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!

Spectrogram / Pitch Track of File Data

Spectrograms or Pitch Tracks of long files of wave data (.DQA, .WAV, or .DAT) can be viewed just like live signals by hitting unPause once the file is opened. In this condition normal Trigger operation is available, if desired. The progress of the Spectrogram or Pitch Track display is then controlled by the Trace Update Interval, as usual.

When Trigger is toggled off, the timing between spectra (Sgram/PT vertical columns) of file data is that of the Read Step Size in the DDisk Controls dialog. This defaults to 512 input samples, which means that the spectra overlap: Each spectrum uses 512 new data points and 512 prior data points.

You can move through the file manually in Paused Sgram/PT mode, with the cursor keys or by direct entry of the desired file position, as explained under Reading DDisk Files. The timing in Pause mode always uses Read Step Size.

Setting Read Step Size to smaller values gives better Spectrogram time resolution, usually much better that you can obtain in real-time viewing. This can be very important if you are trying to analyze the fine structure of speech, for example. (You may also wish to reduce Spectrum Window Width for possible further improvements in time resolution at the expense of frequency resolution. See the Screen Shots section of the Daqarta Website for examples of wide and narrow Width applied to a speech spectrogram.)

For file data, Single trigger mode behaves like it is unPaused only until is finds the initial trigger event; the actual Spectrogram is created using Read Step Size as if Paused.

When viewing the Spectrogram or Pitch Track of a file, the file position readout/control below the right end of the X axis shows the start position of the displayed screen within the file. The end position is shown by a separate readout-only panel below that.

Whether live or from a file, Spectrograms or Pitch Tracks only show one channel at a time. If only one Display button is active, that will be the channel used. If both Left and Right are active, only the Left is shown. If both Input and Output are active, only the Input is shown.


See also Spectrogram / Pitch Track (Sgram/PT), Spectrogram (Sgram) Color Palette Dialog

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