Forums

continuous-play DAC

Started by John Larkin April 2, 2012

Hi, 

We have a customer who has a mess of digitized data from some sort of
aircraft system, and wants to play it back into some box for testing.
It will be 2 channels of 16-bit data originally sampled at about 500
KHz, several hours worth. They want us to design a VME module with
dacs and a huge amount of DRAM to store the data. We don't really want
to do it - they only need a couple of boards - but we don't like to
say no to these guys either.

So, couldn't he just use a small-box PC and a sound card? How fast can
a high-end sound card output points? The CD standard was 44KHz, but I
think there are 4x versions at least. Depending on his analog
bandwidth requirements, 196K might work.

Can a fast sound card accept data at the 4x (or whatever) rate, or
does it always accept 44K data and interpolate?

Who makes good high-end sound cards?

Thanks

John



-- 

John Larkin         Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro   acquisition and simulation
On Mon, 02 Apr 2012 13:15:45 -0700, John Larkin wrote:

> Hi, > > We have a customer who has a mess of digitized data from some sort of > aircraft system, and wants to play it back into some box for testing. It > will be 2 channels of 16-bit data originally sampled at about 500 KHz, > several hours worth. They want us to design a VME module with dacs and a > huge amount of DRAM to store the data. We don't really want to do it - > they only need a couple of boards - but we don't like to say no to these > guys either. > > So, couldn't he just use a small-box PC and a sound card? How fast can a > high-end sound card output points? The CD standard was 44KHz, but I > think there are 4x versions at least. Depending on his analog bandwidth > requirements, 196K might work. > > Can a fast sound card accept data at the 4x (or whatever) rate, or does > it always accept 44K data and interpolate? > > Who makes good high-end sound cards?
If you want to do this with the least muss and fuss, your best off-the- shelf solution is probably something from National Instruments or DAQ. I'm just guessing -- but I'd look there first. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com
John Larkin <jlarkin@highlandtechnology.com> wrote:

> > >Hi, > >We have a customer who has a mess of digitized data from some sort of >aircraft system, and wants to play it back into some box for testing. >It will be 2 channels of 16-bit data originally sampled at about 500 >KHz, several hours worth. They want us to design a VME module with >dacs and a huge amount of DRAM to store the data. We don't really want >to do it - they only need a couple of boards - but we don't like to >say no to these guys either.
500kHz, 16 bits and 2 channels adds up to 4MB/s. I'd go for an SD card and an NXP ARM controller. Use an SPI DAC and use the SPI timing to get the sample rate right. Piece of cake :-) -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico@nctdevpuntnl (punt=.) --------------------------------------------------------------
"John Larkin" <jlarkin@highlandtechnology.com> wrote in message 
news:al1kn7h5afo6arossnjmpe2f8t1aupto4o@4ax.com...
> > > Hi, > > We have a customer who has a mess of digitized data from some sort of > aircraft system, and wants to play it back into some box for testing. > It will be 2 channels of 16-bit data originally sampled at about 500 > KHz, several hours worth. They want us to design a VME module with > dacs and a huge amount of DRAM to store the data. We don't really want > to do it - they only need a couple of boards - but we don't like to > say no to these guys either. > > So, couldn't he just use a small-box PC and a sound card? How fast can > a high-end sound card output points? The CD standard was 44KHz, but I > think there are 4x versions at least. Depending on his analog > bandwidth requirements, 196K might work. > > Can a fast sound card accept data at the 4x (or whatever) rate, or > does it always accept 44K data and interpolate? > > Who makes good high-end sound cards? > > Thanks > > John > > > > -- >
Direct Stream digital recording is interesting.... <https://en.wikipedia.org/wiki/Direct_Stream_Digital> pretty cheap recorder... <http://www.bhphotovideo.com/c/product/461177-REG/Tascam_DV_RA1000HD_DV_RA1000HD_High_Definition_CD_DVD_.html>

John Larkin schrieb:
> > Hi, > > We have a customer who has a mess of digitized data from some sort of > aircraft system, and wants to play it back into some box for testing. > It will be 2 channels of 16-bit data originally sampled at about 500 > KHz, several hours worth. They want us to design a VME module with > dacs and a huge amount of DRAM to store the data. We don't really want > to do it - they only need a couple of boards - but we don't like to > say no to these guys either. > > So, couldn't he just use a small-box PC and a sound card? How fast can > a high-end sound card output points? The CD standard was 44KHz, but I > think there are 4x versions at least. Depending on his analog > bandwidth requirements, 196K might work.
Hello, 5 hours with 500 kHz sampling rate, 2 channels with 2 bytes each will need about 36 GB of RAM. So look for a small-box PC with 40 GB of RAM and 64 bit adressing. Or a disk with more than 2 MB per second data rate, sustained for hours. Bye
On 3 Apr., 09:47, Uwe Hercksen <herck...@mew.uni-erlangen.de> wrote:
> John Larkin schrieb: > > > > > Hi, > > > We have a customer who has a mess of digitized data from some sort of > > aircraft system, and wants to play it back into some box for testing. > > It will be 2 channels of 16-bit data originally sampled at about 500 > > KHz, several hours worth. They want us to design a VME module with > > dacs and a huge amount of DRAM to store the data. We don't really want > > to do it - they only need a couple of boards - but we don't like to > > say no to these guys either. > > > So, couldn't he just use a small-box PC and a sound card? How fast can > > a high-end sound card output points? The CD standard was 44KHz, but I > > think there are 4x versions at least. Depending on his analog > > bandwidth requirements, 196K might work. > > Hello, > > 5 hours with 500 kHz sampling rate, 2 channels with 2 bytes each will > need about 36 GB of RAM. So look for a small-box PC with 40 GB of RAM > and 64 bit adressing. Or a disk with more than 2 MB per second data > rate, sustained for hours. > > Bye
you don't need all that ram, most PCs will play HD video just fine so bandwidth from disk shouldn't be an issue I wonder if you could graft an SD card onto one of your arbitrary waveform generators it is basically spi so it not that many pins and if the data on it is just a big flat file it shouldn't be that hard to read from an FPGA or maybe something like this:http://apple.clickandbuild.com/cnb/shop/ ftdichip?productID=161&op=catalogue-product_info- null&prodCategoryID=121 -Lasse
On 4/2/2012 4:15 PM, John Larkin wrote:
> > > Hi, > > We have a customer who has a mess of digitized data from some sort of > aircraft system, and wants to play it back into some box for testing. > It will be 2 channels of 16-bit data originally sampled at about 500 > KHz, several hours worth. They want us to design a VME module with > dacs and a huge amount of DRAM to store the data. We don't really want > to do it - they only need a couple of boards - but we don't like to > say no to these guys either. > > So, couldn't he just use a small-box PC and a sound card? How fast can > a high-end sound card output points? The CD standard was 44KHz, but I > think there are 4x versions at least. Depending on his analog > bandwidth requirements, 196K might work. > > Can a fast sound card accept data at the 4x (or whatever) rate, or > does it always accept 44K data and interpolate? > > Who makes good high-end sound cards? > > Thanks > > John > > >
24 bit 192kHz sample rate soundcards are commodity hardware these days: http://www.musiciansfriend.com/pro-audio/m-audio-audiophile-192-pci-interface/703610000000000?src=3WWRWXGB&ZYXSEM=0&gclid=CLv-xNyGma8CFYNo4AodPC6x0g among many others. They can playback 192kHz sample rate files, no interpolation needed.
bitrex <bitrex@de.lete.earthlink.net> wrote:
> On 4/2/2012 4:15 PM, John Larkin wrote: >> >> >> Hi, >> >> We have a customer who has a mess of digitized data from some sort of >> aircraft system, and wants to play it back into some box for testing. >> It will be 2 channels of 16-bit data originally sampled at about 500 >> KHz, several hours worth. They want us to design a VME module with >> dacs and a huge amount of DRAM to store the data. We don't really want >> to do it - they only need a couple of boards - but we don't like to >> say no to these guys either. >> >> So, couldn't he just use a small-box PC and a sound card? How fast can >> a high-end sound card output points? The CD standard was 44KHz, but I >> think there are 4x versions at least. Depending on his analog >> bandwidth requirements, 196K might work. >> >> Can a fast sound card accept data at the 4x (or whatever) rate, or >> does it always accept 44K data and interpolate? >> >> Who makes good high-end sound cards? >> >> Thanks >> >> John >> >> >> > > 24 bit 192kHz sample rate soundcards are commodity hardware these days: > > http://www.musiciansfriend.com/pro-audio/m-audio-audiophile-192-pci-interface/703610000000000?src=3WWRWXGB&ZYXSEM=0&gclid=CLv-xNyGma8CFYNo4AodPC6x0g > > among many others. > > They can playback 192kHz sample rate files, no interpolation needed.
I wouldn't bet much on the analog output of this being flat up to 90-odd kHz.
On Tue, 03 Apr 2012 12:04:07 -0400, bitrex <bitrex@de.lete.earthlink.net>
wrote:

>On 4/2/2012 4:15 PM, John Larkin wrote: >> >> >> Hi, >> >> We have a customer who has a mess of digitized data from some sort of >> aircraft system, and wants to play it back into some box for testing. >> It will be 2 channels of 16-bit data originally sampled at about 500 >> KHz, several hours worth. They want us to design a VME module with >> dacs and a huge amount of DRAM to store the data. We don't really want >> to do it - they only need a couple of boards - but we don't like to >> say no to these guys either. >> >> So, couldn't he just use a small-box PC and a sound card? How fast can >> a high-end sound card output points? The CD standard was 44KHz, but I >> think there are 4x versions at least. Depending on his analog >> bandwidth requirements, 196K might work. >> >> Can a fast sound card accept data at the 4x (or whatever) rate, or >> does it always accept 44K data and interpolate? >> >> Who makes good high-end sound cards? >> >> Thanks >> >> John >> >> >> > >24 bit 192kHz sample rate soundcards are commodity hardware these days: > >http://www.musiciansfriend.com/pro-audio/m-audio-audiophile-192-pci-inte=
rface/703610000000000?src=3D3WWRWXGB&ZYXSEM=3D0&gclid=3DCLv-xNyGma8CFYNo4= AodPC6x0g
> >among many others. > >They can playback 192kHz sample rate files, no interpolation needed.
And that ain't half the incoming sample rate. 500 ksps. Playing with a small disk and an arb sounds like the way to go. ?-)