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Topic: Toy oscilloscope - 200 ksamp/sec on Arduino Uno/ATmega328P (Read 366 times) previous topic - next topic

avhohlov

inoscope
Not all finished, but sample rate seems real.
ADC Clock frequency are set to 4 MHz (this is 4x of max allowed value).

MarkT

What performance can you get at that speed?  I presume the input must be very
low impedance to charge the S/H cap at that rate.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

avhohlov

It is seems that amplifier with 1k output impedance are sufficient.

First channel (green) connected to pwm pin 11 via resistor, second channel (yellow) - to pwm pin 3 directly.
PWM frequency - 3906 Hz. ADC speed - 2x100 ksamp/sec.

1k:


10k:


110k:



Now this amplifier used (R1 = 2.7 .. 110k, Q2 - BC547B), but op amp with rail-to-rail output may be better:


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