Noise in Traveling-Wave Tubes

After a discussion of gain, noise factor and attenuation in conventional traveling-wave tubes (twt), a dispersive twt is described and experimental results given. Examination of results and theory lead to the recognition of several types of partition noise as the cause of much of the noise in traveling-wave tubes. These are analyzed and approximate expressions for their magnitude are obtained. Noise due to electron-wave type amplification and thermal noise originating in the resistive part of the helix are also discussed. Experiments are described.