[time-nuts] Cutler NAA on 24.0kHz....

Kenneth G. Gordon kgordon2006 at frontier.com
Sat Aug 16 12:58:34 EDT 2014


On 16 Aug 2014 at 12:48, paul swed wrote:

> 
> As a test this morning I connected the fluke 207 vlf radio that has a 1.1KHz IF
> out to a XY scope using a very stable 1.1 Khz synth function gen. Indeed the msk
> is a classic 4 corner eye pattern.

Kewel.

> Also I looked at the tracor 900 de-MSK-r
> option and they split the path and create a new signal that according to
> calculations would be 180 degrees and then sum it with the original.

But from my VERY preliminary glance at that schematic, it looks as though 
the signal passes through two op amps. Doesn't the phase through any amp 
change by 180 degrees? Therefore, through two op amps, it would swap a 
full 360, which would equal zero at the output?.

> That is
> perplexing as that would be 0. They do pass it through a 100 Hz BPF. I wonder if
> in reality the phase shift is 90 degrees and then summed. Its not really making
> sense as to how that gets rid of the MSK. No description either. But it does
> some how because that signal is simply re-inserted into the 100Hz IF that feeds
> the phase detectors and correction/locking circuits. Lets see if the diagram of
> the tracor d-msk-r will come through

It did. Thanks.

Ken W7EKB



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