w4kek/WSJT-X
1
0
Fork 0
mirror of https://github.com/saitohirga/WSJT-X.git synced 2024-11-29 07:39:43 -05:00
Code Issues Packages Projects Releases Wiki Activity

Add degrade_snr.f90

Browse Source 
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6167 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Joe Taylor 2015-11-23 18:20:55 +00:00
parent 621b1dde9f
commit 29616b0f96
1 changed files with 20 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
lib/degrade_snr.f90 Normal file
View File

@ -0,0 +1,20 @@
subroutine degrade_snr(d2,npts,db)
integer*2 d2(npts)
real dat(60*12000)
dat(1:npts)=d2
p0=dot_product(dat(1:npts),dat(1:npts))/npts
s=sqrt(p0*(10.0**(0.1*db) - 1.0))
do i=1,npts
d2(i)=nint(dat(i) + s*gran())
enddo
! dat(1:npts)=d2
! p1=dot_product(dat(1:npts),dat(1:npts))/npts
! print*,db,p0,s,10.0*log10(p1/p0)
return
end subroutine degrade_snr