3 Clarified the phrase "output frequency"
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I've inherited some matlab code and I can't really understand what the resultant signal really means. The input is audio and the code first performs an STFT/spectrogram (sliding window FFT of size 1024 with 50% overlap, hanning window applied). The output is then filtered to the range (using Matlab notation) to the range (2:N/2). In other words, the first bin is dropped and the negative half frequencies too. Just to be clear, for each 1024 window of audio data (audio_chunk below) the code does:

y = abs(fft(hann_win.*audio_chunk));
filt_y = y(2:length(y)/2);

The value filt_y is then summed and that becomes the output signal:

output = sum(filt_y);

So, for every window's FFT we get a single output value. The output sampling frequency is audio_frequencyaudio_sampling_frequency/512 because we slide the 1024 sample window along by 512 samples at each step.

My question is: what would you call that output signal? What sort of physical significance does it have, or what use is it for analysis?

I've inherited some matlab code and I can't really understand what the resultant signal really means. The input is audio and the code first performs an STFT/spectrogram (sliding window FFT of size 1024 with 50% overlap, hanning window applied). The output is then filtered to the range (using Matlab notation) to the range (2:N/2). In other words, the first bin is dropped and the negative half frequencies too. Just to be clear, for each 1024 window of audio data (audio_chunk below) the code does:

y = abs(fft(hann_win.*audio_chunk));
filt_y = y(2:length(y)/2);

The value filt_y is then summed and that becomes the output signal:

output = sum(filt_y);

So, for every window's FFT we get a single output value. The output frequency is audio_frequency/512 because we slide the 1024 sample window along by 512 samples at each step.

My question is: what would you call that output signal? What sort of physical significance does it have, or what use is it for analysis?

I've inherited some matlab code and I can't really understand what the resultant signal really means. The input is audio and the code first performs an STFT/spectrogram (sliding window FFT of size 1024 with 50% overlap, hanning window applied). The output is then filtered to the range (using Matlab notation) to the range (2:N/2). In other words, the first bin is dropped and the negative half frequencies too. Just to be clear, for each 1024 window of audio data (audio_chunk below) the code does:

y = abs(fft(hann_win.*audio_chunk));
filt_y = y(2:length(y)/2);

The value filt_y is then summed and that becomes the output signal:

output = sum(filt_y);

So, for every window's FFT we get a single output value. The output sampling frequency is audio_sampling_frequency/512 because we slide the 1024 sample window along by 512 samples at each step.

My question is: what would you call that output signal? What sort of physical significance does it have, or what use is it for analysis?

2 added 41 characters in body
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I've inherited some matlab code and I can't really understand what the resultant signal really means. The input is audio and the code first performs an STFT/spectrogram (sliding window FFT of size 1024 with 50% overlap, hanning window applied). The output is then filtered to the range (using Matlab notation) to the range (2:N/2). In other words, the first bin is dropped and the negative half frequencies too. Just to be clear, for each 1024 window of audio data (audio_chunk below) the code does:

y = abs(fft(hann_win.*audio_chunk)); filt_y = y(2:length(y)/2)

y = abs(fft(hann_win.*audio_chunk));
filt_y = y(2:length(y)/2);

The value filt_y is then summed and that becomes the output signal.:

output = sum(filt_y);

So, for every window's FFT we get a single output value. The output frequency is audio_frequency/512 because we slide the 1024 sample window along by 512 samples at each step.

My question is: what would you call that output signal? What sort of physical significance does it have, or what use is it for analysis?

I've inherited some matlab code and I can't really understand what the resultant signal really means. The input is audio and the code first performs an STFT/spectrogram (sliding window FFT of size 1024 with 50% overlap, hanning window applied). The output is then filtered to the range (using Matlab notation) to the range (2:N/2). In other words, the first bin is dropped and the negative half frequencies too. Just to be clear, for each 1024 window of audio data (audio_chunk below) the code does:

y = abs(fft(hann_win.*audio_chunk)); filt_y = y(2:length(y)/2)

The value filt_y is then summed and that becomes the output signal. So, for every window's FFT we get a single output value. The output frequency is audio_frequency/512 because we slide the 1024 sample window along by 512 samples at each step.

My question is: what would you call that output signal? What sort of physical significance does it have, or what use is it for analysis?

I've inherited some matlab code and I can't really understand what the resultant signal really means. The input is audio and the code first performs an STFT/spectrogram (sliding window FFT of size 1024 with 50% overlap, hanning window applied). The output is then filtered to the range (using Matlab notation) to the range (2:N/2). In other words, the first bin is dropped and the negative half frequencies too. Just to be clear, for each 1024 window of audio data (audio_chunk below) the code does:

y = abs(fft(hann_win.*audio_chunk));
filt_y = y(2:length(y)/2);

The value filt_y is then summed and that becomes the output signal:

output = sum(filt_y);

So, for every window's FFT we get a single output value. The output frequency is audio_frequency/512 because we slide the 1024 sample window along by 512 samples at each step.

My question is: what would you call that output signal? What sort of physical significance does it have, or what use is it for analysis?

1
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What's a good physical description of the following matlab code?

I've inherited some matlab code and I can't really understand what the resultant signal really means. The input is audio and the code first performs an STFT/spectrogram (sliding window FFT of size 1024 with 50% overlap, hanning window applied). The output is then filtered to the range (using Matlab notation) to the range (2:N/2). In other words, the first bin is dropped and the negative half frequencies too. Just to be clear, for each 1024 window of audio data (audio_chunk below) the code does:

y = abs(fft(hann_win.*audio_chunk)); filt_y = y(2:length(y)/2)

The value filt_y is then summed and that becomes the output signal. So, for every window's FFT we get a single output value. The output frequency is audio_frequency/512 because we slide the 1024 sample window along by 512 samples at each step.

My question is: what would you call that output signal? What sort of physical significance does it have, or what use is it for analysis?