In my earlier short ramble the question was how much inductance do we need? First stop in search of the answer was the catalog. notice the larger coils have lower frequency limits. The most common practice is to use a trifilar wound toroid with a few turns maybe 10 - 12? (I think I saw one with 7 turns) Part of that would depend on the core. We also need to consider the Z matching, does it serve a useful purpose to dissipate half the power in the generator? How much current do we need to switch the diodes? Looking at the charts tells us we could use less than 100uh for MW. I'll just post some test and we can look at them to decide how much of my ramble is worth considering.
With 700mv driving a 1mh coil we lose more than half our signal inthe generator drop and we are driving with 4ma. Thus my question, how much drive do we need?
Here I set the reference at +V2 so we can see the drop across R7.
With 10 uh coils the signal is still strong but the current is still 4ma.
Here I cut the drive to 350mv and the output went UP to 45uv with 1 ma in the coils. Notice the transformer. I did not use a trififar winding. the secondary is equal to the primary. The step down transformer provide higher current and reduces the load on the LO.
Here I had lowered the drive and got less loading on the LO with the output holding level.
Another look at the generator lose. the red is the drop across the 50 ohm resistor.
Another look at the original circuit. 700mv drive and 300mv across the coil with 4ma in it. Now what did I find out with all this that we may be able to use?
I lowered the drive to 350mv and center tapped the secondary coil at 100uh.I now have 300mv across the coil and 1ma current in the coil. What about the output?
45 uv out.
So it is time to wind a new transformer. If not trifiliar then how?
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