analogetildigitalomformere

Analogetildigitalomformere are devices that convert continuous-time, continuous-valued analog signals into discrete-time, discrete-valued digital data. They enable digital systems to process real-world signals by sampling the input and quantizing the result into binary codes.

Operation relies on two steps: sampling, where the analog signal is measured at discrete instants, and quantization, where those samples are mapped to finite levels. A sample-and-hold circuit often precedes the conversion. The sampling rate must exceed twice the highest frequency of interest (the Nyquist criterion) to avoid aliasing; an anti-aliasing filter is typically used.

Common architectures include: flash (parallel comparators for very fast conversions; high power and cost); successive-approximation register or SAR (moderate to high speed with low power); pipeline (high speed; subdivides the conversion into stages); and delta-sigma (sigma-delta) modulators (high resolution via oversampling, suitable for audio and instrumentation).

Key performance metrics are resolution (bits), sampling rate (samples per second), signal-to-noise ratio and effective number of bits (ENOB), integral nonlinearity (INL), differential nonlinearity (DNL), total harmonic distortion (THD), and spurious-free dynamic range (SFDR). Practical choices depend on the application’s bandwidth, dynamic range, power budget, and cost.

ADCs are used in audio interfaces, medical equipment, instrumentation, data acquisition, automotive sensors, and consumer electronics. They are commonly integrated on microcontrollers and systems-on-a-chip or implemented as standalone ICs. Important design considerations include input impedance, reference voltage stability, clock jitter, temperature dependence, and linearity across the input range.