[GreenKeys] Demod Bds & some help

[WA5CAB at cs.com]

Eric,

Teletype machines are asynchronous.  Unless you are trying to simulate one 
of the Crypto systems, there is no requirement to keep receivers synced.  
And almost all HF radio sets since AN/GRC-19 either come with built-in FSK 
transmit capability or have outboard modulators available.

In a message dated 09/03/2011 01:04:29 AM Central Daylight Time, 
epvgk at limpoc.com writes: 
> On Fri, Sep 02, 2011 at 10:23:42PM -0700, Norm wrote:
> >Hi
> >I just received two of Eric Volpe's demod boards, anxious to wire them up 
> and try them. they really look professional.  I have a demod ckt now, is 
> there anybody out there wanting to tackle a mod board, or has someone built 
> some already?  I would be interested in one or two.  Could someone help me 
> out on this, someone awhile back a month or two, mentioned he had some 
> rectifiers for sale.  It sounded like they were on boards also.  I must have 
> deleted that message ,because I don't have it in my files.  Thanks Eric you 
> done yourself proud.
> >
> >Norm
> >WB7WEQ 
> 
> A mod board is not impossible... Would this be for radio use, or something
> else? It seems like it's a little more complex than the demodulator. 
> 
> I had a couple of ideas on how to do it cheaply but I'm curious what 
> people 
> would be after in terms of features - I suppose we'd need adjustable 
> center 
> frequency, split, output level, mark/space swap? Anything else? I suppose 
> also it would have to be able to adapt to whatever loop voltage/current 
> you 
> threw at it, as well, and put out a nice clean sine wave. 
> What about more fancy features like sending nulls when there's no data 

> coming, to keep receiver in sync? That would of course require receiving, 
> retiming and retransmitting the signal. 
> 
> eric

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480