*5.1.1 ASK advantages and disadvantages*

The major advantage of ASK includes high bandwidth efficiency and simplicity in its design. In ASK the modulation and demodulation processes are comparatively inexpensive.

Its disadvantages include lower power efficiency, and it is very susceptible to noise interference.

**25**

**Figure 21.**

*Frequency shift keying.*

*Multiplexing*

*5.1.2 Application*

rate increases.

*5.2.2 Application*

**5.2 Frequency shift keying**

*DOI: http://dx.doi.org/10.5772/intechopen.85866*

• Used in our infrared remote controls

• Used in fiber optical transmitter and receiver

carrier is shifted between two discrete values (**Figure 21**).

implementations are simple for low data rate application.

Many modems used FSK in telemetry systems.

*5.2.1 Advantages and disadvantages of FSK*

The principle of frequency shift keying is that the frequency of the carrier wave is modulated in accordance with the digital message signal, i.e., FSK signal represents the binary data in the form of variations in the frequency of the carrier signal. When an ON condition of digital pulse exists, then carrier will be switched to one frequency, and when an OFF condition encounters the carrier, it will be switched to another frequency, i.e., in "frequency shift keying," the frequency of a sinusoidal

Its advantages include lower probability of error and provide high signal-tonoise ratio. It has higher immunity to noise due to constant envelope. Therefore the probability of error-free reception of data is high. FSK transmitter and FSK receiver

The disadvantage of FSK includes the usage of larger bandwidth than other modulation techniques such as ASK and PSK. Hence it is not bandwidth efficient and is extensively used in low-speed modems having bit rates below 1200 bits/sec. It is not preferred for the high-speed modems because with increase in speed, the bit

**Figure 20.** *Amplitude shift keying.*
