Re: [time-nuts] 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. There are two issues with this problem. One is clock recovery. The other is getting a large chunk of data into memory and presumably on to disk. This leads in to a question I've been meaning to ask for a while. I've been looking for a low cost FPGA on PCI board. This might be a wild goose chase, but I think it would be handy for a bunch of time-nut type applications. If I had the board I'm thinking of, you would just plug your data signal into a SMA connector and grab the data. It might take some FPGA hacking, but clock recovery at 10 MHz isn't a big deal and before long we'd have a good collection of FPGA code. What I'm looking for is a FPGA on a PCI card with a front end where I could add my own interface circuitry probably on a daughter card. I'm picturing a connector of some sort on the PCI card, probably standard 0.025 inch pins on 0.1 centers, but I'd be happy with anything low tech and inexpensive. I'd want it as far back from the front panel as is reasonable to leave room for my stuff. I also want a couple of good mounting holes. (and drawings and part numbers...) The daughter cards would be flipped upside down. Cooling would be poor but shouldn't be a problem with low power interface chips. It would get exciting if you wanted to put a fast ADC out there. I'd expect the vendor to make a few popular interface daughter cards available. There are a couple of obvious ones. One is N data lines with a clock on whatever ribbon cable type connector fits on the front panel. Another is several SMA connectors, one going to a clock input on the FPGA. It might make sense to layout something on the front section of the board. As long as that section isn't stuffed it won't get in the way. Whatever is likely to be most popular. Does anybody know of an inexpensive FPGA card like that? There are a handful of reasons why FPGA and PCI don't play together well. The main one is that old 5V PCI can generate 11V spikes from reflections and that is off scale with modern silicon technology, or at least the branch of it used in the FPGAs that I'm familiar with. There is a 3V PCI spec, but (almost?) no mother boards implement it. I think that's mostly a chicken/egg problem. It didn't take off so nobody built cards that depend on it so it didn't take off... Lots of people make cards that run on either 3V or 5V. That's easy. Does anybody know of any mother boards with 3V PCI slots? I think the 66 MHz option for PCI needs them. There are 2 ways that I know of to connect a FPGA to 5V PCI. One is to use FET bus switches. The other is to use some other chip to connect to the PCI bus. One possibility is a PCI-PCI bridge. Another is an older technology FPGA. A 3rd is one of the PLX chips designed to connect to external logic. I think they can all be made to work, but they seem ugly to me. There are a couple more possibilites. One is to cheat. That means putting a scope on your PCI bus and noticing that even though it's a 5V bus, it's only got 3V signals on it. You would have to get out the scope again every time you wanted to plug in a new card. Ugly. Another option is to use PCI-Express. I'm not sure what is available for low cost FPGAs, but lots of mother boards now include PCI-Express slots. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 10 MHz data capture, help
It might make sense to layout something on the front section of the board. As long as that section isn't stuffed it won't get in the way. Whatever is likely to be most popular. Does anybody know of an inexpensive FPGA card like that? Tom eventually went with a USBee SX board. The manufacturer doesn't say, but I'm guessing there's a fair bit of RAM on those boards, because they claim to support continuous streaming at 24 megabytes/second with no data loss. As it turned out he had a clock line available for the NRZ bitstream, so he didn't have to sample at 20 MHz. I fooled around a bit with a Xylo USB board and was able to recover a clocked bitstream at 10 MHz, but with only the 512-byte FIFO on the FX2, there's not much time for Windows to go out to lunch. It's probably possible to synthesize a large-enough FIFO in the gate array to make the process reliable. There are a handful of reasons why FPGA and PCI don't play together well. The main one is that old 5V PCI can generate 11V spikes from reflections and that is off scale with modern silicon technology, or at least the branch of it used in the FPGAs that I'm familiar with. KNJN has been selling their Dragon PCI board ( http://www.knjn.com/?pg=catsrc=3 ) for awhile, and it looks like they just glued the Spartan-2 chip to the bus. Looks simple enough, if not especially inexpensive. They have a habit of not fully documenting their hardware in a way that allows you to build standalone applications with it, though. If inspired to do anything with their hardware, make very sure the documentation is adequate for the job. -- john, KE5FX ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 10 MHz data capture, help
There are two issues with this problem. One is clock recovery. The other is getting a large chunk of data into memory and presumably on to disk. This leads in to a question I've been meaning to ask for a while. I've been looking for a low cost FPGA on PCI board. This might be a wild goose chase, but I think it would be handy for a bunch of time-nut type applications. Let me give you an update. First, thanks to all of you with suggestions on my original data capture question. As John mentioned I looked at a lot of alternatives with a special eye towards USB 'scope and logic analyzer products, eventually trying out the USBee SX. I found a clock edge to go with my NRZ data so that made my problem easier (avoiding having to oversample the data). I was quite amazed at the performance of the USBee device. Even on a tiny netbook PC it will stream 8-bit logic samples at 10 MHz (24 max) with no dropouts into available memory (which on my netbook is usually over half a gigabyte, giving over 50 seconds of continuous capture). I'm still working on the PC software to decode this mass of data (maybe even in real-time) and working on longer runs, but mostly I was pleasantly surprised how easy it is to obtain high rates over USB2.0. I was worried that I'd have to go with some expensive or very complicated PCI-card based acquisition. So Hal, give USB2.0 some consideration before you settle on PCI. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] 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 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 10 MHz data capture, help
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 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 10 MHz data capture, help
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 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 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. 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/ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 10 MHz data capture, help
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 BillWB6BNQ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 10 MHz data capture, help
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 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 10 MHz data capture, help
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 BillWB6BNQ I forgot to point out that the price is $499.00. QUITE reasonable ! BillWB6BNQ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 10 MHz data capture, help
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/ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 10 MHz data capture, help
In message f75434b2bb1f4c31b339d06b495ed...@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 p...@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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 10 MHz data capture, help
-- Forwarded message -- From: Tom Van Baak t...@leapsecond.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Date: Fri, 10 Apr 2009 13:38:55 -0700 Subject: [time-nuts] OT: 10 MHz data capture, help 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. Maybe you can use one of those products: http://www.usbee.com/ just to not waste samples memory, you can deserialize the signal with a 8 bit Shift register and use the clock/8 as trigger for sampling received data. Unfortunately, the cheaper one (SX) lets you use only your PC memory as capture buffer. You have to resort to more expensive models to directly stream your data to HDD. Elio. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 10 MHz data capture, help
Hello Tom, Not sure if someone said this already, the Wavecrest units can sample your data. Up to 40K samples per second continuous according to their literature, via GPIB. Their PC application software (VISI) has a scope mode where you can make this data visible just like on a two-channel sampling scope. If you are lucky, you can pick one up for ~$500 on Ebay, or rent one. bye, Said In a message dated 4/10/2009 16:13:59 Pacific Daylight Time, elio...@gmail.com writes: -- Forwarded message -- From: Tom Van Baak t...@leapsecond.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Date: Fri, 10 Apr 2009 13:38:55 -0700 Subject: [time-nuts] OT: 10 MHz data capture, help 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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
