a.out (eh dot out)

n. An object file format output by some compilers and read by related linkers and loaders. See also ELF, COFF.

A/D (A-to-D)

abbr. See A/D converter.

A/D converter

n. A hardware device that reads an analog signal typically a voltage compares it to a reference signal, and converts the resulting percentage to a digital value. Short for analog-to-digital converter. The reference signal represents 100%. An n-bit A/D converter has a maximum value of 2 ⁿ - 1 and a resolution of V _ref/2 ⁿ.

A/D converter, dual-slope

n. A commonly used device to digitize an analog input that measures capacitor charge times. Dual-slope A/Ds charge a capacitor for a particular number of counts of a clock. The A/D then discharges the capacitor until the capacitor s voltage meets some reference level, while counting clock cycles.

Dual-slope A/Ds can be very accurate but are slow; worse, their conversion time varies depending on the input voltage.

A/D converter, flash

n. A device that very quickly digitizes an analog input voltage. A flash converter compares the input to a number of reference sources in a single clock cycle. They re fast! But they use one comparator per input step (16 for a 4-bit A/D, 256 for 8 bits), so they are expensive for any but the smallest resolution applications. And they re power hogs too.

Here, flash means lightning quick, rather than having any similarity to flash memory technology.

A/D converter, single-slope

n. A device that converts an analog input to...