Gardner 算法原文
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4.6 Gardner Algorithm
109
Figure 4.10: Self-noise in two-point difference algorithm.
4.6 Gardner Algorithm
The algorithmis based on delay differencing betweenthe currentsample and another
sample delayed by half the symbol period, i.e.
x
d
(t)=p
r
(t)
;
p
r
(t
;
T / 2) (4. 37)
By passing x
d
(t) through a square-law rectifier, the following is obtained
u(n)=x
2
d
(t)=p
2
r
(t)+p
2
r
(t
;
T / 2)
;
2p
r
(t)p
r
(t
;
T / 2) (4. 38)
It is due to the above squaring that the operation of the Gardner algorithm
becomes independent of the carrier phase. Substituting the early sampling time,
t
e
= nT +
τ
, and the late sampling time, t
l
= nT +
τ
+ T / 2 in (4.38) gives
u(n)=p
2
r
(
τ
+ nT)
;
p
2
r
(
τ
+[n
;
1]T)
;
2p
r
(
τ
+[n
;
1 / 2]T)
f
p
r
(
τ
+ nT)
;
p
r
(
τ
+[n
;
1]T)
g
(4.39)
By simulation, it has been shown that the first two terms have a major contribu-
Chapter 4 Symbol Timing Synchronisation Algorithms
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noface00112021-09-16请问这是什么书？
