initiation of an analog signal noise

Here's the idea (the concept is available in commercial software) - to remove the background noise of an audio event, acquire a small sample pre-event, and do a FFT to discover the strength of the signal in multiple bands; It's the characterization of noise. Then set a threshold for each a little higher than the intensity of the noise signal. It is then applied to the 'event' to each frequency band - if the signal for the event does not exceed the threshold of this band, which is not part of the event, but just background noise. This I did, my question is how to better implement the filter in LabVIEW - I think both approaches, (a) filter in the frequency domain (should be easy), but can only be returned in audio in the time domain? or (b) the audio sample run through a series of band pass filter beginning by stripping the lower frequencies and working to the highest and what remains is the audio event with any other deleted. Whoever did this in LabVIEW?

Or of your approaches can be used in principle. In practice you can't get as good performance as you want.

With both methods a few time delay between the audio input and audio output will exist.  How much delay you can tolerate?

(A) to two FFT. One of the pre-event segment. The other is the segment of the event. If the sgements are of different lengths, df will be different and this will make the rest of the complicated treatment. The shorter segment with zeros to fill is the easiest way to match the DSV, but will present amplitude errors. After resetting in the case where the bins below thresholds segment FFT, do the inverse FFT. Be sure to use complex numbers on all frequency domain calculations to avoid losing the key stage information.

(B) you will have to deal with transient responses and delays of the filters. Each filter with different center frequency and bandwidth will have a different response and delay. Compensate for these effects can be very inconvenient.  With continuous data spikes fade, but for your process based on events, it can be a viable solution.

Lynn

Tags: NI Software

Similar Questions

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    Since you have no generator hardware signals of NOR, I'm not sure why you are posting to this Board. Generic questions of LabVIEW. Post to this Board.

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  • Help stairs analog signal

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    Dear Kriváň

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  • Compare two analog signals.

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  • Output of different analog signals through 4 outputs

    Hi all

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  • Problem when the PWM signal combinning and analog signal TOGETHER!

    Hello everyone,

    first I DAQmx 6212, and I need to run the water pump small (9V - 16V) that should be driven by a PWM signal; I also have a motor (5V - 13V) for a water supply which must be controlled by an analog signal and it has built in a force feedback potentiometer, I logged onto this potentiometer correction + 5V the DAQmx and used the output voltage of the third extremety as a value to diagnose to know the position of the engine.

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  • Reading of analog signal using DAQPad-6016

    I'm reading an analog signal using DAQPad-6016.  An entry is on the ground, the other is Vdc.  I can't operate at MAX and I'm confused becaue MAX alone gives me an option for differential reading, but the list of pins give enough information on how to connect in a different way.  Is there a reference as well?

    Hello, Bernadette.

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  • read the analog signal 0-10 volts of NI6123

    I'm reading the analog signal of NI 6123. The range of the analog signal is 0 to 10 volts. This works well when the signal voltage is 0 to 5v (0 ~ 32767). But when the signal is 5 to 10 volts, the value read is always 32767. I also tried the different reading function: DAQmxReadBinaryI32, DAQmxReadBinaryU16, DAQmxReadBinaryU32. The value is identical to DAQmxReadBinaryI16. My OS is windows vista. Here's the part of my codes.

    **************************************************************************************************************************************************************************

    Create analog data tasks.

    DAQmxErrChk (DAQmxCreateTask("",&datHandler));

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    DAQmxErrChk (DAQmxCfgSampClkTiming(datHandler,"",RATE,DAQmx_Val_Rising,DAQmx_Val_ContSamps,RATE*MAXLAS));

    DAQmxErrChk (GetTerminalNameWithDevPrefix(datHandler,"ai/SampleClock",trigName));

    Create counter tasks.

    DAQmxErrChk (DAQmxCreateTask("",&ctrHandler));

    DAQmxErrChk (DAQmxCreateCICountEdgesChan(ctrHandler,"Dev1/ctr1","",DAQmx_Val_Rising,0,DAQmx_Val_ExtControlled));

    DAQmxErrChk (DAQmxCfgSampClkTiming(ctrHandler,trigName,RATE,DAQmx_Val_Rising,DAQmx_Val_ContSamps,RATE));

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    DAQmxErrChk (DAQmxRegisterDoneEvent(datHandler,0,DoneCallback,));

    Start the task.

    DAQmxErrChk (DAQmxStartTask (ctrHandler));

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    write data to the file.

    data.cfile.Write (data.counter, sizeof (int32) * RATE);

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    **************************************************************************************************************************************************************************

    Thanks in advance

    To make sure that your device is working properly, I recommend first to test the entry in measurement and Automation Explorer (MAX) analog.  You can test your device by right clicking on it in the configuration tree and selecting test panels.  See if you acquired signal 0 - 10V as you expect.  The next step would be to try one of the sample programs that perform a task of analog input.  These examples can be found in the start menu > programs > National Instruments > NOR-DAQ > text based code supported.  Try an example that does an analog input continues and double bed (instead of binary data not adjusted).

    Your program looks good at first so I found nothing that stood out.  However, one thing to check is if your function generator (or signal source) expects a 50 ohm or high impedance.  This could cause reflections of the signal and cause the device to possibly read a voltage of half of the desired value.

  • 6033 PCI analog measurement noise

    I want to assure you that I do everything I can to get the best measurement possible

    IM using a SCB-100; I use a card PCI 6033.

    I have connected my analog son

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    My measure is close but there are a few milliamperes noise 4.30 should I get 4.80 on some units

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    I connected a wire to the GND AI for my units I measure power supply ground wire is short less than 10 inches, 16 gauge.

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    This post is also in the forum of Labview, I think it belongs here.

    Kurt,

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    -Christina

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