From 53db514d4201cb1ba9d0e94e5bd7b82bfee3cff9 Mon Sep 17 00:00:00 2001
From: Joe Taylor <joe@princeton.edu>
Date: Mon, 8 Jan 2024 08:56:26 -0500
Subject: [PATCH] Enable decoding of MSK144 in jt9[.exe].  Thanks to Alex,
 VE3NEA!

---
 CMakeLists.txt        |  1 +
 lib/decode_msk144.f90 | 57 +++++++++++++++++++++++++++++++++++++++++++
 lib/jt9.f90           | 14 ++++++++---
 lib/jt9a.f90          | 11 +++++++--
 4 files changed, 78 insertions(+), 5 deletions(-)
 create mode 100644 lib/decode_msk144.f90

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d3c0f86d6..d38f8be95 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -493,6 +493,7 @@ set (wsjt_FSRCS
   lib/msk144sim.f90
   lib/mskrtd.f90
   lib/nuttal_window.f90
+  lib/decode_msk144.f90
   lib/ft4/ft4sim.f90
   lib/ft4/ft4sim_mult.f90
   lib/ft4/ft4_downsample.f90
diff --git a/lib/decode_msk144.f90 b/lib/decode_msk144.f90
new file mode 100644
index 000000000..17110cf47
--- /dev/null
+++ b/lib/decode_msk144.f90
@@ -0,0 +1,57 @@
+subroutine decode_msk144(audio_samples, params, data_dir)
+  include 'jt9com.f90'
+
+  ! constants
+  integer, parameter :: SAMPLING_RATE = 12000
+  integer, parameter :: BLOCK_SIZE = 7168
+  integer, parameter :: STEP_SIZE = BLOCK_SIZE / 2
+  integer, parameter :: CALL_LENGTH = 12
+  
+  ! aguments
+  integer*2 audio_samples(NMAX)
+  type(params_block) :: params
+  character(len = 500) :: data_dir
+
+  ! parameters of mskrtd
+  integer*2 :: buffer(BLOCK_SIZE)
+  real :: tsec   
+  logical :: bshmsg = .false. ! enables shorthand messages  
+  logical :: btrain = .false. ! turns on training in MSK144 mode
+  real*8 :: pcoeffs(5) = (/ 0.0, 0.0, 0.0, 0.0, 0.0 /); ! phase equalization
+  logical :: bswl = .false.
+  character(len = 80) :: line
+  character(len = CALL_LENGTH) :: mycall 
+  character(len = CALL_LENGTH) :: hiscall
+
+  ! local variables
+  integer :: sample_count
+  integer :: position
+  integer :: message_count = 0
+
+
+  ! decode in 0.3s blocks
+  sample_count = params%ntr * SAMPLING_RATE
+  mycall = transfer(params%mycall, mycall)    ! string to char[]
+  hiscall = transfer(params%hiscall, hiscall)
+
+  do position = 1, sample_count - BLOCK_SIZE + 1, STEP_SIZE
+    buffer =  audio_samples(position : position + BLOCK_SIZE - 1)
+    tsec = position / REAL(SAMPLING_RATE)
+
+    call mskrtd(buffer, params%nutc, tsec, params%ntol, params%nfqso, params%ndepth, &
+      mycall, hiscall, bshmsg, btrain, pcoeffs, bswl, data_dir, line)
+
+    if (line(1:1) .ne. char(0)) then
+      line = line(1:index(line, char(0))-1)
+      write(*, 1001) line
+      1001 format(a80)
+      message_count = message_count + 1;
+    end if
+  end do
+
+  if (.not. params%ndiskdat) then
+    write(*, 1002) 0, message_count, 0
+    1002 format('<DecodeFinished>', 2i4, i9)
+  end if
+
+end subroutine decode_msk144
\ No newline at end of file
diff --git a/lib/jt9.f90 b/lib/jt9.f90
index 3621a0a9f..d284f6dd2 100644
--- a/lib/jt9.f90
+++ b/lib/jt9.f90
@@ -27,7 +27,7 @@ program jt9
   logical :: read_files = .true., tx9 = .false., display_help = .false.,     &
        bLowSidelobes = .false., nexp_decode_set = .false.,                   &
        have_ntol = .false.
-  type (option) :: long_options(32) = [                                      &
+  type (option) :: long_options(33) = [                                      &
     option ('help', .false., 'h', 'Display this help message', ''),          &
     option ('shmem',.true.,'s','Use shared memory for sample data','KEY'),   &
     option ('tr-period', .true., 'p', 'Tx/Rx period, default SECONDS=60',    &
@@ -64,6 +64,7 @@ program jt9
     option ('ft8', .false., '8', 'FT8 mode', ''),                            &
     option ('jt9', .false., '9', 'JT9 mode', ''),                            &
     option ('qra64', .false., 'q', 'QRA64 mode', ''),                        &
+    option ('msk144', .false., 'k', 'MSK144 mode', ''),                      &    
     option ('QSOprog', .true., 'Q', 'QSO progress (0-5), default PROGRESS=1',&
         'QSOprogress'),                                                      &
     option ('sub-mode', .true., 'b', 'Sub mode, default SUBMODE=A', 'A'),    &
@@ -91,7 +92,7 @@ program jt9
   TRperiod=60.d0
 
   do
-     call getopt('hs:e:a:b:r:m:p:d:f:F:w:t:9876543WYqTL:S:H:c:G:x:g:X:Q:',     &
+     call getopt('hs:e:a:b:r:m:p:d:f:F:w:t:9876543WYqkTL:S:H:c:G:x:g:X:Q:',     &
           long_options,c,optarg,arglen,stat,offset,remain,.true.)
      if (stat .ne. 0) then
         exit
@@ -129,7 +130,9 @@ program jt9
            read (optarg(:arglen), *) fhigh
         case ('q')
            mode = 164
-        case ('Q')
+         case ('k')
+           mode = 144
+         case ('Q')
            read (optarg(:arglen), *) nQSOProg
         case ('3')
            mode = 66
@@ -352,7 +355,12 @@ program jt9
         call multimode_decoder(shared_data%ss,id2a,      &
              shared_data%params,nfsample)
         cycle
+
+     ! MSK144        
+     else if (mode .eq. 144) then
+      call decode_msk144(shared_data%id2, shared_data%params, data_dir)
      endif
+
 ! Normal decoding pass
      call multimode_decoder(shared_data%ss,shared_data%id2, &
           shared_data%params,nfsample)
diff --git a/lib/jt9a.f90 b/lib/jt9a.f90
index f9399f4a0..546ef9246 100644
--- a/lib/jt9a.f90
+++ b/lib/jt9a.f90
@@ -70,8 +70,15 @@ subroutine jt9a()
      call multimode_decoder(shared_data%ss,id2a,local_params,12000)
      local_params%nzhsym=50
   endif
-! Normal decoding pass
-  call multimode_decoder(shared_data%ss,shared_data%id2,local_params,12000)
+
+  if(local_params%nmode .eq. 144) then
+    ! MSK144
+    call decode_msk144(shared_data%id2, shared_data%params, data_dir)
+  else
+    ! Normal decoding pass
+    call multimode_decoder(shared_data%ss,shared_data%id2,local_params,12000)
+  endif
+
   call timer('decoder ',1)