1 Introduction

In the audio world, a common technique to increase the dynamic range of a system is to connect two, four or more ADCs in parallel with inputs tied together. This method uses the principle that correlated signals add on linearly whereas uncorrelated signals, such as noise sources, add on as root-sum-square. When using two ADCs, this results in a signal-to-noise ratio (SNR) magnitude increase by 1.414 or 3 dB for two equal amplitudes. In this application note, this technique is discussed in more detail and the equations that yield the improvement are derived.