How to minimise the noise of the oscilloscope itself?
1. Bandwidth Limiting Filter
Most digital oscilloscopes are equipped with bandwidth limiting filters. These filters remove excess noise from the input waveform and reduce the bandwidth of the noise, thus improving the vertical resolution. Bandwidth limiting filters can be implemented in hardware or software. You can choose to enable or disable most of the bandwidth limiting filters as needed.
2. High Resolution Acquisition Mode
Most digital oscilloscopes have 8-bit vertical resolution in normal acquisition mode. Some oscilloscopes provide higher vertical resolution, usually up to 12 bits, in high resolution mode, where vertical noise is reduced and vertical resolution is increased. Generally, the impact of high resolution mode can be significant when using slower time/grid settings where there are many data points captured on the screen. The sampling rate and oscilloscope bandwidth will be reduced because the capture in high resolution mode averages the data points adjacent to a single trigger point.
3. Average Mode
If you are working with periodic or DC signals, you can use the average mode to remove vertical noise from the oscilloscope. The average mode samples the waveform multiple times and generates a running average to reduce random noise. Compared with the high resolution mode, the averaging mode does not reduce the sampling rate and bandwidth of the signal. However, the average mode is slower to process because it needs to make multiple acquisitions and calculate the average value of the waveform to display the trace on the screen. And when more averages are selected, the denoising effect can be significantly improved.
