[time-nuts] Trimble Thunderbolt, any easy way to create 500 MHz

Chris Wilson chris at chriswilson.tv
Wed May 15 13:14:17 EDT 2013

> Re: Trimble Thunderbolt, any easy way to create 500 MHz
> Richard -

> I can think of several ways to do this, but "easy" depends upon
> your skill set and the equipment you have. Actually - none of these are easy!

> I have done a lot of synthesizers and sources over the years and
> here are some thoughts; hopefully helpful.

> 1. A straight class C multiplier chain. If you use push pull odd
> order multipleirs and push push doublers to cancel out the
> fundamentals, the inter stage filtering becomes easier. Requires
> discrete old-fashioned RF Design methods and perhaps a filter design
> program. X5 filter, X2, filter, X5, filter will do it, with low
> power bi-polars, but the filters have to be multi-pole to keep the spurs down.

> 2. Use one of the modern phase lock loop chips with internal VCO
> from National, Analog Devices, and others. The down side is that
> most of these require an associated PIC or similar processor to load
> - even for one frequency. However for one with the required software
> skills this would most likely be the lowest cost and most straight forward approach.

> 3. Cook up your own PLL with discrete pre-scaler, phase detector
> and loop amplifier. Easier than #1, harder than #2 except for the software advantaged.

> 4. Mix down to IF PLL - eliminates the high speed counters but
> required a low output multiplier to create a reference line near 500 MHz. Complex.

> Any of the PLL schemes will have fewer non-harmonic spurs and some
> makers web sites have tools to help with the design of the loop filter.

> -73 john k6iql

15/05/2013 18:12

My skill level is pretty low, so was hoping a fairly cheap
commercially made solution was possible? Thanks for the ideas so far
everyone, appreciated.

Will draft out a basic description of what I am attempting to do
later, should still be working :)

       Best Regards,
                   Chris Wilson.

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