[time-nuts] FE 5680A "new version" - Filtering the 10 MHz

Sylvain Munaut 246tnt at gmail.com
Wed Nov 16 01:22:18 EST 2011


>>> It's not generated from a DDS. It's from a xilinx PLD,
>
> I think the DDS is implemented inside the PLD.
>
> Sying "that is not a DDS, it's a PLD, is like saying "That is not an
> amplifier, it is a transistor."

But a DDS would require a DAC somewhere. Here, I see can see the trace
from the PLD pin, to the LC filter to the RF connector ... and I
probed the PLD output, it's a square wave.


> In the description of how the device works in the data sheet they say
> there is a DDS inside the programmable synthesizer.   It seems
> reasonable that several functions are implemented inside the PLD and
> this seems to be supported by the data sheet.

There is a DDS, but not there. Someone described those new units in a
previous post.

Cheers,

    Sylvain




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