PULSEd CW and RUN TIME RF Changing on 5644R

[Zarrar]

HI everyone!

                  I have generated Two CWS on two 5644rR which  are syncronized and delay can be controlled usinf phase offset. What I want is that I want to generare the Two CWS in pulsed like it should be on for 20 ms and off means no rf out at 10 ms so like Radar pulses. Please give me solution how to implement this kind of funcionality. Control of ON time and OFF time is user specific. 

I also want to let you know that when I try to change RF at RUN time error comes for synchronization VI of Two CWS. For Run Time RF changing what should I do for TWO cws.

[Case_in_Point]

Hello Zarrar,

There would definitely be numerous ways to cause your output to pulse on and off. What software are you using for your programming? Assuming you're using the LabVIEW RFSG driver, the simplest (and least deterministic) way would be to just use the Configure Output Enabled VI and alternate between True and False for Output Enabled to turn the output on and off as needed.

You could also make one long waveform that just alternates between your desired pulse and stretches of 0, so you go back and forth between outputting your tone and "outputting" nothing. Or you could use the Configuration List feature and make a simple list of your desired tone and a 0 power signal. Set the list to repeat, specify how much time to dwell on each output (your desired tone and nothing) and let it run. There are a few Configuration List examples included in the driver, if you open Example Finder and go to Hardware I/O >> Modular Instruments >> NI-RFSG >> Configuration List.

Could you also elaborate on what you mean by changing RF at run time? What error are you getting, and what exactly are you trying to change? 

Cason

NI AE

[Zarrar]

I am trying to change RF at RUN TIME in  Syncronized CWs which is example provided by Micheal. I am using is putting phase offset on each run. I want to change VI in order to put sweep between 1GHZ TO 2GHZ wih 1000 steps. I saw RF Sweep example which is for a single CW. I want to do this in example attached in which LO are shared also in TWO 5644R. How should this task will be accomplished. I also want to generate trigger on PFIO out.

[Case_in_Point]

I have no idea what you mean by "change RF at run time." What are you trying to change? Are you talking about changing what signal you're outputting, or changing a frequency, or something else? What are you not able to do right now? Are you getting an error of some kind, or are you getting an output signal that doesn't match your requirements? If you can elaborate more on precisely what you're after and what's you're getting right now people will be much more capably of helping out.

Generating a trigger on a PFI line should be quite easy. Are you trying to export the start trigger, from the beginning of the RF generation, or are you trying to generate a trigger at a different point in time?

Cason

NI Applications Engr.

[Zarrar]

Here I have attached a VI ,which is made after doing changing in 5644R syncronization VI and RF frequency list configuration VI. Currently, one RF is getting sweep but other is not negative sweeping like it going down. One power level is fine but other is low.I have to generate CWS on Same power but differnet RF. Please see this VI and let me know where should I do changes in order to implement RF configuration list mode with Syncronized CWS having 75ps delay.

[Case_in_Point]

Hi Zarrar,

The VI you've posted looks like it should synchronize a CW generation across multiple devices. I'm not seeing how that VI is executing any kind of sweep; it looks like it's just configuring the center, synchronizing the output, and then generating continuously while giving you the ability to change the output power. What kind of output are you getting? Could you post screenshots of some kind showing your output, and also describe specifically what kind of output you want to get? It sounds like you're describing having two separate generators output a sweep, one from a low to high frequency while the other sweeps from a high to low.

Currently what's confusing you about the configuration list feature? I had suggested a few examples to look at, but it doesn't look like this code you've posted has any of the list mode code included.

Regards,

Cason

NI Applications Engr.

[Zarrar]

Hi Cason,

              I have posted this VI in which as you can see I have used configuration list feature in order to put RF sweep and Syncronization in Two CWS. I want to know If I have to put RF sweep like from 1GHZ to 6GHz in two CWS having FIX delay of 75ps How should I achieve it? should I have to change upconvertor frequency or not? If yes what should be upconvertor frequency. Keeping delay constantI am trying to take help for many days but yet no one has correct answer.....Please reply with any solution. I want to generate two cws having 75ps delay and want tp put RF sweep like in example which is done for one RFout. I have attached example also

[Case_in_Point]

Zarrar,

I can say for sure that to sweep from 1 GHz to 6 GHz will absolutely require retuning your center frequency. Looking at your code, it looks like what you're writing to the Upconverter frequency property is reasonable, but I can't tell for certain since there's a missing subVI. Just to explain about that property, it's not necessary for the configuration list mode. Normally RFSG will retune the center with each new configuration step. However, if you write the center frequencies into the upconverter property, it will optimize in-band retuning as much as possible. So if one step is going from 1 GHz to 1.05 GHz, ideally you don't want to retune if you don't have to. When you next step from 1.05 to 1.1 GHz, now you've moved 100 MHz in totality, which will naturally require a retune for the 5644. Using the upconverter frequency property should minimize retuning as much as possible.

As far as what you change the upconverter frequency to, it depends entirely on your step size. If you're sweeping from 1 GHz to 6 GHz in 100 MHz steps, for instance, then you're going to have to retune every time anyways so don't bother. It's only if your steps are smaller than the 80 MHz bandwidth that you can benefit from that property.

It's also unclear what you mean by a 75 ps delay between your two tones. Is that the time between each step, so one is always one step behind the other? So CW1 is at 1.1 GHz and CW2 is at 1.0 GHz, then 75 ps later CW1 is at 1.2 GHz and CW2 is at 1.1 GHz?