AGC and ADC effects on receiver performance in FDM based narrowband wireless systems

This paper discusses the effects of automatic gain control (AGC) and analog to digital converter (ADC) on receiver performance in frequency division multiplexing (FDM) based narrowband wireless communication systems. Each communication channel is very narrow in these systems, so the channels are packed without breaks, making it difficult to extract the desired signal using an analog bandpass filter. Therefore, other multiple communication signals are in-band interferences in these systems. One method for overcoming this problem is the use of a low intermediate frequency (IF) architecture. The purpose of this paper is to provide a theoretical analysis of the effects of the AGC and ADC on receiver performances in this environment. The analysis results indicated that i) in-band interferences decreased the bit resolution at the amplitude of the desired signal, and ii) the effects did not depend on the desired signal power relative to the sum of the undesired ratio (DUR), but it did depend on the amplitude intensity of each interference and the number of channels (the number of interferences) in the IF bands.