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Sec. 5–5 Asymmetric Sideband Signals 329<br />

m(t)<br />

Modulation<br />

DBS<br />

Modulator<br />

s(t)<br />

DBS<br />

VBS Filter<br />

(Bandpass Filter)<br />

H v (f)<br />

s VSB (t)<br />

VSB<br />

(a) Generation of VSB Signal<br />

S ( f )<br />

B<br />

1<br />

f c<br />

0<br />

f c<br />

f<br />

(b) Spectrum of DSB Signal<br />

H v (f)<br />

1<br />

f ∆<br />

f c<br />

f c<br />

f<br />

(c) Transfer Function of VSB Filter<br />

S VSB (f)<br />

1<br />

f c<br />

f c<br />

f<br />

(d) Spectrum of VSB Signal<br />

H v (f-fc)+H v (f+fc)<br />

C = 1<br />

H v (f-fc)<br />

H v (f+fc)<br />

f c B f ∆ f ∆ B<br />

f c<br />

(e) VSB Filter Constraint<br />

Figure 5–6 VSB transmitter and spectra.<br />

f

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