Req: portable handheld oscilloscope proposal,

[okmn]

portable handheld oscilloscope proposal,
I will usually use at home in my projects with PIC mcu (8 bit or 16 bit)
or in home electronic card repair works.

I have used the lowest 1Gs/S oscilloscopes until now, but now I see 250Ms/s or 500Ms/s oscilloscopes due to their very affordable prices and I did not know which one to buy.

How are 250Ms/s and 500Ms/s oscilloscopes, 50Mhz and 100Mhz ones have at least 2 channels.

such as uart 115200, i2c, rs485 (not necessarily protocol analysis feature, but at least it can capture communication signals)
and
  For pwm signals, it's definitely not at the MHz level.
If you have comments, if you have model suggestions, I request them.

My first priority is to have the most affordable price in terms of price performance.

[keytapper]

I think Hantek has one.

[Giuseppe]

Also Owon can fit HDS242 / HDS242S / HDS272 / HDS272S models

[JonW]

Why do you want a handheld?  They are very limited in the screen size and performance.  I have a number of scopes in the lab and the most used are the PC based ones from picoscope.  These are really powerful and when you get into the higher bandwidths you can use FFT for a simple but fairly powerful Spectrum analyser. The really high speed ones are fairly costly but are still cheaper than the bench top types and are constantly updated as the processing is on PC and not within the hardware.  They also include a signal source and many decoders as standard.

Other good low cost scopes are from Rigol and Siglent and they seem to be in constant competition with each other and thus have some really good offers, these scopes have the advantage that these have an inbuilt screen however they are very portable and lightweight.  Here is a link for a 100M scope with a free software bundle for less than £300 which is extremely good value.  Rigol and Siglent often have ex demo stock too so you could try to contact your local distributor to see if they have any ex demo kit at cut down price.

https://telonic.co.uk/product-category/digital-oscilloscopes/rigol-ds1000z-series-oscilloscopes/

[Stephen Moss]

How are 250Ms/s and 500Ms/s oscilloscopes, 50Mhz and 100Mhz ones have at least 2 channels.

You really need to decide what features are important as determined by its intended primary usage, for example, as an Oscilloscope looking at low frequency digital up to say 100KHz, a low sample rate combined with a small, and thus probably low resolution screen will be fine as any noise on the displayed signal can be largely ignored. Where as if your looking at 100MHz RF then a low sample rate, low resolution display will not give the full picture.

The sample rate and frequencies you listed will not provide a very good result in my opinion, for example a specification of 500MS/s @ 100MHz = only 5 sample per period which is very low, which is OK for hobbyists/anything under 10MHz, but otherwise not that good as at 100MHz they are probably interpolating a lot of the samples in order to produce a reasonable display and so you are seeing a representation of the signal, not the actual signal. As at 500MS/s any over sampling to minimise noise/quantisation errors would require dropping the actual, usable bandwidth down to 20-30MHz.
Personally, think you need a minimum of 20 samples per period for a reasonably accurate display of the actual signal, 10 for an OK one, and that is without any oversampling, so as a absolute minimum your sample rate should be at least 10 time higher than the maximum frequency you would want to look at.

It always pays to carefully look at the full specs of equipment as manufactures can have a tendency talk up the headline specs, particularly on lower end/lower price items, like quoting audio power in PMPO  instead of RMS per channel. When you get into it they are often not as good as they initially sound, i.e. the headline spec may be 250MS/s @ 50MHz bandwidth, but when you look closer that is only when running as a single channel oscilloscope and is halved when using two channels (125Ms/s @ 25MHz per channel) and/or the AWG as it is likely that they are sharing that 250MS/s sample rate, which is how they keep the cost down.

[John Lawton]

I can second these comments.

I have a Siglent SDS1204X-E and it was a good decision to get a 4 channel scope, it is very useful if you want to debug an SPI bus for instance. 

It connects to external equipment such as the Arbitrary Waveform Generator SAG1021 which I use to perform frequency response tests on production signal processing boards, but as it works up to 25MHz it could prove useful for some RF work.

A limitation is that the above scope uses 8 bit ADC, whereas 10 bit or more would be far preferable for better measurement resolution.

[HAL]

Hello okaman

I was in the market for an entry level 100MHz'scope about 4-5 years ago.  I purchased a Siglent SDS1102CML+ directly from Siglent because they had the best price (about $270 then)..  A two channel, light weight, portable oscilloscope w/LCD screen. I have been very happy with it, as it does everything that I want and need it to do. It is A.C. mains powered (120vAC in my case), however a small inverter off of the car's battery should work just fine.  I would have purchased a four channel version but the price was about double.  It isn't hand held but take a look at the SDS1102CML+ data sheet and see if it meets most your needs.

Regards  Hal