It's selling for 
US$199, and comes with all the software tools to get you started.

Al: something else to add??

Regards,

-- 
------------------------------
Jaime Andr�s Aranguren Cardona
jaac@sanjaac.com
SanJaaC Electronics
Soluciones en DSP
www.sanjaac.com


<jd76duke@bigpond.com.au> escribi&#2013265923; en el mensaje 
news:1111787363.506774.37810@l41g2000cwc.googlegroups.com...
> Hi, > Thanks in advance to anyone who reads this and may offer some help. > > I am an undergraduate student and I have an idea for my big Capstone > Project. I want to create a digital audio system. I have designed the > basic SPDIF in->upsample->DAC->analog audio out path using the many > ASICS available today. > > To get a superlative grade, I want to insert a module in between the > upsampler and the DAC stage to do LPF, BPF and HPF. The idea is that I > can then have 3 DAC stages and create a digital crossover (ie a > seperate signal to drive seperate amps for tweeter, midrange and bass > speakers). > > It seems that DSP is the place to do this kind of number crunching. > Problem is, I've never used DSPs before and my university can't really > support a custom project like this one. Can anyone suggest some HW, > software that I can buy to implement my filter module? Basic > requirments are: > > 1 serial digital in (24 bit, 96Khz or 192khz) > 3 serial digital out (24 bit 96khz or 192khz) > latency is OK as long as the 3 outputs are synchronized > student price (maybe up to US$200)-the achilles heel of my project! > > Of course it would be nice if the hardware had specific ports to handle > the serial digital audio streams so that I wouldn't have to do > conversion in software. > > Any help with hardware selection and development environment is > appreciated! > > Many thanks, > > John Callaghan >
"Jaime Andr&#2013265929;s Aranguren Cardona" <jaac@nospam.sanjaac.com> wrote in
news:1111838121.fb173026beb26a58bf5d12792cbc119a@teranews: 

> Maybe the newest kit from Danville Signal Processing fits your needs. > It has an Altera FPGA an an Analog Devices' floating point DSP. It's > selling for US$199, and comes with all the software tools to get you > started. > > Al: something else to add?? > > Regards, >
Thanks Jaime for mentioning the new kit. The package is described in detail on our website. It comes with Altera tools (including a ByteBlaster) and Analog Devices tools. The board functions just like an Analog Devices EZ-Kit LITE development board since we have a license for the on board debugger. The special pricing is limited to one per customer (we would like to sell you production boards). The price is being subsidized by Analog Devices and Altera and the kit (ADDS-21261/Cyclone) is being sold exclusively by Arrow Electronics. The promotional price is not forever and I am happy to say they are selling well. -- Al Clark Danville Signal Processing, Inc. -------------------------------------------------------------------- Purveyors of Fine DSP Hardware and other Cool Stuff Available at http://www.danvillesignal.com
jd76duke@bigpond.com.au wrote:
> I am an undergraduate student and I have an idea for my big Capstone > Project. I want to create a digital audio system. I have designed the > basic SPDIF in->upsample->DAC->analog audio out path using the many > ASICS available today. > > To get a superlative grade, I want to insert a module in between the > upsampler and the DAC stage to do LPF, BPF and HPF. The idea is that I > can then have 3 DAC stages and create a digital crossover (ie a > seperate signal to drive seperate amps for tweeter, midrange and bass > speakers).
Before you go too far down that path, you might want to check out this project: http://www.dtweed.com/circuitcellar/caj00160.htm#2820 There are COTS chips such as the Philips SAA2505 and Apogee DDX4100 that can basically do what you want to do. -- Dave Tweed
Hi Tony,
I think that you are less of a novice than myself!  I'll start by being
honest and saying that I am going to upsample just because everyone
else does it.  Of course I am not under the impression that upsampling
adds any new information to the audio signal.

I THINK that upsampling is done because with more resolution in that
data, any rounding errors in calculations are less significant.  Also,
the upsampled data stream can be converted back to Analog with a much
simpler LPF.

It looks like I'll order the Danville kit.  It is just in my price
range and seems to pack alot in.

John

Tony wrote:
> I'd like to incorporate something similar into an FPGA project (many > now include multiple MACs, and can be configured to do repetitive > DSP-like tasks such as filters). A MF-HF crossover can easily use FIR > filters, and keep the outputs "synchronized" (I'm playing with 200
tap
> linear phase filters). But that will be more difficult for the LF-MF > crossover, especially if it's allowed to go arbitrarily low (eg
50Hz).
> Also, I wonder if you could help another novice by explaining why you > need to upsample? > > On 25 Mar 2005 13:49:23 -0800, jd76duke@bigpond.com.au wrote: > > >Hi, > >Thanks in advance to anyone who reads this and may offer some help. > > > >I am an undergraduate student and I have an idea for my big Capstone > >Project. I want to create a digital audio system. I have designed
the
> >basic SPDIF in->upsample->DAC->analog audio out path using the many > >ASICS available today. > > > >To get a superlative grade, I want to insert a module in between the > >upsampler and the DAC stage to do LPF, BPF and HPF. The idea is
that I
> >can then have 3 DAC stages and create a digital crossover (ie a > >seperate signal to drive seperate amps for tweeter, midrange and
bass
> >speakers). > > > >It seems that DSP is the place to do this kind of number crunching. > >Problem is, I've never used DSPs before and my university can't
really
> >support a custom project like this one. Can anyone suggest some HW, > >software that I can buy to implement my filter module? Basic > >requirments are: > > > >1 serial digital in (24 bit, 96Khz or 192khz) > >3 serial digital out (24 bit 96khz or 192khz) > >latency is OK as long as the 3 outputs are synchronized > >student price (maybe up to US$200)-the achilles heel of my project! > > > >Of course it would be nice if the hardware had specific ports to
handle
> >the serial digital audio streams so that I wouldn't have to do > >conversion in software. > > > >Any help with hardware selection and development environment is > >appreciated! > > > >Many thanks, > > > >John Callaghan > > Tony (remove the "_" to reply by email)

Al Clark wrote:

> The package is described in detail on our website.
Al, I found that these links there are broken: http://www.analog.com/processors/processors/sharc/technicalLibrary/manuals/2126x_core.html http://www.analog.com/processors/processors/sharc/technicalLibrary/manuals/2126x_peripheral.html Is there information (I couldn't find any at your site) on the Altera and Analog Devices software tools that come with the eval board? Thanks, Bob -- "Things should be described as simply as possible, but no simpler." A. Einstein
Bob Cain <arcane@arcanemethods.com> wrote in
news:d2a2ku02kej@enews4.newsguy.com: 

> > > Al Clark wrote: > >> The package is described in detail on our website. > > Al, I found that these links there are broken: > > > http://www.analog.com/processors/processors/sharc/technicalLibrary/manu > als/2126x_core.html > http://www.analog.com/processors/processors/sharc/technicalLibrary/manu > als/2126x_peripheral.html >
I guess they got moved again. We'll fix this tomorrow.
> Is there information (I couldn't find any at your site) on > the Altera and Analog Devices software tools that come with > the eval board?
The board comes with VisualDSP++ Ver 4.0. The version we ship includes an EZ-Kit License. An EZ-Kit License works like a full version with no restrictions for 90 Days after which it limits you to a maximum program size of 1/4 the memory. From a VDSP point of view, our cards look like a EZ-Kit. I am very pleased to announce that we just got a license from ADI to use the EZ-Kit debugger on our dspstak SHARC based boards. This means that our boards work just like an EZ-Kit. We currently can support the ADSP- 21261, ADSP-21262 & ADSP-21364. You can use VisualDSP with the same restrictions that any other EZ-Kit has. The Altera Tools are Quartus II Web Edition and an Altera ByteBlaster. You can download the user manuals from our web site to get more details. You can buy the whole kit from Arrow for $199. This is a special promotional price that is limited to one per customer. Details are also on our web site. -- Al Clark Danville Signal Processing, Inc. -------------------------------------------------------------------- Purveyors of Fine DSP Hardware and other Cool Stuff Available at http://www.danvillesignal.com

Al Clark wrote:

> The board comes with VisualDSP++ Ver 4.0.
Awesome!
> The version we ship includes an > EZ-Kit License. An EZ-Kit License works like a full version with no > restrictions for 90 Days after which it limits you to a maximum program > size of 1/4 the memory. From a VDSP point of view, our cards look like a > EZ-Kit.
Oops. Not so good. Terrible, in fact. The cost of the unencumbered SW is absolutely prohibitive without corporate deep pockets and 1/4 memory is not a viable solution for the long term. Ah, well, it does say "evaluation", not "development." Thanks, Bob -- "Things should be described as simply as possible, but no simpler." A. Einstein
Bob Cain <arcane@arcanemethods.com> wrote in
news:d2dkr901rek@enews1.newsguy.com: 

> > > Al Clark wrote: > >> The board comes with VisualDSP++ Ver 4.0. > > Awesome! > >> The version we ship includes an >> EZ-Kit License. An EZ-Kit License works like a full version with no >> restrictions for 90 Days after which it limits you to a maximum >> program size of 1/4 the memory. From a VDSP point of view, our cards >> look like a EZ-Kit. > > Oops. Not so good. Terrible, in fact. The cost of the > unencumbered SW is absolutely prohibitive without corporate > deep pockets and 1/4 memory is not a viable solution for the > long term. Ah, well, it does say "evaluation", not > "development." > > > Thanks, > > Bob
The license restrictions are exactly the same as an EZ-Kit. The SHARC has a fairly large memory. You may find that your programs don't grow large enough to matter. If you are building large projects, I would speculate that your total costs are significantly higher than the tools cost. ADI does not charge for upgrades either. VDSP 1.0 customers can update to VDSP 4.0 for free. I know that tool costs are a significant burden to small guys. My wife and I own all the shares in Danville, so every tool purchase I make is "real" money to me as well. -- Al Clark Danville Signal Processing, Inc. -------------------------------------------------------------------- Purveyors of Fine DSP Hardware and other Cool Stuff Available at http://www.danvillesignal.com