Maybe this could help: http://www.murata.com/products/catalog/pdf/p50e.pdf http://www.murata.com/products/catalog/pdf/p11e.pdf Chetan Bhargava http://microz.blogspot.com On Thu, Aug 16, 2012 at 10:11 AM, Herbert Graf wrote: > On Thu, 2012-08-16 at 09:39 -0700, Harold Hallikainen wrote: >> I don't have datasheets on those specific parts, and they may be OEM par= t >> numbers. The ceramic filters I used were from Murata. You might check th= em >> out. > > I don't believe so, it seems to be some sort of industry standard > marking since I've seen many other boards with similar filters marked > similarly. > >> A "ceramic discriminator" is just a ceramic resonator that is used in a >> discriminator (FM demodulator). It replaces a parallel LC filter used in= a >> quadrature detector FM demodulator. As I recall, the IF is applied to th= e >> filter (whether ceramic or LC). As the frequency varies (as in FM), the >> phase between the voltage and current varies. This phase difference is >> used to determine the instantaneous frequency and demodulate it. > > I'm sorry, but this is way over my head, do you have a pointer to > something that describes this sort of stuff from a more fundamental > point of view? > >> So, good luck with your filters! The band pass and notch filters probabl= y >> have an input, an output, and a ground terminal. They need to be driven >> and loaded with a specified resistance for them to work properly. The >> discriminator is probably a two terminal device that is designed to work >> with a specific chip (like the SA639 I mentioned before). > > Ahh, see, as mentioned in my post, the 3 devices are 3 pin, so I don't > think it is a discriminator? > > I've looked at another board I have. It contains a TDA9800 VIF-PLL > demodulator and FM-PLL detector chip. > > I've traced the filters involved (they again look very similar to the > link) and referencing the typical circuit in the datasheet, it looks > like the one labeled T4.5C is a sound trap (so notch filter to rid the > 4.5MHz sound carrier from the video side) and the other is labelled > F4.5E, labelled sound filter, so I assume that means it's a pass filter. > > Still would love if someone could confirm/deny my suppositions here! :) > > Thanks, TTYL > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .