Daqarta
Data AcQuisition And Real-Time Analysis
Scope - Spectrum - Spectrogram - Signal Generator
Software for Windows
Science with your Sound Card!

Sound Card - Spectrogram (Voiceprint) Screen Images

[Daqarta Spectrogram 1 (109K image)]

Spectrogram (Sgram) of spoken "DAQARTA", with approximate location of features shown in the Notes below it. The initial portion of the "DA" is distinguished by the upsweep of the first formant and the downsweep of the second, which then hold steady for the "A" portion of the syllable.

Note the stacked horizontal streaks in vowel regions, particularly prominent in the accented "QAR" syllable. Each line is a harmonic of the "glottal impulse" that excites the vocal tract at the fundamental frequency of the speaker's voice.

The waveform was recorded Direct-to-Disk ( DDisk) with the built-in microphone of a laptop, using a 22050 Hz sample rate. The recording was then analyzed in Sgram mode with Trigger off and a Hann spectrum window applied. The Sgram file DDisk start position and Read Step Size were adjusted so that the utterance just filled the screen width.

Although this spectrogram was viewed "live" during recording, playback analysis allows for much finer temporal resolution by adjustment of Read Step Size.

Still finer temporal resolution can be obtained at a sacrifice of some frequency resolution by reducing the Spectrum Window Width from its default of 1024 samples. The spectrogram below was obtained from the one above by simply toggling from 1024 to 256:




[Daqarta Spectrogram 2 (167K image)]

In this view the individual harmonic frequencies are blurred together, but the glottal pulses that created them are easily resolved as a series of vertical lines in the "DA" and "TA" syllables. The spacing of the lines reflects the fundamental frequency of the male voice at about 100 pulses per second (10 msec line spacing).

The dB range of the spectrogram is shown via the color bar at the right edge of the trace area. By reducing the overall sensitivity (using the PgDn key), the brightness of the "QAR" syllable could have been reduced to allow its glottal pulses to be easily resolved.

The above spectrograms were created using the default Sgram Color Palette, but you can easily create any palette you desire using the built-in controls. You can save and load different palettes at any time, or change the palette that Daqarta loads at start-up.

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

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