What is the difference between antenna and transmitter

In order for digital signals to be received, however, consumers must own a digital transmitter and receiver or a device which has them.

There are some devices that have a transmitter and receiver all in one unit. In these cases, the combined unit is called a transceiver. These are generally used in devices such as phones where the user receives and sends audio signals at the same time.

When choosing electronics, it is important to pick items that have receivers designed for the signals one hopes to listen to or watch. For instance, a digital receiver will often not read an analog signal and vice versa.

Specialize converter boxes can be purchased to convert a receiver into the correct kind for the signal being used. This is especially important now that many television stations are required by law to feature all digital programming, because many consumers own televisions with outdated analog receivers.

You use microphones to capture the sounds of people's voices and turn them into electrical energy. You take that electricity and, loosely speaking, make it flow along a tall metal antenna boosting it in power many times so it will travel just as far as you need into the world.

As the electrons tiny particles inside atoms in the electric current wiggle back and forth along the antenna, they create invisible electromagnetic radiation in the form of radio waves. These waves travel out at the speed of light , taking your radio program with them.

What happens when I turn on my radio in my home a few miles away? The radio waves you sent flow through the metal antenna and cause electrons to wiggle back and forth. That generates an electric current—a signal that the electronic components inside my radio turn back into sound I can hear. How a transmitter sends radio waves to a receiver. This produces an electric current that recreates the original signal.

Transmitter and receiver antennas are often very similar in design. For example, if you're using something like a satellite phone that can send and receive a video-telephone call to any other place on Earth using space satellites , the signals you transmit and receive all pass through a single satellite dish—a special kind of antenna shaped like a bowl and technically known as a parabolic reflector , because the dish curves in the shape of a graph called a parabola. Often, though, transmitters and receivers look very different.

But you don't need anything that big on your TV or radio at home: a much smaller antenna will do the job fine. Waves don't always zap through the air from transmitter to receiver. Depending on what kinds frequencies of waves we want to send, how far we want to send them, and when we want to do it, there are actually three different ways in which the waves can travel:.

Artwork: How a wave travels from a transmitter to a receiver: 1 By line of sight; 2 By ground wave; 3 Via the ionosphere. Photo: This telescopic FM radio antenna pulls out to a length of about 1—2m 3—6ft or so , which is roughly half the length of the radio waves it's trying to capture. The simplest antenna is a single piece of metal wire attached to a radio.

Antennas transmit and receive electromagnetic waves. Generally composed of metals mainly copper or aluminum , antennas can convert an electric current into electromagnetic radiation and vice versa. Every wireless communication device contains at least one antenna.

Transmission antennas produce radiofrequency radiation that propagate in space. Receiving antennas perform the reverse process: they receive radiofrequency radiation and convert them into the required signals e,g.

The simplest type of antenna consists of two metal rods, and is known as a dipole. One of the commonest types of antennas is the monopole antenna, consisting of a rod situated vertical to a large metal board that serves as a ground plane. The antenna mounted on vehicles is usually a monopole, with the metal roof of the vehicle serving as the ground plane. The shape and size of the antenna determines its operative frequency and its other radiation characteristics.

One of the important attributes of an antenna is its directionality. In communication between two fixed targets, as in communication between two fixed transmission stations, or in radar applications, a directional antenna is required, in order to direct the transmission energy to the receiver exclusively.

Conversely, when the transmitter or receiver is not stationary, as in cellular communication, a non-directional system is required. In such cases an omnidirectional antenna is required, that transmits and receives all frequencies uniformly in all directions of the horizontal plane, while in the vertical plane, radiation is not uniform and very low.

A transmission antenna is the basic element of radio technology. This type of antenna is composed of a conductor that carries an electric current whose intensity fluctuates over time and converts it into radiofrequency radiation that propagates in space. A receiving antenna performs the reverse of the process performed by the transmission antenna. It receives radiofrequency radiation and converts it into electric currents in an electric circuit connected to the antenna.

TV and radio broadcasting stations, use transmission antennas to transmit specific types of signals that propagate through the air.