1 Introduction

In audio equipment, measurement systems, and communication devices, is crucial to make sure signals are reproduced as accurately as possible. Whether you are designing high fidelity speakers, calibrating sensitive lab instruments, or making sure clear data transmission, distortion and noise can degrade performance. That is where metrics like Total Harmonic Distortion (THD) and Total Harmonic Distortion plus Noise (THD+N) come in. THD measures the extent to which a system introduces harmonic content that was not present in the original signal. While THD+N includes both that distortion and any added noise, which makes this a more broader performance metric and more indicative of real-world performance.

Higher THD levels can result in a more distorted or degraded output, which can cause undesirable artifacts, such as muffled or static sound in audio applications. While a low THD makes sure the system accurately reproduces the original signal without introducing interference that can compromise performance. This becomes increasingly important in critical applications like medical devices or Test and measurement DAC's and ADC's where even the slightest distortion can have significant negative impacts on the precise measurements required. The THD performance of a device help engineers evaluate and compare components to make sure of clean and reliable signal outputs in the systems.