On 5/6/2010 10:35 AM, James wrote: > Hi Guys, We have been experimenting with building CTCSS Units using > the 567 Tone Chip and good components, i.e. Caps, multi turn pots > etc. The stability is not good in my opinion. We will set it to 107.2 > and the next time you check it is off enough to where it won't decode > until it is re-tuned slightly. I am wondering what your experiences > may have been with this CTCSS Chip. Many articles say they work well > with the addition of a stable voltage regulator, so we added a five > volt regulator, no difference in stability. Any comments and > experiences with this and other chips would be appreciated. The > availability of CTCSS Chips seems limited.
I've never seen anyone have real succes with those chips in that application. Frankly, I think the internal components in the IC do not have the tolerance and stability to handle it, so no amount of high-tolerance components on the outside will make it usable. They were never designed for that purpose anyway. They were for broad decode app's in the audible range...cheap. Like a 1050Hz decoder in a weather radio.
