Anritsu MP2110A BERTWave - Page 51

1.5 Technical Terms
1-25
1
Outline
DDPWS (Data Dependent Pulse Width Shrinkage)
DDPWS is the amount of pulse width shrinkage by data dependent jitter.
Figure 1.5-6 DDJ Measurement Method
In Figure 1.5-6, the red line is the ideal symbol waveform and the blue
line is the measured waveform with jitter. Let t
1
, t
2
, t
3
... be the time of
the blue line at the cross point, and let the time differences between the
red line and the blue line be

t
1
,

t
2
,

t
3
....
DDJ and DDPWS are defined by the following formulas.
DDJ=max(

t
1
,

t
2
,

t
3
…,

t
n
)–min(

t
1
,

t
2
,

t
3
…,

t
n
)
DDPWS=T–min(t
2
– t
1
, t
3
– t
2
, t
4
– t
3
, …t
n
– t
n-1
)
T: Symbol cycle
t
1
t
2
t
3
t
4
…