Analysis of Variable Premodulation Gain in AM Baseband Systems

In a multichannel transmission system for which the baseband power is proportional to the cumulative channel activity, an improvement in the perchannel SNR is possible by use of variable premodulation gain. This is an average improvement which results from maintaining the baseband signal power level at its maximum value by use of variable gain prior to modulation. For such a system the SNR improvement is proportional to the log of this gain.