What Is Modulation?
Modulation is the process of encoding information from a massage source in a way that is suitable for transmission. This is achieved by altering the characteristics of a wave. By superimposing a message on to a high frequency signal referred to as carrier wave (or sinusoidal signal), video, voice and other data can be transmitted. A carrier signal is one with a steady waveform- constant height or amplitude and frequency.
In the process of modulation, a parameter of the carrier wave (such as amplitude, frequency or phase) is varied in accordance with the modulating signal. This variation acts as a code for data transmission. The modulated signal is then transmitted by the transmitter. The receiver demodulates the received modulated signal and gets the original information signal back. Modulation is usually applied to electromagnetic signals: radio waves, lasers/optics and computer networks.
There are five types of modulation: Frequency modulation, Amplitude Modulation, polarization modulation, pulse-code modulation, quadrature amplitude modulation and Phase modulation.
Advantages Of Modulation
Advantages of implementing modulation in communication include:
- Antenna size gets reduced
- No signal mixing occurs
- Communication range increases
- Multiplexing of signal occur
- Adjustments in the bandwidth are allowed
- Reception quality improves.
What You Need To Know About Modulation
- Modulation is the process of influencing data information on the carrier.
- Modulation is done at the transmitter side of a communication system.
- In modulation, original message signal is mixed with carrier wave whose parameters are required to be changed.
- Modulation requires a modulator section for mixing of the two signals.
- Modulation is done to convert the low-frequency signal into a high frequency signal.
- Modulation is essentially conducted to transmit data to longer distance.
- Modulation is fairly simple.
- There are five types of modulation: Frequency modulation, Amplitude Modulation, polarization modulation, pulse-code modulation, quadrature amplitude modulation and Phase modulation.
What Is Demodulation?
The process of extracting an original message signal from the modulated wave is referred to as detection or demodulation. The electronic circuit or computer program that is used to recover the information content from the modulated carrier wave is referred to as demodulator. The signal output from a demodulator may represent sound (an analog audio signal), images (an analog video signal) or binary data (a digital signal).
Some of the common demodulators (detectors) used for demodulating include:
- Square law demodulator
- Envelope detector
There are several other ways of demodulation depending on how parameters of the base-band such as amplitude, frequency or phase are transmitted in the carrier signal. For instance, for a signal modulated with a linear modulation like AM (amplitude modulation), a synchronous detector can be used whereas for a signal modulated with an angular modulation, an FM (Frequency modulation) demodulator or a PM (phase modulation) demodulator can be used.
What You Need To Know About Demodulation
- Demodulation is the recovery of original information at the distant end from the carrier.
- Demodulation is done at the receiver side of a communication system.
- In demodulation, the combination of carrier and message signal are separated from each other, to have original information signal.
- Demodulation requires demodulator to recover the original signal. A demodulator is an electronic circuit that is used to recover the information content from the modulated carrier wave.
- At the time of demodulation, the low-frequency signal is achieved from high-frequency signal.
- Demodulation is conducted to regain the original message signal.
- Demodulation is typically complex.
Also Read: Difference Between SDMA, TDMA, FDMA & CDMA
Difference Between Modulation And Demodulation In Tabular Form
| BASIS OF COMPARISON | MODULATION | DEMODULATION |
| Description | Modulation is the process of influencing data information on the carrier. | Demodulation is the recovery of original information at the distant end from the carrier. |
| Implementation | Modulation is done at the transmitter side of a communication system. | Demodulation is done at the receiver side of a communication system. |
| Message Signal | In modulation, original message signal is mixed with carrier wave whose parameters are required to be changed. | In demodulation, the combination of carrier and message signal are separated from each other, to have original information signal. |
| Requirement | Modulation requires a modulator section for mixing of the two signals. | Demodulation requires demodulator to recover the original signal. |
| Signal Conversion | Modulation is done to convert the low-frequency signal into a high frequency signal. | At the time of demodulation, the low-frequency signal is achieved from high-frequency signal. |
| Purpose | Modulation is essentially conducted to transmit data to longer distance. | Demodulation is conducted to regain the original message signal. |
| Complexity | Modulation is fairly simple. | Demodulation is typically complex. |
Similarities Between Modulation And Demodulation
- Both modulation and demodulation aim to achieve transfer of information with the minimum distortion, minimum loss and efficient utilization of spectrum.
- Modulation and demodulation are performed by modem.
- Both modulation and demodulation occurs during transmission.