2005-12-22 11:40:53 -05:00
|
|
|
subroutine detect(data,npts,f,y)
|
|
|
|
|
|
|
|
|
|
C Compute powers at the tone frequencies using 1-sample steps.
|
|
|
|
|
|
|
|
|
|
parameter (NZ=11025,NSPD=25)
|
|
|
|
|
real data(npts)
|
|
|
|
|
real y(npts)
|
|
|
|
|
complex c(NZ)
|
|
|
|
|
complex csum
|
|
|
|
|
data twopi/6.283185307/
|
|
|
|
|
|
|
|
|
|
dpha=twopi*f/11025.0
|
|
|
|
|
do i=1,npts
|
|
|
|
|
c(i)=data(i)*cmplx(cos(dpha*i),-sin(dpha*i))
|
|
|
|
|
enddo
|
|
|
|
|
|
|
|
|
|
csum=0.
|
|
|
|
|
do i=1,NSPD
|
|
|
|
|
csum=csum+c(i)
|
|
|
|
|
enddo
|
|
|
|
|
|
2006-04-05 16:07:32 -04:00
|
|
|
y(1)=real(csum)**2 + aimag(csum)**2
|
2005-12-22 11:40:53 -05:00
|
|
|
do i=2,npts-(NSPD-1)
|
|
|
|
|
csum=csum-c(i-1)+c(i+NSPD-1)
|
2006-04-05 16:07:32 -04:00
|
|
|
y(i)=real(csum)**2 + aimag(csum)**2
|
2005-12-22 11:40:53 -05:00
|
|
|
enddo
|
|
|
|
|
|
|
|
|
|
return
|
|
|
|
|
end
|
