R3267 Series Spectrum Analyzer Operation Manual (Vol.1)
4.2.2 Root Nyquist Filter
4-6
4.2.2
Root Nyquist Filter
The analyzer has the capability of correcting for the Root Nyquist filter when measuring the adjacent chan-
nel leakage power.
When calculating the power of each channel by integrating the trace data, the corresponding Root Nyquist
filter’s coefficient at the frequency (H
(n)
) is multiplied.
Root Nyquist filter’s coefficient (H(n)) is calculated by substituting Symbol rate (T) and Rolloff factor (a)
into the formula shown below.
The characteristics of the Root Nyquist filter is shown in Figure 4-5.
Figure 4-5Characteristics of the Root Nyquist Filter
P’’
U
=
∑
b
n = a
10
(
10
P(n)
)
×
H
(n)
a = f
Uch
-
2T
(1 +
α
)
, b = f
Uch
+
2T
(1 +
α
)
P’’
L
=
∑
b
n = a
10
(
10
P(n)
)
×
H
(n)
a = f
Lch
-
2T
(1 +
α
)
, b = f
Lch
+
2T
(1 +
α
)
