Personal Electronics

Selection and Solution Guides

Application Notes

AN-1496 Noise, TDMA Noise, and Suppression Techniques (Rev. D)


The term “noise” is often and loosely used to describe unwanted electrical signals that distort the purity of the desired signal. Some forms of noise are unavoidable (e.g., real fluctuations in the quantity being measured), and they can be overcome only with the techniques of signal averaging and bandwidth narrowing. Other forms of noise (for example, radio frequency interference and “ground loops”) can be reduced or eliminated by a variety of techniques, including filtering and careful attention to wiring configuration and parts location. Finally, there is noise that arises in signal amplification and it can be reduced through the techniques of low-noise amplifier design. Although noise reduction techniques can be effective, it is prudent to begin with a system that is free of preventable interference and that possesses the lowest amplifier noise possible1. This application note will specifically address the problem of TDMA Noise customers have encountered while driving mono speakers in their GSM phone designs.