Browse Definitions:
Definition

traveling-wave tube (TWT)

A traveling-wave tube (TWT) is a specialized vacuum tube used in wireless communications, especially in satellite systems. The TWT can amplify or generate microwave signals. Two common types of TWT include the Klystron and the magnetron .

In the Klystron, a negatively charged cathode emits a beam of high-speed, high-energy electron s that travel through the cylindrical tube in straight lines to a positively charged anode. A coil is wound around the tube. When the coil is energized with a radio-frequency ( RF ) signal, the electrons in the beam alternately bunch up and spread out. In the magnetron, the electrons move in circles rather than in straight lines. The circular motion, produced by magnets at either end of the tube, allows the electrons to pick up energy over a greater distance.

Inside the TWT, the regions of high and low electron concentration move along or around the tube in waves. When the tube is properly operating, some of the energy from the electrons is imparted to the signal in the coil. The result is amplification of the signal.

A TWT can be made to function as an oscillator by coupling some of the output back into the input. This configuration is called a backward-wave oscillator , because the feedback is applied opposite to the direction of movement of the electrons inside the tube. Such an oscillator can generate up to approximately 0.1 watt of signal power in the microwave range.

A parametric amplifier is a TWT amplifier that operates from a high-frequency alternating current ( AC ) power source, rather than the usual direct current ( DC ) source. Some characteristic of the circuit, such as its impedance ,is made to vary with time at the power-supply frequency. Parametric amplifiers are useful because they generate very little internal noise . This makes it possible to obtain excellent sensitivity in receiving systems, minimizing data-transfer errors.

This was last updated in March 2011

Join the conversation

3 comments

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.

This article needs to be retraced and researched, the information presented is very WRONG. I believe the author is confusing velocity modulation with traveling waves.
Cancel
I would be most happy to give information on TWTs except of coarse classified information. Ask a real expert. ed xzimppledink@hotmail.com
Cancel
I was giving a technically accurate description of TWT but my blog disappeared off the screen. I have a lot of classified information but was not listing any of it Guess G O V doesn't want to take chances. ed xzimppledink, TWT Engineer retired
Cancel

-ADS BY GOOGLE

File Extensions and File Formats

SearchCompliance

  • PCAOB (Public Company Accounting Oversight Board)

    The Public Company Accounting Oversight Board (PCAOB) is a Congressionally-established nonprofit that assesses audits of public ...

  • cyborg anthropologist

    A cyborg anthropologist is an individual who studies the interaction between humans and technology, observing how technology can ...

  • RegTech

    RegTech, or regulatory technology, is a term used to describe technology that is used to help streamline the process of ...

SearchSecurity

  • application whitelisting

    Application whitelisting is the practice of identifying applications that have been deemed safe for execution and restricting all...

  • security

    Security, in information technology (IT), is the defense of digital information and IT assets against internal and external, ...

  • insider threat

    An insider threat is a malicious hacker (also called a cracker or a black hat) who is an employee or officer of a business, ...

SearchHealthIT

  • Affordable Care Act (ACA or Obamacare)

    The Affordable Care Act (ACA) is legislation passed in 2010 that changed how uninsured Americans enroll in and receive healthcare...

  • HIPAA Privacy Rule

    The Standards for Privacy of Individually Identifiable Health Information, commonly known as the HIPAA Privacy Rule, establishes ...

  • HIPAA business associate agreement (BAA)

    Under the U.S. Health Insurance Portability and Accountability Act of 1996, a HIPAA business associate agreement (BAA) is a ...

SearchDisasterRecovery

  • data recovery

    Data recovery restores data that has been lost, accidentally deleted, corrupted or made inaccessible. Learn how data recovery ...

  • disaster recovery plan (DRP)

    A company's disaster recovery policy is enhanced with a documented DR plan that formulates strategies, and outlines preparation ...

  • fault-tolerant

    Systems with integrated fault tolerance are designed to withstand multiple hardware failures to ensure continuous availability.

SearchStorage

  • data deduplication

    Deduplication retains one unique data instance to reduce storage and bandwidth consumed by remote backups, replication and ...

  • byte

    In most computer systems, a byte is a unit of data that is eight binary digits long. Bytes are often used to represent a ...

  • Secure Digital card (SD card)

    SD cards use flash memory to provide nonvolatile storage. They are more rugged than traditional storage media and are used in ...

SearchSolidStateStorage

  • flash file system

    Flash file systems are designed specifically for memory devices. A well-designed flash device and flash file system ensure ...

  • IOPS (input/output operations per second)

    IOPS measures the maximum number of reads and writes to non-contiguous storage. It is not an actual benchmark since vendor ...

  • eMMC (embedded MultiMediaCard)

    An embedded MultiMediaCard (eMMC) is a small storage device made up of NAND flash memory and a simple storage controller.

SearchCloudStorage

  • RESTful API

    A RESTful application program interface breaks down a transaction to create a series of small modules, each of which addresses an...

  • cloud storage infrastructure

    Cloud storage infrastructure is the hardware and software framework that supports the computing requirements of a private or ...

  • Zadara VPSA and ZIOS

    Zadara Storage provides block, file or object storage with varying levels of compute and capacity through its ZIOS and VPSA ...

Close