Anritsu BERTWave Series, Operation Manual, Page: 67 / 466

1.5 Technical Terms
1-41
1
Outline
Sampling Oscilloscope
The sampling oscilloscope is a function for monitoring the waveform of
the input signal. It requires a clock input sampling and the waveform is
drawn out of the clock timing. For a periodic signal like PRBS, the
waveform data is obtained by slightly varying the sampling timing. This
waveform data is drawn by superimposing the waveforms.
Clock timing
First measurement
waveform
Second measurement
waveform
Third measurement
waveform
Fourth measurement
waveform
Superimposed waveform
Figure 1.5-25 Drawing Method of Sampling Oscilloscope
SNR (Signal to Noise Ratio)
This is the ratio of the signal amplitude to the noise amplitude.
The sampling oscilloscope can be calculated by the following formula.
SNR= (1 Level–0 Level)/( 
1
+ 
0
)

1
: 1 Level Standard Deviation

0
: 0 Level Standard Deviation
Symbol Rate
Symbol rate is the modulation speed of the signal and the unit is baud. As
one NRZ modulated signal (symbol) carries 1 bit of data, the Symbol Rate
value is the same as Bit Rate. As one PAM4 modulated signal carries 2
bits of data, the Bit Rate value is the twice of Symbol Rate.