One is the amplitude modulation (AM) radio tuner, and the other is the frequency modulation (FM) radio.

Tuning capacitors are popular type of variable capacitors. The rotor plates when moved into the slots of stator, they come close to form plates of a capacitor. When the rotor plates sit completely in the slots of the stator then the capacitance value is maximum and when they don’t, the capacitance value is minimum.

A tuner is a subsystem that receives radio frequency (RF) transmissions and converts the selected carrier frequency and its associated bandwidth into a fixed frequency that is suitable for further processing, usually because a lower frequency is used on the output.

This radio circuit therefore, is tuned by adjusting the capacitance of the variable capacitor to equalize the inductive and capacitive reactance for the desired resonant frequency, or in other words, to tune in the desired radio frequency.

Variable capacitors

As previously mentioned, electric field antennas can be related to capacitors. Consider a simple parallel plate capacitor shown in Figure 2(a). The electric field that occurs when a charge is placed on each of the plates is contained in between the plates. Such current is called antenna mode current.

Typically the simplest is to consider two types of loss: ohmic loss and ground loss.

How does an antenna work? The antenna at the transmitter generates the radio wave. A voltage at the desired frequency is applied to the antenna. The voltage across the antenna elements and the current through them create the electric and magnetic waves, respectively.

Whether it be radio, LAN, or otherwise, an antenna is extremely important. The antennas primary function is to transmit and receive clear signals between multiple wireless points. It is safe to say that an effective and efficient wireless network will require antennas to operate properly.

There are two main types of WiFi antennas – omnidirectional and directional. Outdoor Omni Antennas: Used to improve WiFi signal outdoors. To successfully improve the wireless coverage outside, they are typically connected to a router, access point, or an outdoor access point.

3.3. Types of Antennas. There are three main antenna categories available for wireless LANs: Omnidirectional, Semidirectional and Highly directional.

That’s more or less what an antenna (sometimes called an aerial) does: it’s the metal rod or dish that catches radio waves and turns them into electrical signals feeding into something like a radio or television or a telephone system. Antennas like this are sometimes called receivers.

The Best Indoor HDTV Antenna

• Our pick. Antennas Direct ClearStream Flex. A powerful TV antenna with flexible installation options.
• Runner-up. RCA ANT3ME. For easier, quicker setup.
• Upgrade pick. Winegard Flatwave Amped Pro. For finding hard-to-receive stations.
• Budget pick. 1byone Digital Amplified Indoor HDTV Antenna.

An antenna is a metallic structure that captures and/or transmits radio electromagnetic waves. Antennas come in all shapes and sizes from little ones that can be found on your roof to watch TV to really big ones that capture signals from satellites millions of miles away.

A transmitter is an electronic device used in telecommunications to produce radio waves in order to transmit or send data with the aid of an antenna. The transmitter is able to generate a radio frequency alternating current that is then applied to the antenna, which, in turn, radiates this as radio waves.

As its name implies, the general purpose of a transmitter is to transmit signals. These signals contain information, which can be audio, video, or data. In essence, a transmitter launches signals into the air via a transmitting antenna.

What are the main features of a transmitter? Explanation: Some of the main features which make the transmitter complex are higher clock speed, higher transmit power, directional antennas and need for a linear amplifier.

The important feature of the transmitter is extremely fast current, turn-off time, less than 1 μs for the shallowest depth, while the current after the ramp time is practically absent.

The block diagram of AM transmitter is shown in the following figure. The working of AM transmitter can be explained as follows. The audio signal from the output of the microphone is sent to the pre-amplifier, which boosts the level of the modulating signal. This wave is finally passed to the antenna to be transmitted.

Pressure transmitters are divided into three types: Absolute Transmitter: This transmitter take vacuum pressure as its base, and then measures process pressure. Gauge Transmitter: This type measures process pressure with the location’s atmospheric pressure as a base.