Hey everyone, I want to buy my an oscilliscope for hobbyist applications. This guy here is what is what I'm currently considering getting
https://www.tomtop.com/p-e1269eu.html
Seems to be pretty good value for money (even after £30 on shipping), I also like the fact that it comes with a function generator too as I don't have one. I appreciate that it probably isn't the best but it'll be better than nothing. The two things which are currently holding me back is that it's memory could be bigger, 40k points isn't nearly as much as some other slightly pricier scopes which have 1 or 2M points. However I can't really think of too many applications where I will be using it where I would need more, but I would hate to have to buy new scope a year down the line when I start some new project. Is 40k generally enough?
The other thing which gives me pause is I would like to get a bit in audio stuff and I'm considering building my own sound systems; I read an article which said that 8-bit oscilloscopes don't give high enough resolution for audio applications. Do I need to go for a scope with a higher vertical resolution? Would 10-12 bits be enough? Can you actually get anything that is the sub £400 mark with that kind of resolution (even if it a USB oscilloscope)?
The Hantek DSO4102S is an outdated design, so I would not consider one nowadays. On the other hand it is cheap and comes with a built-in AWG, so I can certainly see why it appears attractive to you. And of course a scope like this would be better than no scope at all.
There are certainly better scopes within your price range up to some €450, but without built-in AWG. A proper external AWG alone would almost eat up your budget.
For the use as just an oscilloscope, 8 bits should certainly do the job. Even analog scopes (equivalent to a near infinite number of bits) can’t give you significantly more information when looking at a signal in the time domain. The limitation only arises when you want to use the DSO as a signal analyzer (which analog scopes cannot do from the outset), because then the 8 bit limit of some 48dB for the dynamic range poses a hard limit at high quality audio applications. The dynamic range can be extended a bit in certain situations by using averaging techniques, but not by nearly as much as some seem to believe, because a low noise floor achieved by digital signal processing does not extend the dynamic range without a dither and the INL (integral nonlinearity) of the ADC sets a hard limit anyway.
As for the memory depth, 40kpts is certainly usable in general – especially at higher frequencies, but a major limitation (or at least inconvenience) for low frequency work. It means that the maximum sample rate can be maintained only up to 40us record length. When working on audio, you are much more likely to use record lengths of e.g. 40ms and that means your sample rate will drop down to 1MSa/s or even just 500kSa/s with both channels in use. Consequently, any signal content above 250kHz will cause signal distortion due to aliasing – that’s quite the opposite of what you want when working on audio. One could claim that this should not be a problem because audio has a well defined frequency spectrum, but this would only be true for a perfect working analog system. Stability problems (ringing or even self oscillation in amplifiers) for instance could cause problems even in old style analog audio applications, not to mention modern class-D equipment and digital audio in general.
When a DSO shall act as a signal analyzer, the FFT function becomes important. With just 1024 FFT points (as in the Hantek DSO4102S) you won’t get very far. Frequency resolution is poor and noise floor will be high with just 8 bits. And with only 40kpts memory, the FFT cannot be fancy, even if the hardware were capable of processing more FFT points within a reasonable time.
So what are your options?
The PicoScope 4262 would certainly be a brilliant choice for low frequency applications, with 16 bits physical resolution, low noise frontend, 5MHz bandwidth, 16Mpts total memory and a powerful FFT up to 2Mpts, which turns this device in a high end dynamic signal analyzer. The built-in AWG produces super clean waveforms with low noise and distortion, but is limited to 20kHz. As a general purpose scope it is obviously limited because of the 5MHz bandwidth, but you can at least utilize the 17 serial decoders (a lot more than in other scopes) for slower serial protocols up to some 1Mb/s.
Here’s a demonstration of its capabilities at analyzing very low frequency signals <1Hz with 725uHz resolution bandwidth and using the multiport capabilities to run two FFT windows at the same time:
https://www.eevblog.com/forum/testgear/low-frequencies-on-spectrum-analyzers/msg1468441/#msg1468441The main problem with the Pico 4262 is its price. The 12-bit 4224 would be cheaper and has 20MHz bandwidth, but still above your budget. If you can afford it, this would still be my recommendation.
Then there’s the Analog Discovery 2, 14bit, 30MHz, AWG, with pattern generator and logic analyzer, but it’s a soapbox with only 16kpts memory total (8k dedicated for the analog channels by default), which is even worse than the Hantek and might explain why Digilent cannot be bothered to specify the FFT length for the spectrum analyzer. Even more importantly, signal distortions due to aliasing will defeat the purpose of having 14bit vertical resolution in many situations.
That leaves us with 8-bit DSOs.
The Siglent SDS1202X-E would be within your budget; high bandwidth, 14Mpts, 500uV/div full resolution sensitivity low noise frontend, 1Mpts FFT – but no built-in AWG.
So finally your best bet might be a PicoScope 2206B. It stays within your budget quite easily, has 50MHz bandwidth, 32Mpts memory, 1Mpts FFT and a built-in AWG up to 1MHz. Like any PicoScope, it has lots of mid-range and even high-end features like full HD screen support with multiple views, very advanced math, a bunch of serial decoders and it gets regular updates at no cost. Despite its fairly low price, it comes from a well known reputable brand and is certainly not a toy.
https://www.picotech.com/oscilloscope/2000/picoscope-2000-overviewMind you, the prices in the Pico web shop are usually higher than the actual street prices, so it pays off to look around a bit.