Filter signals below amplitude

Hello again,
I have another probable rookie question. I am wanting to write a program that filters signals below a certain amplitude, but allows the rest to pass, I've tried doing the attached but its not working, or the chart isnt scaling to show it?
My ultimate intention is to analyse live wind speeds with a DAQ that is not yet installed. I'd like to test the program im going to use with historic data as a simulated signal, so I can swap it straight out when the time comes.
Anyone have any ideas where I'm going wrong? (I've saved the .lvm file as a text to allow upload, first colum time second results)
Many thanks
Thom
Attachments:
Filtersignal.vi ‏54 KB
09-10 12m2.txt ‏125 KB

I think you have the right idea in general
I am not sure what the comparison and selector functions actually do with the Dynamic Data.
If you convert the data to an array, it will do what you want.
Lynn

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Filter signal with noise values... help!.

Hi guys,
I have the problem this signal have noise from the sensor. I get the readings and i need smooth this values, filtering like average values, but the problem is BEFORE I need remove the the bad pulses of signal, I cant loss any value, since they are related with another array, and I was thiking in change the bad values to the previous index or average between previous and next value on array...
But i got problems, since I need to do it manually, and sometimes the signal takes 2 bad values continued or several, or bad value positive and bad value negative. The idea is use any threstld and i dont care if this values are the average or simply the last good value on normal curve... I tried a vi, but it is very simple and i got problems with another signals, when the error values appear together...
I would like to know if exist any easy way to get it... The key is I can't remove any value, it would be easy to do...
Any help or advise??.
I attached the vi and signals files...
Regards, Fonsi.
Attachments:
files.zip ‏31 KB

A good way to remove spikes or bursts from a signal is Median Filtering. You can use Median Filter.vi to do this.
Good luck!

Daqmx split or filter signal

Goodday,
On a PC 4461 card, there are 2 mic's connected. I use the Read.Vi from the DAQmx for this with "ai0:1" as physical adresses.
These signals are use to calculate the rms value.
And this value is send to
Ai0 => Ao0
and
Ai1 => Ao1
However sometimes i want to use only one mic, and thus only for example use "ai1" however when i do this the signal from Ai1 goes to Ao0.
Ai1 => Ao0.
It seems that the Read.vi write every channel to "waveform channel 0" instead of "Ai1 to waveform channel 1"
How can this be changed or filtered?
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Solved!
Go to Solution.

Added a picture for example
Attachments:
daqmx filter.jpg ‏67 KB

Passband IIR filter does not have correct cutoff

I am trying to implement a bandpass filter using the digital IIR filter vi. The input comes from a signal generator and the output is displayed as a waveform on the screen of my PC. When I test it out by varying the frequency of my input, the cutoff is always not where I programmed. Does anyone know what could be wrong? Is there some limitations of the software filter which could explain this phenomenon?
Thanks
hlseck

What is the amplitude of the desired signal (the 1 kHz signal)? Can it change frequency? If so, how much?
The amplitude of the desired signal is around 0.5V.The frequency can change by around 20Hz.
What is the nature of the undesired signal(s)? Single tone interference? Multiple interfering tones? Broad band noise?
The noise is broadband noise from electronics circuit.
What are the amplitude(s) and frequency(ies) of the interferring signal(s)?
I am not aware of the amplitude of the interfering signal but the frequency would be broadband.
How much attenuation of the desired signal is
acceptable? Can you amplify it after the filter? Is the phase of the
signal important? If so, how much phase shift can be tolerated?
The attenuation of the signal is not so crucial as it can be amplified but the phase is important. As the filter signal will eventually be used to drive an external circuit, any phase shift would reduce the accuracy. My computer is acting as the feedback since I am not using any hardware, my pc is actually filter the input signal and feeding it back to the system. So any delay or phase shift would not be undesireable.
How much of the interfering signal can the system
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My estimate is that the interfering signal be -10dB below the desired signal.

Narrow Band Pass filter using DFD tool kit.

Hi,
This is in continuation of my other posts for the same subject. We are now designed a working filter but are presently facing some problems as mentioned below:
The filter does not work for any input frequency which varies in the second decimal place,
Eg
if the input freq is say 2.15 Hz the filter does not work well, we observe amplitude errors and some random dips in the amplutude response, however the freq is ok.
With all settings the same and only the input changed ot 2.1 Hz the filter starts to work fine.
This phenomenom is observed over the either filter range of 0.1 Hz to 5 Hz
In brief, our porblem is that, while acquiring dynamic signal from a daq (NI 6229), we may encounter any signal between 0.1 hz to 5 hz, since it is an analog signal and the freq can go to an accuracy of at least 10 exp -6 we are not able to filter these signals since out filter can filter signal only up to the first decimal place which is 10 exp -1.
We are attaching a doc to this post. containing further details.
We are in a time critical situation.
Thanks and regards.
sunil
Attachments:
Details of the filter settings.doc ‏47 KB

Hi,
Thanks for the reply.
The vi is designed but we are having an issue of speed of processing.
This filter takes a long time to process.
We are looking for the following:
Since our signal can range from 0.1Hz to 5Hz our sampling freq needs to be higher, about 8000 samples/s, this is necessary since the shape needs to be maintained for accurate phase measurements (the signal is always sinewave and with noise on it).However you may suggest this sampling rate based on your experience.
Since the phase in the pass band needs to be linear we have to select FIR and since the filter roll off needed is very sharp as provided in the attachment, the resulting design has a large number of taps(coefficients), this makes the processing slow.
--What would be the appropriate sampling frequency for such a filter design.
--Is it that such filters are slow, if so how can they be put in the front end filtering of signals acquired from a daq (PCI-6229)analog channel in a continuous acquisition mode.
we would be thankful for a quick response.
PLS refer to the attachment for filter characteristics.
thanks & regards,
sunil
Apna Technologies and Solutions
Bangalore,
Karnataka,
India

How to design a good 60Hz notch filter?

I tried to design a 60Hz notch filter(59-61 as stop band,tried different kind filters/orders,cont.true)But I can't have a stable output. When test on 60 Hz input,the output signal's amplitude will change in a repeated pattern,sometime the ripples is very small, but sometimes it's big, especially at the waveform beginning. The Fs is 5000, data is sampled every few seconds. Are there any refined 60Hz notch filter can be used, or any better way to design a notch filter?
Averaging is one way to remove the ripples after filtering,but I hope the filter can give a steady output.Thanks!

sfhj wrote:
please if you have this example or know about it ,send it
thanks
@sfhj
Hijacking a old thread is never a good idea. I suggest you start your own. Also in order to get help you must explain better what you have done so far, why and how you struggle. The best way to do this, is to post your code, and some signals examples. I know a lot of tricks. And none of them need a fancy toolkit. But you must start your own thread in order to get help from me.
Edit: I noticed you have started a new thread, do you want to move the discussion to that thread?
Besides which, my opinion is that Express VIs Carthage must be destroyed deleted
(Sorry no Labview "brag list" so far)

Tone measurement express vi affect the output signal?

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Figure 1: without tone measurement express vi
Figure 2: with tone measurement express vi

I would like you to prove the "bug" that you're describing by creating an example that shows the calculated and the expected results. By opening the code of the "Spectral Measurements" Express VI you can dig into the heart of the calculation, and there (in the "ma_FFT Power Spectrum and PS Density no State.vi") you will see that the Power Spectral Density indeed IS calculated by using the formula PSD = (Power Spectrum/(df*Noise Power BW of Window)). See the attached PSD.jpg that shows where the calculation happens.
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- Philip Courtois, Thinkbot Solutions
Attachments:
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I didn't know that the logs didn't work; I tested it and they are not generated for ASO updates in 9.3.1. I didn't see any other setting that would cause them to be created; my guess is that the logs are created based on block manipulations that Essbase does internally using BSO. As there are no blocks in ASO then the same algorithm doesn't apply.
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Custom Filter in Universe on top of BEX Query is not working in BO Explorer?

Hi,
I have created Condition(Filter) for an Dimension Object "Submitted by Group Hierarchy" in Universe designer tool on top of SAP BEx Query and then exported the universe to Repository.
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where as in Explorer, i am not able to enter input values for my custom filter as below.
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Thanks in advance.
Regards,
Ramana.

Hi Ramana,
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SSRS filter a dataset if parameter is "Yes"

hello i have a report as below
with date Parameters this all works fine!
date from date too
01/01/2011 21/02/2013
name amount date
test1 100
01/01/2012
test2 200 01/02/2013
but what i want is to have another parameter which says something like yes or no and a filter on the data set which responds to the parameter
so that if the parameter = "yes" then filter the data set so as "not" too include test1 as a company but if "NO" then include all records!
Steve mason

Add new parameter in SSRS report and pass it down to query .
In the query add a filter like below
WHERE....
AND (name <> 'test1' OR @NewParameter = 'No')
or if you want to do this in SSRS dataset do like below
=IIF(Parameters!NewParameter.Value="Yes",Fields!Name.Value,0) for Expression
<> for operator
and
=IIF(Parameters!NewParameter.Value="Yes","test1",1) for Value
in dataset filter tab as per below
Please Mark This As Answer if it helps to solve the issue Visakh ---------------------------- http://visakhm.blogspot.com/ https://www.facebook.com/VmBlogs

Or between prompted columns in report filter

Hi,
If I give an 'Or' between two prompts in the report filter, as below:-
Value Date is prompted
OR Trade Date is prompted
... then the condition does not apply on the report.
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thanks,
Gaurav

Hi,
If I hard code in the report filter and use or between the conditions then it works fine.
The prompted filters are not working with 'Or' in between.
It looks like a bug. Can something be done about it?
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thanks,
Gaurav

Sender ID Filter running very slowly

Hi,
I have recently deployed a test Exchange 2013 with the mailbox role and client access roll on Windows server 2012 R2
The test machine is also a DC, DNS server, DHCP Server. I have no edge transport server, the Frontend transport connector, ie SMTP service is being used.
Exchange 2013 has been updated to CU7 and windows server 2012 has all the latest updates installed from windows update.
The problem i am having is the Sender ID filter, installed with the anti-spam configuration, is running very slowly.
If i use the Test-SenderID cmdlet with any external address it can sometimes take minutes to come back with the test result.
However sometimes it comes back quite quickly - its somewhat intermittent. It doesn't matter what 'PurportedResponsibleDomain' i use or IPaddress for the test - the majority of the time its very slow, although occasionally it will come back within a second
with the result, but do the same test again with the same parameters and its back to a minute or 2 again.
This slow response is replicated with a SMTP test via telnet, upon the final '.' to send the email, it can hang for a minute or 2. If i disable the SenderID filter i get the acknowledgement from the SMTP server within a second. This occurs if i telnet direct
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Things i have observed:
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im back to the slow running.
-Internal email is being delivered fast, no delays
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Things i have checked:
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-InternalSMTPServers on the TransportConfig has been set to the IP assigned to the adapter. I have also tried adding all IP's on this adapter (there are 4), and even 127.0.0.1 to this InternalSMTPServers list, but it makes no difference for external
mail or the Test-SenderID cmdlet. It does however speed up a telnet smtp test direct from the exchange machine as the internalSMTPServers list results in a bypass.

Hi Gavin,
I notice that there are some performace counter errors from Exchange 2013, sometimes performance issue can cause mailflow delay. Would you like to list some errors without sensitive information for the further troubleshooting?
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If everything goes well without configuring Sender ID filter, it seems an issue on Sender ID filter configuration.
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http://technet.microsoft.com/en-us/library/dd639388.aspx
Thanks
Mavis Huang
TechNet Community Support

Estimate AC/DC of a sine signal

Hi,
i capture an analog signal (a sine) with labview and i want to extract several informations from the signal like : Amplitude, offset, peak value, frequency, etc.
I almost get what i want, but i can't get the correct value of AC / DC components of my signal.
For example, i receive a signal like this one :
y = 1.25 + 1.25 * sin (2*Pi*3000*t).
I except the following value :
f = 3000 Hz (I got it)
Peak = 2.5 (I got it)
Ampl = 2.5 (I got It)
DC = 1.25 (I got it)
AC = 1.25 and there is the problem. I don't have this value.
Maybe i forgot a vi in my design, or maybe labview can't process this value or maybe i'm do it wrong because i don't exactly talk about AC value.

mhed wrote:
Hi,
i capture an analog signal (a sine) with labview and i want to extract several informations from the signal like : Amplitude, offset, peak value, frequency, etc.
I almost get what i want, but i can't get the correct value of AC / DC components of my signal.
For example, i receive a signal like this one :
y = 1.25 + 1.25 * sin (2*Pi*3000*t).
I except the following value :
f = 3000 Hz (I got it)
Peak = 2.5 (I got it)
Ampl = 2.5 (I got It)
DC = 1.25 (I got it)
AC = 1.25 and there is the problem. I don't have this value.
Maybe i forgot a vi in my design, or maybe labview can't process this value or maybe i'm do it wrong because i don't exactly talk about AC value.
Look at the terms you reported and compare to your equation. There is a "DC=1.25" and an "Ampl=2.5" in your list. Your equation describes a sine wave with an amplitude of 2.5 units (peak-to-peak) centered at 1.25 units. I believe you are trying to solve for an extra term!
Jeff
Jeffrey Zola

BEx - empty value(#) in navigation Block (filter)

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i have navigation attribute in navigation block (query). It means that data in filter are read directly from master.
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i can see value in filter as below.
#/#/001
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IPS Event Action Filter is not working properly.

Hi,
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This is ASA-SSM-20 installed on ASA 5520 version 7.1(6)E4, mode: inline
Bug search tool didn't show any related bugs.
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Filter settings below:
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Firewall LOG:
4          Feb 14 2014          15:33:22                              39715                    514          IPS requested to drop UDP packet from SOURCE_VLAN_NUMBER:/39715 to DESTINATION_VLAN_NUMBER:/514
IPS LOG (when enabled):
evIdsAlert: eventId=1352793300955167909 vendor=Cisco severity=low
originator:
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time: Feb 14, 2014 15:33:22 UTC offset=0 timeZone=GMT00:00
signature:   description=IP Fragment Too Small id=1206 version=S212 type=anomaly created=20030801
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riskRatingValue: 50 targetValueRating=medium attackRelevanceRating=relevant
threatRatingValue: 50
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protocol: udp
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Thanks for all your help so far. Any more suggestions are most welcome. I'll keep you up to date.
Regards
Mariusz

Filter signals below amplitude

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