By Brian L. Jones, Fairchild
Transistor amplifiers produce distortion. This is a commonplace to everyone who is familiar with the cross-modulation of an overloaded CATV amplifier. Such amplifiers have a certain VSWR when introduced into a 75 n system and if this ratio is too high, reflections appear on the picture in the form of "ghosts". If an amplifier is inserted into a system backwards, that is, with the input signal to the output and the output signal to the input, the signal will be attenuated instead of amplified. The ratio of the input power to the output power under such circumstances is known as the reverse transmission. Similarly the gain of the amplifier is the forward transmission.
Now it may not be immediately obvious what connection these quantities may have and the purpose of this talk is to point ·out the inter-relationship between them. In order to do this I shall start by discussing some of the properties of transistors.