PAM vs PWM vs PPM-Difference between PAM,PWM,PPM
This page on PAM vs PWM vs PPM describes difference between PAM, PWM and PPM. All these are pulse analog modulation techniques.
PAM
In PAM, the modulating signal modulates the carrier pulse amplitude. As mentioned here amplitude of train of high frequency carrier is varied in accordance with the sampled values of message signal.
In this modulation type, message information is encoded in amplitude of
series of signal pulses at modulation side.
The demodulation is carried out by detecting amplitude level of
carrier at every symbol period.
Fig.1 PAM
The figure depicts time domain representation of the PAM technique which mentions analog message signal and PAM modulated signal as output.
PWM
The PWM signal is a pulse signal which pulse width is proportional to the amplitude of the modulating analog signal.
Fig.2 PWM
The figure depicts time domain representation of the PWM. One of the application of PWM is in speed control of the DC motor.
PPM
The PPM signal is a pulse signal which pulse position is proportional to the amplitude of the modulating signal amplitude. The time domain representation of PPM is mentioned in the figure.
Fig.3 PPM
555 Timer IC is most popular to generate waveforms for PPM and PWM modes. PWM is generated using 555 timer in monostable multivibrator mode. PPM is generated using 555 timer by using PWM as a trigger signal in monostable multivibrator mode.
The following table summarizes difference between PAM, PWM and PPM.
| Method | B.W. | Power Efficiency(SNR) | Complexity |
|---|---|---|---|
| PAM | Less | Lowest | Lowest |
| PWM | High | Moderate | Moderate |
| PPM | High | Highest | Highest |
Refer advantages and disadvantages of PAM, PWM and PPM modulation types.
Modulation types
BPSK -This page describes BPSK modulation technique with equation and constellation diagram.
QPSK -This page describes QPSK modulation technique with equation and constellation diagram.
QAM-This page describes QAM modulation technique with equation and constellation diagram.
MSK-GMSK MSK modulation,GMSK modulation and GMSK demodulation.
8PSK 8-PSK modulation or multilevel PSK or phase shift keying modulation technique.
BPSK vs QPSK -Difference Between BPSK and QPSK modulation techniques.
QPSK vs OQPSK vs pi/4QPSK-Difference between QPSK,OQPSK and pi/4QPSK modulation techniques
Differential Encoder and Decoder
What is Difference between
FIR filter Vs. IIR filter
difference between FDM and OFDM
Difference between SC-FDMA and OFDM
Difference between SISO and MIMO
Difference between TDD and FDD
Difference between 802.11 standards viz.11-a,11-b,11-g and 11-n
OFDM vs OFDMA
CDMA vs GSM
Bluetooth vs zigbee