Kees_01 wrote:Good news, and good news. The 1st good news is that the IDE terminal presented the good news, "Trackgen V1.0" after sending "Version".
That is very good news indeed. A couple of points to consider:
40MHz is the default spot, and sweep centre frequency. This set by the Arduino firmware.
control is only used to set a spot frequency, it has no effect of the sweep frequency. I should disable it when in tracking mode.
I've found a small bug in the way the tracking generator is working. The tracking sweep frequency should be set automatically according to the sweep width the anaylser is set to. This is not happening as it should. In order to get the tracking generator to pick up the correct sweep range, you need to do the following:
1 - Start the analyser sweeping.
2 - Click the tracking generator Enable
button if not already enabled
3 - Click Track
4 - Click Spot
5 - Click Track
6 - Click Start
If the analyser is running and you change the sweep centre frequency, you will need to :
1 - Click Stop
2 - Click Spot
3 - Click Track
4 - Click Start
What happening is that generator sweep settings are only being updated when the Track
button is clicked. Changes to the analyser sweep settings are not being sent to the generator as they should. A final point. If the generator is in Track
mode and running, and you close the analyser, the tracking generator continues sweeping. Either press Stop
on the generator, or the Arduino reset button to stop tracking.
The above problems will be fixed in the next release.
In addition, I've added another output to the Arduino. A selected pin will pulse high at the start of each tracking sweep to allow synchronisation with an external device, such as an oscilloscope. In addition, another sync pin will be included to indicate the start of a wideband sweep by the analyser - It may be useful to have.
The Trackgen software actually started out as part of a project similar to what you are doing. I was building a vector analyser using the AD8307. I got the system pretty well up and running, and then got distracted with the analyser project. I'm having some thoughts about incorporating the VNA system into the analyser to give it added utility.
In addition, I was driving two DDS chips, they could be run as two independent generators, or slaved to each other with a fixed phase (and/or a frequency) difference between them, such as 90 degrees to give a quadrature output. That work very nicely, and the next release of the firmware may include that facility. As well as using it to generate a quadrature signal, the two outputs could be fed to a mixer to allow higher tracking sweep frequencies to be generated. This would extend the sweep output up to around 180MHz with two AD9851 devices. The only drawback with the quadrature system is that a minor bit of surgery is required so both DDS ic's are running off a common clock.
Let me know how you go with your project, I'd be interested to hear.