ModulationsModulationsAmplitude Shift Keying ASK (OOK)Amplitude Shift Keying ASK (OOK)

BW for ASKBW for ASK

Nbaud is baud rate

Ex. Given a BW of 10,000 Hz (1,000-Ex. Given a BW of 10,000 Hz (1,000-11,000) for a full-duplex ASK. Find the 11,000) for a full-duplex ASK. Find the carriers and the BW in each direction. carriers and the BW in each direction. Assume there is no gap between the Assume there is no gap between the bands in two directions. bands in two directions. What is the What is the maximum baud rate and bit rate?maximum baud rate and bit rate?

Frequency Shift Keying (FSK)Frequency Shift Keying (FSK)

BW for FSKBW for FSK

EXample: Find the maximum bit rates for EXample: Find the maximum bit rates for an FSK signal if the bandwidth of the an FSK signal if the bandwidth of the medium is 12,000 Hz, and the difference medium is 12,000 Hz, and the difference between the two carriers must be at least between the two carriers must be at least 2000 Hz. Transmission is in full-duplex 2000 Hz. Transmission is in full-duplex mode. mode.

Phase Shift KeyingPhase Shift Keying (PSK)(PSK)

PSK Constellation diagramPSK Constellation diagram

4-PSK4-PSK

4-PSK Constellation diagram4-PSK Constellation diagram

88--PSKPSK

BW for PSKBW for PSK

The same as ASKThe same as ASK Ex. Given a bandwidth of 5000 Hz for an Ex. Given a bandwidth of 5000 Hz for an

8-PSK signal, what are the baud rate and 8-PSK signal, what are the baud rate and bit rate?bit rate?

PSK is not susceptible to the noise PSK is not susceptible to the noise degradation that affects ASK, nor the BW degradation that affects ASK, nor the BW limitations of FSK.limitations of FSK.

Quadrature amplitude Quadrature amplitude modulation (QAM) modulation (QAM)

BW for QAMBW for QAM

The same as ASK and PSK.The same as ASK and PSK.

MultiplexingMultiplexing multiple links on 1 physical linemultiple links on 1 physical line common on long-haul, high capacity, linkscommon on long-haul, high capacity, links have FDM and TDM alternativeshave FDM and TDM alternatives

Frequency Division Frequency Division MultiplexingMultiplexing

FDMFDMSystem System

OverviewOverview

FDM Voiceband ExampleFDM Voiceband Example

Wavelength Division Wavelength Division MultiplexingMultiplexing

FDM with multiple beams of light at FDM with multiple beams of light at different freqdifferent freq

carried over optical fiber linkscarried over optical fiber links

Synchronous Time Division Synchronous Time Division MultiplexingMultiplexing

TDM TDM SystemSystem

OverviewOverview