The Filter popup selects the type of filter to apply: Low Pass, High Pass, Band Pass or Notch. The Enable check box turns the selected filter on or off. The Center Frequency slider allows you to shift the view so that a selected frequency is at the center of the display. The Bandwidth slider allows you to select the bandwidth resolution of the display, the options are 1, 2, 5, 10, 20 and 40 hz /pixel. When you uncheck this option the program only FFTs and plots every third block of samples. This is useful if you have an older/slower system. The Faster CPU check box allows to reduce the load on your system. The Source popup controls the display of the grid line overlay. The Play Through checkbox allows you to send the filtered audio to an output device (speaker etc.) Midway on marker is displayed the frequency and relative db value. The marker can also be moved by mouse clicking on a point of interest in the FFT view. The frequency marker can be moved by using the left or right arrow keys. Marker checkbox controls the display of the frequency marker. The Output device popup allows you to select which audio output device the data is sent to after passing through the filters if Pass Through is enabled. The Input device popup allows you to select which audio input device data is captured from. The Filter button causes the Filter Drawer and filter center frequency marker to appear. The amount of attenuation or amplification possible is determined by the input device you are using. This slider amplifies or attenuates the sampled audio signal. The Input Gain slider can only be used when the plot popup is set to standard and the input device has volume controls. This can help eliminate a good deal of noise from the displayed plot. The Average popup allows you to plot the average of 2, 4, or 6 FFT samples. The Pause button allows to freeze all views. When the Normalized plot is selected, the Input Gain slider is disabled. If you would like to see a Normalized plot (a plot in which everything is plotted relative to the highest signal) then select Normalized. When the samples have been run through the FFT it can be plotted as is by selecting Standard from the plot popup. The Input channel popup allows you to select which audio channel (Left/Right) is used to collect the audio samples that are to be plotted. The window popup allows you to select what windowing function is applied. The size of the FFT is determined by the bandwidth you select using the Bandwidth slider. The audio is always sampled at 44.1Kz and run through an FFT. Using you mouse and click on the FFT plot also causes the frequency marker to move to the point of you choosing.įFT view displays an FFT plot of data from the audio input device you select using the Input device popup. Also you could enable the Frequency Marker and using the left and right arrow keys move the marker over to the signal of interest to get an accurate frequency reading. To determine the frequency of any pixel on the waterfall view, enable grid lines by checking the Grid Lines check box. The lighter the color the stronger the corrisponding signal. The display scrolls up as each entry is added. Waterfall view, in which a one pixel high line is added to the bottom for each FFT plot that is shown in the FFT view below it. Selecting the Oscilloscope button switches the display to the Oscilloscope view. Selecting the Waterfall button switches the display to the Waterfall and audio Spectrum views.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |