Operator`s manual

SECTION 8. PROCESSING AND PROGRAM CONTROL EXAMPLES
8-13
TABLE 8.8-3. FFT Power Spectra Results
0.25 and 1.25 Hz Signal
BIN # Hz FFT PSi
0 0 1.0859
.
22 0.214852 0
23 0.224618 0.49212
24 0.234384 84.152
25 0.24415 811.01
26 0.253916 980.79*
27 0.263682 162.4
28 0.273448 1.4764
29 0.283214 0
.
125 1.22075 0
126 1.230516 3.9369
127 1.240282 108.76
128 1.250048 284.94*
129 1.259814 108.76
130 1.26958 3.9369
131 1.279346 0
.
511 4.990426 0
Program: The first part of this program
generates a dummy data set that represents two
signals superimposed on top of each other. One
signal has a frequency of 1.25 Hz and a zero to
peak amplitude of 1 while the other signal has a
frequency of .25 Hz and a zero to peak
amplitude of 2. The data simulates a sampling
rate of 10 Hz or a .1 sec scan rate.
This program generates power spectra FFT
results with out bin averaging.
Flag Usage: Flag 1 is automatically set once
the inst. have been executed once.
* 1 Table 1 Programs
01: 1 Sec. Execution Interval
01: P91 If Flag
01: 11 1 is set
02: 0 Go to end of Program Table
The 2nd through 11th instructions are used to
generate and combine the 1.25 and 0.25 Hz
signals for the FFT.
02: P30 Z=F
01: 0 F
02: 1025 Z Loc :
03: P30 Z=F
01: 0 F
02: 1026 Z Loc :
04: P87 Beginning of Loop
01: 0 Delay
02: 1024 Loop Count
05: P48 Z=SIN(X)
01: 1025 X Loc
02: 1027 Z Loc :
06: P48 Z=SIN(X)
01: 1026 X Loc
02: 1028 Z Loc :
07: P37 Z=X*F
01: 1028 X Loc
02: 2 F
03: 1028 Z Loc :
08: P33 Z=X+Y
01: 1027 X Loc
02: 1028 Y Loc
03: 1-- Z Loc :
09: P34 Z=X+F
01: 1025 X Loc
02: 45 F
03: 1025 Z Loc :
10: P34 Z=X+F
01: 1026 X Loc
02: 9 F
03: 1026 Z Loc :
11: P95 End
The FFT is now computed and the power
spectra results sent to Final Storage.
12: P60 FFT (OSX-2)
01: 10 Log(base 2) of Samples
02: 1 Power Spectra/Taper
03: 0 Log(base 2) of Bins
04: 1 First Sample Loc
05: 1 Multiplier