Title :
Frequency noise in travelling-wave tubes
Author :
Liebscher, R. ; M¿¿ller, R.
fDate :
5/1/1958 12:00:00 AM
Abstract :
The C.C.I. specifications for the signal/noise ratio of microwave relay systems set an upper limit for the noise of travelling-wave tubes used in such a system. It is shown that two noise components of the travelling-wave tube, namely the background noise and the frequency-modulation noise, affect the signal/noise ratio of the relay system. Background noise is the conventional type of tube noise and is represented by the noise figure. The frequency-modulation noise is a frequency modulation of the carrier by noise and is characterized by its relation to the r.m.s. value of the frequency deviation. Ion oscillation present in travelling-wave tubes with poor vacuum will also cause frequency modulation. Techniques for the measurement of the noise components are described in the paper. The results of measurements on several travelling-wave tubes are compared with the upper limits specified for noise components in a relay system.
Keywords :
travelling wave tubes;
Journal_Title :
Proceedings of the IEE - Part B: Radio and Electronic Engineering
DOI :
10.1049/pi-b-1.1958.0180