| 24-Hour Time-of-Day Mode |
Counter/Timer circuits able to control triggering based on the time of da which may be used as real-time clocks. |
A/D Conversion Time |
Defines the length of time that an A/D converter requires to convert an analog signal into a digital value. The theoretical maximum speed is the inverse of this value. The FAST 1611 high-speed A/D board provides a full 1MHz speed from a micro's conversion timeis. |
A/D, D/A |
Analog Outputs convert D/A (Digital to Analog), usually supplying a voltage or current. Analog Input boards allows your PC to acquire data from analog sources and convers analog signals into digital values (A/D-Analog to Digital), |
AC (alternating current) |
Сurrent that repeatedly alternates direction from a positive maximum to a negative maximum. Standard house current alternates at a frequency of 60 such cycles per second (or 60 Hz) |
AC voltage |
Voltage associated with an alternating-current (ac) signal; since it is constantly varying it is expressed in both "peak" and "average" (or rms) values; the normal home wall outlet supplies 120 Volts rms and has a peak voltage of 169.7 Volts. |
Accelerator board |
An expansion board that accelerates computer by adding a faster CPU or FPU. Most modern computers are designed to accept simpler upgrades. Built into the motherboard is a socket in which the CPU sits. It is usually possible simply to remove the CPU and replace it with a faster model. This is particularly easy if the socket is a zero insertion force (ZIF) socket. |
Accuracy |
The maximum deviation that can be expected between the meter reading and the actual value being measured, under specified conditions. |
AGP |
Accelerated Graphics Port. A video port design by Intel (R) to increase video data transfer performance up to 8x beyond the standard PCI bus. Slots come in standard AGP shapes, and in longer AGP PRO shapes. |
Alias |
A false lower frequency component that appears in data sampled at too low a sampling rate. (See the Nyquist Sampling Theorem). |
Analog |
Having the property (electrical) of varying in continuous, rather than incremental or discrete steps. А continuous, smoothly changing signal where any piece of information can take on any of an infinite set of values. For example: real world sound, heat, and pressure, are analog. |
Analog Slope Trigger |
All DAP, FAST, & HSDAS series boards include this useful triggering option. Sampling can be triggered at a user-selectable point on an incoming analog slope. Triggering can be set to occur at a specific threshold level, including select modes of +/- slope, level high, & level low. |
ANSI |
American National Standards Institute. |
Application |
Designed for end users program or group of programs. Two general classes of software are: systems software and applications software. Systems software consists of low-level programs that interact with the computer at a very basic level. This includes operating systems, compilers, and utilities for managing computer resources. In contrast, applications software (also called end-user programs) includes database programs, word processors, and spreadsheets. Figuratively speaking, applications software sits on top of systems software because it is unable to run without the operating system and system utilities. |
Arc lamp (see gas discharge lamp) |
А gas discharge lamp in which light is produced by the passage of electricity, through a gas, across two electrodes enclosed in a quartz envelope; high-pressure arc lights (such as mercury vapor lamps, high-pressure sodium arc lamps, and metal-halide arc lamps) produce light in a physically small bulb of high-pressure gases; low-pressure arc lights (such as fluorescent lights, germicidal ultraviolet lamps, and neon sign lamps) employ a physically big tube of low-pressure gas plasma. |
ASCII |
American Standard Code for Information Interchange-numeric values assigned to letters, numbers, and other characters to enable exchange of information between devices. i.e. A=65, B=66, etc. |
ASIC |
Application Specific Integrated Circuit, an integrated circuit with a large number of logic gates that are connected to meet a specific application requirement. |
ASIC (application-specific integrated circuit) |
ASIC can be pre-manufactured for a special application or it can be custom manufactured ussually using components from a "building block" library of components, unlike standard parts like microprocessors and general-purpose memory ICs, for a particular customer application. Since the building blocks already exist in a library, it is much easier to produce a new ASIC than to design a new chip from scratch. |
Asynchronous |
A serial communication method where ready data is sent without being referenced to a timing clock, rather than waiting until the receiver signals that it is ready to receive. |
AT Bus |
Also known as the ISA bus, the AT bus is the original 16-bit expansion bus featured in the IBM AT. See ISA Bus for more detailed info. Other bus types include PC, EISA, PCI. |
ATM |
Asynchronous Transfer Mode |
Attenuation |
Reducing the amplitude of a waveform without introducing distortion. An adjustable passive network (filter) may be used to reduce power level of a signal without introducing any appreciable distortion |
Audio |
Sound frequencies that can be heard by the human ear - range extends from approximately 20 Hz to 20,000 Hz; the human voice extends over a frequency range of about 100 Hz to 3,000 Hz. |
| Auto-Polarity |
An ability of digital instruments to measure and display values of either polarity without the need to interchange test lead connections |
Autoranging |
When autoranging, a board can be set to monitor the incoming signal and automatically select an appropriate gain level based on the previous incoming signals. |
