Transmitter

Transmitter

A transmitter is an electronic device that produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating current, the antenna radiates radio waves. Transmitters are necessary components of all electronic devices that communicate by radio, such as radio and television broadcasting stations, cellular phones, walkie-talkies, wireless networks, Bluetooth-enabled devices, garage door openers, two-way radios in aircraft, ships, spacecraft, radar sets, and navigational beacons.

Components

A typical transmitter consists of several key components:

Power Supply

The power supply provides the necessary electrical power to operate the transmitter.

Oscillator

The oscillator creates the alternating current at the frequency on which the transmitter will transmit. This is the carrier wave.

Modulator

The modulator adds the information to be transmitted to the carrier wave. This can be done by varying the amplitude, frequency, or phase of the carrier wave.

Amplifier

The amplifier increases the power of the signal to a level suitable for transmission.

Antenna

The antenna converts the amplified signal into radio waves.

Types of Transmitters

Radio Transmitters

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A radio transmitter for WDET-FM

Radio transmitters are used in broadcasting to send audio signals to radios. They can be AM or FM transmitters, depending on the modulation technique used.

Television Transmitters

Television transmitters send both audio and video signals to television receivers. They use frequency modulation for audio and amplitude modulation for video.

Communication Transmitters

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A CB radio transmitter in a truck

These transmitters are used in various communication devices such as cell phones, walkie-talkies, and CB radios.

Radar Transmitters

Radar transmitters send out pulses of radio waves and receive the echoes to determine the location and speed of objects.

Microwave Transmitters

Microwave transmitters are used for point-to-point communication links and in satellite communication.

Signal Processing

Signal processing system

Signal processing in transmitters involves the manipulation of the signal to improve transmission quality and efficiency. This includes filtering, modulation, and amplification.

Historical Transmitters

Vacuum Tube Transmitters

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A vacuum tube AM transmitter

Early transmitters used vacuum tubes to generate and amplify signals. These were large and required significant power.

Solid State Transmitters

Modern transmitters use solid-state devices such as transistors, which are more efficient and compact.

Modern Transmitters

Digital Transmitters

Digital transmitters use digital modulation techniques to transmit data. They are used in modern digital television and digital radio broadcasting.

Software-Defined Radio

Software-defined radio (SDR) transmitters use software to perform signal processing tasks that were traditionally done by hardware.

Applications

Broadcasting

Transmitters are used in radio and television broadcasting to send audio and video signals to the public.

Telecommunications

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Cordless phone

Transmitters are essential in telecommunications for sending voice and data over long distances.

Navigation

Transmitters are used in navigation systems such as GPS to send signals to receivers.

Related Pages

• Antenna (radio)
• Modulation
• Radio wave
• Broadcasting
• Telecommunication