Linearization Technique
Intentional addition of low-level noise to an analog signal before quantization improves the linearity of an analog-to-digital converter. By breaking up the correlation between quantization error and the input signal, dither injection transforms distortion into a less harmful white noise floor. It is necessary when resolving signals that are smaller than the least significant bit of the converter.
Dynamic Range
Small amplitude signals often become trapped within a single quantization step, resulting in a loss of information. The application of dither injection ensures that the signal crosses multiple quantization thresholds, allowing the average value over time to represent the true input level. Dithered systems effectively increase the usable dynamic range of the measurement chain at the cost of a slightly higher overall noise power.
High-resolution audio and precision sensor interfaces rely on this mechanism to maintain signal fidelity.
Noise Characterization
The added noise is typically Gaussian or triangular in distribution to provide the best decorrelation. Proper dither injection ensures the best results between the error and the signal.
Operational Boundary
Over-application of this noise can swamp the primary signal and reduce the sensitivity of the receiver. The success of dither injection depends on balancing noise power against the resolution requirements of the specific application.
