With the addition of an additional radio frequency pulse and additional manipulation of the magnetic gradients, a T < sub > 2 </ sub >- weighted sequence can be converted to a FLAIR sequence, in which free water is now dark, but edematous tissues remain bright.

One way to measure the distance to an object is to transmit a short pulse of radio signal ( electromagnetic radiation ) and measure the time it takes for the reflection to return.

This works similarly to RADAR ( radio detection and ranging ): An ultrasonic pulse is generated in a particular direction.

The accuracy of this technique is limited by the need to create a sharp " pulse " of radio so that the start of the signal can be accurately defined.

Most radio systems utilize amplitude modulation for the radio signal and encode the control positions with pulse width modulation.

Upgraded radio systems are available that use the more robust frequency modulation and pulse code modulation.

Typical radio control systems for radio-controlled models employ pulse width modulation ( PWM ), pulse position modulation ( PPM ) and more recently spread spectrum technology, and actuate the various control surfaces using servomechanisms.

PWM is most commonly used in radio control equipment today, where transmitter controls change the width ( duration ) of the pulse for that channel between 920 µs and 2120 µs, 1520 µs being the center ( neutral ) position.

The broadcaster periodically sends out a short pulse of a power radio signal, and a small amount of that signal is also sent to the oscilloscope to " trigger " it, sending its beam sweeping quickly across the display.

Ultra wideband was formerly known as " pulse radio ", but the FCC and the International Telecommunication Union Radiocommunication Sector ( ITU-R ) currently define UWB in terms of a transmission from an antenna for which the emitted signal bandwidth exceeds the lesser of 500 MHz or 20 % of the center frequency.

Servos made for model radio control include some of the electronics required to convert the pulse to the motor position – the receiver is merely required to demultiplex the separate channels and feed the pulses to each servo.

EY-NPMA codes priority choices and other functions into one variable length radio pulse preceding the packet data.

The MRI machine emits an RF ( radio frequency ) pulse that specifically binds only to hydrogen.

Image resolution of SAR in its range coordinate ( expressed in image pixels per distance unit ) is mainly proportional to the radio bandwidth of whatever type of pulse is used.

The rate in the calculation is the velocity of the radio pulse, which is the speed of light ( roughly ).

In 2012, a pulse oximeter with integrated 802. 11 wireless radio and a touchscreen interface was introduced by Masimo, allowing clinicians to monitor patients wherever they are at within the hospital.

Radar systems generally work by connecting an antenna to a powerful radio transmitter to emit a short pulse of signal.

Electromagnetic ( radio or sound ) waves are conceptually pure single frequency phenomena while pulses may be mathematically thought of as composed of a number of pure frequencies which sum and nullify in interactions creating a pulse train of the specific amplitudes, PRRs, base frequencies, phase characteristics, etcetera ( See Fourier Analysis ).

The multipath channel through which a radio wave transmits can be viewed as transmitting the original ( line of sight ) wave pulse through a number of multipath components.

The velocity factor ( VF ), also called wave propagation speed or velocity of propagation ( VoP or ), of a transmission medium is the speed at which a wavefront ( of an acoustic signal, for example, or an electromagnetic signal, a radio signal, a light pulse in a fibre channel or a change of the electrical voltage on a copper wire ) passes through the medium, relative to the speed of light.

This signal can be a simple radio pulse or a unique coded signal from the chest strap ( such as Bluetooth, ANT, or other low-power radio link ); the latter prevents one user's receiver from using signals from other nearby transmitters ( known as cross-talk interference ).

* 1920 – Telecommunications: the first transatlantic two-way radio broadcast takes place.

* 1910 – The first public radio broadcast takes place ; a live performance of the opera Cavalleria rusticana is sent out over the airwaves from the Metropolitan Opera House in New York, New York.

With a radio operator initiating a call, the process normally takes a few minutes for the ALE to pick an HF frequency that is optimum for both sides of the communication link.

Path loss normally includes propagation losses caused by the natural expansion of the radio wave front in free space ( which usually takes the shape of an ever-increasing sphere ), absorption losses ( sometimes called penetration losses ), when the signal passes through media not transparent to electromagnetic waves, diffraction losses when part of the radiowave front is obstructed by an opaque obstacle, and losses caused by other phenomena.

By instead comparing the radiated power in a given direction to the actual power that the antenna receives from the transmitter, the power gain takes into account that poorer efficiency, making it a more useful figure of merit for the ability of a transmitter in sending a radio wave toward a receiver.

At breakfast the next morning, during alarming radio reports, Klaatu takes in his fellow boarders ' suspicions and speculations about the alien visit.

An RF modulator ( or radio frequency modulator ) is a device that takes a baseband input signal and outputs a radio frequency-modulated signal.

International mediumwave broadcasting in Europe has decreased markedly with the end of the Cold War and the increased availability of satellite and Internet TV and radio, although the cross-border reception of neighbouring countries ' broadcasts by expatriates and other interested listeners still takes place.

In the United States and Canada, some radio stations are granted clear channel status, meaning that they broadcast on frequencies with few other stations allocated, allowing an extended coverage area when skywave propagation takes over at night, starting at or near local sunset.

Ed takes the radio back to his room and, to his great relief, finds it still operational.

A confused pursuit then takes place through London, with Holland using the radio in the police car to give false descriptions of the vehicle in which the crooks are riding.

Paxson resigned shortly after the season to join Neil Funk on radio broadcasts, saying " I knew full well the time commitment coaching takes.

It also takes credit for the first non-commercial IPv6 / Internet2 radio stream.

* Fredda Gibson takes her professional name, " Georgia Gibbs ", and began appearing on the popular Camel Caravan radio program, hosted by Jimmy Durante and Gary Moore ( It was Moore who bestowed the famous nickname " Her Nibs, Miss Georgia Gibbs " upon her.

In broadcast media a presenter is, especially in British English, the person who hosts, narrates, or otherwise takes the main role in presenting a radio or television programme.

Larry finds a radio playing the tune, takes it and heads back to the arena.

Broadcasting by radio takes several forms.

Illegal use of licensed radio spectrum ( also known as bootlegging in CB circles ) is fairly common and takes several forms.

With the help of Katie's three big, strong brothers ( James Arness, Lex Barker, Keith Andes ), Glenn takes Petree away from the goons Finley assigned to watch him, and makes him confess over the radio.

Typically it takes the form of a radio transmitter in the plane, and a receiver held by the pilot on the ground.

A special Camp Stage show takes place on Thursday night, hosted by WXPN radio for the nationally-syndicated " Live From the World Cafe.

Typical wardriving software actually takes control of the wireless radio, making it impractical, if not impossible, to wardrive and piggyback simultaneously.

Brad, forced into early adulthood, helps his mother and takes over the radio for Henry Abhart, who eventually dies.