Distributed amplifier with low noise

780,774. Television. BENDIX AVIATION CORPORATION. May 26, 1955 [June 2, 1954], No. 15276/55. Drawings to Specification. Class 40 (3). [Also in Group XL (c)] A local-viewing television system employing a camera tube connected to supply signals to a cathode-ray tube via amplifying circuits is characterized in that each and every element or group of elements in the electric circuits which might be shock-excited by a transient to oscillate within the pass-band of the system is provided with damping means to an extent that each said element or group of elements is at least critically damped. The invention is described as applied to a system for intensifying X- ray images at a low light level and is effective to reduce the noise level produced on the cathode-ray tube screen to a figure close to that predicted from classical noise theory. The amplifier circuit comprises three cascadecoupled distributed amplifiers (see Group XL (c)), and in carrying out the invention, damping resistors are inserted in all leads where an oscillatory condition could exist. This is done, not only in the video channel itself, but in auxiliary circuits such as those concerned with power supply and the introduction of blanking and shading signals. In addition, the lines between the amplifier sections and the camera and cathode-ray tubes are damped. Reference is made to the need for damping the dynode circuits where the camera comprises an image orthicon. Preferably the signals are limited in frequency at the input to the pass-band of the system.