Tuesday, August 30, 2016

ADF4351a

The latest test  is using a 74AC14 Schmidt trigger to shape up the 10MHz signal to the REF inout
now the 10MHz is at  TTL level  about the same shape the onboard oscillator
But still the 1296.200  shows -40dB  AM  tone modulated side-bands

So my conclusion is this ADF4351A  can not generate a clean signal.

When  I get new information maybe i will have another try.





Have been testing the ADF4351 demo board some time now

But the signal from the PLL  is very IMD distorted and unstable
Useless  sofar ...


Arduino Uno  controling ADF4351A      F1CJN sketch

QRPLABS   Progrock / SI5351    and  GPS QLG1 receiver

all locked
the Progrock output 10MHz ttl level signal  matches the ADF REF input good




output  1296.200    T9 + huge IMD  hum about 400Hz?
the signal is locked  with 10MHz GPS DO
but it does not sound stable at all
 tuning with a 23cm receiver there is a huge AM tone  IMD around the carrier

When locking to the ADF onboard 10MHz  X-tal oscillator ref
this AM tone IMD  is much weaker but still not clean

still searching for a solution that makes the ADF4351A output clean to be useful as LO generator

The Progrock output is more clean but  also showing irregularities  absolute not Xtal T9
It can not be used  to replace the 23cm l.o.  96MHz Xtal
this experiment seems to end  here

 to make a GPSDO 96MHz  LO  for the 23cm  have to find a better solution

video clip + sound    94MB     https://we.tl/zSyHc2yW3w

    broad  spectrum  output




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