The optimum gain for a CATV line amplifier

It is well known that in a CATV trunk line, where all amplifiers are spaced for identical gain and all have the same noise figure and distortion characteristics, the individual amplifier gain resuiting in the longest usable system is one napier (8.69 dB). The gain of amplifiers used in CATV today is usually near 20 dB. This paper attempts to develop two reasons why the optimum gain in a real situation is higher than the ideal number. 1) The operating levels in a real system have an inevitable uncertainty which increases with the number of amplifiers used. 2) The noise figure and distortion performance of real amplifiers are dependent on the gain, with higher gain amplifiers generally having better performance in these respects.