EMRFD Message Archive 9958

Message Date From Subject
9958 2014-04-26 17:03:26 Mark Meyer Problems with Digital Freq Readout
Today at 5:31 PM
I am currently using an Allmost All Digital Electronics DFD3 frequency readout for a homebrew transceiver project. 
It is working fine for the frequency readout application, but it is introducing birdies and various odd noises in the received signals.  If I turn off the DFD3, all the extraneous signals and noises go away.  I have used separate batteries to power the DFD3 and the transceiver, but this does not help.  I have tried using a fairly large resistor (5k) between the connection to the VFO to isolate the DFD3, but this did not help (any higher resistor and the DFD3 could not read the frequency). 
If the DFD3 is disconnected from the VFO, but still powered up, there is no problem. 
The VFO runs at 5.0—5.5MHz. 
I do not know it the DFD3 is feeding garbage back into the VFO and that is causing the problems, or if it is actually radiating the spurious stuff and the rcvr picking it up.
Has anyone had a similar problem?  Does anyone have ideas to fix this problems?

10008 2014-05-12 09:29:35 mvs_sarma@ymail.c... Re: Problems with Digital Freq Readout
I suppose that signals  to LCD or LED signal lines, do cause harmonics and this the interference.
I would propose that the counter can be enabled only during any change and later automatically turned off. May be some triggering mechanism for powering the DRD is needed but timed.