In the actual waveform measurement process, selecting different vertical gears often results in different waveform peak values; If a vertical gear with a large range is selected, there will still be significant voltage measurement deviation, and the core reason is that there are significant differences in the quantization error of the oscilloscope at different ranges.

The vertical resolution and set range of an oscilloscope jointly determine the theoretically distinguishable minimum voltage change. The vertical resolution of a digital oscilloscope is the core indicator for measuring the precision of converting analog voltage signals into digital quantities, and it is also a key performance parameter of the oscilloscope, directly determining the lower limit of amplitude measurement accuracy. On the hardware level, the core of vertical resolution is determined by the number of bits of the built-in ADC (Analog to Digital Converter) in the oscilloscope.

The vertical resolution is related to the range as follows:

Among them, full-scale voltage=vertical gear (V/div, i.e. the voltage value corresponding to each grid) x the total number of grids in the vertical direction of the screen. In theory, with the same oscilloscope, the smaller the range selected, the smaller the quantization error. But the main purpose of an oscilloscope is to observe the changes in waveform shape. Choosing a too small range can only see local waveforms and cannot see the full picture of the signal. Therefore, selecting a vertical range that matches the amplitude of the signal is necessary to effectively reduce quantization errors, fully utilize the vertical resolution of the oscilloscope, and balance waveform observation integrity and amplitude measurement accuracy while presenting the overall waveform shape in its entirety.

Adjusting the vertical range can follow the principle of "maximizing the proportion from overall to local": first, estimate the amplitude range of the measured signal, select the order from large range to small range, and roughly adjust the vertical gear step by step to observe the overall signal, observe the peak to peak value of the signal until the waveform vertical proportion reaches about 80% of the screen; When fine-tuning the vertical gear, it is necessary to continuously observe the waveform display status to ensure that the waveform peak does not exceed the screen and avoid clipping distortion. For waveforms with DC bias and easy to exceed the screen after switching to a small range, they can be switched to AC coupling mode to filter out the DC component, or manually adjusted to shift the waveform to the vertical center position of the screen and then finely adjusted.

Oscilloscopes are the eyes of electronic experimenters. Only by reasonably utilizing their core performance and mastering standardized measurement methods can we dispel the fog of interference and error, and capture the true and accurate signal form.