Lowest Cost Bode Plotting Oscilloscope Suggestions - Page 1
Forum section: electronics / testgear

author: DA270
author_rank: Newbie
timestamp: August 03, 2025, 07:44:39 pm
content: New guy here on the forum to say hello and also asking for your ideas.I'm setting up a hobby bench after a long hiatus from electronics and would like an inexpensive, but capable oscilloscope to cover my needs. I'm mostly interested in audio frequency measurements, so bandwidth is not likely to be an issue for my purposes. I'm particularly interested in experimenting with op-amp active audio filter circuits, so the built in bode plotting feature of several different oscilloscopes I've researched is certainly an attractive feature for that area of experimenting. However, built-in bode plotting seems to be a feature that is not available on entry level, low cost models.I know there are some USB low cost solutions like the ADLAM2000, Analog Discovery 3, etc., but I would like to have something standalone and with physical controls(not a tablet scope either).Just a brief background on me. I haven't touched an oscilloscope in over 40years! I have an AS in electronics tech from the late '70s and worked in the field for about five years before changing my career path. I have a lot of hands-on experience and a solid grasp of the fundamentals from those ancient times, but it would probably be best to consider me a total novice with regard to modern test equipment. Think of me as a tech student learning most of this for the first time.I'd love to purchase something like the Keysight EDUX1052G as it would fit my requirements perfectly, but the $1K price tag is hard for me to justify for occasional hobby usage.What would be the entry point of a capable oscilloscope that would cover my needs? I would appreciate your ideas on this topic.Thank you,Dave

author: tautech
author_rank: Super Contributor
timestamp: August 03, 2025, 08:04:33 pm
content: Welcome to the forum.If a 70 MHz 2ch model is sufficient to meet your needs consider a SDS802X HD but you will also need an AWG for the Bode plot stimulus.All Siglent AWG's are plug and play for Bode plot use.

author: Songhua
author_rank: Contributor
timestamp: August 03, 2025, 09:32:52 pm
content: TBH, a handheld Digital Oscilloscope such as HDS200s from Owon can do it. But you need to run a python script on PC for operating it.Here's the link for the opensource project:https://bodeplotter.github.io/BodePlotter/which uses SCPI commands.https://www.owon.com.hk/products_owon_hds200_series_digital_oscilloscopeJust make sure it comes with a signal generator. Or you buy these seperately and write programs by yourself.----But clearly you need something for the bench.I have been using the Rigol DHO924S for a while. And it comes with a very simple 25MHz signal generator(but you can load any pre-defined signal files), 4 CH 250MHz (hackable, upgradable), 50M (depth, hackable to 128M) and it has bode plotting inside. it's very easy to do. It runs on Android 7 (cool and nice). Comparing to other entry-level oscilloscopes, it can be a little pricy. But it almost has all. I had the same question before: buy seperate devices or buy an all-in-one. Then I bought the all-in-one because it's handy.For people who need very precise signal syncing, DHO800/900 won't work because the DHO800/900 don't have a signal clock syncing BNC port at the back, which means it can't sync with signal generator at the same clock. Only "expensive" Oscilloscope (DHO4000) and signal generator have the clock syncing BNC port at the back, sometimeson Oscilloscopeit can be called asTriggerOutor10MHz Ref Out(sends 10MHz to a signal generator which has 10MHz Ref in),10MHz Ref In(receives 10MHz from a signal generator which has 10MHz Ref out)for syncing clocks!I tested the signal generator on DHO924S and other signal generator sending same wave at the same freqency to the DHO924S CH1 and CH2, the 2 signals drifted regularly. It's explained above. Some low-end used Oscilloscopes even has10MHz Ref inwhich can happily work with external signal generators.Probably Rigol only want users to buy DHO4000. But DHO4000 doesn't have bode plotting built-in. lolThe recent released Rigol MHO5000 has Bode Plot (Available Only for MHO5054/5104). The only improvement comparing to DHO924S was that the MHO5000 has an option for choosingImpendance [high-z or low-z]. And it has10MHz Ref Inand10MHz Ref OutBNC ports. The price is not for entry-level.Buy the one that you need, and then focus on the things worthy.

author: Fungus
author_rank: Super Contributor
timestamp: August 04, 2025, 12:27:50 pm
content: For audio frequencies you can download the Analog Discovery "waveforms" software and use it for free with a PC sound card (line in jack, or get a USB sound device to help protect your PC from overloads).You'll get way better results with a 16 or 24 bit ADC than with an oscilloscope.Download it and have a play around.Quote from: DA270 on August 03, 2025, 07:44:39 pmForget Keysight, they're overpriced and don't even sell to people without a business account.

author: DA270
author_rank: Newbie
timestamp: August 16, 2025, 07:51:46 pm
content: I wanted to follow up with my decision on an oscilloscope purchase.I decided that the best overall value for what I wanted to be able to do was go with the Siglant SDS804x HD and the SDG830 function generator.This gives me plenty of room to expand my capabilities as future interest may require and does everting I want now. I'm very pleased with the equipment.The built-in bode plotting works great and is the exact feature I was looking for.Thanks for the replies and suggestions.Dave