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472
Random Processes and Spectral Analysis Chap. 6
r(t)=s(t)+n(t)
where s(t)=PSK
Integrator r 0 (t)
Sample
A Reset B
and hold
C
Waveform at A
(PSK plus noise)
cos( c t)
(from carrier sync circuit)
E Clock Clock
D
Clocking signal
(from bit sync circuit)
Output
r 0 (nT)
t
Waveform at E
(carrier sync)
T c =1/f c
t
Waveform at B
t
Waveform at C
Waveform at D
(bit sync)
t
T
Figure 6–19
Correlation (matched-filter) detection for BPSK.
t
Similarly, for the output noise,
N
n 0 (t) = a a k n(t - (k - 1)T)
The average noise power is
k=1
(6–169)
n 0 2 (t) =
N N
a a k = 1
l = 1
a k a l n(t - (k - 1)T)n(t - (l - 1)T)