SDS1000X-E&SDS1000X-U User Manual
43
2. Waveform Confusion: when the sample rate is lower than twice the actual
signal frequency (Nyquist Frequency), the frequency of the waveform rebuilt
from the sample data is lower than the actual signal frequency. The most
common aliasing is the jitter on fast edge.
3. Waveform Leakage: when the sample rate is too low, the waveform rebuilt
from the sample data does not reflect all the actual signal information.
Bandwidth and Sample Rate
An oscilloscope's bandwidth is typically described as the lowest frequency at which
input signal sine waves are attenuated by 3 dB (- 30% amplitude error).
At the oscilloscope bandwidth, sampling theory says the required sample rate is f
S
= 2f
BW
. However, the theory assumes there are no frequency components above f
MAX
(f
BW
in this case) and it requires a system with an ideal brick- wall frequency
response.
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