What type of interface is used in PC-based scopes to communicate with ACQ board? - Page 1
Forum section: electronics / testgear

author: Mykeil
author_rank: Contributor
timestamp: April 22, 2017, 03:45:36 pm
content: Hi,I am looking for information how many lanes is used in pc-based scopes to communicate with acquisition board and what is the type of interface.Is it PCI or PCIe? 1.0, 2.0, 3.0? Lanes x1 x2 x8 x16?I am looking for high data transfer rate scope to my multi-channel measuring system. I think the fastest will be, which uses PCIe with more lanes. The data will be read on Labview installed on the scope, so no physical medium will be used to transfer the data.If you have pc-based scope please put information what is the version of PCI/PCIe used to communicate with acquisition board and how many lanes.Mostly I am interested in LeCroy scopes:- LeCroy WaveSurfer Xs-A- LeCroy WaveSurfer 400- LeCroy WaveRunner 6000/6000A- LeCroy SDA 3000-6000- LeCroy WaveMaster 8000AWhat I know:- Tektronix TDS5000: PCI 2.0- Tektronix TDS7000: PCI 2.0- Agilent 5483x: PCI 2.0- LeCroy DDA 3000-5000: PCI- LeCroy WavePro 7000A: PCI- LeCroy WaveSurfer Xs: PCIThank you. Have a nice day,Mykeil

author: Mykeil
author_rank: Contributor
timestamp: April 22, 2017, 04:55:14 pm
content: I am looking for cheap Windows-based oscilloscope which uses PCI Express interface to communicate its PC motherboard with acquisition board.Anyone with any?

author: ebclr
author_rank: Super Contributor
timestamp: April 22, 2017, 05:24:17 pm
content: With scopes with ethernet and Usb with lcd priced at 299 USD, this can be considered legacy stuff, Usb scopes still there but old PCI exp cards hard to find in now days

author: Mykeil
author_rank: Contributor
timestamp: April 22, 2017, 05:42:52 pm
content: Thanks for reply.PCIe digitizer cards are good option but not cheap. I am looking for standalone Windows-based oscilloscope which uses PCIe as interface to communicate its pc builded board and acquisition board.

author: nctnico
author_rank: Super Contributor
timestamp: April 22, 2017, 05:56:14 pm
content: IMHO you are going at this the wrong way. The PCI version is not going to tell you anything about how fast the data transfer actually is. This depends greatly on the acquisition hardware, PCI bus utilisation and speed of the post processing software. If you want guaranteed speeds then you'll be better off with dedicated hardware. What are your requirements (number of channels, bandwidth, acquisition length, cycle time)? Perhaps some of us know a better way to achieve your goal.

author: Mykeil
author_rank: Contributor
timestamp: April 22, 2017, 06:16:45 pm
content: I want to make multi-channel acquisition system for scanning voltage on pcbs. The amount of channels will depend how fast is ADC in the scope. I wan to have 10-100MS per channel. If the scope will have 5GS/s it will be 50-500 channels. I will use multiplexer. The sample rate is not a problem. The problem is with the record memory. If I want to record 500ms with 5GS/s sample rate I need 2.5 Giga points record. I will not have, so I am trying to solve this issue by continuously grabbing recorded data by Labview. Labview will be installed on oscilloscope, so there will be no physical medium between Labview and oscilloscope.If the pc board will be too slow I can change it into new one or use PCIe link adapter to connect it to another more powerful motherboard, so it is not a problem. The problem is slow data rate between acquisition board and pc motherboard.Thanks for reply.

author: nctnico
author_rank: Super Contributor
timestamp: April 22, 2017, 06:25:20 pm
content: Using a multiplexer isn't going to work to slice 5Gs/s into seperate channels. Forget about that. What you need is a stack of cheap acquisition modules. The cheapest are the USB (maybe ethernet) ones like from Hantek and others. An oscilloscope like you listed before will cost at least 4000 euro in good condition used. Add to that the price of a multiplexer (which can't really do what you want) and you'll be in the >6000 euro ballpark.

author: ebclr
author_rank: Super Contributor
timestamp: April 22, 2017, 06:35:49 pm
content: http://www.ti.com/tool/adc12j2700evm

author: Mykeil
author_rank: Contributor
timestamp: April 22, 2017, 06:51:01 pm
content: Quote from: nctnico on April 22, 2017, 06:25:20 pmI am ready for that.I did not found PCI/PXI 30-channels acquisition card with 100MS/s/ch sampling rate and 300MHz bandwidth.Quote from: ebclr on April 22, 2017, 06:35:49 pmNice piece of hardware. USB 3.0 output. It should give 5Gbit/s. It has 32GB SRAM and can store 2 Giga points of 16-bit records.I found 4GS/s modelhttp://www.ti.com/tool/adc12j4000evm

author: abraxa
author_rank: Frequent Contributor
timestamp: April 22, 2017, 07:43:34 pm
content: QuoteWhat's the point of 300 MHz bandwidth if you have 100 MS/s?Anyway, to give you inspiration to look also in other directions:http://tmi.yokogawa.com/ea/products/data-acquisition-equipment/high-speed-data-acquisition/sl1000-high-speed-data-acquisition-unit/16 channels per unit at 100 MS/s, so up to 128 channels when synchronizing 8 units. Real-time streaming via optional gigabit ethernet or onto optional built-in harddrive, so may fit your bill if you can live with the 20 MHz bandwidth (which imo is reasonable for 100 MS/s).

author: Mykeil
author_rank: Contributor
timestamp: April 22, 2017, 09:13:25 pm
content: Maybe 100MS/s is not too much for 300MHz bw, but after a full scan I plan to make deeper scanning with higher sample rate and lower channels amount.That is an advantage between idea of acquisition cards and one big adc.For now the best is Texas Instruments evaluation boardhttp://www.ti.com/tool/tsw14j56evmwithhttp://www.ti.com/tool/adc12j4000evm. All for $3250.It has 4GS/s, 4GB record memory and USB 3.0 for data transfer.I need to look for PCIe digitizers for this job.It don't have to have high data output transfer rate if it has about 4GB record memory.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 23, 2017, 12:53:01 am
content: Quote from: abraxa on April 22, 2017, 07:43:34 pmI've looked at very few signals that are non-periodic while demanding that much bandwidth.Tim

author: Mykeil
author_rank: Contributor
timestamp: April 23, 2017, 04:29:18 pm
content: Only one Windows-based scope uses PCIe to transfer data from acquisition board. It is LeCroy WaveSurfer Xs-A. It uses PCIe 1.0 x1 which means it can transfer data with 250MB/s speed and theoretically I can reach 250MS/s sample rate with unlimited memory. It is too low for my needs. This solution not satisfies my needs.Now I am looking for the cheapest scope with Giga points record memory. Anyone?I made a research and I think the cheapest is Agilent/Keysight DSO9104A. 1GHz bw, 40 GS/s (20GS/s/2ch) and 1Gpts record memory.

author: Mykeil
author_rank: Contributor
timestamp: April 23, 2017, 07:11:43 pm
content: https://www.xilinx.com/products/boards-and-kits/1-f31o3b.html56 GSPS/channel4 channel24 GB of DDR-4 Memory (3 banks of 64-bit)8-bit ADC at up to 56 GSPSXilinx UltraScale™ XCKU115 FPGA

author: nctnico
author_rank: Super Contributor
timestamp: April 23, 2017, 07:44:55 pm
content: How do you expect to interleave the signals using a multiplexer?

author: Mykeil
author_rank: Contributor
timestamp: April 23, 2017, 08:01:06 pm
content: Quote from: nctnico on April 23, 2017, 07:44:55 pmThe plan is to control multiplexers by NI FPGA card. When all data will be captured it will be cut it into separate traces in Labview after measurements. I will not separate the data in real time.

author: nctnico
author_rank: Super Contributor
timestamp: April 23, 2017, 08:32:55 pm
content: Quote from: Mykeil on April 23, 2017, 08:01:06 pmBut how do you plan to correlate the data? With a multiplexer you'll get a piece of data from time X on channel 1, a piece of data from time X+1 on channel 2. Much like a video monitor multiplexer you sometimes see to watch multiple cameras on one monitor. You can see what happens everywhere but you can't see what happens at the same time.

author: MrW0lf
author_rank: Frequent Contributor
timestamp: April 23, 2017, 08:51:29 pm
content: Quote from: Mykeil on April 23, 2017, 04:29:18 pmhttps://www.picotech.com/oscilloscope/6000/picoscope-6000-specificationsPicoScope 6404D500MHz analog, 2GSa memory, 5GSa/s single ch, 1.25GSa/s 4ch.€6,295This is actual scope. Not RF ADC.

author: Mykeil
author_rank: Contributor
timestamp: April 23, 2017, 09:19:01 pm
content: Quote from: nctnico on April 23, 2017, 08:32:55 pmSamples will be in their original time moment. I will not correlate the data in the time and move samples.Lets assume that I have 1GS/s scope and 3-channel multiplexer. I will see on recorded data:1. ch. sample | mux switch to 2. ch. | 2. ch. sample | mux switch to 3. ch | 3. ch sample | mux switch to 1. ch. | ...0 - 1ns : 1. channel sample1ns - 10ns : mux switch to 2. ch.10ns - 11ns: 2. channel sample11ns - 21ns: mux switch to 3. ch.21ns - 22ns: 3. channel sample22ns - 32ns: mux switch to 1. ch.32ns - 33ns: 1. channel sample33ns - 43ns : mux switch to 2. ch.43ns - 44ns: 2. channel sample44ns - 54ns: mux switch to 3. ch.54ns - 55ns: 3. channel sample55ns - 65ns: mux switch to 1. ch.65ns - 66ns: 1. channel sample66ns - 76ns : mux switch to 2. ch.76ns - 77ns: 2. channel sample77ns - 87ns: mux switch to 3. ch.87ns - 88ns: 3. channel sample88ns - 98ns: mux switch to 1. ch.It is always 33ns sample rate.I assumed 10 ns time for mux switching operation and stabilization, but I think it may be longer. I hope not. I could have higher sample rate if I would have faster multiplexer.Now I have 30 MSamples 3-channel oscilloscope with accuracy in time 33ns.I don't need to know did the scope recorded the sample. If 1GS/s is set I will switch the multiplexer after 1ns and that is all. If I would be not synchronized with adc clock I would increase this time to 2ns, but I will loose sample rate or just synchronize with adc.So, I also need fast 1xN multiplexer with lot of channels

author: nctnico
author_rank: Super Contributor
timestamp: April 23, 2017, 09:31:11 pm
content: This seems rather wasteful to me. For one of my customers I did an FPGA design for a distributed data acquisition system based on a time synchronisation system developed by CERN using similar acquisition modules like this one (100Ms/s 30MHz 14 bit):http://www.ohwr.org/projects/fmc-adc-100m14b4cha/wikiThis module goes onto a base board which can be used standalone or in a PC.The beauty of this system is that it is all open source/open hardware so you can build whatever you like with it. The time synchronisation system enables to synchronise two nodes in the ps range.

author: Mykeil
author_rank: Contributor
timestamp: April 23, 2017, 09:33:23 pm
content: Did you had to use multiplexer?

author: nctnico
author_rank: Super Contributor
timestamp: April 23, 2017, 09:42:45 pm
content: No, each signal has it's own input. Also nodes can be far away (10km) from eachother without losing time correlation.