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Showing posts from September 30, 2016

PLL ADF4351A Progrock QLG1 GPS

Meanwhile  some progress made
My Trimble GPSDO 10MHz output  30mV tt   amplified  a filter  followed by 3 stage amplifier
then shaped by hex inverting Schmitt trigger  74AC14
a reasonable clean signal at 1296.210
Shielding and grounding and a clean 5V power are important
the AM 350Hz hum side-bands are weaker
-60 dB at 144.550     -40dB 1296.210

The ADF4351  REF in seems to be a straight TTL input  without analog interfacing.
It  omits  a trigger circuit.  I had to  make that myself.
The specs only give the maximum signal level for this REF  nothing about the shape or minimum
usable  level.
It does not work with  a relative weak or  sinus shape 10MHz signal.
Some other types PLL chips seem to have no issue with the reference  level.

 2V / division    .5 uSec /devision  10MHz signal at the ADF REF input

test setup
 10dB / dev.

discrete 10MHz  booster  3 stage  and a band filter  after a lot of modifications this one can amplify the  30mV 10MHz Trimble out to 5V tt square wave  derived from …