Spectrum of PAM with flat-top sampling ■Spectrum of Input Iw(f)I ■Spectrum of PAM ▣xTs=1/3,fs=4B f ■B=3fs=12B -BB IWs(f) 1/72mU- D=1/3 -3fs -2fs -fs -BB fs 2fs 3fs
Spectrum of PAM with flat-top sampling ◼ Spectrum of Input ◼ Spectrum of PAM ◼ /Ts=1/3, fs=4B ◼ BT= 3fs = 12B |W(f)| -B B f 1 |Ws(f)| -3fs -2fs -fs -B B fs 2fs 3fs D=1/3 sin s f T f 1 ( ) ( )s s n H f W f nf T =− −
Summary of PAM Require very wide bandwidth Bad noise performance Not good for long distance transmission Provide means for converting a analog signal to PCM signal Provide means for TDM(Time Division Multiplexing) Information from different source can be interleaved to transmit all of the information over a single channel
Summary of PAM ◼ Require very wide bandwidth ◼ Bad noise performance ◼ Not good for long distance transmission ◼ Provide means for converting a analog signal to PCM signal ◼ Provide means for TDM(Time Division Multiplexing) ◼ Information from different source can be interleaved to transmit all of the information over a single channel