Message-ID: <C3CF97ABE7DD42C09DA2EAC1D428BE8F@AGB>
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
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Date: Mon, 25 Feb 2013 13:52:55 -0000
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Subject: Re: LF: DSP app  to  multiply   tone  by  4  ?
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Tobias


Yes that's  the  other way  I suppose , harmonic  generator and some  filter 
.the   ssb tx  will   do  the  rest  ( we hope)...may be a  email to  Patric 
, multi psk  , he  did  make a test  version  some time  ago , with a  wider 
tone  spacing

Those  station  with  logic  divider  chain  driving  a   class  e/d  amp 
..only  need  to  square  up  1.9 MHz with a  x4  tone spacing  ,feed  it to 
the chain  and  the  output  is the  data  mode  on 477  , with the  x1 
spacing  .. simple !


Be nice if  there  was a  app  that looked like a  soundcard  , could 
select  as  the  tx  card  .......but its a simple way  to  run data  on 477 
, the  mfsk  mode's   , proved  a lot  better  than psk in the  past  and do 
not  need  a  linear  tx/rx  path

250  Hz b/w  mfsk   or the  ros-mf mode   100hz   all could be  used , 
(olivia needs a  linear  tx/rx)

73-G.

--------------------------------------------------
From: "Tobias DG3LV" <DG3LV@gmx.net>
Sent: Monday, February 25, 2013 1:21 PM
To: "Graham" <g8fzk@g8fzk.fsnet.co.uk>; <rsgb_lf_group@blacksheep.org>
Subject: Re: LF: DSP app  to  multiply   tone  by  4  ?

> Hi Graham !
>
> An alternative would be to use hardware like two cascaded active 
> rectifiers using OP-amps to get the frequency x 4. As those digital modes 
> do not need linear sine waves on transmit, it is no problem using even 
> square-wave-tones for modulation. Maybe some filtering is necessary to not 
> overload the AF-input of the transmitter.
>
> This circuit could be realised as an inline-PCB between soundcard output 
> and TRX input.
>
> Certainly such a "solution" is not really "elegant", but should do the 
> trick.
>
> 73 de dg3lv Tobias
>
> Am 25.02.2013 13:24, schrieb Graham:
>> DSP app  to  multiply   tone  by  4 ?
>> One thing that one of the PA (Dutch PA) stations spotted , is the 477
>> band is a handy divide by 4 from 1.9MHz .. and if you use two
>> flip-flops , you can divide from 1.9 to 477
>>
>> Setting the rtty shift x 4 in fl digi 340 HZ , then gives 85 Hz at 477
>>
>> A problem with the multi tone modes , unless its possible to write a 
>> 'dsp'
>> app , that multiplies the tones by 4 , single tone fixed amplitude in
>> real-time or slightly after ,
>> That would open up all the (non linear) modes
>> to 477 , X2 for 'logic' drive amps, X2 drive, and X4 for conventional on
>> frequency amps ?
>> Q  Is this  a  possibility ?
>> Could  something  be coded  , that  either looked  like a  sound  card
>> , or  took  audio in , and outputted  a  multiplied  frequency  by 2  or 
>> 4
>> Could  have delay  as  long  as  the delay  was   fixed ?
>> G..
>