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Spectrogram

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11	11	There are many usage scenarios where these expanded buffer lengths are useful. One such usage scenario is monitoring channel activity. With over 3 seconds of received waveform at a full 40 MHz of bandwidth, we can see a large extent of channel activity at very fine timescales (25 ns samples). One popular visualization of frequency content across time is known as a [http://en.wikipedia.org/wiki/Spectrogram spectrogram]. In this example, we will use this technique to visualize activity in the 2.4 GHz band.
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13		MATLAB offers a sophisticated [http://www.mathworks.com/help/signal/ref/spectrogram.html spectrogram tool] as part of the Signal Processing Toolbox. In this example, our simple implementation of a spectrogram does not offer the same advanced features like windowing or FFT overlap. Instead, our implementation works by simply plotting the ~~output of {{{M}}} sequential FFTs of {{{N}}} samples each~~.
	13	MATLAB offers a sophisticated [http://www.mathworks.com/help/signal/ref/spectrogram.html spectrogram tool] as part of the Signal Processing Toolbox. In this example, our simple implementation of a spectrogram does not offer the same advanced features like windowing or FFT overlap. Instead, our implementation works by simply plotting the magnitude of the output of {{{M}}} sequential FFTs of {{{N}}} samples each on a dB scale.
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15	15	[[Image(spectrogram_steps.png, width=800)]]