Active 2nd order analog lowpass filter in a feedthrough module SCC-FT01.

I would like to build an active 2nd order lowpass filter with cutoff frequency of 4000Hz in a feedthrough module SCC-FT01 for antialiasing purposes. Since I am not an electronic expert, I would like some advice on which components I can use (and how I can dimension them) and on how I can connect them on the module board.

Caccia,
I would recommend that you build an external box with your filter in if you require hardware filtering. The feedthrough panel FT01 is just a piece of wire really with connections on each end, so there isn't room to build a filter in there.
Unfortunetly I can't really recommend what components to use, but there are lots of websites and books out there that you could use to help you, none of them specific to NI but that shouldn't matter.
After a quick search on Google I found the following website which seems to have a lot of information.
http://my.integritynet.com.au/purdic/lcfilters.htm
Hope this helps, please post again if you require any further information from me.
Regards,
Peter H
Applications Engineer
National Instruments

Similar Messages

  • Noisy Analogue Signal and Lowpass Filter Questions

    Hi everyone,
    I am getting analogue signals from a strain gauge that are a bit more noisy than I would like... Normally, I jump right in an smooth the signal using a lowpass filter of whatever order gave me the result that was acceptable, without overkill and smootig the signal to nothing... However, I am settingup a new DAQ device and would like to a little more informed about what and how am doing this...
    So, here are my questions:
    1. How do I determine the filter order? I usually use a 2nd order filter for smoothing.. I understand the comncepts of roll-offs and phase delay as they relate to the order numbers... On what basis should I decide which order filter to use for this specific signal?
    2. I am still thinking that using a lowpass filter is the best approach... I assume the lower cutoff freq is in Hz (i.e. 10Hz) and is NOT a normalised freq [i.e. cutoff freq / (sample rate/2)]?.. The default value is 0.125, which seems too low for a Hz value? Also, on what basis should I decide what cutoff freq to use for this specific signal?
    3. I need to synch the filtered strain gauge signal with other, unfiltered signals... But as the filter will add a phase delay it will affect signal synchronisation... I heard somewhere that a 4th order filter is zero-phase, but I can't see how that could be right as the filter only operates in one direction... Any suggestions for what I could do to maximise the timing alignment between the filtered and unfiltered signals?
    All comments welcome!
    Regards,
    Jack

    Jack,
    I was the Instrumentation Engineer at a university for 24 years and worked with several execise physiologists, biologists, and neuroscientists on similar projects.  My group was the "lab/tech staff" you have little of.  There were 3.5 (engineer, 1.5 electronics technicians, and machinist) of us for the entire university.
    OK.  The strain gauge signals probably have no information above a few tens of Hz (hummingbirds) or a few Hz for most larger species.  EMG is usually filtered in the amplifiers to slightly larger bandwidths (few hundred Hz) unless you are trying to see the individual action potentials.  Does the dynamometer have specifications on the bandwidth or sampling rates used?
    Since your bandwidths are realtively low, I suggest that you sample all the analog inputs (and the trigger outputs, if the boards have the capability) from the same clock.  You can later decimate or average data on channels where less data is needed.  Record the trigger signals on an unused analog input if you have one available.  It can be very handy to have the information about when the triggers actually occurred in the same dataset as the response data.
    Delay equalization is a complex topic. Suppose that you are sampling all your channels at 1 kS/s. Suppose you have a 10 Hz low pass filter, 2 pole Butterworth, on a strain gauge channel and a 50 Hz filter, 4 pole, elliptical, on an EMG channel and you want to synchronize the filtered data with some unfiltered channels.  The two filters have very different phase and delay responses over the 0-500 Hz frequency range. To equalize you would need to determine the maximum delay at any frequency in the range for both filters. Then you would need to design THREE all-pass filters. One would have a phase response which compensates the 10 Hz filter. Another would compensate the 50 Hz filter.  These would need to be designed so that the total delays through the low pass plus all-pass filters is the same.  Then you need a third all pass filter with that same total delay to compensate the unfiltered data.  This is may be a non-trivial job for an expert, depending on the low pass filters.
    What kind of noise are you seeing and how is it affecting your measurements?  Can you post some data?
    Lynn

  • Does Strain task in DAQmx include lowpass filter?

    I am using a load cell with a 2.232 mv/V with an excitation voltage of 10V.  When I put a scope to the output, there is a lot of high frequency noise which causes me to have to use an amplifier with a lowpass filter built in.
    I would like to be able to accomplish this same task without having to purchase the amplifier (I have 3 load cells per machine, 6 machines so cost does add up).  I am currently using a PCIe-6320 for some encoder measurements on this same application and did find where I can use the analog inputs to measure Strain using DAQmx.
    My question is does the Strain measurement in DAQmx have a built in lowpass filter to clean up the signal?  If not, is there a solution to this that does not require a Toolkit or additional module for signal processing?  We have the basic LabView 2009 SP1.

    aeastet wrote:
    I would also look at why you are getting so much noise. How do you have your channels hooked up to the system?
    Yes.
    Using a strain guage module the bridge is built into the terminal block and the hardware does the mv/V thing so there must be some place the noise is entering the system, long, non-shielded, non-twisted pairs, bad ground...
    Ben
    Ben Rayner
    I am currently active on.. MainStream Preppers
    Rayner's Ridge is under construction

  • HT1498 do you have to have your computer active, in order for apple tv to work?

    Do you have to have your computer active, in order for apple tv to work?

    Setting up Home Sharing for Apple TV (2nd generation)
    Troubleshooting Home Sharing with Apple TV (2nd gen)
    Apple TV (2nd and 3rd gen)- How to use AirPlay Mirroring

  • How can I eliminate a ringing noise from a 60 Hz analog notch filter?

    Using 60Hz analog notch filter may cause some ringing noise for the signal of cutoff frequency edges. Do you have a method excluding such a ringing noise? I guess that a deconvolution method will be helpful for the problem but I cannot apply that properly.

    ELCA,
    A different approach is to average in the time domain.
    I suggest a method called 'boxcar' used in physics labs sometimes.
    Slice your time between two triggers in let's say twelve equal time slots and do a lowpass (f0) on
    each slot.
    The result is a stepwise approximation of your curve. In the frequency domain this is about the same
    as a bandpass at the cardiay frequency with the bandwith f0
    60 Hz signal is problem only if your rats heart beats inside this bandpass. But when it is at 60 Hz
    you might have lots of difficulties anyhoe ;-)
    Urs
    ELCA schrieb:
    > Ron,
    >
    > My signals are the cardiac beatings of a rat through a 60 Hz analog
    > notch filter. For averaging, I obtained several dozens of epochs with
    > a fixed trigger
    positon.
    > I tried averaging the epochs in the frequency domain(FFT and averaging
    > only for the amplitude) and took the inverse FFT of the averaged
    > signal. However, the result was not satisfactory. It gave me a more
    > noisy shape and still 60 Hz ringing. If you have some comment about
    > that, please let me note that.
    >
    > ELCA

  • Lowpass filter in modulation

    hello
    i'm using LABVIEW to implement LSB-SSB modulation, this requires a VSB signal passed through a lowpass filter, the problem i couldn't get my required spectrum, i wonder if the problem is in the filter or elsewhere, i hope you can help me in that , i only need to know how the filter in labview works , thanks
     here is the right attachment (the previous one was wrong sorry
    Solved!
    Go to Solution.
    Attachments:
    ssb1.png ‏71 KB

    The realities of real filters!
    1. It is not possible to implement an ideal filter in the real world. *
    2. All filters, hardware or software, have a transient when the signal is first applied (or changed).
    3. The narrower the bandwidth or the sharper the cutoff, the more significant the transient.
    4. All software filters have errors due to the finite size of the numbers used in the calculations.
    5. Many filters and all spectral measurements are affected by the finite size of the data set provided as inputs. The mathematics of the Fourier transform assume the signal behaves the same for all time from -infiinty to +infinity. Since people are unwilling to wait infinite time to get results, errors occur.
    How did I design the filter in the VI I posted?
    - I selected a filter type -elliptic- based on my knowledge that elliptic filters can provide a very deep null close to the cutoff frequency.  I used the default passband ripple of 1 dB because the passband ripple is somewhat irrelevant in this situation and 1 dB is a small change for an audio signal. Then I experimented with the filter order until I got what I thought seemed like a reasonable upper sideband suppression. If I had detailed specifications for a filter, I wold have looked up the characteristics in a filter handbook to see if the selected parameters met all the requirements.
    * You can sometimes approximate one by calculating the Fourier transform, setting all the undesired frequency bin values to zero, and then doing an inverse transform. However, if there is any spectral leakage, this technique does not work. In any case it is limited by the same numeric concerns in item 4 above.
    Lynn

  • Add Order as a Filter to a Report

    Hi Experts,
    Iam a Bw Report called Bonus tracking report and Iam supposed  to add Order as a filter to it.
    How can I do that?
    Thanks
    SP

    Hi,
    I think your users are looking for a variable on Order InfoObject. You can place Order in the rows or free chars area and restrict with a variable.
    Hope this helps...

  • How to configure the lowpass filter integrated to the serie M DAQ (6280)

    It's written that for the NI 62xx serie M DAQs, a lowpass filter can be programated (to prevent noise or aliasing), but I can't find where I can configure it ...
    I use LV 7.1, DaqMX 7.3 and MAX 3.1.1.3003.
    Thanks for your help !
    Mathieu

    Bonjour,
    Effectivement, la valeur du filtre de la carte NI-6280 est 40kHz.
    En simulant la carte, j'ai pu faire le test avec le VI joint.
    Si ce VI ne fonctionne pas, quelle est le code d'erreur obtenu et à quelle fonction apparaît-il ?
    Salutations,
    Isabelle
    Ingénieur d'applications
    National Instruments France
    Attachments:
    filtre 6280.vi ‏73 KB

  • Conversion of LTP Planned orders to Active planned orders

    Hi PP Guru's,
    I want to convert LTP Planned orders of Multiple Materials to active planned orders. Using MD43 (Interactive planning), I am able to covert only one material LTP Planned orders to active planned orders.
    Can any one advise me if there is any way (or) options to convert the Multiple Material's  LTP Planned orders to Active planned orders.
    Please let me know if required any further information on the issue.
    Regards,
    Purna

    Hi Anil,
    Thank you for quick reply.
    COHV Transction is meant for mass execution of transactions for Normal Planned order or Process order. I did not find any option to convert LTP Planned order to Normal Planned order in COHV Transaction.
    Please advise me the with further details.
    regards,
    Purna

  • ACTIVITY PROCESS ORDER

    Hi,
    Is there any report to get the list of Process orders or Material codes where a specified activity or work centre assigned
    The requirement is to get the data of One activity is assigned in which different Process orders (Material codes).
    Regards
    Bhanu Prakash

    Function module documentation BAPI_PROCORDCONF_CREATE_TT is for Process Order.

  • Lowpass filter help for thermocouple reading

    Hello
    I have an old legacy E-Series AI-16SE 12bit 500KHz PCI card.
    I am attempting to setup a temperature reading test program. I will have the E-Series connected to a SCB-68, which will have five T type thermocouples connected. I realize this is not the best test setup but it is an attempt at a quick setup on a bench so hopefully any noise interferance will be minimal.
    I will be using LV 8.2 professional development.
    I was wondering if I setup a software based lowpass filter if that would be helpful in this situation?
    If so can someone show an example the has a cutoff freq for 2Hz? I am unfamilular with all the settings of the lowpass filter VI and some guidance would be much appreciated.
    Thanks in advance
    Tim C.
    1:30 Seconds ARRRGHHH!!!! I want my popcorn NOW! Isn't there anything faster than a microwave!

    Tim,
    Rob's idea is probably what you should try first.  It is in effect a low pass filter with about a 10 Hz corner frequency.
    If you find that you have strong power line frequency interference, you may need to do more aggressive signal conditioning.  Especially watch out for ground loops.
    Lynn 

  • No active purchase order item for shipment cost

    Hi,
         When I'm entering a shipment cost document for a shipment using Vi01, I'm getting an information like "No active purchase order item for shipment cost", When I check in the service procurement tab there is no purchasing document and entry sheet found.
    Please let me know what is causing the problem and what needs to be done to resolve this
    Regards,
    Ashwin

    Hi,
    Does your shipment document contains any stage?This problem might be because of this reason.
    Regards,
    Sumit

  • Need Help Solving a 2nd order Differential Equation

    I need to write a computer program in MATLAB to solve the following 2nd order differential equation:
         y" + (1/r)y' + (200/80) = 0
    I can't remember which method I'm supposed to use to get an equation for y(r)? Once I know the method... I'm sure I can implement it.
    Thanks for your time

    You can implement Java code in MATLAB??? Is that what you're saying? If so, please tell me how because that would be helpful to me!

  • SCXI 1125 lowpass filter

    Hello I am using a SCXI 1000 chase with two SCXI 1125 cards. My question is how can I configure a software filter that works like the one implemented in the SCXI 1125 card. More exactly i what to build a 4 Hz cuttoff lowpass filter. Thank you. 
    Attachments:
    filter.jpg ‏139 KB

    Which module are you using?
    I suppose you could always just run your signal through the Filter express VI (in the Express » Signal Analysis palette) or one of the VIs on the Signal Processing » Filters palette.
    Kyle B  |  Product Support Engineer  |  ni.com/support

  • 2nd Order Differential Problems

    Hey I'm creating a second order differential solver and I'm using the differential solver VI's that come with the package. However, the solver won't do 2nd Order ODE's that are critically damped. Does anyone know what this problem is and how I can remedy it? I put a copy of my program here to show you the problem. For an example of a critically damped equation, input 4 in both "dy/dt" and "y". Thanks.
    Attachments:
    2nd_Order_Solving2.vi ‏170 KB

    Hey Jay,
    The modification I made is not that complex, so I'll explain what I did step by step. Before I go through the process, I should offer a disclaimer.
    When modifying ODE Linear nth Order Numeric VI, you may want to save a local copy for yourself. This will ensure that the shipping version of the VI is not altered. If you modify the shipping version, then leave it that way, you may run into errors when you try to use the VI in the future.
    Also remember to verify the results of the critically damped case. Since the VI is not designed for ODE's with repeated eigenvalues, it's possible that you could be getting incorrect results after the modification. With that said, here's the procedure I used to modify the VI so that it runs even with repea
    ted eigenvalues.
    1. The modification I made was to the ODE Linear nth Order Numeric.vi. You can access the VI's code by simply double clicking on it from your VI.
    2. The change I made is located in the red circle on the bitmap I sent you.
    3. Look for the "Multiple Roots.vi", the gray one with a sigma in the upper left corner and some arrows and dots on it. The output of this VI is a boolean, and it is connected to a not gate.
    4. Delete the wire from the output of the "Multiple Roots.vi" to the not gate.
    5. Right click the input port of the not gate and create a constant.
    6. Make sure that the boolean constant connected to the not gate is false.
    This is what I did to ensure that the VI will run regardless of the eigenvalues. Please be aware of the issues I addressed above. Otherwise, good luck!
    Marcus G.
    National Instruments

Maybe you are looking for

  • After a recovery reinstall of 10.8.5, using Safari 6.0.3, I get the message "Safari won't open because of a problem"

    After a recovery reinstall of 10.8.5 and using Safari 6.0.3, I get the message "Safari won't open because of a problem" I'm not sure if this Safari is compatible. I also have Safari 7.0.4 in my applications folder, which i downloaded as an attempt to

  • Apple Mail Groups

    Is there a way to consrtuct groups for email contacts in Apple Mail?

  • Unsigned Long in java

    Hi all, I have a code in C which i want to convert into java.. Iam facing problem because java does not support unsigned long.The code in c look like this: WCD.cardno = ( SerBuf[3]* 0x00010000UL+ SerBuf[4]* 0x00000100UL+ SerBuf[5]* 0x00000001UL); I w

  • Doctype added to top of portal page

    Does anyone know how to get a doctype to output at the top of a portal page (we are on the 7.3 portal)?  I have an external facing site that absolutely needs a doctype specified. You used to be able to use the deprecated PortalHtmlResponse.getHtmlDoc

  • Inconsistent JBO-27122 errors with VO.setQuery

    Hi, I am using ADF BC Vo with some query.At runtime we construct the whole query and set it using setQuery(). Sometimes it throws JBO-27122 Sql error :Error during sql statement preparation. We are not able to reproduce consistently. Once it starts h