OT: 10 MHz data capture, help
I have a old data device that is spitting out TTL data at 10 MHz.
There's just a data line (no clock) but the edges clearly indicate
an internal 10 MHz clock.
I'd like to do a continuous capture of the bits, for up to tens of
minutes, into a PC. That comes to about 1 GB of raw data. I can
handle the decoding of the bits in software after the capture is
done. This is a one-time experiment.
What is the best/quickest/easiest way to capture data like this?
I've looked at various USB or LAN logic analyzer and 'scopes
but most seem to work on batches of data. I need a continuous
capture.
/tvb
Hi TVB,
How about directly capturing it by reading one of the logic bits of the parallel
port ?
Bill....WB6BNQ
Tom Van Baak wrote:
I have a old data device that is spitting out TTL data at 10 MHz.
There's just a data line (no clock) but the edges clearly indicate
an internal 10 MHz clock.
I'd like to do a continuous capture of the bits, for up to tens of
minutes, into a PC. That comes to about 1 GB of raw data. I can
handle the decoding of the bits in software after the capture is
done. This is a one-time experiment.
What is the best/quickest/easiest way to capture data like this?
I've looked at various USB or LAN logic analyzer and 'scopes
but most seem to work on batches of data. I need a continuous
capture.
/tvb
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Tom Van Baak wrote:
I have a old data device that is spitting out TTL data at 10 MHz.
There's just a data line (no clock) but the edges clearly indicate
an internal 10 MHz clock.
I'd like to do a continuous capture of the bits, for up to tens of
minutes, into a PC. That comes to about 1 GB of raw data. I can
handle the decoding of the bits in software after the capture is
done. This is a one-time experiment.
What is the best/quickest/easiest way to capture data like this?
I've looked at various USB or LAN logic analyzer and 'scopes
but most seem to work on batches of data. I need a continuous
capture.
/tvb
Tom,
The common way to do this is with a fast PCI analog input card. There are models
that run at several tens of MSPS. You should be able to write a very small C
application using their drivers to continuously log the digitized data to a file
as binary or ASCII values.
Here's a 30MSPS card:
http://www.advantech.com/products/PCI-1714U/mod_GF-HQHV.aspx
--David Forbes, Tucson
Tom Van Baak skrev:
I have a old data device that is spitting out TTL data at 10 MHz.
There's just a data line (no clock) but the edges clearly indicate
an internal 10 MHz clock.
I'd like to do a continuous capture of the bits, for up to tens of
minutes, into a PC. That comes to about 1 GB of raw data. I can
handle the decoding of the bits in software after the capture is
done. This is a one-time experiment.
What is the best/quickest/easiest way to capture data like this?
I've looked at various USB or LAN logic analyzer and 'scopes
but most seem to work on batches of data. I need a continuous
capture.
Have a look at the GNSS sampler for instance. It can handle the data
rate fairly easilly. A GNSS sampler would be easy to modify for this
application. Using a standard 8 bit serdes clocking in at 10 MHz and
outputing data in the rate of 1,25 MB would make it efficient. It's a
standard USB chip in there and it handles continous streams fairly
easilly. It's the same as in the software defined radio stuff, which
would be another option. Regardless it would be able to handle your
datastream without too much trouble.
Cheers,
Magnus
Tom Van Baak wrote:
I have a old data device that is spitting out TTL data at 10 MHz.
There's just a data line (no clock) but the edges clearly indicate
an internal 10 MHz clock.
I'd like to do a continuous capture of the bits, for up to tens of
minutes, into a PC. That comes to about 1 GB of raw data. I can
handle the decoding of the bits in software after the capture is
done. This is a one-time experiment.
What is the best/quickest/easiest way to capture data like this?
I've looked at various USB or LAN logic analyzer and 'scopes
but most seem to work on batches of data. I need a continuous
capture.
/tvb
Tom,
As others have suggested, perhaps a Software Defined Receiver would do the
trick. The best one on the market and the cheapest uses a very high speed A/D
process for a range of 500Hz to 30MHz.
Look at the following URL: http://www.rfspace.com/SDR-IQ.html
Bill....WB6BNQ
I am on the road right now, so I am not in front of it, but I have
the HandyScope HS3 100MHz USB which can run a strip chart recorder
for days / years if you like; depending on hard drive space. The
strip chart may be only available at lower speeds? I dunno... I
can't remember.... but the Handyscope supports both block transfer
and streaming transfer over USB last I knew for certain speeds...
They also have exposed functions available in the DLLs that can
probably be accessed via standard ActiveX / COM methodologies from
any language include VB, C# / C++, PERL (win32 OLE) etc.
http://www.tiepie.com/uk/products/External_Instruments/
USB_Oscilloscope/Handyscope_HS3.html
Maybe you have seen this one already... I dunno if it could work for
you? maybe?
Cheers,
-chris
On Apr 10, 2009, at 5:15 PM, Magnus Danielson wrote:
Tom Van Baak skrev:
I have a old data device that is spitting out TTL data at 10 MHz.
There's just a data line (no clock) but the edges clearly indicate
an internal 10 MHz clock.
I'd like to do a continuous capture of the bits, for up to tens of
minutes, into a PC. That comes to about 1 GB of raw data. I can
handle the decoding of the bits in software after the capture is
done. This is a one-time experiment.
What is the best/quickest/easiest way to capture data like this?
I've looked at various USB or LAN logic analyzer and 'scopes
but most seem to work on batches of data. I need a continuous
capture.
Have a look at the GNSS sampler for instance. It can handle the data
rate fairly easilly. A GNSS sampler would be easy to modify for this
application. Using a standard 8 bit serdes clocking in at 10 MHz and
outputing data in the rate of 1,25 MB would make it efficient. It's a
standard USB chip in there and it handles continous streams fairly
easilly. It's the same as in the software defined radio stuff, which
would be another option. Regardless it would be able to handle your
datastream without too much trouble.
Cheers,
Magnus
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time-nuts
and follow the instructions there.
WB6BNQ wrote:
Tom Van Baak wrote:
I have a old data device that is spitting out TTL data at 10 MHz.
There's just a data line (no clock) but the edges clearly indicate
an internal 10 MHz clock.
I'd like to do a continuous capture of the bits, for up to tens of
minutes, into a PC. That comes to about 1 GB of raw data. I can
handle the decoding of the bits in software after the capture is
done. This is a one-time experiment.
What is the best/quickest/easiest way to capture data like this?
I've looked at various USB or LAN logic analyzer and 'scopes
but most seem to work on batches of data. I need a continuous
capture.
/tvb
Tom,
As others have suggested, perhaps a Software Defined Receiver would do the
trick. The best one on the market and the cheapest uses a very high speed A/D
process for a range of 500Hz to 30MHz.
Look at the following URL: http://www.rfspace.com/SDR-IQ.html
Bill....WB6BNQ
I forgot to point out that the price is $499.00. QUITE reasonable !
Bill....WB6BNQ
In message F75434B2BB1F4C31B339D06B495ED97F@pc52, "Tom Van Baak" writes:
What is the best/quickest/easiest way to capture data like this?
I've looked at various USB or LAN logic analyzer and 'scopes
but most seem to work on batches of data. I need a continuous
capture.
GNUradios USRP ?
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
I have a old data device that is spitting out TTL data at 10 MHz.
There's just a data line (no clock) but the edges clearly indicate
an internal 10 MHz clock.
I'd like to do a continuous capture of the bits, for up to tens of
minutes, into a PC. That comes to about 1 GB of raw data. I can
handle the decoding of the bits in software after the capture is
done. This is a one-time experiment.
Assuming this is a single data line, that's over 1MB per second, more
than a traditional parallel port can easily handle. There are no
cheap ubiquitous means to get that amount of data into a PC. The
methods that I know of are expensive, either in money or engineering
effort, including:
-
Get a digital I/O card. There are few of these around which can
support your required data rate. One that I used in the distant past
is the ADLink PCI-7200; I suspect NI may have a few offerings. You
may have to DIY a shift register to get the data from serial to
parallel. -
Get a fast analog I/O card, record the data (now several GB worth)
and apply some DSP to recover the digital data. This looks like a
roundabout way, but analog I/O cards are more common and thus easier
to borrow for an afternoon. Again NI has a few, but something like
the HPSDR Mercury (http://www.hpsdr.org/) might work too; I'm not
sure if the Mercury FPGA code can do 'wide' baseband sampling yet. A
variant of this scheme would include a shift register and a simple
D/A converter to get the rate down. -
Build a board that converts the data stream to Ethernet or USB. I
know of no COTS solutions for this, although I suspect the HPSDR Ozy
FPGA can be re-coded to handle this. -
Build a standalone data recorder, either with a microcontroller or CPLD/FPGA.
JDB.
[currently working on the standalone data recorder for a data capture
application]
LART. 250 MIPS under one Watt. Free hardware design files.
http://www.lartmaker.nl/
At 14:31 -0700 10-04-2009, WB6BNQ wrote:
As others have suggested, perhaps a Software Defined Receiver would do the
trick. The best one on the market and the cheapest uses a very high speed A/D
process for a range of 500Hz to 30MHz.
Look at the following URL: http://www.rfspace.com/SDR-IQ.html
Doesn't the SDR-IQ use an AD6620 digital downconverter to reduce the
bandwidth to a few hundred kHz? I've never used it, but its block
diagram would appear to suggest so, plus it uses a FT245RL USB
interface which is limited to full speed USB (ie 12Mbit). If so,
that's not enough bandwidth for Tom's 10Mbit/sec signal.
JDB.
LART. 250 MIPS under one Watt. Free hardware design files.
http://www.lartmaker.nl/