Portable scope with good FFT - Page 1
Forum section: electronics / testgear

author: radhaz
author_rank: Regular Contributor
timestamp: September 02, 2017, 06:10:34 pm
content: A requirement for measuring frequency in the audio spectrum at installation sites came up at work. The device to be measured is a vortex flow meter's raw flow sensor signal. In the lab I use a Keysight MSOX3014T for this purpose, so a portable device that approaches that functionality is what I would be interested in.

author: stmdude
author_rank: Frequent Contributor
timestamp: September 02, 2017, 06:13:21 pm
content: Have you looked at the Keysight 1000X ?It would feel very familiar, and it does have FFTs. It's light and has a handle, so that qualifies as portable, right ?

author: lem_ix
author_rank: Regular Contributor
timestamp: September 02, 2017, 06:18:42 pm
content: Check out the Micsig to1104, or a lesser model from the series, doesn't get more portable than that. Can probably find some tests of the fft function herehttps://www.eevblog.com/forum/testgear/micsig-tablet-oscilloscope-tbook-mini-to1000/

author: radhaz
author_rank: Regular Contributor
timestamp: September 02, 2017, 06:22:07 pm
content: It would need to be battery operated, the installations are sometimes difficult to access.

author: don.r
author_rank: Frequent Contributor
timestamp: September 02, 2017, 06:34:56 pm
content: Micsig has a battery option.

author: nctnico
author_rank: Super Contributor
timestamp: September 02, 2017, 06:47:45 pm
content: I second the suggestion for the MicSig TO1000 (with the battery option).

author: radhaz
author_rank: Regular Contributor
timestamp: September 02, 2017, 07:31:02 pm
content: The suggested Micsig looks useful. Would any owner of the scope show me fft sweeps from 0 to 3kHz?

author: JPortici
author_rank: Super Contributor
timestamp: September 02, 2017, 07:32:27 pm
content: if all you're looking at is audio frequencies, how about your laptop/tablet/phone + audio interface + your software of choice? even with the crappiest audio interface you will have better dynamic range and resolution than probably any oscilloscope at those frequencies. Also a bunch of processing power and and whatever frequency resolution you want.you are not limited by what the embedded scope software lets you do

author: radhaz
author_rank: Regular Contributor
timestamp: September 02, 2017, 07:54:19 pm
content: The signal strength of the piezo crystal in a vortex flow meter is in the millivolt range at it's low end of around 300Hz. There is also a tremendous amount of environmental noise (mechanical, electrical). The environments can be quite harsh and difficult to access.The form factor of the tablet looks suited to this task.

author: alm
author_rank: Super Contributor
timestamp: September 02, 2017, 09:12:19 pm
content: If the signal is very noisy, the low vertical resolution of a scope might not be the best tool for the job (especially if you want to avoid the signal from messing up your frequency response by over driving the inputs). Something like a high-resolution Picotech scope or the already proposed audio interface might give you better results. Or possibly an external analog filter.

author: Rich@RohdeScopesUSA
author_rank: Frequent Contributor
timestamp: September 03, 2017, 01:43:51 am
content: You might check out our handheld RTH1000. It comes standard with a good FFT and you can add a spectrum analysis capability that uses digital down conversion. It also has a 10-bit ADC.https://www.rohde-schwarz.com/us/product/rth-productstartpage_63493-156160.html-Rich

author: nctnico
author_rank: Super Contributor
timestamp: September 03, 2017, 09:10:44 am
content: Quote from: alm on September 02, 2017, 09:12:19 pmThe MicSig tablet scope has input filtering. Besides that if a signal has a lot of noise surrouding the signal of interest then FFT won't do you any good.