Allison wrote:
It can also be done with a small amount of ttl.
An analog PLL data separator using a 74LS629 VCO or the like is fairly
easy to make, though you do have to be somewhat careful with the PCB
layout. IIRC, such a design is given in the 179x app note.
Building a good digital data separator out of TTL takes a fair number of
parts, which is why it was so rarely done. The DPLL design in the 179x
app note isn't very good.
Eric