A
Antonio
Morning all
Need to calculate time cycles, can anyone help??
Tks in advance
Need to calculate time cycles, can anyone help??
Tks in advance
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P
Pete_UK
Well perhaps ... if you can explain what you mean in a bit more
detail.
Pete
detail.
Pete
S
Stephen
Antonio said:Morning all
Need to calculate time cycles, can anyone help??
Tks in advance
In Excel, dates are stored as number of days since 31st Dec 1899 (that is,
one day =1). So, for example, today (3rd Dec 2007) is 39419. Time is just
the fractional part of these numbers. 6:00am is quarter of the way through
the day, so 6:00am this morning is 39419.25. Formatting just displays these
numbers in a conventional date/time format. But once you understand the
underlying numbers, you can calculate with them as you wish. If you still
need help, please explain what you mean by "time cycles".
A
Antonio
Hi Pete
Have two columns
1st date and 2nd temp. Need to find the temp cycles over time
Tks
Have two columns
1st date and 2nd temp. Need to find the temp cycles over time
Tks
B
Bob Phillips
That adds nothing to your first post.
Give a worked through example and then show what your starting data will
look like.
--
---
HTH
Bob
(there's no email, no snail mail, but somewhere should be gmail in my addy)
Give a worked through example and then show what your starting data will
look like.
--
---
HTH
Bob
(there's no email, no snail mail, but somewhere should be gmail in my addy)
A
Antonio
Hi again
Pls advise a email to where to send data
Tks in advance
Pls advise a email to where to send data
Tks in advance
H
Herbert Seidenberg
Assume your data looks like the one posted at
http://tinyurl.com/3c8o9t
Fourier Analysis will be used to find the period of the waveform.
Cut the 2 columns to 128 row.
Only lengths of 64, 128, 256 etc are allowed.
Name the 2 columns MyTime and MyVal.
Shown here are only 4 of 128 data rows:
MyTime MyVal FFT MyPower MyPowCu MyFreq
1.00E-11 0.19
-21.7
1.00E-07 0.00 -30.5-6.5i 972.9 972.9
9.922E-08
2.00E-07 -0.19 -38.2-3.1i 1473.3 2446.2
1.984E-07
3.00E-07 -1.24 -42.5+3.5i 1820.6 4266.9 2.977E-07
Half_Area
226338
Period
1.091E-06
Tools > Data Analysis > Fourier Analysis
Input Range: MyVal
Output Range: FFT
If the above matrix starts at A1, enter at D3, E3 and F3 respectively
=IMABS(C3)^2
=MyPower+E2
=(ROW()-2)*(MAX(MyTime)-MIN(MyTime))/COUNTA(MyTime)
Copy them down and name the ranges as shown in the above table.
Half_Area and Period have these formulas
=INDEX(MyPowCu,COUNTA(MyVal)/2+1,)/2
=LOOKUP(Half_Area,MyPowCu,MyFreq)
http://tinyurl.com/3c8o9t
Fourier Analysis will be used to find the period of the waveform.
Cut the 2 columns to 128 row.
Only lengths of 64, 128, 256 etc are allowed.
Name the 2 columns MyTime and MyVal.
Shown here are only 4 of 128 data rows:
MyTime MyVal FFT MyPower MyPowCu MyFreq
1.00E-11 0.19
-21.7
1.00E-07 0.00 -30.5-6.5i 972.9 972.9
9.922E-08
2.00E-07 -0.19 -38.2-3.1i 1473.3 2446.2
1.984E-07
3.00E-07 -1.24 -42.5+3.5i 1820.6 4266.9 2.977E-07
Half_Area
226338
Period
1.091E-06
Tools > Data Analysis > Fourier Analysis
Input Range: MyVal
Output Range: FFT
If the above matrix starts at A1, enter at D3, E3 and F3 respectively
=IMABS(C3)^2
=MyPower+E2
=(ROW()-2)*(MAX(MyTime)-MIN(MyTime))/COUNTA(MyTime)
Copy them down and name the ranges as shown in the above table.
Half_Area and Period have these formulas
=INDEX(MyPowCu,COUNTA(MyVal)/2+1,)/2
=LOOKUP(Half_Area,MyPowCu,MyFreq)
B
Bob Phillips
Oh no, I mean lay it out in text form here.
--
---
HTH
Bob
(there's no email, no snail mail, but somewhere should be gmail in my addy)
--
---
HTH
Bob
(there's no email, no snail mail, but somewhere should be gmail in my addy)