[EE] Phase locking DRO's
Alan B Pearce email (remove spam text)
>One also has to match the cable delays to within an IF wavelength. One also
>introduces an 'offset' in the LO to accommodate the look angle and it's effects
>on path length.
Perhaps it did not come across clearly enough in what I wrote, but I envisaged
that these could be taken care of by the phase offset of the LO. I guess the
problem here is the cable length can be significantly more than 360 degrees at
the LO frequency! Certainly I expected to be able to adjust the look angle
factor with the LO, but I guess the physical spacing again becomes more than 360
>In theory one doesn't even need a D/A, just PWM and a LPF.
I would have thought this could introduce a heap of unwanted sidebands on the LO
due to filtering difficulties. Also I figured that the D/A would have much finer
control steps for the LO, without going through the math of just how fine they
may need to be.
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