[time-nuts] f-multipliers from VHF to 10 GHz

[ed breya]

Gerhard, you didn't mention a budget number for this. You should be able 
to find a commercial synthesizer ready to go if you have enough money. 
If it's a one-off, DIY thing, then it's a different story. If this is 
the case, I'd recommend looking at the methods used in microwave 
counters. They often use synthesized VHF sources and SRD multipliers and 
YTFs to make and select sampling frequencies for down-converting 
microwave inputs.

All I can say is that there are lots of ways, and the usual things apply.

Start as high as possible. An XO may be good up to 200 MHz or so. A SAW 
resonator may be good to a GHz - noisier, but less multiplication 
needed. You may be able to PLL a DRO well enough directly at 10 GHz, and 
not need multiplication, with a high enough low-noise reference 
frequency for comparison.

Going with a multiplier chain is reliable and straightforward, but can 
get complicated due to the number of stages and filters that may be 
needed. My favorite multiplier is the classic SRD. If you start with a 
high enough drive frequency, selecting the desired harmonic is fairly 
easy with a fixed or yig-tuned BPF. I always figure that if SRDs are 
good enough to multiply by hundreds of times in Cs and Rb standards, 
they're good enough for my simple needs.

An alternative to the SRD is to use extremely fast logic or line or 
laser driver type parts running at VHF, that have edge speeds with 
enough juice at 10 GHz, then BP filtered and amplified.

Ed