Yes, in the 5650 there's only DDS on opt 58, in the 5680 there is one in the main loop too, my bad for not being precise/muddled.
On 10 Jan 2017 01:43, "wb6bnq" <wb6...@cox.net> wrote: > HI Bob & Clint, > > If you look at the second message of this thread, I attached the manual > that applies to Option 58. Look at PDF page # 16 and you will see that > there is no DDS in the physics package. The DDS is only used down stream > in some variations of the product such as the Option 58 being discussed. > > Bill....WB6BNQ > > Bob kb8tq wrote: > > Hi >> >> In most Rb’s (including the FE 56xx’s) the DDS is mixed with a fixed >> microwave frequency signal. The DDS only has to make up “part” of the total >> offset. You get >> roughly a three orders of magnitude improvement because of this. Rick has >> gone >> into all the gory details of why it gets done this way in talking about >> the 5071. It >> is the same thing on an Rb. >> So, your basic math is correct about a normal DDS. In this case you are >> in the >> PPT rather than PPB range due to the multiplication. >> Bob >> >> >> >> >>> On Jan 9, 2017, at 10:40 AM, Scott Stobbe <scott.j.sto...@gmail.com> >>> wrote: >>> >>> A 32-bit DDS synthesizing at 1/5 Fs, yields a tuning resolution of ~ 1 >>> ppb. >>> So, I would imagine a slightly lower frequency is programmed into the DDS >>> and the c-field is trimmed to yield a higher precision. If the new >>> synthesized tone you wish to generate is an integer number of DDS codes >>> you >>> could start by assuming the c-field is trimmed to be on frequency, but if >>> the new tone is a fractional number of 32-bit DDS codes you will have to >>> manually trim if you want higher precision. >>> >>> On Mon, Jan 9, 2017 at 4:48 AM, wb6bnq <wb6...@cox.net> wrote: >>> >>> >>> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/m >> ailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.