Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.mso.anu.edu.au/~fbriggs/WAARNEEM/build_data.5.sm Дата изменения: Tue Oct 9 09:59:07 2001 Дата индексирования: Sat Dec 22 06:09:09 2007 Кодировка:

define N 1024
set x=1,$N
erase
window 1 1 1 1

limits 0 $N -.7 0.7
box
ptype 1 1
# generate a lot of points to uniformly cover -0.5 to 0.5
# -and- at the same time do averages of 10 samples => pseudo-gaussian
set y=x*0
do i=1,10 {
set t=random($N)-0.5
set y=y+t
}
set z=x*0
do i=1,10 {
set t=random($N)-0.5
set z=z+t
}
echo * Uniformly Distributed between -0.5 and 0.5 *
toplabel * Uniformly Distributed between -0.5 and 0.5 *
# use call to "cursor" in order to pause
# cursor
# prepare and plot the pseudo gaussian points
set y[0]=0
set y[$($N-1)]=0
set y=y/10
set z[0]=0
set z[$($N-1)]=0
set z=z/10
set s=0.15*cos(6.2832*x*100/$N)*exp(-((x-450)/60)**2)
set r=0.15*sin(6.2832*x*100/$N)*exp(-((x-450)/60)**2)
set y=y+s
set z=z+r

# print data.5 {y z}

set aa=sqrt(y*y*z*z)


# FIRST PLOT is just the REAL PART (noise+signal)
lweight 1
erase
ctype default
limits x y
box
connect x y
# set s=abs(x-450)<40?.06:0
ctype blue
# cursor
lweight 3
# connect x s
lweight 1
set ynew=y
ctype 0
cursor
# ADD to FIRST PLOT... the REAL SIGNAL (green)
ctype green
connect x s
cursor
# ADD to FIRST PLOT... the IMAGINARY SIGNAL (red)
ctype red
connect x r
ctype 0
# ADD to FIRST PLOT... smoothed REAL SIGNAL (blue)
smooth ynew ysmo 50
ctype blue
connect x ysmo
ctype 0
stats ysmo ave sig kur
cursor

# SECOND PLOT: Amplitude = sqrt(R**2+I**2)
erase
limits x aa
box
connect x aa
# ADD smoothed Amplitude
smooth aa asmo 60
ctype blue
connect x asmo
ctype 0

cursor
# THIRD PLOT ... the FFT amplitude
set yi=z *-1.0**int(x)
set ynew=ynew*-1.0**int(x)
fft 1 ynew yi re im
set a=sqrt(re*re+im*im)
limits x a
erase
box
connect x a
stats a ave sig kur
echo ...
echo stats a ave sig kur
echo ave=$ave sigma=$sig
echo ...
echo vecminmax a mn mx
vecminmax a mn mx
echo min=$mn max=$mx
echo

# FOURTH PLOT: only + frequencies of FFT (amplitudes)
cursor
erase
set x=1,1024
set x=x-513
limits 0 512 a
box
connect x a
relocate (16000 23000)
label Amplitude of FFT coefs
# FIFTH PLOT: the POWER SPECTRUM
cursor
set amp=a*a
erase
vecminmax amp an ax
limits 0 512 amp
box 1 2 3 3
connect x amp
relocate (18000 26000)
label Power Spectrum

# sixth plot filtered signal
cursor
ctype red
set wgt=0*amp
set wgt=x>91 &&x<108 ? 1:0
set re=re*wgt
set im=im*wgt
set wgt=wgt*$ax
connect x wgt
ctype 0
fft -1 re im yr yi
set t=1,1024
set yr=yr*(-1)**t
set yi=yi*(-1)**t
vecminmax yr yn yx
limits t $($yx-2.5*($yx-$yn)) $yx
box 3 3 1 2
connect t yr
ctype red
cursor
connect t yi
ctype 0

cursor
set wgt=exp(-((x-100)/7)**2)
set re=re*wgt
set im=im*wgt
ctype blue
set wgt=wgt*$ax
limits 0 512 amp
connect x wgt
fft -1 re im yr yi
set yr=yr*(-1)**t-($yx-$yn)
set yi=yi*(-1)**t-($yx-$yn)
limits t $($yx-2.5*($yx-$yn)) $yx
connect t yr
ctype green
cursor
connect t yi
ctype 0