Quantization Error Caused by A/D Conversion

Compared to an analog signal, a binary signal which represents only two states contains very little information. If a quantitiy to be represented digitally requires a wider range of values, it must be described by several bits.Analog quantities are processed digitally, when are converted into digital values first. An analog quantity can assume an infinite number of intermediate values while a digital quantity can only assume a limited number of values, therefore when analog signals are converted into discretized digital signals, quantization errors occur. Increasing the number of bits used for digital representation and the sampling rate of the analog signal reduces quantization errors. The complexity of data processing and transmission is increased with an increasing number of bits. The range of values must be adapted to the particular task, while choosing a binary representation that is not too extensive, in order to keep the loss of information during conversion as low as possible.

Quantization error caused by reduced discretization
and sampling rate

Determining the quantization error for displacement measurement:
Analog measuring range --- 0 to 30 cm
Range of values of an 8-bit unit --- 256
Quantization error --- (30/256) cm = 1.2 mm
Range of values of a 12-bit unit --- 4096
Quantization error --- (30/4096) cm = 0.073 mm