ADWandlern

ADWandlern, short for Analog-Digital-Wandler, are electronic devices that convert continuous, real-valued analog signals into discrete digital representations. They perform sampling and quantization and output binary codes that digital systems can process. Typical input ranges are defined by a reference voltage, and practical devices include anti-aliasing filters to prevent high-frequency content from folding into the measured band.

Operation is based on three steps: sampling the input signal at a defined rate, quantizing the sampled amplitudes to a finite number of levels, and encoding those levels into a binary word. The sampling rate must satisfy Nyquist criteria for the signal bandwidth, and a track-and-hold or sample-and-hold circuit is often used to stabilize the input during conversion.

ADWandlern come in several architectures, each with trade-offs between speed, resolution, and power consumption. Flash ADCs use a large array of comparators for extreme speed but are power- and area-intensive and typically offer modest resolutions. SAR (successive-approximation) ADCs use a binary search with a DAC and comparator, providing a good balance of speed and resolution for many microcontroller and embedded applications. Sigma-delta (oversampling) ADCs shape quantization noise to achieve very high resolution at moderate bandwidths, common in audio and instrumentation. Pipeline ADCs combine multiple stages to achieve high speed and resolution, useful in communications systems.

Key performance metrics include resolution (bits), sampling rate, signal-to-noise ratio (often expressed as ENOB), integral and differential nonlinearity, and total unadjusted error. ADWandlern are integral to sensor data acquisition, audio processing, communications, and control systems, with interfaces such as parallel words, SPI, or I2C and required reference voltages for accurate conversion.