Can counter measure pulse width difference between two signals

I am interested in determining the high pulse width time that two signals have when they are in various phases between eachother.

Why don't you try one of the pulse width examples. I don't know what ADE you are using, but you can search for examples (http://www.ni.com/devzone/dev_exchange/ex_search.htm) with the key words "+pulse +width" and find several examples in different languages. This will measure the pulse width of one signal, but you can program most of the counters to do multiple tasks at the same time. Just copy the code twice and change the counter number to program counter 2 as well. If you want the ORed pulse width time, I would recommend adding a OR gate to your circuit and then feeding that into a counter.
I hope this helps.
Joshua

Similar Messages

Better estimation of phase difference between two signals with variable frequency!

Hello LabView Gurus,
Being a power engineer and having just a little knowledge of signal processing and labview, I have been pulling my hair out for the last couple of days to get a better estimation of phase difference between two signals.
We have two analog voltage signals; 1. sine wave (50Hz ± 1Hz) and 2. a square wave with exactly half of sine wave frequency at any time.
At the starting point of operation (and simulation/acquisition) both signals will have no phase difference. However, the square wave's frequency changes unpredictably for a just a few millisecond but then it gets synchronized with sine wave's frequency again. This means that the square wave will be phased out from its original position. The task of the labview is to find the phase difference between the two signals continuously.
My approach to determine the phase difference is to measure the time when sine wave crosses zero amplitude and the time when the very next square wave changes amplitude from zero volts to +ve voltage (I have a 0.5volts threshold just to avoid any dramas from small line noise). The difference between these times is then divided by the time period and multiplied by 360 to get this phase difference in angles.
As this part is just a small block of a big project, I can only allow 5000Hz sampling rate each for both signals. I read 500 samples (which means I read data from 5 cycles of sine wave and 2.5 cycles of square wave).
Now the problem is, as long as the frequency of sine wave stays constant at exactly 50Hz, I get a good estimation of the phase difference but when the frequency changes even a little (and it will happen in the real scenario i.e 50Hz ± 1Hz and the square wave's frequency is dependent of sine wave's frequency), the estimation error increases.
I have attached my labview program. From front panel, you can set the phase of square wave (between -180 and 0) and you should see the labview's calculated phase in the indicator box named 'Phase'. Then you can press 'Real Frequency' switch that would cause the frequency to change like it would in real operation.
You can observe that the estimation error increases after you push the button.
All I need to do is to reduce this estimation error and make it as close to the actual phase difference as possible. Any help would be greatly appreciated.
I am using LabView 2009 for this task.
The application is for electric machines and the stability/performance of machines under different faults.
Thank you for reading this far!
Regards,
Awais
Attachments:
v603.png ‏320 KB
v603.vi ‏186 KB

Jeff Bohrer wrote:
Basic math gives me a bit of pause on this approach. You are sampling at 50 times the frequency of interest so you get 50 samples per cycle. your phase resolution is 1/50th cycle or 7.2 degrees +/- noise. You will need to samlpe faster to reduce phase resolution or average multiple readings (at a time cost that is signifigant)
Jeff- (Hardly Working)
I am sampling at 100 times the sine wave's frequency and 200 times the square wave's frequency. Increasing the sampling rate completely solves my problem. But since I am acquiring several other inputs, I cannot afford a sampling rate higher than 5kHz.
F. Schubert wrote:
I'm not a signal processing expert, but here my basic understanding.
If you simulate sampling with 5kHz and a frequency of 50 Hz (and both are 'sync' by design), you always get an exact 5 periods. Any variation of your signals frequency gives you a propability to get 4 or 6 'trigger' events. That's an up or down of 20%!
The one measure to reduce such problems is using 'window functions'. They don't fit your current approach (counting instead of a DSP algorithm), so this needs to be reworked as well.
My approach would be to use the concept of a Locki-In amplifier. You need to phaseshift your ref-signal by 90°. Then multiply your measurement signal with the ref signal and the phase shifted ref signal. The obtained values for x/y coordinates of a complex number. Calculate the theta of the complex number (with the LV prim). Feed this in a low pass filter.
The trick on this is, that the square wave has harmonics in it, in this you are interested in the second harmonic which is the sine wave.
To get rid of the effect that the sync between sampling rate and ref signal frequency gives an error, you then can use the window I mentioned above (place it before the lock-in).
For a design that really plays well, use a producer-consumer design pattern to get the calculations done in parallel with the DAQ.
I suggest you to check on wikipedia for some of the keywords I mentioned. Go also for the external links which lead to great tutorials and AppNotes on the signal processing basics.
Sorry, it's not a simple solution I offer and we will have quite some conversation on this forum if you follow this path. Maybe someone else knows a simpler way.
Felix
www.aescusoft.de
My latest community nugget on producer/consumer design
My current blog: A journey through uml
An interesting view. the sine wave can indeed be looked as a second harmonic of the square wave. I will implement your idea and get back to you as soon as I get some results. But since I have very limited knowledge of signal processing, it might take me a while to get my hear around the solution you mentioned.

How to find the phase difference between two signals using Hilbert transform

hi,
I am new to LabView.... I am trying to find phase difference between two signals. I sucessfuly found out the phase difference between two predefined waves using single tone measurement. .... But I really want to know how can I measure phase difference between two signals( not predefined... ie we don't know the initial conditions) using hilbert transform or any transformation techniques (without using zero cross detection).. I tried by using hilbert transform based on algorithm... bt I am getting error.... plz help me
Attachments:
phase_differece.vi ‏66 KB

you could try something similar to this, for each table pair that you want to compare:
SELECT 'TABLE_A has these columns that are not in TABLE_B', DIFF.*
FROM (
        SELECT COLUMN_NAME, DATA_TYPE, DATA_LENGTH
          FROM all_tab_columns
         WHERE table_name = 'TABLE_A'
         MINUS
        SELECT COLUMN_NAME, DATA_TYPE, DATA_LENGTH
          FROM all_tab_columns
         WHERE table_name = 'TABLE_B'
      ) DIFF
UNION
SELECT 'TABLE_B has these columns that are not in TABLE_A', DIFF.*
FROM (
        SELECT COLUMN_NAME, DATA_TYPE, DATA_LENGTH
          FROM all_tab_columns
         WHERE table_name = 'TABLE_B'
         MINUS
        SELECT COLUMN_NAME, DATA_TYPE, DATA_LENGTH
          FROM all_tab_columns
         WHERE table_name = 'TABLE_A'
      ) DIFF;that's assuming, column_name, data_type and data_length are all you want to compare on.

How can I measure the time difference between spikes (interspike intervals)

I have used NI USB-6008 (DAQ) to sample a continous signal, after sampling I compared the amplitude of the resulted signal with a value. If the amplitude is greater than a specific value (threshold) then it can pass. Now I want to measure the time difference between the resulted samples. The samples look like spikes. (May be if I trigger a timer, then I can measuer the time difference, but I have not seen such a timer).
Thanks in advance,
Saraydin

Oops just occured to me that you are using a 6009 which is not very fast, 48ks/sec, this will not get you very much time resolution and you could have issues seeing much of a 50 us sample. Another approach is to use the counter but you would have to preprocess the spikes to generate a trigger for the counter.
Paul
Paul Falkenstein
Coleman Technologies Inc.
CLA, CPI, AIA-Vision
Labview 4.0- 2013, RT, Vision, FPGA

How can I measure the phase difference of two input signal?

Hello,
I'm trying to measure the phase difference of two input sine waves with the
same frequency.
Is there anybody how I can do this with labview?
Thanks,
Dae-han

This is my case! I have TDS3034 which can measure phase. However when I open Read Waveform Measurement vi that comes with tkds30xx.llb, I have a number of options under "measurement function" but not the phase measurement. May be I need another vi to do this?

How to measure time difference between two continous encoder pulse (PULSE A & PULSE B)

im trying to figure out the time difference between two square
wave pulse (PULSE A and PULSE B) from an encoder. I tried to modify many code but fail to capture thephase difference for each pulse. the
pulse only rise to 5V and fall to 0V like normal square wave pulse
can you and all of experts here help me out with this?
my problem
1) Encoder pulse are continous (pulse A and pulse B)
2) Square wave pulse have "0V" and "5V" please rapidly
if possible someone show me correct method , Im using LABVIEW 7.1 and Hardware NI SCOPE (PCI 5102)
your advice are highly appreciated
among my idea as in attachment , but I failed to get it
Attachments:
Need to Get this wave.JPG ‏34 KB

Hi Amirul,
Check the attached JPG file. i think this will be use full to you
Regards,
Santhosh M

I need to upgrade my OS from Snow Leopard 10.6.8. I can't decide between Lion or Mountain Lion can anyone tell me the difference between the two?

I need to upgrade my OS from Snow Leopard 10.6.8. I can't decide between Lion or Mountain Lion for my upgrade can anyone tell me the difference between the two?

Click here for information.
(125089)

Can anyone tell me the difference between these String methods?

There are methods that can convert a byte[] into string:
String(byte[] ascii, int hibyte, int offset, int count)
String(byte[] bytes, int offset, int length)
String(byte[] bytes)
I am now sticking on it. The first one runs great in my project, but it is deprecated. The remaining two return wrong answer I need. Can anyone expain what the difference between them? Really appreciate the help, thanks in advance.

It seems like the first one translates each byte into one character. The other two use the default character encoding to translate possibly more than one byte into each character. Look up Unicode character encodings to understand the difference.

Need to find the Difference between two table

Hello ,
I have stucked in program as below scenario:-
I have two tables of huge data of same structure in a same schema.I need to find the difference exact values in tables.
By using MINUS we can find the difference between two table ,i need to find the what exact difference in the there values with colunm and value at that column.
Example TableA
Col1 col2 col3 col4 col5.... col50
10 ABC 2001 EE 444 TT
40 XYZ 3002 RR 445 TT3
80 DEF 6005 YY 446 YY8
TableB
Col1 col2 col3 col4 col5.... col50
10 ABC 2001 EE 444 TT
40 XYZ 3002 RR 445 TT3
81 DEF 6005 Yu 447 YY8
I need to the out put like this :-
The Diffence between two table is
TableA.COL1=80 TableB.Col1=81, Different
TableA.Col4=YY TableB.col4=Yu,Different
TableA.Col5=446TableB.col5=447,Different
Please suggest me to write the pl/sql program for the same
thanx in advance
KK

Thanx friends for all your efforts
I have a sample code for the same,this will compare the two tables for single row in each table .
what r the modification needed for the multiple rows of values in the two tables??
Please suggest!!
CREATE OR REPLACE PROCEDURE test_compare
IS
TYPE t_col
IS
TABLE OF VARCHAR2 (30)
INDEX BY PLS_INTEGER;
l_col t_col;
j NUMBER := 0;
l_sql VARCHAR2 (2000);
col1 VARCHAR2 (30);
col2 VARCHAR2 (30);
val1 NUMBER;
val2 NUMBER;
status VARCHAR2 (30);
CURSOR c1
IS
SELECT column_id, column_name
FROM all_tab_columns
WHERE table_name = 'TEST1';
BEGIN
FOR i IN c1
LOOP
j := j + 1;
l_col (j) := i.column_name;
END LOOP;
FOR k IN 1 .. j
LOOP
l_sql :=
'SELECT '
|| ''''
|| l_col (k)
|| ''''
|| ', '
|| 'TEST2.'
|| l_col (k)
|| ', '
|| ''''
|| l_col (k)
|| ''''
|| ', '
|| 'TEST1.'
|| l_col (k )
|| ', '
|| 'DECODE(TEST2.'
|| l_col (k)
|| ' -TEST1.'
|| l_col (k)
|| ', 0, ''NO CHANGE'', ''CHANGED'') FROM TEST2, TEST1';
EXECUTE IMMEDIATE l_sql INTO col1, val1,col2, val2, status;
IF status = 'CHANGED'
THEN
DBMS_OUTPUT.put_line( 'TEST2.'
|| col1
|| '='
|| val1
|| ', TEST1.'
|| col2
|| '='
|| val2
|| ', '
|| status);
END IF;
END LOOP;
EXCEPTION
WHEN OTHERS
THEN
DBMS_OUTPUT.put_line ('Error:- ' || SQLERRM);
END;
/

Difference between two text(String) in percent

I am currently building a project require to generate the differences between two text store in (String) in precentages. The fuction should look something likde this:
    double compare(String text1, String text2){
        //doing the smart comparison
        //return percentage in double
    }The text1 and text2 should be a long document and the compare function should return the percentage of difference of those texts. Examples of usage:
    System.out.println(
        compare(
    );Thanks for every reply. Please kindly correct me for any mistake.

Let us define an elementary operation as one of
1) inserttion of a character,
2) deletion of a character or
3) replacemen tof a character. Woo - my first ever post!
The distance measure described in the above post is called the edit distance, or "Levenshtein distance". If you google that, you're bound to find some ready-made java code that does it for you.
Happy hunting!
Btw, I was chatting to a friend about distance measures. He was telling me about a proposed distance measure between two arbitrary files: You 1) zip both files together, and 2) zip the two files separately, then compare the file sizes of the two zip files. I love this idea! Apparently some guys compared files containing the same block of text in different languages, and were able to show that languages from the same language groups (eg slavic, germanic) cluster together.

How to get the difference between two columns in a column group

Hi All,
My first time here and really new to programming. I would like to get the difference between 2 columns that are inside
a column group.
Here is my sample table below: The Column Group is PeriodNumber and can only choose 2. like 1 and 2.. I would like to have a third row which will simply calculate the difference between the amounts in PeriodNumber 1 and 2.
PeriodNumber
Account 1 2
1) Cash 10,000 15,000
2) Receivables 12,000 11,500
3) Equipment 5,000 5,500
Total Assets 27,000 32,000

Hi yabgestopa,
From your description, you want to get the difference between two columns in a column group. After testing it in my environment, we can use custom code to achieve your requirement. For more details, you can refer to the following steps:
Copy the custom code below and paste it to your report. (Right-click report>Report Properties>Code)
Dim Shared Num1 As Integer
Dim shared Num2 As Integer
Public Function GetAmount(Amount as Integer, Type as String)
If Type = "1" Then
Num1=Amount
Else
Num2=Amount
End If
Return Amount
End Function
Public Function GetDif()
Return Num1-Num2
End function
Right-click the second column to insert a third column with Outside Group-Right.
Then use the expressions below in the matrix.
=Code.GetAmount(Fields!Amount.Value,Fields!PeriodNumber.Value)
=code.GetAmount(Sum(Fields!Amount.Value),Fields!PeriodNumber.Value)
=Code.GetDif()
The report looks like below.
If you have any questions, please feel free to ask.
Thanks,
Katherine Xiong
Katherine Xiong
TechNet Community Support

Difference between two date in bex query

Hi all,
I need to do a difference between two date using formula variable processing type customer exit beaucause I must use factory calendar in the formula.
How can I do it?
Can you give me an example of the routine?
Thanks a lot
Gianmarco

Hi,
You can still use the same code to copy it and customize as per your need. All you need to do is to subract the dates using the class: CL_ABAP_TSTMP after converting to timestamp and resulting seconds you convert back to days....Please get help from the developers to do this...
Also, ensure that you write back this difference value to your variable so you get it on the reports for your calculations...
Cheers,
Emmanuel.

Find the difference between two internal table

how can i see the difference between two interal tables?
The requirement is as follows
1. We have a transparent table, which stores the employee data with EMP ID as key.
2. We load the transp table data into a interal table (B).
3. We get data from legecy system as file and it gets loaded into another internal table (A) (this also has the same EMP ID key and this will have latest addition/update to those emplyees).
Now we need to seperate out these data into three interal table Inserted (I), Deleted (D) and Updated (U).
We want to do followign things
I = A - B
D = B - A
Both A and B will have around 40k records. Hence we are trying to avoid the looping.
Please suggest the best option for us.
Thank you in advance.
Raghavendra

>
RAGHAV URAL wrote:
> how can i see the difference between two interal tables?
> The requirement is as follows
>
> 1. We have a transparent table, which stores the employee data with EMP ID as key.
> 2. We load the transp table data into a interal table (B).
> 3. We get data from legecy system as file and it gets loaded into another internal table (A) (this also has the same EMP ID key and this will have latest addition/update to those emplyees).
>
> Now we need to seperate out these data into three interal table Inserted (I), Deleted (D) and Updated (U).
>
> We want to do followign things
> I = A - B
> D = B - A
>
> Both A and B will have around 40k records. Hence we are trying to avoid the looping.
>
> Please suggest the best option for us.
>
> Thank you in advance.
> Raghavendra
Hi Raghavendra,
Currently as of my knowledge, these operations are only possible through LOOPs. But LOOPign can be really fast here if you properly utilize the SORTING, READ with BINARY SEARCH and FIELD-SYMBOLS usage. I would say:-
Steps for Insert:-
SORT: A, B.
LOOP AT A ASSIGNING <WA_A>.
READ TABLE B WITH TABLE KEY key = <WA_A>-key BINARY SEARCH.
IF SY-SUBRC NE 0.
APPEND <WA_A> TO I.
ENDIF.
ENDLOOP.
Steps for Delete:-
SORT: A, B.
LOOP AT B ASSIGNING <WA_B>.
READ TABLE A WITH TABLE KEY key = <WA_B>-key BINARY SEARCH.
IF SY-SUBRC NE 0.
APPEND <WA_B> TO D.
ENDIF.
ENDLOOP.
Regards,
Ravi.

Find the difference between two columns in an ssrs matrix ? MSCRM

Hi All,
I am working in reporting part of our project (On-line MSCRM 2013) & in reporting services.
I am trying to create report using fetch xml based. Below is the snap what we required the result.
Kindly help me, how to get the difference in both column. (Its a matrix table where year is grouped).
We need difference between both year Like (Plan Revenue of 2013 & Plan Revenue of 2014 difference in Plan Revenue Diff section) and same for Actual
Revenue.
https://social.microsoft.com/Forums/en-US/054d5ca4-0d38-4dc6-84a8-88866cc228fe/find-the-difference-between-two-columns-in-an-ssrs-matrix-mscrm?forum=crmdevelopment
Thanks,
Mohammad Sharique

Hi Bro,
I used parametrized option for year and done the report,Currently we are getting values in Difference column now i want to show
that value in percentage. How can we show the percentage based on that value. Means i want to show the Difference in Percentage.
Kindly help me i tried but getting some issue. Below i am mentioning the code and snap with result.
Below expression using to showing Plan Revenue in Percentage for year.
=
Sum(IIF(Fields!new_year.Value =Parameters!StartYear.Value,cdec(Fields!new_planrevenueValue.Value/1000), cdec(0)))
- Sum(IIF(Fields!new_year.Value =Parameters!EndYear.Value,cdec(Fields!new_planrevenueValue.Value/1000), cdec(0)))
/IIF(Sum(IIF(Fields!new_year.Value = Parameters!StartYear.Value,cdec(Fields!new_planrevenueValue.Value/1000), cdec(0)))>0,
(Sum(IIF(Fields!new_year.Value = Parameters!StartYear.Value,cdec(Fields!new_planrevenueValue.Value/1000), cdec(0))))
,1)
)*100))
Result issue is as below in snap with highlighted in red colour.
Kindly help me on this issue also :)

Extract Time from date and Time and Need XLMOD Funtion to find the Difference between Two Time.

X6 = "1/5/15 5:16 AM" & NOW ....................difference by Only Time
not date
X6 date and Time will be changing, Its not Constant
Dim myDateTime As DateTime = X6
            Dim myDate As String = myDateTime.ToString("dd/MM/yy")
            Dim myTime As String = myDateTime.ToString("hh:mm tt")
            Dim myDateTime1 As DateTime = Now
            Dim myDate1 As String = myDateTime1.ToString("dd/MM/yy")
            Dim myTime1 As String = myDateTime1.ToString("hh:mm tt")
Need to use this function to find the Difference between Two Time. due to 12:00 AM isuue
Function XLMod(a, b)
    ' This replicates the Excel MOD function
    XLMod = a - b * Int(a / b)
End Function
Output Required
dim dd = XLMod(myTime - myTime1)
Problem is myTime & myTime1 is String Need to convert them into Time, Later use XLMOD Funtion.

Induhar,
As an addendum to this, I thought I'd add this in also: If you have two valid DateTime objects you might consider using a class which I put together a few years ago
shown on a page of my website here.
To use it, just instantiate with two DateTime objects (order doesn't matter, it'll figure it out) and you'll then have access to the public properties. For this example, I'm just showing the .ToString method:
Option Strict On
Option Explicit On
Option Infer Off
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, _
ByVal e As System.EventArgs) _
Handles MyBase.Load
Dim date1 As DateTime = Now
Dim date2 As DateTime = #1/1/1970 2:35:00 PM#
Dim howOld As New Age(date1, date2)
MessageBox.Show(howOld.ToString, "Age")
Stop
End Sub
End Class
I hope that helps, if not now then maybe at some point in the future. :)
Still lost in code, just at a little higher level.
Thanx frank, can use this in Future....

Can counter measure pulse width difference between two signals

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