XPost: rec.radio.amateur.equipment, uk.radio.amateur   
   From: et472@ncf.ca   
      
   On Mon, 26 Jan 2015, Jerry Stuckle wrote:   
      
   > On 1/25/2015 12:46 PM, gareth wrote:   
   >> "G3XBM via rec.radio.amateur.moderated Admin"   
   >>  wrote in message   
   >> news:047d7b5d612a205e9c050d737a33@google.com...   
   >>>   
   >>> Although not impossible, it is quite difficult to demodulate a DSB signal   
   >>> on a simple direct-conversion receiver. DSB rigs are ideal as simple   
   >>> transceivers to communicate with SSB rigs.   
   >>   
   >> The reason being that to resolve DSB, the injected carrier must have a   
   >> very close phase relationship with the original carrier, and at a certain   
   >> phase relationship (don't remember but probably 90 degrees) there's   
   >> no output at all!   
   >>   
   >> Gareth G4SDW   
   >>   
   >>   
   >   
   > Wrong again, Gareth.  Phase relationship is immaterial.  It's hard to   
   > demodulate because a direct-conversion receiver does not generally have   
   > a means of injecting a carrier.   
   >   
   By definition a direct conversion receiver has a BFO, which is why they   
   aren't so good for receiving AM with carrier signals.   
      
   The term wasn't really used until 1968 when that article by Hayward   
   appeared in QST showing a receiver that used a schottky diode mixer and   
   called it a "direct conversion receiver".  That's when simple receivers   
   changed from regenerative receivers (and the occasional simple superhet)   
   to direct conversion, that era lasting until home made ladder filters   
   flopped things back to simple superhets.   
      
      Michael   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)