High Resolution FFT Analyzer (PRO Only)

 

General description

 

High resolution FFT display is used for very accurate spectrum analyzing. It provides the frequency resolution up to 0.04 Hz (11025 Hz sampling rate, FFT length 262 144). It also provides the frequency markers. The display can be zoomed by selecting the viewed area by mouse (press left mouse button over the spectrum to define the area). Frequency marker can also be set (press left mouse button twice). The marker can be removed by selecting the marker frequency (selected marker frequency is shown on white background) and pressing ‘d’ character in keyboard. The markers and selected frequency is shown in the picture below. There are two sine tones in the frequencies 2756 and 2757 Hz.

 

 

 

 

Configuration

Pressing the right mouse button over the spectrum display will open the following menu.

 

Parameters

 

Stop/Start

The spectrum calculation and display updating can be started or stopped with this switch.

Zoom out

This returns the zoom to the original value.

 

Zoom back

This changes the zoom to the previous value in the Zoom value buffer.

 

Zoom forward

This changes the zoom to the next value in the Zoom value buffer.

 

Grid

This activates the grid in the spectrum display.

 

Average

This activates the spectrum value averaging in the spectrum display.

 

Maximum

This activates the ‘max and hold’ function in the spectrum display.

 

Properties

This opens the configuration dialog shown below:

 

 

 

 

The properties parameters are:

 

MIN FFT LEN

This is the minimum FFT length used in spectrum calculation with any zoom value.

 

MAX FFT LEN

This is the maximum FFT length used in spectrum calculation with any zoom value.

 

OVERLAP

This is the block size of FFT calculation. If this is low, then the display is updated more often even the FFT length value would be high.

 

WINDOW TYPE

This is the window type used in FFT calculation.

 

MIN NOISE LEVEL

With this parameter the background noise level can be adjusted. This allows better display dynamics to be used if the level is properly adjusted

 

AVERAGE IIR FACTOR

With this parameter the spectrum average filter bandwidth can be adjusted. Small value means narrow filter. This parameter is active only when averaging is activated.

 

UPDATE INTERVAL

This parameter defines how often the display will be updated. If the FFT length is big update interval can be much longer than the parameter value.

 

 

Copy to Clipboard

Copies the spectrum display to the Windows Clipboard

 

Help

Activates the help file