Math
153
13.2.3
ERES
The oscilloscope filters the sample, which rejects noise in the high frequency domain, so the signal-to-noise ratio
(SNR) is improved. As a result, the effective number of bits (ENOB) of the oscilloscope is enhanced.
Figure 13.5
ERES Example
ERES operation does not require the signal to be periodic, nor does it require stable triggering, but due to the digital
filtering, the system bandwidth of the oscilloscope will degrade when acquiring data in ERES mode. The higher the
enhanced bits, the lower the bandwidth. The following table shows the relationship between ERES bits and bandwidth:
ERES Bits
-3dB bandwidth
0.5
0.25*Sample rate
1
0.115*Sample rate
1.5
0.055*Sample rate
2
0.028*Sample rate
2.5
0.014*Sample rate
3
0.007*Sample rate
Table 13.2
ERES Bits and Bandwidth
