Digital Radio Mondiale  455 Khz to 12 Khz

DRM  reception most commonly uses the sound card of your PC  for the number crunching . Because the sound card  has limited frequency response due to the maximum audio sampling rate  of typically 48 Khz , the drM signal must be mixed down to a frequency the card can handle , 12 Khz seems to be the designed IF requirement  for the  "Dream  " software commonly used to demodulate this signal .

I have used a good ol ne612 or 602 mixer oscillator chip to achieve this , There are various permutations if this design , Crystal locked oscillators ( expensive ), free runing using a 455 IF transformer as the frequency determining element ,    and  Ceramic resonator controlled oscillators   which have improved temperature frequency stability when compared to a perfectly satisfactory IF  can , but not the stability of an expensive quartz crystal cut for the wanted L.O frequency . 
The Dream software has a build in tolerance to the I.F. and will cope with small amounts of  drift anyway .
The most important aspect of good  DRM reception is to have a radio with a good low phase noise Local Oscillator .  I tapped into the end of the 455 Khz IF  chain in my Icom R75 receiver and  bought the 12 Khz output to the back panel terminated in a RCA female connector . into which my computer sound card  connection plugs , ........... more to add later

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