Daqarta
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:

Features:

Oscilloscope

Spectrum Analyzer

8-Channel
Signal Generator

(Absolutely FREE!)

Spectrogram

Pitch Tracker

Pitch-to-MIDI

DaqMusiq Generator
(Free Music... Forever!)

Engine Simulator

LCR Meter

Remote Operation

DC Measurements

True RMS Voltmeter

Sound Level Meter

Frequency Counter
    Period
    Event
    Spectral Event

    Temperature
    Pressure
    MHz Frequencies

Data Logger

Waveform Averager

Histogram

Post-Stimulus Time
Histogram (PSTH)

THD Meter

IMD Meter

Precision Phase Meter

Pulse Meter

Macro System

Multi-Trace Arrays

Trigger Controls

Auto-Calibration

Spectral Peak Track

Spectrum Limit Testing

Direct-to-Disk Recording

Accessibility

Applications:

Frequency response

Distortion measurement

Speech and music

Microphone calibration

Loudspeaker test

Auditory phenomena

Musical instrument tuning

Animal sound

Evoked potentials

Rotating machinery

Automotive

Product test

Contact us about
your application!

DDisk Write Decimate Lock

Controls: DDisk Dialog >> Decimate Lock
Macro: DDiskDecimate

By default, DDisk files are recorded at the full Sample Rate, even if Decimate is active. This allows you to toggle Decimate or change the Decimate Factor (or the equivalent Decimate Rate), or even toggle special modes like Envelope during the recording. These changes only affect the way the data is displayed, not the way it is saved.

With Decimate Lock active when the DDisk recording starts, all the Decimate controls are locked in their current states, and the recording saves only decimated data at the Decimate Rate. This can result in a huge savings in file size when the Decimate Factor is large.

Note, however, that you can't undo the decimation later, when the file is opened, as you can if the file is saved without Decimate Lock.

In general, Decimate Lock makes sense for most slow "chart recorder" operations, where Trigger is off and data scrolls across the screen at a few hundred samples per second or slower. Consider that at one sample per second, a whole day can be monitored with only 24 * 60 * 60 = 86400 samples per channel. Compare that to a normal 48000 samples per second, which would consume over 4 Gigasamples per channel. (And which at 2 bytes per sample would exceed the 4 GB limit imposed by the Microsoft RIFF .WAV format, which is also used by Daqarta's own .DQA files.)


Macro Notes:

DDiskDecimate=1 sets Decimate Lock mode, DDiskDecimate=0 cancels it, and DDiskDecimate=x toggles the current mode.


See also Direct-To-Disk (DDisk) Toggle, DDisk Controls Dialog

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