I did measure the Xtal and it is 60 MHz. That is the only thing I know for sure. I did not probe the output of the DDS because with my 69 years old hands I do not want to slip and destroy the unit, some one else may want to test it. As a group we should be able to solve the problem since the prices are free falling. Sooner than later every time nut will have one. Bert In a message dated 11/12/2011 2:34:06 P.M. Eastern Standard Time, [email protected] writes:
Bert, Your comment about the AD9832 being a 25MHz part made me think, and I too wonder how it might all work. The data sheet calls it a 25MHz part, and I agree with you that it might be expected that some extra division occurred between the ~60MHz Rb loop and the synthesizer MCLK. That's not the case however. I don't know how it's achieved, but the FE-5650A and FE-5680A (the versions with AD9832 and user-programmability, I mean) do in fact appear to operate with a ~60MHz MCLK. I support that statement with two facts: 1. The AD9832 in these models is capable of generating moderately good 12MHz output, which it certainly would not with a 25MHz MCLK. 2. The frequency calculations used give you a step size of about 10mHz, and as you will realize, 50MHz/2^32 is about 10mHz. I've used the ~50MHz figure (actually either 50.255MHz or 60MHz) in my software. Does anyone know how we can resolve this apparent inconsistency? 73, Murray ZL1BPU _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https:// www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
