Carrier Signals and demodulation of audio waveforms

[ADDA]

Is the failure to remove the carrier frequencies the problem with the audio output in the following videos?

 

[Tom.G]

I haven't captured and analyzed the wavefroms but they all sound like gradual onset severe clipping and severe intermodulation distortion as a result.

 

[ADDA]

In my haste this morning due to java, I had over looked a few details. Input volume was a factor. The frequencies were not scaled properly. Meaning that as I demodulated the signal on the bottom, the program would expect a low carrier signal or band to store data from a uniform distribution of the four or two bands in the above deleted videos. What was needed is a biased distribution of the initial gray background data. There are still high frequency waveforms along the edges of the frame in the above video, as well as this one:

original audio

 

[Tom.G]

Before more analysis is practical:

• What is the source of the recordings?
• What processing was done to them?
• What do the labels "what your radio hears 5" and "frequency division multiplexing" have to do with the sounds?
• What is your desired end result?

Can you make the recording(s) available at a high sample rate in .WAV format?

 

[ADDA]

more analysis

It's okay, I honestly wanted this thread deleted, yet it is against the forums policy.

 

[berkeman]

It's okay, I honestly wanted this thread deleted, yet it is against the forums policy.

Well, if @Tom.G agrees, I can delete the thread if you are not happy with your content. We just don't want good replies like Tom's to get deleted without a good reason.

 

[Tom.G]

Now I'm curious as to what is going on! Let's see if the OP comes thru with responses in, say, the next 24Hrs. If responses show up by then we can re-evaluate; if not then kill it. (that is if @berkeman doesn't mind being strung along til the morrow )

Cheers,
Tom

 

[ADDA]

I've been fickle lately, and I need to find employment. So I'll at least answer Tom.G's questions in reverse.

Can you make the recording(s) available at a high sample rate in .WAV format?

see edit above.

What is your desired end result?

A job

What do the labels "what your radio hears 5" and "frequency division multiplexing" have to do with the sounds?

I was creatively thinking what a radio wave's transmitted data would sound like, should we be able to hear it:



What processing was done to them?

The input in blue is fed through a transmultiplexer system, which my understanding of is a scaled (in terms of magnitude) inverse z transform with a varying radius centered around in this case a carrier frequency. I'll be honest again, I had to re look up the formula, and I've forgotten to scale the inverse z transform. Going to try again with my sample application soon. Tom.G would you like to keep a clean audio copy?

What is the source of the recordings?

A usb dac

 

[Tom.G]

I got a GOOD laugh out of that! Very creative. No, I would not have deduced that process no matter how much time I spent on it!

I will suggest that this thread be kept for posterity and an occassional light-hearted chuckle for future readers. I will, however, bow to whatever decision @ADDA chooses as to its longevity.

p.s. ADDA, with your approach to life you would probably fit best in a startup company; there are too many suits in the big ones.

 

[ADDA]

Can you make the recording(s) available at a high sample rate in .WAV format?

Tom.G, were you referring to real time processing:



original:

 

[ADDA]

The frequencies were not scaled properly. Meaning that as I demodulated the signal on the bottom, the program would expect a low carrier signal or band to store data from a uniform distribution of the four or two bands in the above deleted videos. What was needed is a biased distribution of the initial gray background data.

Wrong. I looked again, a uniform distribution is proper, for those that understand this material.

 

[Tom.G]

Can you make the recording(s) available at a high sample rate in .WAV format?
Tom.G, were you referring to real time processing:

I was requesting a copy of the .WAV file for the audio. Don't need it now since there is not a "problem to be solved" or a "solution needed."

 

[ADDA]

I suppose that I'm still needing help. I reverted to a uniform distribution.Why does this video still sound fuzzy?

 

[Tom.G]

Come on, you are modifying the waveforms and then wondering why they don't sound the same?

 

[ADDA]

I'm studying a digital signal processing book, and making progress on my own, yet am reaching out for help for certain things which I do not understand.

Here is a breakdown:

z = r * e^(2.0*pi*k*j)

with r as one, it is a normal Fourier transform.

a transmultiplexer system is

F(z,n) = a * z^(n)

taking (2.0*pi*k*j)^n and forming log [base n] (2.0*pi*k*j), we are able to apply Euler's formula on that log [base n]. I'm using only real values and also trying to center around a carrier frequency without losing information. Am I missing something?

 

[ADDA]

Another example:

 

[Tom.G]

I'm studying a digital signal processing book, and making progress on my own,

Ahh! That explains it. At this point I'm lost. Hopefully some signal processing experts can jump in here.

 

[ADDA]

Thanks, I was sort of misunderstanding you, perhaps:

I got a GOOD laugh out of that!

Were you laughing at the video, or my inability to properly do this?

 

[Tom.G]

The problem presentation convincingly indicated (to me at least) that there was a troubleshooting situation you were trying to solve.

My laugh was that I was cuckolded^* down that path, and the admission that your purpose was to get a job! As I said in an earlier post "Very creative" on your part, even if it wasn't entirely intentional. (benefit of a doubt there )

[*] Cuckold ...the term is also applied to males who are unwittingly investing parental effort in offspring that are not genetically their own.

 

[ADDA]

At times it is best to simplify and get back to the basics:

 

[ADDA]

And Rock and Roll:

 

[ADDA]

Or find a woman to court and spark:

 

[ADDA]

cleaner example:



Started to get copyright issues on youtube, so I decided to delete everything. I must be reproducing the signal correctly!

 

[berkeman]

Thread paused temporarily for Moderation...

Thread will remain closed since OP's question was answered. Thanks folks.