Problems with analogRead speed and precision

Hello, i want to sniff the data exchange from two devices. I have CLK and DATA pins and i want to register in arduino memory the voltages on high frecvency to detect the bits from data, but now the arduino is to slow and can't read this with analogRead function to detect the up and down voltage, but i see the oscillations on my mini oscilloscope DS203.

How i can get from arduino the same data as my oscilloscope for sniffing?

Those are digital signals. They're either HIGH or LOW. Never in between. Use digitalRead.

You can use the A/D in “free running” mode and crank up the clock speed at the sacrifice of data bits. You will need to read the datasheet and manipulate the registers directly. The normal clock frequency is 50 kHz to 200 kHz. If you run the ADC clock at 1 MHz you can get a 74+kHz sample rate but the bottom 4.5 bits won’t be accurate.

Or you could switch to a processor with a faster A/D.

Or you could add an external A/D.

...or you could be sensible, and use digital reads.

Hello, i want to sniff the data exchange from two devices

Then get the correct software tool for the job.