Hi everyone, a debut post here. I really enjoy the forum and of course, Dave's video postings. I'm at the point where I'm ready to buy a DSO + signal generator (budget < £1000). I'm a hobbyist with some distant electronics engineering from University. I currently have an analogue Tek 2245A (4ch 100MHz) which I find a real joy to use, a beautiful example of late '80s design and engineering.
I made for my son a DCC model railway injector (DCC++ project, Arduino based). This superimposes digital comms on the power to model trains by inverting the power lines at a variable pulse width. The stream of messages from the device while repetitive, is quite long and I really couldn't get the analgoue scope to get me a stable view -- lots of twiddling of trigger filter, long A timebase, short B, hold-off and then hold your breath! So I've became quite eager for a DSO where I can grab a frame of data and just freeze, zoom and pan the image! The other job I did recently was convert the battery power for a little audio generator from 9V batteries to 2xAA, using one of the low cost DC-DC converters you can buy on Ebay. I noticed quite some fuzz on the signal output but it was only when I zoomed right in that I saw alarming oscillations after the 'on' and 'off' switching pulses (c. 900kHz switching). The ringing on the power lines was 140MHz! I know the amplitude of my trace will have been attenuated and maybe accuracy not so important for this example but nonetheless I'm not super enthusiastic about having a new instrument with <100MHz. I'm an electrical engineer and the other maker project I'm planning is a compact and safe device to measure power quality/harmonics. Single phase, Teensy based ADC with bluetooth to send data to a simple phone app. I'm therefore quite keen that the scope I buy has an 'adequate or good' FFT for the tests I will need to do. I can also see myself using an FRA/Bode plot feature if I can get that to optimise the performance of my circuits when using op-amps etc.
I've done quite some research, reading and shortlisted Siglent and Keysight:
1. Siglent SDS1104X-E (£455) + SDG1032X generator (£277), from Telonic, total cost £732. I could add the Micsig differential probe (DP10007, £162) which I could really use for my power projects and still stay well within budget. This is the sensible, logical option.
2. Keysight DSOX1202G (£921), Mouser. Or the DSOX1202A without generator (£727) and get a separate economy generator from Aliexpress, like the UTG932 (~ £100). (With the second option I’d lose the built in FRA feature of the oscilloscope, but could still use the ‘gain only’ Bode plot technique demonstrated by Dave by just sweeping the signal generator). This oscilloscope has fewer features and channels than option one, but does have Keysight internal engineering and user interface, and will likely do everything I need it to do. I don’t indulge myself very often..
Both will be huge improvements on what I currently have. I’m flipping between these two and can’t decide, and wondering if people on the forum could help weigh this with me. Siglent and Keysight are quite different companies, and I have problems with both of them. It’s great that Siglent are engineering led, and investing in their staff development and R&D, but I have noticed some explicit plagiarism in their oscilloscope manual from - I guess - Keysight. Compare bottom of p75
https://www.siglenteu.com/wp-content/uploads/dlm_uploads/2021/03/SDS1000X-ESDS1000X-U_UserManual_UM0101E-E05A.pdf with bottom of p131
https://www.batronix.com/files/Keysight/Oszilloskope/1000X/1000X-Manual.pdf.Copying a technical explanation word for word just isn’t playing the game fairly. And Keysight, I resent them de-speccing their product via bandwidth filters, and then charging hefty license fees just to restore the natural bandwidth of the hardware. I think that policy really grates in the low end scope market. It is like you have bought a camera with a really good lens but the manufacturer smeared it on the inside with some grease, to deliberately blur the image! The people who don’t pay are hacked off that the hardware they bought has been ‘degraded’ by the manufacturer, and the people who do pay the bandwidth charge are annoyed that they are being tapped to lift the average selling price of the hardware. Why not make everyone happy by just raising the price (a little, to the average sell price) and give everyone 200MHz? Maybe keep the EDUX as a special case.
The others…
3. GW Instek. GDS-1054B often recommended on the forum, but it’s priced rather high in the UK market, about the same as the Siglent but with less bandwidth and only one ADC. But I do like that it can do arbitrary maths functions on the signals and selectable digital filters.
4. Rigol. DS1054Z is getting old but has withstood assaults from above and below for literally years. I hear people grumble about the lack of velocity control or laggy UI, but it does seem to do the job, well made with great maths and trigger options. It deserves its place as a classic of its time that transformed the low end oscilloscope market. The thing that lets it down for me is the constrained FFT. Maybe I should be considering MSO5000 series but was put off by them using Keysight-type software locks for literally everything and the low vertical sensitivity. I don’t need touch screen or MSO.
5. Micsig. I do like the idea of using Android as a modern platform for the software but I’m worried about tying tablet hardware to the oscilloscope. Tablets only last 3-5 years (software updates stop, battery dies). If it was a hardware sampling module that plugged into a bog standard tablet then it would feel more optimised/efficient and I would be quite interested.
6. Rhode & Schwarz. RTC1000 a bit too pricy. For people with more budget there is a good promotional deal at the moment that enables all the bandwidth and options. I didn’t like the low-resolution screen.
7. Tektronix. Sigh. They seem to be lost in the woods. They have version bumped the TBS1000 series and increased the sample memory from 2.5k to just 20k points. What is going on?
Really interested to hear any comments people have to help me jump one way or the other.