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5421/22 synchronization

Hi, I'd like to phase lock two AWGs (5421, 5422) together in order to generate a pair of 10MHz phase locked sinewaves of the same amplitute but with a seperate DC offset.  The only sync information I can find is for the AWG functions and not the higher freq standard application. 

Anyone know a how-to on this ?.

Thanks.
Message 1 of 13
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Hi Haket,

If your cards are PXI, than the two AWG’s can have synchronized clocks by using NI-TCLK. I have linked some great explanations about NI-TCLK below. If you are using LabVIEW, examples using NI-TCLK can be found here: Help >> Find Examples… >> Hardware Input and Output >> Modular Instruments >> NI-FGEN >> Synchronization.

Using NI-TClk to Synchronize Signal Generators

National Instruments T-Clock Technology for Timing and Synchronization of Modular Instruments

David L.
Systems Engineering
National Instruments
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Message 2 of 13
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Thats great info, thanks a mill David.

                                                               MARK

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I've gotten the two PXI ARBs phase locked now, but I see a 30-35deg phase difference in two sinewaves at 10MHz.  (and 8deg at 5MHz)  Can you advise ?.

The "start phase" input is not accurate enough to compensate for this error.
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Mark,

 

I was unable to produce the same results as you describe – what example program were you running? I used the example ‘niFgen_Arb_Synchronize_Example_(TClk).vi’, and the screenshot below (TCLK Sync.jpg) is my result. I also used the example ‘niFgen_Arb_Synchronize_Sequence_Example_(TClk).vi’, and ‘sine wave Sync.jpg’ was my resulting waveform. Please note that you may have to look closely at the pictures to see both channels, but they are both there.

What device are you using as a scope? (benchtop? NI PXI-?? ) Are the signals generated properly individually? Are you generating the exact same signals? How long have you had these cards, and have they worked properly in the past?

Message Edited by David L. on 04-04-2007 10:48 AM

David L.
Systems Engineering
National Instruments
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Thanks David.  I used those programs you mentioned previously (and get the same results as you), however as I want sinewave frequencies of 10MHz I abandoned them and wrote my own VI (based on the tutorials you supplied previously). 

1.  I dont see how I can increase the frequency output of the ARBs using the (niFgen_Arb_Synchronize_Example_(TClk).vi)   I may have missed it though. 

Because of this I discounted the "ARB" function and focused on the standard function thinking they are generated differently.

2.  I include my VI below.  there are some bells/whistles, just run it and hit GO !.


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Mark,

 

There are a few flaws with your code, which is why it is not operating correctly. The main one is that the while loop is placed around the entire sequence. This starts, initialize, etc…and stops the arbs every iteration.

I have attached an altered example VI (built in LabVIEW 8.2) which outputs sine wave at 10Mhz, with 2 different DC offsets. Please note that the DC offsets are only allowed to be set to ½ of what the gain is.

David L.
Systems Engineering
National Instruments
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Thanks David,  I tried your program and it results in a similar phase difference to mine (see attached plot)

In response to previous questions:

> What device are you using as a scope? (benchtop? NI PXI-?? )

A Tektronics scope TDS5034B, should be well able to capture these signals.  I attached both scope channels to one PXI output first to confirm there is no phase delay caused by the probe/channel itself.


> How long have you had these cards, and have they worked properly in the past?

The PXI-5422 is 12 months old, I've used it infrequently and seemed to be fine, the PXI-5421 is a loaner from one of your NI collegues to me so I can evaluate two ARBs working together prior to purchasing a second 5422.

Could the mix of models be causeing this difference ?.

                                                                                                   MARK
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Mark,

I did some testing using a PXI-1045 chassis with 8106 embedded controller, using a 5421(slot 17), 5422 (slot 11), and digitizing with a 5122(slot 15). I had the 5421 connected to ch0 of 5122, and 5422 connected to ch1 of 5122. With this setup, I could not reproduce the phase shift you are seeing.

 

I would like to ask that you detail your setup for me. What Chassis, cards (all in chassis), location of cards, connections, etc. What version of the driver do you have? (This can be found in Measurement and Automation explorer >> expand the software folder >> click on NI-FGEN, and the version will be on your right) Also, what version of LabVIEW are you using?

Lastly, please try the attached example. I want to see if you are getting the same problem when doing arbitrary waveform generation instead of standard function generation. Please post back with answers and pictures, as it is very helpful to see what you are scoping.

David L.
Systems Engineering
National Instruments
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Hi again,

Thanks for the response, please see my replies below:

>I would like to ask that you detail your setup for me. What Chassis, cards (all in chassis), location of cards, connections, etc.

I'm running a PXI-1045 with the following cards:

Slot
Model
18 Slot PXI Rack
1 PXI-PCI8331 Card + cable for PC to PXI rack.  (PTC)
5 PXI-GPIB GPIB Controller (PXI)
12 PXI-4071 7 1/2 Digit DMM
18 PXI-2532 8x64 crosspoint switch
4 PXI-5122 Digitizer, 14-bit, 100MHz, 2-ch., 32MB mem
2 PXI-5422 Signal Generator / ARB, 32MB mem
3 PXI-6552 * 20 Ch. High Speed Digital waveform/pattern generator100Mhz, 10mV resol., 1Mb mem.
6 PXI-2567 64 Channel relay driver
11 PXI-6723 32 channel DAC output card
10 PXI-6289 Multi-func 48ch I/O & 32ch DAC input card (18bit) &  counters (2)
7 PXI-2593 High Speed 16:1 Mux  (500Mhz BW)
8 PXI-2593 High Speed 16:1 Mux
9 PXI-2593 High Speed 16:1 Mux



>What version of the driver do you have? (This can >be found in Measurement and Automation explorer >> expand the software folder >> click on NI-FGEN, and the version >
>will >be on your right)

Version 2.4.1

>Also, what version of LabVIEW are >you using?
8.20

>Lastly, please try the attached example. I want to see if you are getting the same problem when doing arbitrary waveform generation instead of standard function generation. >Please post back with answers and pictures, as it is very helpful to see what you are scoping.

I ran that VI and here is the plot, the waveforms seem in phase at 1MHz

Regards,

                                                                                 MARK


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