Narrowing down the correct scope - Page 1
Forum section: electronics / testgear

author: Plasmateur
author_rank: Regular Contributor
timestamp: October 30, 2017, 02:45:50 am
content: Hello,After going through all the specs listed in the Digital Oscilloscopes Chart thread, I've narrowed my choices down to a few scopes.The scopes are listed in the attachment.Ideally I would use a PXI scope module from National Instruments, however they are cost prohibitive.I need to be able to trigger the scope, quickly dump waveform data, and repeat multiple times.Currently I'm using a tektronix DPO3054 for this application. When I acquire waveforms on all 4 channels with 1M data points, the whole process can take up to about 1.5 seconds...which is pretty much an eternity for me.Does anyone here have experience with programming one of the scopes I've selected for repeated data acquisition, with a faster repetition rate than 1.5 seconds per trigger to acquisition? I would like to shorten this time by at least an order of magnitude if possible.Thanks!

author: Plasmateur
author_rank: Regular Contributor
timestamp: October 30, 2017, 03:43:42 am
content: Thank you for the response.I'll contact their applications engineer tomorrow and see if they might have a ballpark figure on how long the process will take.

author: ADT123
author_rank: Regular Contributor
timestamp: October 30, 2017, 06:45:02 am
content: I am biased but if you are connecting to a PC / writing your own code and have been considering a PXI scope with no screen / display then consider also the PicoScope 6000 series:https://www.picotech.com/oscilloscope/6000/picoscope-6000-overviewBased on the specs you have highlighted the PicoScope 6402C is similar. Cost is $3295, bandwidth is 250MHz (faster models available), sampling rate 5GS/s, memory is 256MS (up to 2GS available). The waveform update rate is 170,000 per second or if you want to use rapid triggering / segmented memory then its trigger re-arm time is less than 1us so >1 million waveforms per second can be captured.If you are writing your own software then the sped of data transfer back to the PC is important. Using USB3.0 this is > 150MS/s.

author: abraxa
author_rank: Frequent Contributor
timestamp: October 30, 2017, 08:32:45 am
content: QuoteHow are you transferring the data? USB2? Ethernet? Which software?The reason I'm asking is because scopes usually allow different data encoding schemes for the raw data values. Inhttps://assets.tequipment.net/assets/1/26/Documents/Tektronix/dpo3000_programmermanual.pdfit says on page 57:QuoteSo if you use ASCII encoding, the transfer time doesn't surprise me at all.Depending on how quickly your "trigger the scope, quickly dump waveform data, and repeat multiple times" must happen, remote controlling the scope may be too slow. I'd be willing to bet that LeCroy's XDEV option provides the highest data throughput for any standalone scope - simply because you can write a C/C++ lib to directly interface with LeCroy's XStream software, both running on the scope itself. I'm not aware of anything comparable from Keysight or R&S, though that may have changed since the last time I checked.http://teledynelecroy.com/options/productseries.aspx?mseries=289&groupid=144

author: nctnico
author_rank: Super Contributor
timestamp: October 30, 2017, 08:46:02 am
content: Let's do some math first: 4x1Mpts =4MB. In 1.5 seconds means a transfer rate of 2.6MB/s. Most scopes won't be able to transfer that amount of data because they lack the processing power (the R&S RTB2000 can't even do half the datarate). How much data do you need in total? If the number of acquisitions is limited you could use segmented recording on a scope with a lot of memory.

author: _Wim_
author_rank: Super Contributor
timestamp: October 30, 2017, 08:42:43 pm
content: For fast streaming to a pc, I would use a PC digitizer card. Do not know what the price is (nor have used something like this), but this can transfer data FAST:https://spectrum-instrumentation.com/en/m4i2234-x8

author: fonograph
author_rank: Frequent Contributor
timestamp: October 31, 2017, 07:17:51 pm
content: Rte = lower noise,superior fft,bigger memoryKeysight = super fast,can be hackedI definately go either Keysight 3000 or RTE,I prefer RTE becose it have lower noise and better fft,but keysight have fastest update rate and it can be hacked if its the non touchscreen version.You have to be masochist to take Rigol over Keysight or R&SBTW,there is 6000 euro RTO 1000 ex demo unit on R&S bargain site,its 600 MHz two channel,would buy that if I was you.http://shop.rohde-schwarz.com/bargain/r-srrto1002-2.html

author: Plasmateur
author_rank: Regular Contributor
timestamp: November 01, 2017, 05:58:48 pm
content: Quote from: abraxa on October 30, 2017, 08:32:45 amI am transferring the data via USB. All programing is done in LabVIEW. The data is in binary.

author: Plasmateur
author_rank: Regular Contributor
timestamp: November 01, 2017, 06:09:52 pm
content: Quote from: _Wim_ on October 30, 2017, 08:42:43 pmThis is exactly what I need. Thank you so much!