Question

9. What is the uncertainty of the measurement of a voltage measurement on the oscilloscope when the vertical scale is set to 2V / division, given that it uses an 8-bit D/A converter?

Answer 1

Answer:

Accuracy of measurement = ± 0.19%

Explanation:

For a 8-bit D/A converter,

Accuracy of measurement = 1/2ⁿ = 1/2⁸ = 1/256 = 0.0039 = 0.39% or ± 0.19%

Given that vertical scale is set to 2V/division so the absolute value of the error is 2*0.0019 = ± 3.8 mV

Example:

In a digital oscilloscope, 1 volt/division means that each division on the oscilloscope shows exactly 1 volt, similarly, 0.5 V/division means that each division shows exactly 0.5 volt so 1 V will take 2 divisions hence the signal will appear larger (zoomed in) on the other hand, setting it on 2V/division will make the signal appear smaller (zoomed out).

Note: Volts/division doesn't change the amplitude of the signals, it only makes them appear zoomed in or out so that the required signal can fit on the oscilloscope screen.