Re: DDS Module is not functioning

John King

Nick and Jim:

Good news, guys!.  Adding the jumper to the DDS module to shift from parallel to serial mode did the trick.  The DDS is now putting out frequencies and successfully doing sweeps.  Oddly enough, I had not seen any data in the previous files concerning a requirement to make this change.  The only clue was the image I mentioned to Nick showing the jumpers and their use.  One thing I did notice is that some of the conversation threads seem to be missing if they are more than about a year old.  Perhaps it is a space limitation from Yahoo.

In any event, the main board is now working.

I did make some measurements of signal level from the -10 dBm port on the main board.  From 2 MHz to 6 MHz, the output level varied from -10 dBm to -12.5 dBm.  At 11 MHz, the level falls to -21 dBm and then rises to -15 dBm at 12 MHz.  Output then rises and falls within a 6 dB range from 12 MHz to 60 MHz.  By comparison, the counter output port falls monotonically from +7.5 dBm at 2 MHz to -16 dBm at 60 MHz.  Admittedly, this data was taken with all the equipment in an "experimenter's lash up" with wires all over the place.

Is this normal amplitude behavior for these two output ports?  If not, what should I be seeing?

Also, what should the configuration of the four jumpers on the DDS board be?  Obviously, the one at the top left should be shunted but what about the other three?


John, W5IDA

Join { to automatically receive all group messages.