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The gain and the noise figure of the helical traveling wave tube

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Published by Courant Institute of Mathematical Sciences, New York University in New York .
Written in English

Book details:

Edition Notes

Statementby William Sollfrey and Mortimer Weitz.
ContributionsWeitz, Mortimer
The Physical Object
Pagination29 p.
Number of Pages29
ID Numbers
Open LibraryOL17866903M

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Increasing the tube length to achieve desirable high gain tends to make the tube unduly long, and reduces the band-width that is of such importance in travelins-wave tube applications. In practicing the present invention, the advantage of low noise figure of low-gain tubes is combined with high gain and broad-band characteristics of tubes of Cited by: In December the first tube gave a gain of about 8 dB at a cm wavelength, with a 13 dB noise figure. The work was later transferred to the Clarendon Laboratory, Oxford. Much of the mathematical analysis of twt operation was developed by John R. Pierce, of Bell Labs [1], and in Kompfner joined Pierce to continue twt research.   Effects of thermal‐velocity spread on the noise figure of a traveling‐wave tube have been computed by extending a method of Hahn. To accomplish this, it has been necessary to work out a new theory for the diode‐drift tube and traveling‐wave tube that includes the effect of the thermal‐velocity spread at very high frequencies. Some computations are given for conditions met in Cited by: 4. Pierce calculated the gain of the amplifier in terms of these three forward waves, assuming the tube to be terminated so that no reflected Dec., THE TRAVELING WAVE TUBE wave is created, having first found expressions for the dependence of the propagation coefficients on beam voltage and current and on circuit losses.

The Traveling Wave Tube (TWT) is a high-gain, low-noise, wide-bandwidth microwave amplifier. It is capable of gains greater than 40 dB with bandwidths exceeding an octave. (A bandwidth of one octave is one in which the upper frequency is twice the lower frequency.) Traveling-wave.   Small velocity spreads in an electron beam appear to cause a decrease in gain and noise figure of a traveling‐wave tube. The actual decrease depends on a quantity μ, which can be interpreted physically as a measure of the ratio of the coupling of the electrons to each other via the hydrostatic pressure to the coupling of the electrons to the external wave guide circuit.   e - m By helical Method. Us TB (Traveling-wave tube.) 20 October 13 However, there seems to be no end to the creative ways in which tubes may be constructed, F is the TWT noise figure in dB Gnoise is the gain of the noise in the TWT 20 October 48 Conventional Microwave Tubes.   The primary purpose of the helix in a traveling-wave tube is to. a. prevent the electron beam from spreading in the long tube. b. reduce the axial velocity of the RF field. c. ensure broadband operation. d. reduce the noise figure.

The RF field forces of a helical traveling wave tube (TWT) have been calculated using an accurate three-dimensional (3-D) coldest (no electron beam present) circuit model and compared to radial. A «10 log 10 1/9 s db Gain is A + B C N Gain is +CN Experimental Data used in Design The design procedure outlined in this section is representee of the typical con- siderations which are made during the basic design of traveling-wave tube amplifiers and backward- wave oscillators. USA USA USA USA US A US A US A US A US A US A US A US A US A US A US A US A Authority US United States Prior art keywords tube body portion wave collector cooling Prior art date Legal status (The legal status is an assumption and is not a . Traveling Wave Tube. Traveling Wave Tubes (abbr.: TWT, pronounced: “twit”) are vacuum tubes used as high-gain, low-noise, wide-bandwidth microwave wideband amplifiers.A TWT is capable of gains from 40 to 70 dB with bandwidths exceeding two octaves. (A bandwidth of 1 octave is one in which the upper frequency is twice the lower frequency.).