Filtering a RF Signal in Labview

I created a signal in labview using I and Q data from separate text files. I need to add in a transmit filter but everything I try does not work. I am using a PXI 1045 with signal generation upconversion and downconversion capabilities. Does anyone have a vi that shows how to filter a signal created from I and Q data files.
Thanks

Hi jstarustka,
The solution to your problem lies with the Modulation Toolkit. The Modulation Toolkit contains tools for working with complex I and Q signals in software, including pulse-shaping and matched filters for modulation and demodulation applications, respectively.\
I'm attaching a screenshot of the MT Generate Filter Coefficients VI in LabVIEW, showing QAM Root Raised Cosine filter generation.
Here is a link to the Modulation Toolkit product page on National Instruments' website:
http://sine.ni.com/nips/cds/view/p/lang/en/nid/12855
Regards,
Andy Hinde
National Instruments
Attachments:
Modulation Toolkit.JPG ‏14 KB

Similar Messages

Want to input interference signal in labview + perform bandpass filtering/demodulation

Hello to whom it may concern,
I have a fiber-based OCT system linked to a Tektronix TDS 2024B digital oscilloscope, with which is showing the interference fringes of the low-coherence lightsource. The signal is linked to the computer using the NI DAQ Board USB-6251. I want to input the fringes using Labview and not only that, but to perform a high-pass filter command, along with an active full-wave rectifier and a lowpass filter to see the group velocity of the interference pulse. Now I am new to using Labview so this question be a little elementary, however I am struggling here. Any helps are greatly appreciated.

Hello!
Basically you will need to measure a signal in LabVIEW and then perform some processing on it. First I suggest, if you haven’t, getting familiar to LabVIEW and DAQmx that are basically what you will use for acquisition. For processing, you might find useful some toolkits we have for filters and signal processing. I’m linking information on these subjects, if you wish, you can download them in evaluation mode and take a look at the examples on how to use those functions.
NI LabVIEW Digital Filter Design Toolkit
NI LabVIEW Advanced Signal Processing Toolkit
Getting Started with NI-DAQmx
Getting Started with LabVIEW
Regards,
Alina M

How can I get the DC component out of a signal in Labview

I was trying to get the DC component of a signal using lowpass filters provided by Labview(professional version 8.2). I used the FIR windowed filter but I couldn't get what I expected. The sample rate is 20* the maxium signal frequency. I simulated a function like y= 10(volt)+Sin(2*pi*f*t+phase). If I set the low cutoff to be less than the frequency f, shouldn't I get 10 volt as the outputs? See the attachment for vi. Thanks!
Attachments:
Simulation03062008.vi ‏53 KB

Hi,
You can use the filters located in Signal Processing -> Filters, then create a constant from the "filter type" input and select "Lowpass". There is also an AC & DC estimator vi, located in: Signal Processing -> Measurement.
You may also use something like "running mean" filter. To do it you need to calculate the mean value in some range around every point. It will decrease the value of the noise and will give you the dc value (or slow changing part) of your signal. Finally you can use median filter.
Benjamin R.
R&D Software Development Manager
http://www.fluigent.com/
Attachments:
meanrun.vi ‏21 KB

Using excel to generate signal in labview

Hi there
I am having a trouble in generating a signal in labview using excel and then plotting it as waveform.
In excel file, I have 2199 rows and 9 columns with time in second and I want to plot time against other columns except column 1. In rows, I have text in first one.
Any help much appreciated.
Thanks
Solved!
Go to Solution.
Attachments:
Data File Modified.xlsx ‏554 KB

smercurio_fc wrote:
You haven't shown us any code, so we don't know which columns you're using. However, you should be aware that Excel and LabVIEW use different epochs: https://decibel.ni.com/content/docs/DOC-8733.
Thanks smercurio the link appears to be broken so anyone who tries just remove the "." at the end.
The best solution is the one you find it by yourself

I am trying to log data from 4 voltage input signal using labview, but when i use DAQ assistant i am able to log data from one signal at a time only.

I am trying to log data from 4 voltage input signal using labview, but when i use DAQ assiatant i am able to log data from one signal at a time only.I am trying to get all 4 input data to logged in a single file againt time. I am new to Labview, I need to sample this data within a couple of days can someone help please.

Naveen
Check out the info in the Analog Input section of the document linked below. (Ignore the part about Global Channels.) In Figure 5, notice that you can select multiple channels while holding <Ctrl> or <Shift>.
Developer Zone Tutorial: NI-DAQmx Express VI Tutorial
Kyle B | Product Support Engineer | ni.com/support

How to make PWM signals In Labview 7.1

How to make PWM signals In Labview 7.1, Could someone give me .vi for examples. Thank you.

There is a shipping example that shows PWM if you have installed
NI-DAQmx. You can open the example through Help >> Find
Examples >> Hardware Input and Output >> DAQmx >>
Control >> General PWM-Counter Output VI.
Good luck!
Micaela N
National Instruments

Simulate ECG signal in LABVIEW

Hi,
I am a new user of LABVIEW. I want to get ECG Signal from LABVIEW and give it to MULTISIM, where I am creating a SPICE netlist for a filter design.
I have installed LABVIEW, MULTISIM and the Biomedical Toolkit. I also have installed Advanced Signal Processing Toolkit and Digital filter design toolkit.
In the MULTISIM, under Instruments I am not able to see the LABVIEW icon. I am using 2013 version with windows 7. Can anyone please help me out?
Thanks,
Deepa

I use this occasionally so I don't have to worry with LabVIEW while in Multisim.
Good luck.
TR
><><><><><><
Tommy R.
><><><><><><
Attachments:
ECGsignal_1sec_1kHz.zip ‏39 KB

Catching POSIX signals with labview

Hi,
is there a way to catch POSIX signals with LabVIEW.
Im building a LabVIEW Client (Linux AND Windows) to a non LV Server
(Linux, C). All works fine except the catching of the interrupts sent
by the server. The server sends interupts using POSIX signals. For full
functionality I should be able to catch this signals. How can I do
that?
Thanks for your help
Ulrich

Interesting project!
I looks like a few people have tackled decoding the data (both WWV and WWVB) using reciever modules that create a digital signal stream and Arduinos to decode the data.
How about GPS based time? Here is reciever/decoder module that provides a decoded serial data stream:
http://www.parallax.com/Portals/0/Downloads/docs/prod/acc/GPSManualV1.1.pdf
-AK2DM
~~~~~~~~~~~~~~~~~~~~~~~~~~
"It’s the questions that drive us.”
~~~~~~~~~~~~~~~~~~~~~~~~~~

How come I do not get the same signal in LabView??

Basically, I want to reproduce a force curve on Nanoscope program into Labview, since labview has faster aquisition rate.
Anyways, since there are two voltage signals, I wanted to plot XY graph of them. However, I get a wierd signal that is not quite close to what I am supposed to get.
I am thinking about maybe there are some noise problem, or there is a little delay in getting the two signals (ex, the two signal is not in sync)
If anyone has similar experience or tried to the same experiment, please let me know. It would be really helpful.
Thanks.
Attachments:
ScreenShot048.gif ‏3 KB
ScreenShot016.gif ‏53 KB

Hi,
I just wanted to filter the y signal. Tried using smooth filtering, but didn't work well. Now, I am trying the Lowpass with 30Hz cutoff frequency; however, when I run my VI, it give me this error message
"Analysis: The following conditions must be met: 0 < f_low <= f_high <= fs/2."
If I can get better signal for y axis, I might get a better graph, as you said.
Thanks and if you know what that error is for and what to do to make it run, please let me know.
Mike.
Attachments:
ScreenShot002.gif ‏26 KB
ScreenShot004.gif ‏25 KB
ScreenShot005.gif ‏43 KB

How to reset a counter on external signal in LabView?

Hallo there!
I am using LabView v 8.5 and the NI USB-6211 to acquire signals, among them are the following:
1) angular pulses from a rotary encoder
2) a reference pulse for the rotary encoder witch will give a pulse on a specific position of the movement for every rotation
3) value from a pressure sensor
What I am trying to do is to create a pressure/volume diagram based on the pressure and volume inside a cylinder of an IC engine. To do this, I will need the angle of the engines crankshaft to calculate the pistons position in the cylinder. This way I can calculate the volume and put it in a xy graph to represent the volume (x-axis) and the pressure(y-axis).
I am using clk0 to count the pulses from the angular encoder, and this works great. However I now need the reference pulse to somehow reset the count at the precise time it goes high in order to precisely know the angular position.
How can I do this? And how precise will this be? And will I need any kind of synchronization with my pressure measurements? If so, how?
The relevant part of the program I am working on resembles the Count Digital Events with reset.vi 33 KB as found in this thread. However, I don't know how to get the reference pulse to reset as the stop button is. How can I do this?
In addition: the fast pulses of the angular encoder = 0-> ~10kHz. I seem to lose information if I use the basic level trigger detection.vi when I put this signal on an analog port.
-J

Hi Nick,
If you have an X Series or 2nd Generation cDAQ chassis (basically any cDAQ chassis except for the 9172 or 916x sleeves) then you can implement:
1,2,3,4,5,6,7,8,9,10,(reset),1,2,3,4,5,6,7,8,9,10,(reset),1,2...
You would have to configure an Edge Count Task, set the initial value to 232 - 6 (such that the 6th count causes the counter to rollover, which generates a pulse on the counter output), and enable the count reset using your external signal:
The count reset isn't currently available for other DAQ devices, but I believe it should be available on M Series (62xx) and TIO (660x, 6624) with a future driver release (some time in 2012).
If you don't have an X Series (or gen II cDAQ), don't despair. On other hardware, you can get close to the previous behavior with a counter output task, with the exception that the "reset" signal would only be detected after the 2nd tick after your pulse is output. Also, the reset signal would have to occur at the beginning to arm the counter the first time.
Or, you can get the 3rd behavior that you asked for by doing a continuous counter output task with the external signal as the source of the timebase ticks. For example:
1,2,3,4,5,6,7,8,9,1,2,3,4,5,6,7,8,9
In toggle mode (default):
6 ticks of initial delay, 2 ticks high, 7 ticks low, 2 ticks high, 7 ticks low, ... etc.
In pulse mode:
6 ticks of initial delay, 9 ticks high, 9 ticks low, 9 ticks high, 9 ticks low, ... etc.
See here for an overview of the difference of the two modes. Basically, pulse mode will emit a short pulse when TC is reached, and toggle mode will toggle the state of the counter. You can't have less than 2 ticks as a high time, low time, or initial delay.
Best Regards,
John Passiak

When measuring 6 voltage signals in labview I found that there was a difference in voltage signals in my program but not in the test panel. The test panel is correct. What is wrong with my program?

My labview program is not displaying equivelent voltages, but labview test panel is. So the computer is seeing the correct signals. My program is displaying a small difference in 3 out of 6 channels. All channels should be equal.

G'Day Pops,
You haven't really given us enough to go on - could you please post your VI so we can have a look at it?
cheers,
Christopher
Christopher G. Relf
Certified LabVIEW Developer
[email protected]
Int'l Voicemail & Fax: +61 2 8080 8132
Aust Voicemail & Fax: (02) 8080 8132
EULA
1) This is a private email, and although the views expressed within it may not be purely my own, unless specifically referenced I do not suggest they are necessarily associated with anyone else including, but not limited to, my employer(s).
2) This email has NOT been scanned for virii - attached file(s), if any, are provided as is. By copying, detaching and/or opening attached files, you agree to indemnify the sender of such responsibility.
3) B
ecause e-mail can be altered electronically, the integrity of this communication cannot be guaranteed.
Copyright © 2004-2015 Christopher G. Relf. Some Rights Reserved. This posting is licensed under a Creative Commons Attribution 2.5 License.

Generating 0 and 1 signal using labview Daq card

Hello,
I’m working on a Project on the On/Off control of a pneumatic cylinder via a 5/2 solenoid valve.
On State: Valve O/P 1 pushes cylinder İ/P 1
                Value O/P vents air.
Off State: Valve O/P 2 pushes cylinder İ/P 2
                   Value O/P 1 vents air.
By this way we aim to move the clinder forward and back.
We use Labview 9.0. I did not work on pneumatic system before,
I will be happy if you could help me about 2 points.
1)      How can we enable the On/Off switching between the 2 O/P’s of the solenoid ?
2)      How can we enable the timing between On and Off States. ( On: 0-5 seconds Off: 0-5 seconds )
Do we need special code for Standard labview blocks will be OK ?
Thanks a lot.

The digital out are a great place to start, however they are signal lines which means they don't drive a lot of current (~1mA). If your device isn't setup to accept digital signals you may have to use an external transistor to step up your amperage. See the link on here to get started
Labview can provide all the timing you need. I would search through the shipping examples (Help >> Find Examples) for digital output examples, there should be a bunch and one will probably work for you with just a little modification.
Jesse Dennis
Design Engineer
Erdos Miller

How do you calculate the instantaneous frequency of a signal in LabView?

I'm working with neural signals that can be described as a nonlinear series of action potentials. I've already calculated the spike density function (spikes per second against time) and was wondering if this is the instantaneous frequency? If not, could someone please describe how to calculate instantaneous frequency in LabView without the advanced signal processing toolkit.

Instantaneous frequency is a term which seems to be context-sensitive. In other words the definition can vary depending upon the application.
Spikes per second would be more of an average frequency (averaged over one second).
For your neural signals I would think that an instantaneous frequency would be defined as the reciprocal of the time between successive spikes. Since you can count spikes, you should be able to determine the time of each spike.
Lynn

General Purpose Signaling with LabVIEW 7

I need LabVIEW 7 to handle the following situation. I have 3 concurrent VI's - A, B and C. A and B want to hear different sets of "signals" from C. Specifically, A wants to hear only signals 2, 4 and 6 while B wants to hear only signals 1, 3 and 5. These sets are arbitrary and NOT known at compile-time. Furthermore, A and B can listen for their signals one or more at a time, service any received signals, and loop to listen for one or more additional signals. Neither A or B want to poll and both must hear all their respective signals regardless of the order they are generated by C and regardless of the order A and B choose to listen for them.
LabVIEW 7 Notifiers almost solve this problem except for the timestamp feature that
prevents notifications from being received out of order. For example, if C sends notifier 1 to B while B is waiting on notifier 3, and then C sends notifier 3, notifier 1 will NEVER be heard by B (unless, of course, B has a Wait on Notification icon on his diagram for each possible notification he is to receive).
User defined events look very promising for solving this problem but I am not sure how to get the event structure to hear different sets of events (not known until run-time) at different times. For example, A may first want to listen for signals 2 and 4, say with a timeout, and then listen for signals 4 and 6.
Any insights into solving this problem would be appreciated.
W. Brown

Attached is a workaround that answers this problem.
W. Brown
Attachments:
Notifier_Problem.llb ‏91 KB

Is there a way to amplify a low DC signal in Labview?

I am looking for a way to amplify a signal of only a few millivolts and then read this amplified signal. Is there a way to do this in Labview, using a 6025E DAQ?

Hi,
The smallest signal your board can amplify is +-50mV. The board had an ADC with several gains (0.5, 1, 10, 100). With a gain of 100, the smallest signal it can resolve is +-50mV. To resolve an input less than this, you can use a signal conditioning module such as an SCXI-1100, which can input from +-2.5mV. You can find more information on our different SCXI modules and options at http://sine.ni.com/apps/we/nioc.vp?cid=3002〈=US
Hope this helps!
George
Applications Engineering

Filtering a RF Signal in Labview

Similar Messages

Maybe you are looking for