Tolvan Data



NAQ extraction from inverse filtered oral flow signals

Download example glottal flow signal

Note: S-naq requires the Soundswell signal workstation.

Note: S-naq has now been incorporated in the sound editor Sopran, and any future development will take place there.

You mark two maxima in the flow derivative by clicking and dragging in the lower panel, and S-naq automatically measures the period time (T0), maximum declination rate (MDR) and the peak-to-peak value of the flow (ptp) around the first MDR peak, in order to calculate the amplitude quotient (AQ) and the normalized amplitude quotient (NAQ). The closed quotient determines the duration of the closed phase relative to the period. The ratio between the first two harmonics (H1/H2) is calculated by a discrete Fourier transform of the selected part (only) without zero-padding. The AQ, NAQ and CQ values are defined as

The measured data can be logged and copied to the clipboard for further analysis in eg Microsoft Excel.

The S-naq window. The red lines indicate the selected derivative peaks and the distance between them corresponds to T0. The green line represents the MDR at the left cursor and the distance between the blue lines represents the ptp value. The brown lines represent the closed phase.

Tip: Follow the instruction in the status bar at the bottom of the S-naq window in order to get started.

Tip: The cursors for max and min flow can be moved by using the right mouse button.

Quick start

1. Open the file containing the inverse filtered flow signal in Soundswell
2. Check View|Link in Soundswell
3. Click on the approximate position in the flow signal that you want to analyze. If the file has several channels, make sure that you have selected Channels|edit one
4. The flow waveform should now occur in the upper panel and the derivative of this signal in the lower panel.
5. Locate two consecutive negative peaks in the lower panel. Move the mouse to the first of these, press the left mouse button, drag the cursor to the last peak and release the button.
6. Locate the start and end of the closed phase in the upper panel. Move the mouse to the start, press the left mouse button, drag the cursor to the end and release the button.
7. The measured data appears in the status bar.
8. To log the data, select Edit|log data. The data also appears on the clipboard.

Note: This software is actual freeware, with no ads, time limits, spyware or anything like that.

Note: Tolvan Data takes no responsibility whatsoever for the quality of the software, by using the software you take full responsibility for validating that the software meets your requirements, and whatever legal requirements that might be applicable in your country. In particular, Tolvan Data does not accept the role as a supplier of medical devices (sw. medicintekniska produkter).

Copyright Tolvan Data 2020