From fb19d27602b5e05d9d8d4552f6bbf0dc2c8c32f9 Mon Sep 17 00:00:00 2001
From: Joe Taylor <joe@princeton.edu>
Date: Mon, 19 Feb 2024 13:23:42 -0500
Subject: [PATCH] Compute signal power, noise power, and SNR_2500 explicitly in
ft8sim.f90.
---
lib/ft8/ft8sim.f90 | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/lib/ft8/ft8sim.f90 b/lib/ft8/ft8sim.f90
index fd18dff4f..5943bd082 100644
--- a/lib/ft8/ft8sim.f90
+++ b/lib/ft8/ft8sim.f90
@@ -101,14 +101,24 @@ program ft8sim_gfsk
wave=imag(c)
peak=maxval(abs(wave))
nslots=1
-
+
+ psig=0.
+ pnoise=0.
if(snrdb.lt.90) then
do i=1,NMAX !Add gaussian noise at specified SNR
xnoise=gran()
+ if(i.ge.6001 .and. i.le.157692) then
+ psig=psig + wave(i)*wave(i) !Signal power
+ pnoise=pnoise + xnoise*xnoise !Noise power in signal interval
+ endif
wave(i)=wave(i) + xnoise
enddo
endif
+! Noise power in signal interval and 2500 Hz bandwidth:
+ pnoise=bandwidth_ratio*pnoise
+ snr_2500=db(psig/pnoise) !SNR in 2500 Hz bandwidth
+
gain=100.0
if(snrdb.lt.90.0) then
wave=gain*wave
@@ -125,7 +135,7 @@ program ft8sim_gfsk
open(10,file=fname,status='unknown',access='stream')
write(10) h,iwave !Save to *.wav file
close(10)
- write(*,1110) ifile,xdt,f0,snrdb,fname
-1110 format(i4,f7.2,f8.2,f7.1,2x,a17)
+ write(*,1110) ifile,xdt,f0,snrdb,fname,snr_2500
+1110 format(i4,f7.2,f8.2,f7.1,2x,a17,f8.2)
enddo
999 end program ft8sim_gfsk