sounds good, it might be useful to observe small signal, but I wonder
1. what is the max record length ?
2. 12bits high resolution is realized by hardware or software ?
3. And is it expensive
If you read even one minute this EEVblog and using search you may find all answers and more.
Example this: https://www.eevblog.com/forum/testgear/new-owon-xds-oscilloscopes/msg770683/#msg770683
Shortly
1. 40M
2. Hardware.
3. http://www.saelig.com/product/xds3102a.htm
I still not understand this product all: what is the 40 M for, if there is no search func., no serial decoding. Moreover no stats, no advanced math (except 8192 pts FFT), no nothing. It is basically just able to show a waveform and that's all. (Probably I missed all these in the manual).
There is many reasons for memory.
One and important is for keep samplerate high with also slower timebases.
With this memory it can keep full 1GSa/s down to 2ms/div for one channel (40M) and full 500MSa/s down to 2ms/div for 2 channels. (20M + 20M). So, it have maximum 40ms waveform with full sample rate.
No serial decoding? Of course there is serial triggering standard and (Option) serial decoding. IIC, SPI, UART/RS232 and sub Option for decoding there can add also CAN.
40M is not much! And for two channels 20M+20M just barely enough but still "small" memory today.
(Of course it do not have as rich decoding as example in ZLG what have CAN, LIN, I2C, SPI, UART, USB, PS/2, DALI, Wiegand, 1-Wire, DS18B20, HDQ, SD_SPI, SD_SD, IrDA, Manchester, Differential Manchester, Miller, DHT11, SHT11 , NEC, RC5, RC6, FlexRay, CAN FD).
40ms with full samplerate is some times nice.
Here 50Hz square cycle to cycle time jitter measurement. Trigger edge and next edge in same capture and zoomed for resolution to see jitter. (here used infinite persistence) Of course this measurement can do with long trigger delay but here can also see whole cycle and trigger edge is not out from image. (and this can also use for this kind of measurement because clock do not drift everywhere - because this model reference is in 1ppm class unlike many other cheap scopes. (and it is also tested using High-End reference and long time period.)
Here one trivial basic example. Do this with small memory so that all is also visible on the screen.
(note that 1ppm from 20ms period is 20ns. In image p-p jitter is under 500ps. It is under 25ppb p-p from cycle period and persistence data collected ~ 15min. (Honestly I do not know which one here in this "test" is DUT (siggen or scope))