Anders:
Check out thse links:

http://home.worldnet.att.net/%7Ewa1sov/technical/sync_det.html
http://home.worldnet.att.net/~wa1sov/technical/allpass/allpass.html
http://home.worldnet.att.net/%7Ewa1sov/ver2/Software_Rado.htm

The AD607 has a PLL built in and I don't know why this designer
didn't employ it instead of adding a NEnnn PLL. But at least it shows
one way to use the AD607.
I am presently using a ARRL BFO deign from the early 1970's that
works, but has developed some nasty drift issues in the 30+ years
it has mainly set idle. I am debating using 3 Epson programable
for the BFOs. I can either go with them running at 3 times the desired
Fout,
or hihger mutliples. At 13.nnnMHz the phase noise is on teh edge of
being too high,. but for less then 5MHz the phase noise is minimal. I
have a query
to Espon tech support to find out at which freqs they have minimal
phase noise. Supply them with +5 or +3.3V at 10mA and they give very
stable
Freqs. I have one 455KHz crstal, but it is sluggish in every circuit I
have
tried it in. I can get three of the Epson uints for less then a "good"
crystal.
I want one at 455.0000MHz and one at +1.300 and -1.300 KHz.
I am building this as a series of modules each in it's own Altoid Mints
tin.
A friend gave me a BIG Altoid tin that has more then enough space for
everthing.

Terry

Terry