USRP as a function generator

Is it possible to use USRP as a function generator ? If yes can any one please provide me the sample VI. I want to generate Sine wave, Square wave, Triangular wave etc. Also I need the option to vary Frequency and Voltage. Is it possible to implement Function Generator mechanism on USRP using LabView? Please guide.

Hello josephkirmani,
When you say you want to use the USRP as a function generator, do you mean you want to be able to output and send a function over a certain RF carrier frequency? If so, I think you might find the example below helpful, it uses frequency modulation (must have the modulation toolkit installed) in order to embed a signal of your choosing (square, sine, triangle…) into a FM modulated waveform to be transmitted over a specified carrier frequency. Just switch out the Basic Multi Tone.vi for your preferred function from the Waveform Generation Palette. If that’s not what you are trying to do, please clarify.
Example: https://decibel.ni.com/content/docs/DOC-24206
Matthew R.
Applications Engineer
National Instruments

Similar Messages

I want to use the Function Generator VI to send command signals through the NI 7344 motion controller. This will be a closed loop servo valve system. I want to be able to change from say a square wave to a sine wave on the fly. Idea's?

I am going to run tests that require an actuator to move using various types of arbitrary waveforms such as sine or square. The NI 7344 is hooked to the UMI that is going through a driver for a servo valve. The loop is analog and it is closed. I have played with some of the examples but can't get it to work. I have used the function generator VI to generate a signal but I think I am using the wrong input VI to the motion control board. When I use what I have it moves the servo and then stops. It doesn't continually generate the signal.
I would love to use the controls on the function generator vi to control frequency and amplitude ect. Any help or pointer would be helpful. Thank you in advance.

Hello,
I'm not clear on exactly how you want to use the generated data but I'm assuming they will be used as your target points.
There's a built-in example for motion called 'One-Axis Contour Move.vi'. This example demonstrates how to provide your target points as 1-D array. All you need to do is to replace the input array with the output of the function generator. In order to have it run continuously, use a while loop. You can further program your application so that it'll change the waveform on the fly by monitoring the user interface but this might be little little tricky as you will need to reset the move and load the new generated points while keeping track of your current position.
I hope this helps. Let me know if you have further questions regarding this
application.
Best regards,
Yusuf C.
Applications Engineering
National Instruments

How to read data from a GPIB when sending a function generator command

I'm using Visual C++ with the ComponentWork ActiveX and I'm tring to plot a
CWGraph using the data coming from a GPIB device. When I write command such
as "*IDN?" to the GPIB device, everythings if fine and I can read what the
GPIB device return me. But when I send a command like "SOUR:FUNC SIN;SENS
DATA?", the writing seems to be okay, but when I try to read the data, I
alway get a "Timeout expired before operation completed" error message. I
have tried with the CWGPIB and with the CWVISA but the result are the same
with both.
My reading code looks like this:
COleVariant vReadBuffer;
vReadBuffer = m_VISA.Read( COleVariant( (short) 2000 ) );
and it work fi
ne for "*IDN?" or for multimeters command.
I want to know how I must read the data for function generator commands.
Thank alot

It sounds like your device is not accepting that command string as valid. The string you listed above is probably missing a colon between SENS and DATA. "SOUR:FUNC SIN;SENSATA" Try sending this string in Measurement & Automation Explorer to the instrument first to make sure it is working.
Best Regards,
Chris Matthews
Measurement Studio Support Manager

Oscillioscope and function generator

Hello,
How difficult is it too create a virtual oscillioscope and a function generator that outputs through ethernet or usb to some NI module (Chassis, analog, digital etc) that will send signals to a circuit? So, basically instead of having an oscillioscope or a function generator, you create a virtual one on labview and can send signals to the circuit in the real world. Is that even possible? And if it is how hard do you think the task would be?
Thanks in advance for all the input!

So I happen to have a myDAQ at home and I thought I would try to use it as a scope. Checkout this video after a 1:30 for a demo of some of this software. The software it comes with has all the test panels for various instruments for scopes, DMM, function generator, aritrary waveform generator and several others. The hardware also appears as a normal DAQmx device if you so choose to write your own software.
Honestly it isn't half bad. Maybe it's because the software mirrors normal scope functionality but I was able to see my signal and understand it, when I had no other hardware that was capable. It won't replace a desktop scope but it's what I had on hand.
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How can i add one wave in in our Function generator example?

how can i add one anotehr wave in our function generator example. i want to use superposition and add one more wave to our first wave in function generator and see the result.thanks

Hi hood1,
2 options:
1) You can add many waveforms by combining them into one Array.
2) Use the Waveforms tools, that give you many option for adding waveforms. one after the seconed or adding the Y array of a waveform to other Y array of second wave form, and so on...
Hope it Helps...

Elvis: Is It possible to use the Function Generator and the Oscilloscope simultaneously?

Hi,
We are using the NI Elvis to output a function or a sine wave at a certain frequency and using the oscilloscope on the same board/elvis to read a modified signal. Is this possible? Can we use both the Function Generator and the oscilloscope at the same time? Please help. The oscilloscope would be reading signal from an accelerometer. Thank you in advance. We have no VI as we do not know which to use and if they are possible.

Hi,
There is no problem using the Function Generator and Oscilloscope
at the same time with NI ELVIS. Using the NI ELVIS soft front panels (Start
>> Programs >> National Instruments >> NI ELVIS 3.0 >>
NI ELVIS – see picture attached –‘NI ELVIS soft front panels.JPG’), you can choose
to open more than one instrument at a time. We do this by opening one
instrument, allowing it to begin, and then opening another. We can also program
in LabVIEW using more than one instrument at a time by placing down multiple
Express VI’s taken from the NI ELVIS pallet on the block diagram (see picture
attached – ‘ELVIS Express VI's (LabVIEW).JPG’). One note when doing this,
please see KB 41ODPHX1
for an example of how to program in parallel. If you do not wire the ‘stop’
terminal of the express VI’s, you will get the error described.
David L.
Systems Engineering
National Instruments
Attachments:
ELVIS Express VI's (LabVIEW).JPG ‏74 KB
NI ELVIS soft front panels.JPG ‏56 KB

What is the internal impedance of the NI ELVIS Function Generator?

Does anyone know the load impedance of the function generator? I'm wondering how much it may be tainting the results of Tau for my RC circuit. Thanks.

Impact -
With the NI ELVIS Function Generator, the output impedence is spec'ed
at 50 Ω guaranteed. You can find the block diagram from the
Function Generator on page A-6 and C-6 (Appendix C: Theory of
Operation) of the NI ELVIS User Manual.
NI Educational Laboratory Virtual Instrumentation Suite (NI ELVIS) User Manual - http://digital.ni.com/manuals.nsf/websearch/11E6BA4103D9ADD086257103005C97E0
Good luck with your application!
Mark Walters
Application Engineer

How to write a function generator

How to write a function generator from labview and using PCI-MIO-16

Hallo, [email protected],
Du (x) meintest am 27.07.01 zum Thema How to write a function generator:
> How to write a function generator from labview and using PCI-MIO-16
Look to the examples - there are many VIs with that function.
Viele Gruesse!
Helmut

Create a melody with Labview/ Function Generator

Hi (first sorry for poor english, not my native language)
I have a project at school which is creating a melody using Labview and a function generator. I've worked on it for hours now and i still can't get through it.
I joined the vi file with my post so you can get a look at what i've done so far.
First, i do'nt know which loop i have to use (u'll understand soon enough if u just take a look at the vi file), the problem is that i want to create 4 arrays using 2 text files.
The first one is used as a reference : exemple the frequency to play an A is 440Hz, so my first text file looks like that :
A 440
B 493
the second one is my melody, which includes the notes and the tempo (in ms)
, so it's like :
B 1000
C 1500
I used the first two loops to seperate each string lines of my files so I have at the end 4 different arrays. One containing the note's references, one containing the frequency, one containing my melody's notes and one containing the duration of each notes.
The problem is that when I use a while loop, it seems that my arrays are not containing every elements it should, it only has the last one. Just try to run the vi file.
Could anyone give me some help ? Don't hesitate to ask more questions if u didn't fully understand my problem !
Thx
Attachments:
PR.vi ‏19 KB

Hi claudeuntel,
Your array contains just the last note because at each for loop iteration a new table is created.
You have to send the table you created at one iteration to the next one.
To do this you can use shift register.
I didn't have tested the VI below but it should looks like that.
Valentin
Valentin
Certified TestStand Architect
Certified LabVIEW Developer
National Instruments France
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VIs for Agilent 33250A (function generator) and SR-844 (lock-in)

I am new to Labview. I was unable to find VIs for Agilent 33250A (function generator) and SR-844 (lock-in). Can someone help me find these?
Solved!
Go to Solution.

What did you actually search for? I just went to the Instrument Driver Network, entered '33250A', found it's driver, entered '844', and also found it's driver. I did not try this from the Tools menu in LabVIEW but it should also have found them.

Proportional controller connected to a function generator

Hi....
We'd like to connect some output from a proportional controller to a function generator which
produces a square pulse with variable duty cycle.
The question is what proportional controller to use here and if there is any examples related?
And how to produce this square pulse with a high frequency, while some controllers do not support
any thing more than 1kHz? In addition, if it exceeded this, something wrong happens to the output and disappears?
Thanks in advance
Ray

Ray,
Please be more specific in your description. Proportional controllers usually do not connect to function generators so it is not clear exactly what you are trying to accomplish.
Which parts of your system are hardware and what kind? Which are implemented in LV (which version)? What are the inputs and outputs to both the hardware and software? What frequency range do you need? If you have specific problems with a part of your LV program, posting an example showing the problem is very helpful.
When you say the output disappears, do you mean that the pulses stop? That may simply indicate a 0% or 100% duty cycle.
Many inidviduals with a wide range of experience monitor this forum and will try to help if we understand what you are trying to do.
Lynn

Sending .arb files to function generator

Hi
i am very fresh to labview programming.
I have created some waveforms using HP BenchLink software(and saved in .arb file format). Can i send these wave forms to a function generater through Labview program . if possible   how can i do that
Thanks
jith

Hi
Yes i have downloaded the driver ag3xxx and installed . and   also got some advise from [email protected]
Their comments follows .
                Yes you can read the values from the .arb file into LabVIEW and store
the values in 1D array or text file and then send it to the function
generator you are using.
Basically you would have to use APIs such as read from binary
file(there are examples present in LABVIEW example finder which shows an
example of how you could read a binary file.) After reading from the file
you could store its values in an array or a text file and the read from
this array and send the data to the function generator you are using. If
you are using a function generator which is not made by National
instruments you have to install the device drivers for that instrument fro
LABVIEW, you could install them from www.ni.com/idnet.
             i have used some eg: programmes   given in LV to read binary files .
             The function name is "read binary files vi " . the out put of "read binary files vi "
             is data . I am trying to store this data in an array , but   got stucked , in finding
             a sutable function to send this array valuse to the function generator. Can i send
              the array out put directly to a FG ?
Thanks
jith

DC offset problems in NI-5401 function generator card

When i give a Dc offset of 1 Volt the output of my function generator reads 1.97v. what is the reason behind this,why is it so what setting have to be made so as to get the dc ofset only when no ac signal is given.

Hi. The NI 5401?s output voltage is specified in terms of 50 ohms. This means for a 50 ohm load, you should see 1.0 Volts for a 1.0 Volt setting when the load is 50 ohms. For an other than 50 ohm load, there is a voltage divider action that takes place, where the voltage will vary up to double the size for a high impedance load, such as most default oscilloscope settings. The Connecting Signals>>ARB Connector section of Chapter 1 of the NI 5401 user manual describes this in further detail.
To generate just a DC voltage level, there is an option for DC as the Waveform to use when programming the device. The LabVIEW niFgen Function Generator Example shows this on the front panel. If you are using the Sources Soft Front Panel, when the Standard Function Output is se
lected, there is a DC Voltage level selection button available to be selected to generate a DC voltage.

Labview 6 arbitrary function generator file format?

Hi,
I have old hardware (e.g. DAQcard1200) which I have to use with old versions of Labview (4 or 6) (as they run on "old" hardware - Pentium1 embedded boards with Win98 etc.). With Labview 8 I can load a file in .lvm format and use it as output for A0. But how is this with the "arbitrary function generator" from Labview 6 (benchtop.llb)? I constructed an arbitrary function manually within the vi and saved it to a file, but its format does not make sense - only "strange" characters are displayed, like dŸ¾ “£¾ˆt÷¾ VJ¾– ¾ ñ¾£úD¾ªÛ˜¾±¼ë¾¸ž, if I open the file with an editor...
Thanks!!
;-) Torsten

I don't have LabVIEW 6.1, but if the example hasn't changed, then that example writes out a binary file, which is why you get all those "strange" characters. The file should be an array of SGL values. Thus, you can read it into LabVIEW using the Read From Binary File, and wiring an SGL constant to the "data type" input.
Attachments:
Example_VI_BD6.png ‏1 KB

Problems with the Stanford Reseach Systems DS345 Function Generator

I'm writing a labview program that will allow operation of the Stanford Reseach Systems DS345 Function Generator. The problem that I'm having is in the amplitude calculation. The way the driver finds the amplitude is by recieving an array of what are essentially y-coordiantes (on a cartesian graph system), finding the max and min of the array, and subtracting them.
This is where the problem lies. I've designed my program so I can type in an equation, see the graph of this equation, and send the y values into a the subvi provided by the driver. This subvi is the one that finds the amplitude...etc and sends it to the oscilliscope. However, when I use a formula for something as simple as sin(x), it caclulates the amplitude as 2. This is because the max/min values of sin(x) are 1 and -1. So the function generator reads in an amplitude of 2. This amplitude of 2 results in a sine wave that oscillates between 2 and -2. Obviously, this is not what I'm looking for. I know by dividing the sine wave coordiantes by 2, or just using the max/min value to be sent to the function generator as the amplitude will work in this case, but not for all cases (ex: sin(x)*e^(-3x). I'd appreciate any suggestions on how to fix this amplitude problem for all cases.
In addition to having this sine function, I wrote a subvi that essentially generates a series of pulses depending on the user preferences. It's relativly complicated to explain how it works, but it just sends an array of y-coordinates (similar to above, and they are sent to the same subvi to be sent to the function generator). This array is the one that truly puzzles me.
For example, I have a single pulse, with height 5. The y array is 10 places big. At index 0 to 3, the y value is 0. At 4 to 6, the value is 5. And from index 7 to 9, the index is zero again (Imagine a pulse "_|-|_" , it may help understand this).
I send this array of 10 places to the same subvi as the one described in the sine function earlier. I would expect the amplitude to go in as five (max - min), and it does. However, when determining the actual value from the oscilliscope, it turns out to be 10.8 peak to peak voltage. The values range from -.8 volts to 10 volts. I can't imagine why they do not range from 0 to five as specified in the array which is sent.
If anyone has any answers, suggestions or questions concering this description, I would greatly appreciate it. Feel free to post answers or email me at: [email protected]
I'll be more than happy to post the files if someone wants to look at them.
Thanks again,
Jim Dalton
North American Lighting
[email protected]

I am taking these measurments using the measurment and automation explorer test function. I set my range on all channels to 0-8khz and Have been inputing no more than 8khz. What leads me to believe I have a software or config problem is that I sent in a module to NI for repair and this is the brand new one they sent me back. While testing this module, I also have a 1102 module and 1124 module on the scxi-1000 chasis and both of those are working as specified. I also moved the 1126 module to slot 1 and ran it that way as well when I replaced the chasis.

USRP as a function generator

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