Re: RF out with RF OFF: Clock feed through


The problem that we are dealing with is the 180 MHz clock feedthrough in the output. It was discovered when turning the RF off, but it is present with the same amplitude when it is on, where it matters. RF is turned off for special purposes only, not while measuring, and for me it is ok as is.

BTW, I plan to test the transformer method, as indicated by Clifford and also used in some versions with the Chinese modules and in the experimenters board. I have to get a Minicircuits T1-1T transformer for best results, and this will not happen until September.

73 de Ignacio EB4APL

El 10/07/2017 a las 22:28, wb4jfi1@... [PHSNA] escribió:
Perhaps a better way to turn OFF the RF would be to put the DDS chip in sleep mode, NOT to just program it to 0Hz.  IIRC, putting it to sleep also powers down the internal clock multiplier (AD9851).
73, Terry, N4TLF

Posted by: wb4jfi1@...

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