MPX or MPXO?

Read the datasheet!

If you expect use to give you a useful answer, at least give us the part number of the IC, so we can look at the datasheet.

"MRW" wrote in news: snipped-for-privacy@o13g2000cwo.googlegroups.com:

The chip may have a built-in de-emphasis filter block (75uS?) which also produces some gain to more easily drive a power output stage. This "MPX" output comes in front of that (and therefore lacks the gain) but also has the full bandwidth to carry the added stereo sub-carrier centered at 38KHz.

So, if you want to build a simple, cheap monaural table radio, you ignore the "MPX" output (or maybe attach the 75uS de-emphasis network there) and connect the gain block output to a "power" amplifier chip through a volume controll and you're done.

If you want to go full stereo, you ignore the output gain block, connect the "MPX" output pin to a stereo decoder chip (usually available from the same manufacturer), connect dual de-emphasis networks to the outputs of the stereo demodulator chip then to dual volume controls and dual "power" amplifier chips.

"Power" amplifier chips might be in the neighborhood of 2 Watts with 10% distortion for a small table stereo rig!

HTH

Rick

I suspect that that pin is used to indicate stereo signal carrier detected and locked. That is what it meant back in the '70's when i was using FM stereo decoder chips.

Sorry Peter! The chip is actually a Philips TEA5767. On the datasheet, it just mentions that MPX is just the multiplex output pin. The chip also has outputs for the left and right audio channels, but I only want to use the mono output for now. I guess I can just connect my speaker drive to either one of the left and right channels.

Thanks!