[Lowfer] Homebrewed SSB Filter question - Clarification

[Steve Dove]

Hi Andy,

Just a thought here:  since Jason is actually very narrow band with the 
several tones close together a *very* simple phasing-type exciter would 
work.

Simple, because the has-to-be-accurate quadrature phase shift of the 
audio source (which is ordinarly in analogue a pain to get right over 
the full audio band) only has to be right at effectively a single 
frequency;  it could be achieved with just an equal RC / CR pair to make 
the +/-45 degrees for the quadrature pair, centred at whatever frequency 
Jason pops out of the soundcard.

Smells like a handful of bits in the ever-popular Altoids tin.

Thinking this through a bit further, a single crystal as a bandpass 
filter acting as a sideband filter would work, too, since the required 
bandwidth is small.  No need for anything elaborate.

         73,

                 Steve


Andy - KU4XR wrote:
> Jim & All:
> 
> In this experiment, I have absolutely everything to learn. Allow me
> to give some reason on my thinking. I read an article on the web
> recently by Alberto discussing JASON, and in his article, he said
> that JASON could be ran thru a Non-Linear PA due to the fact that
> no audio tones ever overlapped ( I'll say here that I may be like
> an anxious runner jumping the gun ). But with that in mind, after
> reading his article, my understanding was that ( in simplistic
> understanding ) all I have to do is find a way to drop the carrier,
> and modulate the PA with the JASON audio tones, and that's where
> the MC1496 DBM comes in. The carrier is there, but -65dB below
> the DSB audio. Then I need to get rid of the LSB component,
> with a USB filter so that the only thing left is the attenuated 
> carrier with the audio tones appearing on the USB. Now the 
> simplicity stops, and reality slaps me hard upside the head; I
> like you Jim, have no idea what will happen if you mix a sine wave
> audio tone, with a square wave carrier, and then feed it into a
> switching PA. If I even make it that far, I think that's what I'll
> be trying to do. I may be trying to build a better mouse trap.
> 
> 
> Andy - KU4XR - EM75xr - Friendsville, TN.
> LOWfer Beacon " XR " @ 184.322 KHz ( QRSS-60 )
> Coordinates:  N:  35* 43' 54" - W:  84* 3' 16"
> http://www.myspace.com/beaconxr