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Swept Sine signal generator

Hi
 
I am looking for an example on how to build a continous output, swept sine signal generator from 0 to 1000 Hz. Can someone help me on this.
 
Thanks
 
Mal
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Message 1 of 19
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Hi,

  what are you using in terms of hardware and software?

MIO board (m-series, e-series etc), analog output board (6711 etc), or high speed arbitrary waveform 5421?

Labview, LabWindows CVI, Signal express visual studio etc? What version?

What driver versions?

For AO at 1MHz, you're going to need something that can generate at atlease 10MHz, just to get 10 points in the waveform cycle.

LabVIEW 6i

http://venus.ni.com/stage/we/niepd_web_display.DISPLAY_EPD4?p_answer=&p_guid=B45EACE3DF3356A4E034080...

LabVIEW 7.1

http://venus.ni.com/stage/we/niepd_web_display.DISPLAY_EPD4?p_answer=&p_guid=F4419DE9B12B3A41E034000...

High speed arb

http://venus.ni.com/stage/we/niepd_web_display.DISPLAY_EPD4?p_answer=&p_guid=B45EACE3EC0956A4E034080...

Signal Express

http://venus.ni.com/stage/we/niepd_web_display.DISPLAY_EPD4?p_answer=&p_guid=F705175389622FEEE034000...

Thanks

Sacha Emery

National Instruments (UK)

 

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Hi

 

Many thanks for your reply. I am using Labview 7.1 and Daqmx 3.1. I am having a M6259 daq card. My requirement is to find the frequency response of a speaker by driving it with a swept sine wave from 0 to 1000 Hz and obtain its' spectrum using a mic and a spectrum analyser. For this I want to drive the speaker with swept sine wave signal genearated by labview. Can you help me on this. The links given didn't open up.

Thanks

 

Mal

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Message 3 of 19
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Hi,

  the maximum analog output update rate on the 6259 is only

1 channel..................................... 2.86 MS/s

2 channels ................................... 2.00 MS/s

3 channels ................................... 1.54 MS/s

4 channels ................................... 1.25 MS/s

1kHz should be fine.
I'm attaching the most relevant source for the swept sine output from the first link.
The chirp generated is actually sent to the internal speaker in the main vi, however you should be able to combine it with a finite waveform analog output example for daqmx (since you have an m-series card) available in your labview example finder. Just note the sampling frequency, and make sure it's atleast 10 times the highest frequency component you want to use.
 
Hope this helps
 
Thanks
Sacha Emery
National Instruments (UK)
 
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Hi

 

Thanks for the reply. I wired a PSD vi to the program to view how the spectrum moves from 0 to 1000 Hz. However I don't see any movement. Can you please see whether there is an ommission on my part.

Many Thanks

Mal

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Hi,
  by only passing the raw values onto the PSD, there's no timing information, and the time domain information might as well be DC.
I've modified the raw values into a time domain signal (which is what the sub vi does).
I've also replaced the speaker output with the daqmx components.
 
Hope this answers your question.
 
Thanks
 
Sacha Emery
National Instruments (UK)
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Hi

 

Many thanks. The programme works fine and I get the varying tone from a speaker connected to my M6259 card. I hope to pick up this tone through a mic and with suitable preamplification connect it back again to the M6259 as an input signal. I hope to see the spectrum of this signal using the PSD vi. To do this should I place a while loop arround it or not?

 

Mal

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Message 7 of 19
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Hi,

  the AI would need starting before the AO, otherwise you'll lose some information.

If you want to do it repetitively putting a while loop around it will leave breaks in the data whilst it reconfigures.

Look at a continuous setup instead, and keep feeding the AO repetitively without reconfigureing after setting up for a continuous AI.

Search for things like simultaneous AI and AO.

Hope that helps

Sacha Emery

National Instruments (UK)

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Hi

How can I make the programme to generate signals beyond 5000 Hz up to 10000 Hz. When I tried this (ie making fend 10000 Hz) the signal increases upto 5000 Hz and reduces back again to zero.

 

Thanks

Mal

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Message 9 of 19
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Hi,

  if you've modified your code, can you please re-post it so I can see how you're approaching this now?

Thanks

Sacha Emery
National Instruments (UK)

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