[ARC5] Zero Beat Question

[Sheldon Daitch]

I've scanned the file with Trend Micro.


I will be glad to send the PDF to anyone who wishes to read it.  I realize PDF files may also contain issues, so your virus scan protection can verify what Trend Micro has told me about the file itself.

I think the dot edu site isn't up to date with their site verification and it appears several antivirus programs are flagging it based on the signature for the site.  Mine did, and I added it as an exception.


Bottom line, it is a document based on zero beating by the use of two audio tones and was based on something we did in USAR MARS back in the late 1960s.

Back then, we called it a FATTO process.  The net controller would transmit two audio tones which were harmonically related, and if the recovered audio tones were not harmonically related, as in receiver SSB mistuning.  FATTO meaning Frequency Adjusting Two Tone Oscillator.

If the two tones were, say, 1000Hz and 2000Hz, and the receiver is exactly on frequency, then the recovered tones are 1000 Hz and 2000Hz and harmonically related.  If the receiver was, say, 10 Hz off, then one possibility was that the 1000 Hz tone would be 1010Hz and the second tone would be 2010Hz and a 10 Hz beat note would be noted.

One interesting thought about this is that the better the audio section of the receiver, the harder it would be to hear the beat.  The higher the distortion, it was easier to hear a beat, as there would be more second harmonic energy of the 1000 Hz tone in the receiver audio.

This process can also be noted in using an SSB receiver to tune in programming with music, that when the receiver is closer and closer to the correct frequency, chords are aligned properly in frequency.  Voices, as well, but that really depends on the frequency make-up of voices.

The file is 78 pages and is far more complicated than what I explained above.



73


Sheldon

________________________________
From: kg4kgl at gmail.com <kg4kgl at gmail.com>
Sent: Monday, July 11, 2016 6:08 AM
To: Michael Bittner
Cc: Sheldon Daitch; Kenneth G. Gordon; ARC5 at mailman.qth.net
Subject: Re: [ARC5] Zero Beat Question

Well I clicked on the link, on my iPhone. It is a .edu site. It is a link to a PDF file.

Robert
KG4KGL

Sent from my iPhone

On Jul 10, 2016, at 21:43, Michael Bittner <mmab at cox.net<mailto:mmab at cox.net>> wrote:

My Avast anti virus blocked the referenced URL.  Mike, W6MAB
----- Original Message -----
From: Sheldon Daitch<mailto:SDAITCH at bbg.gov>
To: Kenneth G. Gordon<mailto:kgordon2006 at frontier.com> ; ARC5 at mailman.qth.net<mailto:ARC5 at mailman.qth.net>
Sent: Sunday, July 10, 2016 2:51 PM
Subject: Re: [ARC5] Zero Beat Question


Also see this discussion on zero beat for SSB operations:

https://calhoun.nps.edu/bitstream/handle/10945/15087/methodforaccurat00dayl.pdf?sequence=1

73


Sheldon





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