Novel tube and circuit designs for automatic gain controlled broad band intermediate frequency amplifiers

A special pentode tube for broad band intermediate frequency amplifier application is designed with the purpose of eliminating cathode degeneration while maintaining the capability to control the gain. The amplification of the stage is further increased by utilizing the space charge coupling between the plate current and suppressor grid. The circuits are developed to move the poles of the amplifier and vary the bandwidth in a predetermined manner. The new tube, which can be used either as a sharp cut off or remote cut off pentode, is completely free of run away effects due to gas or grid emission, and because of its inherent characteristics, the clipping of the modulation from the signal cannot occur. As a result of this development, it is now possible to eliminate one of the three stages of video intermediate frequency amplifiers presently used in black and white television sets without loss of performance.