Analysis of the microphone signal-frequency band

[kamwoj1918]

Hi
I made a program to analyze the signal from the microphone (FFT, STFT) but I have one thing to do. I have a graph amplitude-time

I need to change the signal frequency for example 50 Hz for example by moving the slider that on the chart were waveforms amplitudes in certain frequency bands.

How to choose the frequency of the signal to change the band on the graph?

Thank for help.

[mikeporter]

If I understand what you mean, you can put a cursor on the plot and the cursor display will show the X (time) and Y (amplitude) for the datapoint the cursor is currently on.

Mike...

[kamwoj1918]

No, I don't want a cursor. I want switch  "previous frequency" and "next frequency". Change every 50 Hz. 

[mikeporter]

In your analysis results, what is the delta frequency between datapoints? Just increment through the array of amplitude values. For example, if your datapoints are 5Hz apart, simply index out every 10th value in the amplitudes. If the increment is a non-integer value, you will need to do some interpolation, but other than that the process is basically the same.

Mike...