Bode plotting on Micsig oscilloscopes - Page 1
Forum section: electronics / testgear

author: ptluis
author_rank: Frequent Contributor
timestamp: July 21, 2025, 09:02:08 am
content: Well that's today's question!None of Micsig oscilloscopes have Bode Plot capability because none of them includes an internal AWG or a dedicated port to connect an external one.What could be the best approach to bode plot on Micsig scopes?Manual mode with some paper and a pen like the old days or there are other effective ways of doing it in conjunction with a tablet or laptop PC running Windows OS?Thank you

author: tautech
author_rank: Super Contributor
timestamp: July 21, 2025, 09:16:35 am
content: Quote from: ptluis on July 21, 2025, 09:02:08 amAll you need is an AWG that can Sweep.Watch Dave's old video:

author: Fungus
author_rank: Super Contributor
timestamp: July 21, 2025, 03:42:26 pm
content: Quote from: ptluis on July 21, 2025, 09:02:08 amDo you need Bode plot or frequency response plot? They're not the same thing.Getting a basic frequency response curve is easy. Put in some white noise and do an FFT.

author: ptluis
author_rank: Frequent Contributor
timestamp: July 22, 2025, 10:38:40 am
content: Quote from: tautech on July 21, 2025, 09:16:35 amI know that trick but also need phase analysis

author: ptluis
author_rank: Frequent Contributor
timestamp: July 22, 2025, 10:39:57 am
content: Quote from: Fungus on July 21, 2025, 03:42:26 pmI need frequency and phase analysisI don't know the approach "white noise + fft", what should I look for on the fft analysis?

author: Fungus
author_rank: Super Contributor
timestamp: July 22, 2025, 12:18:46 pm
content: Quote from: ptluis on July 22, 2025, 10:39:57 amI don't think there's a "trick" for that.In the old days you'd overlay input+output on the screen then turn the knob on the signal generator while looking at it. Find areas of interest.If this is vitally important and you'll be doing a lot of it then maybe time to get a different device. You outgrew the one you own.

author: mawyatt
author_rank: Super Contributor
timestamp: July 22, 2025, 01:47:34 pm
content: Quote from: ptluis on July 22, 2025, 10:39:57 amMost built-in FFTs on DSOs we're familiar with don't offer Phase, only Amplitude information. One could import the DSO data and perform an FFT on a PC if necessary.Don't think the "White Noise" FFT approach will yield Phase, as what's the "Phase Reference" for a White Noise Source?The Bode Analysis provides Phase and Amplitude directly on DSOs that support this mode. The Siglent DSOs we're familiar with provide this Bode Analysis directly as a built-in feature (no activation required).Best

author: nctnico
author_rank: Super Contributor
timestamp: July 22, 2025, 02:18:18 pm
content: Quote from: ptluis on July 21, 2025, 09:02:08 amWith some programming / scripting. Control scope and generator. Let the scope do a measurement of amplitude and phase difference between two channels (DUT input / output) and plot the results in a graph.

author: ptluis
author_rank: Frequent Contributor
timestamp: July 22, 2025, 03:32:40 pm
content: Quote from: nctnico on July 22, 2025, 02:18:18 pmI know there's some scripts already made out there, haven't use none but it's something I'm considering.Also I don't understand why manufacturers don't develop tablet oscilloscopes with function generators and Bode plot functions. There's a large market for those portable solutions. I found some really nice oscilloscopes, but all missed this feature. I missed my Siglent SDS1204X-E+ AWG, but when I decided to convert all bench equipment to portable, I started to realize how much of a pain it is!

author: Grandchuck
author_rank: Super Contributor
timestamp: July 22, 2025, 05:15:24 pm
content: Quote from: ptluis on July 22, 2025, 03:32:40 pmFnirsi offers a tablet oscilloscope with function generator and Bode plot (DPOS350P) that has been discussed here.

author: ptluis
author_rank: Frequent Contributor
timestamp: July 22, 2025, 06:44:05 pm
content: Quote from: Grandchuck on July 22, 2025, 05:15:24 pmYes I started a topic about it, but actually there's a problem with the phase being inverted that haven't been solved yet, so not an option at the moment

author: Fungus
author_rank: Super Contributor
timestamp: July 22, 2025, 07:07:30 pm
content: Quote from: ptluis on July 22, 2025, 10:39:57 amThe FFT displayisthe frequency response curve. It shows amplitude at all frequencies simultaneously.

author: Fungus
author_rank: Super Contributor
timestamp: July 22, 2025, 07:15:35 pm
content: Micsig supports SCPI so you can read the amplitude/phase of what's on screen over WiFi.See page 66 of the SCPI manual:https://www.micsig.com/uploads/Micsig-Oscilloscope-SCPI-Command-Manual-EN-2024.5.21_1716272598.pdfThis could be scripted to automate readings from a PC and plot a graph there.What frequency range are you interested in? If it's below 100kHz then use your PC sound card instead. Download the Analog discovery software and you can use it for free with a sound card.

author: tautech
author_rank: Super Contributor
timestamp: July 22, 2025, 07:20:45 pm
content: Quote from: ptluis on July 22, 2025, 10:38:40 am

author: ptluis
author_rank: Frequent Contributor
timestamp: July 23, 2025, 09:05:56 am
content: Ok I'll try to answer all questions on this post, Battery powered equipment is mandatory because on most places I work, there are too many different noises injected through AC line, giving wrong signal analysis, specially when I'm dealing with sensors and mv signals. By using battery powered equipment I eliminate around 95% of interferences.I don't have a specific frequency range i work with, could be audio spectrum up to RF.My main business is computer related but I'm involved in other lines of business, automotive ice, EV, audio work mainly music business, etc so the use I gave to an oscilloscope is not limited to one simple feature. the more functions the scope has the better. That's why I always post different questions about different subjects, although most of the time i manage myself to find a solution, some times I need your voice of experience because it's impossible for me to know everything.Since I'm always moving around, my bench equipment stays off for a long time collecting huge piles of dust! so I decided to sell everything and buy portable battery operated ones , although some times it's a pain to find what i need, I don't regret my option.Regarding my posted question, I'm realizing that writing a script with scpi commands could be my way to go.

author: egonotto
author_rank: Super Contributor
timestamp: July 24, 2025, 03:19:09 am
content: Hello,If the MHO1 has average, you should use it.Example:ACQuire:MEAN 16Best regardsegonotto