We are having AD9956 Evaluation board. We could not generate repetitive frequency sweep.
please help me how we can generate repetitive frequency sweep using AD9956 GUI provided with evaluation board.
I checked the AD9956 data sheet regarding its No Dwell function.
The behavior of your sweep is the same as indicated on the data sheet. You can now control the sweep by supplying a square wave signal on PS0 that would meet your sweep time of 1ms. Just follow the parameters below for the input for PS0.
Can you share more details on the repetitive frequency sweep that you would like to generate?
The AD9956 has No Dwell Linear Sweep function wherein the frequency will sweep from the start frequency to the end frequency back and forth.
Thanks for your reply.
We want to generate frequency sweep say from 20MHz to 35MHz and this should be repetitive and it should repeated every 1ms. We had used "No Dwell Linear Sweep function" wherein the frequency is sweeping from 20MHz to 35MHz but after 35MHz its coming back to 20MHz and stays there and not repeating the sequence.
Please suggest what we can do for repeating the signal.
Thanks for your comments.
I just want to say that if we apply external transitions to PS0 pin, subsequently this pin is controlled by GUI as well. There is conflict as this pin is controlled by GUI and external transition, so is there any way to disable this pin by GUI so that we are able to control it by external transitions only. If we apply externally without disabling the GUI control of PS0 pin, will that be recommended and will not affect DDS performance.
Please let me know.
In the Linear Sweep Ramp Control, just keep the setting to Ramp Down then apply the signal to P1 Master for PS0. Positive on the pin near the PS0 label or the right and ground on the left side. I tried to to do this in the lab and it worked, although I did not try the timing that you needed.
I have tried with the solution you have provided in above post but it is loading the applied pulse. Because of that linear sweep is not repeating.
Please suggest for the same.
Here is my setup in the lab.
DUT RF_IN (J1):
Frequency = 400MHz
Level = 0dBm = 223.6mV
Frequency = 1kHz
Amplitude = 2Vrms
Offset = 2V
Pulse width = 100us
And here is my evaluation software settings.
Thank You for your reply.
We have done the experiment as mentioned you, but have some doubts regarding results. For more clarification will you please share the results with us.
Here is the output that I get from my setup. The timing for this sweep is not the timing that you need. You can try to change the ramp up and ramp down step interval to achieve your desired sweep time.
But I am unable to see your results, kindly update it again.
You can try to access this link for the output that I obtained.
Retrieving data ...