In order to digitize an analog waveform so that it can be processed by a digital signal processing (DSP) system or transmitted across a digital communication network, you need to use an analog to digital converter (ADC). The most commonly used ADC types are Pipeline, Successive Approximation Register (SAR), and Sigma-delta. Each has different advantages and applications.

Pipeline, used in digital communication, ultrasound, and video processing, is the fastest but least accurate with limited resolution. Sigma-delta, the slowest but with greater resolution, are used in near-DC applications like weight, pressure, and temperature measurements. SAR, used in test/measurement, analytical instrumentation, and industrial process control, are very good on speed and accuracy, though still falling short of Sigma-delta on resolution and Pipeline on speed.

When searching for ADCs:

1. Buy analog to digital convertor ICs to digitize voltages for measurement.
2. Consider sigma-delta analog-to-digital converters for the benefits of negative feedback.
3. Get analog to digital convertors to digitize power and audio waveforms.

Action Steps
The best contacts and resources to help you get it done

Digitize voltages using analog to digital converter ICs

If you are creating a digital PCB, you will want to find an analog to digital converter integrated circuit that can be installed onto you circuit board.

I recommend: Analog Devices carries a wide range of analog to digital converter IC's, including devices for converting voltage, current, capacitance, energy, synchro/resolver output, or temperature to digital. Maxim also carries a wide range of analog to digital IC's, including ones optimized for high speed, precision, sigma-delta, or display.

Use sigma-delta analog-to-digital converters for near-DC signals

The newest Sigma-Delta ADCs achieve noise-free operation up to 2.4 kHz, enabling faster measurement of smaller signals than before, thus improving the performance of medical monitoring equipment, scientific instruments, process control modules, weight scales and other sensitive equipment.

I recommend: National Semiconductor has analog to digital converters that employ continuous time Sigma-Delta architecture. This provides high resolution at MHz speeds with far superior power consumption efficiency compared to more conventional ADCs. Microchip has a number of Sigma-Delta ADCs, supporting PC, SPI, and 2-wire interfaces.

Get analog to digital converters to digitize power and audio waveforms

Other common applications of ADCs are in support of power measurements and digital processing of audio signals.

I recommend: Cirrus Logic has ADCs specifically designed to support the measurement of complex power. Black Lion Audio sells an ADC to support digital processing of audio signals.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  If you're using an analog to digital convertor to record music, it's best to use the highest combination of sample rate and bit depth possible, as this will result in more data to work with and a better sounding final mix.