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- .MCD 11000 0
- .TXT 1 0 1 23
- 1,23
- IT ALL GOES TOGETHER:
- .TXT 0 24 3 54
- 3,54
- With standard math notation and text to explain what
- you did, your MathCAD documents are A COMPLETE,
- PRESENTATION-QUALITY RECORD OF YOUR CALCULATIONS.
- .TXT 3 -24 1 76
- 1,76
- --------------------------------------------------------------------------
- .TXT 1 0 1 32
- 1,32
- FAST FOURIER TRANSFORM EXAMPLE
- .TXT 2 5 1 45
- 1,45
- Generate sine curve with a random component
- .TXT 0 53 1 13
- 1,13
- TIME DOMAIN
- .EQN 1 -38 3 30
- ! rd=d ct=10 im=i et=6 zt=15 pr=3 mass length time charge
- x[k:sin(k*π/8)+rnd(1)-.5
- .EQN 0 34 7 20
- 2&-2&x[k{1,1,6,15,l}@16&0&k
- .EQN 1 -48 1 12
- k~0;15
- .TXT 3 -1 2 37
- 2,37
- Now take the transform of the curve
- and look at the power spectrum:
- .EQN 3 10 1 14
- z:cfft(x)
- .TXT 0 22 1 18
- 1,18
- FREQUENCY DOMAIN
- .EQN 1 -6 7 24
- 3&0&|z[k,0{1,1,6,15,e}@16&0&k
- .TXT 1 -26 2 20
- 2,20
- The spectrum shows
- two peaks:
- .EQN 2 3 2 23
- z[1=(-0.078+2.14i)?
- .EQN 2 0 2 24
- z[15=(-0.078-2.14i)?
-