Data AcQuisition And Real-Time Analysis
Scope - Spectrum - Spectrogram - Signal Generator
Software for Windows
Science with your Sound Card!
The following is from the Daqarta Help system:



Spectrum Analyzer

Signal Generator

(Absolutely FREE!)


Pitch Tracker


DaqMusiq Generator
(Free Music... Forever!)

Engine Simulator

LCR Meter

Remote Operation

DC Measurements

True RMS Voltmeter

Sound Level Meter

Frequency Counter
    Spectral Event

    MHz Frequencies

Data Logger

Waveform Averager


Post-Stimulus Time
Histogram (PSTH)

THD Meter

IMD Meter

Precision Phase Meter

Pulse Meter

Macro System

Multi-Trace Arrays

Trigger Controls


Spectral Peak Track

Spectrum Limit Testing

Direct-to-Disk Recording



Frequency response

Distortion measurement

Speech and music

Microphone calibration

Loudspeaker test

Auditory phenomena

Musical instrument tuning

Animal sound

Evoked potentials

Rotating machinery


Product test

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your application!

Sound Card Duplex, Half and Full

This term arises from communications use, where full-duplex (sometimes spelled without the hyphen) refers to a system that can send and receive simultaneously, as in a standard telephone (where only politeness prevents both parties from talking at the same time). Half-duplex systems can only do one thing at a time, either send or receive.

The "full-duplex" designation is often applied to sound cards that can acquire input data via an ADC at the same time they are producing output data via a DAC. Note that "full" tells nothing about the bit resolution in each direction, and a sound card may legitimately be called "full-duplex" if it can acquire 16-bit data while generating 8-bit data, or vice-versa. (This was the case with most ISA-bus Sound Blaster cards, for example.)

"Full" also tells nothing about the number of channels in each direction. Most full-duplex cards can achieve stereo operation in both directions, but there are some cards that are stereo in either direction alone but only mono in both directions at once.

Your sound must have full-duplex capabilities in order to produce stimulus outputs with the Daqarta Generator during Input data acquistion.

However, even stereo full-duplex cards may not synchronize the input and output streams properly, or maybe only at certain sample rates. It is thus important to use the Duplex Delay option during Auto-Calibrate to determine the card's capabilities.

See also Full-Duplex Techniques


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