Pulse amplitude modulation (PAM) is a method where the amplitude of pulses is varied proportionally to the message signal voltage. PAM uses flat-top sampling and the signal is easily affected by noise. It can be constructed in the time domain and frequency domain. Ideal sampling can eliminate noise but is difficult to generate, while detection of PAM samples requires the low-pass filter cutoff frequency to be between the message frequency and sampling frequency, plus a guard band.

1. Pulse Amplitude Modulation
(PAM)
VPAM must directly proportional with VM

2. Signal shown of PAM Signal
In the noise aspect, this type of signal is EASILY EFFECTED
by noise
This is type of flat-top sampling signal

3. Construction of PAM signal
Time Domain
Frequency Domain

4. Sampling Methods in PAM
Ideal and natural sampling signal can eliminate noise
Ideal sampling signal is difficult to generate

5. Detection of PAM Sample Signal
fo for the LPF must within
the range of fm < fo < fs - fm
fs = 2fm but usually fs > 2fm because to have GUARDBAND
fm = fs / 2 = 1 / 2T
ms(t) = VPAM

6. Generation and Detection of PAM
Generation of PAM
Detection of PAM

7. Generation and Detection of PAM
Generation of PAM
Detection of PAM