diff --git a/lib/fsk4hf/genwspr5.f90 b/lib/fsk4hf/genwspr5.f90
index 1788e07bd..c052fa2ce 100644
--- a/lib/fsk4hf/genwspr5.f90
+++ b/lib/fsk4hf/genwspr5.f90
@@ -1,6 +1,6 @@
subroutine genwspr5(msg,ichk,msgsent,itone,itype)
-!Encode a WSPR-LF message, produce itone() array.
+! Encode a WSPR-LF message, producing array itone().
use crc
include 'wsprlf_params.f90'
diff --git a/lib/fsk4hf/wspr5_downsample.f90 b/lib/fsk4hf/wspr5_downsample.f90
index 8c8d4f59a..6fdb9021d 100644
--- a/lib/fsk4hf/wspr5_downsample.f90
+++ b/lib/fsk4hf/wspr5_downsample.f90
@@ -1,5 +1,8 @@
subroutine wspr5_downsample(iwave,c)
+! Input: i*2 data in iwave() at sample rate 12000 Hz
+! Output: Complex data in c(), sampled at 400 Hz
+
include 'wsprlf_params.f90'
parameter (NMAX=300*12000,NFFT2=NMAX/30)
integer*2 iwave(NMAX)
diff --git a/lib/fsk4hf/wspr5_wav.f90 b/lib/fsk4hf/wspr5_wav.f90
index 32e4f90a6..0b09ccde2 100644
--- a/lib/fsk4hf/wspr5_wav.f90
+++ b/lib/fsk4hf/wspr5_wav.f90
@@ -1,5 +1,7 @@
subroutine wspr5_wav(baud,xdt,f0,itone,snrdb,iwave)
+! Generate iwave() from itone().
+
include 'wsprlf_params.f90'
parameter (NMAX=300*12000)
integer itone(NN)
diff --git a/lib/fsk4hf/wspr5d.f90 b/lib/fsk4hf/wspr5d.f90
index dc73d7170..7059140d0 100644
--- a/lib/fsk4hf/wspr5d.f90
+++ b/lib/fsk4hf/wspr5d.f90
@@ -1,9 +1,9 @@
program wspr5d
-! Simulate characteristics of a potential "WSPR-LF" mode using LDPC (300,60)
-! code, OQPSK modulation, and 5 minute T/R sequences.
+! Decode WSPR-LF data read from *.c5 or *.wav files.
-! Q: Would it be better for central Sync array to use both I and Q channels?
+! WSPR-LF is a potential WSPR-like mode intended for use at LF and MF.
+! It uses an LDPC (300,60) code, OQPSK modulation, and 5 minute T/R sequences.
! Reception and Demodulation algorithm:
! 1. Compute coarse spectrum; find fc1 = approx carrier freq
@@ -14,6 +14,8 @@ program wspr5d
! 6. Fit complex ploynomial for channel equalization
! 7. Get soft bits from equalized data
+! Still to do: find and decode more than one signal in the specified passband.
+
include 'wsprlf_params.f90'
parameter (NMAX=300*12000)
character arg*8,message*22,cbits*50,infile*80,fname*16
@@ -111,8 +113,7 @@ program wspr5d
a(2:5)=0.
call twkfreq1(c,NZ,fs,a,c) !Mix c down by fc1+fc2
-!---------------------------------------------------------------- DT
-! Not presently used:
+! Find time offset xdt
amax=0.
jpk=0
iaa=0
diff --git a/lib/fsk4hf/wspr5sim.f90 b/lib/fsk4hf/wspr5sim.f90
index 5a3b78c9e..c7326a2dc 100644
--- a/lib/fsk4hf/wspr5sim.f90
+++ b/lib/fsk4hf/wspr5sim.f90
@@ -1,6 +1,7 @@
program wspr5sim
-! Generate simulated data for the 5-minute "WSPR-LF" mode.
+! Generate simulated data for a 5-minute "WSPR-LF" mode. Output is saved
+! to a *.c5 or *.wav file.
use wavhdr
include 'wsprlf_params.f90' !Set various constants
@@ -12,7 +13,7 @@ program wspr5sim
complex c(0:NZ-1)
real*8 fMHz
integer itone(NN)
- integer*2 iwave(NMAX) !Generated full-length waveform
+ integer*2 iwave(NMAX) !Generated full-length waveform
! Get command-line argument(s)
nargs=iargc()
@@ -45,7 +46,7 @@ program wspr5sim
if(snrdb.gt.90.0) sig=1.0
txt=NN*NSPS0/12000.0
- call genwspr5(msg,ichk,msgsent,itone,itype) !Encode the message, get itone()
+ call genwspr5(msg,ichk,msgsent,itone,itype) !Encode the message, get itone
write(*,1000) f0,xdt,txt,snrdb,nfiles,msgsent
1000 format('f0:',f9.3,' DT:',f6.2,' txt:',f6.1,' SNR:',f6.1, &
' nfiles:',i3,2x,a22)
@@ -55,7 +56,7 @@ program wspr5sim
phi=0.0
c0=0.
k=-1 + nint(xdt/dt)
- do j=1,NN
+ do j=1,NN !Generate OQPSK waveform from itone
dphi=dphi0
if(itone(j).eq.1) dphi=dphi1
if(k.eq.0) phi=-dphi
@@ -67,7 +68,7 @@ program wspr5sim
if(k.ge.0 .and. k.lt.NZ) c0(k)=cmplx(cos(xphi),sin(xphi))
enddo
enddo
- c0=sig*c0 !Scale to requested sig level
+ c0=sig*c0 !Scale to requested sig level
do ifile=1,nfiles
if(nwav.eq.0) then
@@ -83,7 +84,7 @@ program wspr5sim
open(10,file=fname,status='unknown',access='stream')
fMHz=10.1387d0
nmin=5
- write(10) fname,nmin,fMHz,c
+ write(10) fname,nmin,fMHz,c !Save to *.c5 file
close(10)
else
call wspr5_wav(baud,xdt,f0,itone,snrdb,iwave)
@@ -91,7 +92,7 @@ program wspr5sim
write(fname,1102) ifile
1102 format('000000_',i4.4,'.wav')
open(10,file=fname,status='unknown',access='stream')
- write(10) h,iwave !Save the .wav file
+ write(10) h,iwave !Save to *.wav file
close(10)
endif
write(*,1110) ifile,xdt,f0,snrdb,fname