# Analog to Digital Converter

A circuit that converts an analog signal, having a continuously varying amplitude, to a digitally quantized representation using binary output signals. The sampling frequency must be at least twice as high as the highest frequency present in the signal to prevent aliasing errors.

### Delta-Sigma Modulating ADC

A high-accuracy circuit that samples at a higher rate and lower resolution than is needed and pushes the quantization noise above the frequency range of interest. This out-of-band noise is typically removed by digital filters.

### Effective Number of Bits

Figure of merit for an A/D converter describing how many bits of effective resolution, this is below the actual A/D word size. This is due to limitations in noise and distortion performance.

### Integrating ADC

An ADC whose output code represents the average value of the input voltage over a given time interval.

### Overs

Term used to describe input signals exceeding the full scale range. It produces the equivalent of a digital code consisting of all 1s.

### Successive Approximation Register

Uses a digital-to-analog converter to determine the output word successively, bit by bit.

**See also: **Anti-Aliasing Filter, Data Acquisition, Digital-to-Analogue Converter, Digitization, Quantization Error, Sample and Hold, Sampling Frequency.

**Subjects: ** Electronics