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082-Engineering-Mathematics-Anthony-Croft-Robert-Davison-Martin-Hargreaves-James-Flint-Edisi-5-2017

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24.15 Discrete convolution and correlation 819

c[n]

2.0

1.5

1.0

0.5

20 40 60 80 100 120 140

Figure24.35

Cross-correlationfunctionc[n] forthe signals f[n] andg[n].

n

We now consider a more realistic case in which there is random noise on the returnedsignalandcarryoutthesamecalculationthatwedidpreviously.Figure24.36

shows the two signals. Although the return signal is still present it is no longer possible

to accurately determine where it actually starts and finishes by just looking at

the graph.

1.0

0.8

0.6

g[n]

0.4

f [n]

0.2

20 40 60 80 100 120 140

Figure24.36

Plotoftransmittedandreceiveddigitalsignalsforaradarsysteminwhichnoiseispresenton

the returnedsignal.

n

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