spacedoggy wrote:ok, I got by power stabilised, and resumed work on this.
-What do i need to check to get the 1300 to lock?
-the 2700 locking at 20.4V seems a little high, is this ok?
*using formula 3.3*((X/10)+1)=Y
where X is Kohm
and Y Voltage limit of the sweep test
Good question, I can't get either VCO to lock. Probably a problem with the feedback circuit.
2700 locking at 20.4 high? What freq are you trying to lock at?
For the ROS2700-1819+: 3.3((64.9/10)+1) = 24.717V (Max Vtune for ROS 2700 is 25V)
Again if the voltage is too high for a lower freq lock then it is probably a problem with the feedback circuit, which is probably the most difficult circuit to understand / tune.
Anyone with in depth knowledge on this particular aspect care to chime on on possible steps to troubleshoot? Specific values for measurement across points, etc. Please feel free. Technically speaking you would need an oscilloscope with double the bandwidth to sample VCO output, i.e. for 1300 you need a scope with at least 3 ghz bandwidth etc.