The frequency shifting of the stereo signal must be doing exactly that, shifting everything down and not filtering
RDS at 57k she says? Stereo signal (or better, the L-R information) is at 38k (double band suppressed carrier, so the carrier would be at 38k). So 57 - 38 = 19k!
RDS at 57k she says? Stereo signal (or better, the L-R information) is at 38k (double band suppressed carrier, so the carrier would be at 38k). So 57 - 38 = 19k!
http://en.wikipedia.org/wiki/FM_broadcasting#Stereo_FM