Difference between revisions of "NVGate Octave Analyzer"

The figure below shows the block diagram of the analyzer (for one channel) with octave set from 20 kHZ to 2,5kHz.

The filter range uses base 10 so that we get exact frequencies at 0.1 Hz, 1.0 Hz, 10 Hz, 100 Hz, 1 kHz and 10 kHz.<br>

The following calculations are used to compute the central frequencies:

* covers range from 90 mHz to 22.1 kHz.

The next step is the detector process for each 1/n^th filter:

A hold box allows to get Maximum and Minimum spectra during one measure.

A stabilization delay is implemented in order to ignore and suppress the transient response of passband filters. It is automatically taken into account after any change of input setup. It is equal to 5 periods of the lower frequency filter for 1/3^rd octave and octave filters. This delay is four times greater for 1/12^th octave filters (i.e. 20 periods of the lower frequency filter) and eight times greater for 1/24^th octave filters (i.e. 40 periods of the lower frequency filter).For example, if lower frequency filter is centered at 1 Hz, then the stabilization delay is equal to 5 seconds for octave and 1/3^rd octave, 20 seconds for 1/12^th octave and 40 seconds for 1/24^th octave. During this delay the detectors are inactive.

* Overall Weighted: This result is available when the 1/n Octave plug-in is in "Running" state. It displays the overall level of the weighted signal between the lower and upper frequency. The weighted filter is chosen by the ''1/n octave/CPB filters/Global Level Weighting ''setting. It is computed before the filter bank, thus it is not the addition of the values of the 1/n octave result.

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1/N Oct Bandwidth: set in ''OCT/FFT analysis/range''

Contains the settings related to the source input.

* '''Source''': input source to be analyzed. It may come from the Front-end input or from the Player in post analysis mode (see the post analysis chapter). In post analysis mode, tracks with a signal bandwidth lower than the Upper central frequency cannot be plugged.

Contains the settings related to triggering events and how to start and stop signal computation.

In case a new event occurs during a previous averaging, this start event won<nowiki>’</nowiki>t be effective because the previous average duration is not over, you can only set other event after the end of the previous one.

Contains the settings related to the type of averaging of the signals to be computed.

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Defines the frequency range and the resolution.

[[Image:Octave_07.png|framed|none]]

All statuses are available to add to the control panel

[[Image:Octave_08.png|framed|none]]

[[Image:Octave_09.png|framed|none]]

* ''Green background and red text'': the current acquisition is real-time, but since start not all the blocks were analyzed.

The following scheme describes the different states of the measurement:

[[Image:Octave_10.png|framed|none]]

This status displays:

In Short Leq mode, the count is stopped at the end of time duration (the repeat mode is made on short duration).

This status displays if during the acquisition, there were an amplitude overload (or not) of the analyzed inputs.