From: rcrowley@xp7rt.net   
      
   "Audio Empire" wrote...   
   >> There is two more type of condensor mic which don't use DC at all:   
   >> Both types use a low voltage RF generated by a low-noise RF oscillator.   
   >>   
   >> The mic capsule of a RF condensor mic is part of a resonant circuit   
   >> that modulates the frequency of the oscillator signal. Demodulation   
   >> yields a low-noise audio frequency signal with a very low source   
   >> impedance.   
   >> In the other type of RF condensor mic the capacitance of the mic   
   >> capsule is used to modulate the amplitude of the RF oscillator.   
   >>   
   >> Norbert   
   >   
   > These were somewhat common back in the 1940's and 1950's but are rare (if   
   > not   
   > outright non-existent) today.   
      
   I just bought a Rode NTG-3 shotgun mic which was just introduced   
   late last year. It is being favorably compared to several of the long-   
   established industry-standard shotgun mics. It uses the RF oscillator   
   design, so the circuit appears to be still going strong.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)