what is ASK | ASK Advantages | ASK Disadvantages | Amplitude Shift Keying | Applications of ASK

What is ASK | ASK Advantages | ASK Disadvantages | Amplitude Shift Keying | Applications of ASK

Amplitude Shift Keying 

Amplitude-shift keying (ASK) is a form of amplitude modulation that represents digital data as variations in the amplitude of a carrier wave. In an ASK system, the binary symbol 1 is represented by transmitting a fixed-amplitude carrier wave and fixed frequency for a bit duration of T seconds. If the signal value is 1 then the carrier signal will be transmitted; otherwise, a signal value of 0 will be transmitted.

Any digital modulation scheme uses a finite number of distinct signals to represent digital data. ASK uses a finite number of amplitudes, each assigned a unique pattern of binary digits. Usually, each amplitude encodes an equal number of bits. Each pattern of bits forms the symbol that is represented by the particular amplitude. The demodulator, which is designed specifically for the symbol-set used by the modulator, determines the amplitude of the received signal and maps it back to the symbol it represents, thus recovering the original data. Frequency and phase of the carrier are kept constant.

Following are the silent features of ASK modulation

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• ASK is digital modulation technique in which carrier is analog and data to be modulated is digital. Modulated output is analog.

• Here strength or amplitude of carrier signal is varied to represent binary 1 and binary 0 data inputs; While frequency and phase of the carrier signal remain constant. Voltage levels are left to designers of the modulation system

Advantages of ASK modulation

Following are the benefits or advantages of ASK modulation.

➨It offers high bandwidth efficiency.

➨It has simple receiver design.

➨ASK modulation can be used to transmit digital data over optical fiber.

➨ASK modulation and ASK demodulation processes are comparatively inexpensive.

➨Its variant OOK is used at radio frequencies to transmit morse codes.

Disadvantages of ASK modulation

Following are the drawbacks or disadvantages of ASK modulation.

➨It offers lower power efficiency.➨ASK modulation is very susceptible to noise interference. This is due to the fact that noise affects the amplitude. Hence another alternative modulation technique such as BPSK which is less susceptible to error than ASK is used.

Applications of ASK

Modulation has an important role in communications. And amplitude shift keying applications are mentioned below. They are:

1. Low-frequency RF applications

1. Home automation devices

1. Industrial networks devices

1. Wireless base stations

1. Tire pressuring monitoring systems

Thus, Ask (amplitude shift keying) is a digital modulation technique to increase the amplitude characteristics of the input binary signal. But its drawbacks make it so limited. And these drawbacks can be overcome by the other modulation technique which is FSK.