C+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
C
C     F F T S    -  General FFT program with optimisations for the IFPAN
C                   multipulse schemes of chirped-pulse
C                   and Balle-Flygare cavity spectroscopy
C
C+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
c
c
C    This program was described in: -
c       Z.Kisiel, J.Kosarzewski, Acta Physica Polonica 131,311-317(2017)
c    which is recommended for citing the use of FFTS.
c
c
C    FFTS can read these types of files on input:
c
c    1/ Files converted from the multipulse traces averaged with the LeCroy 735
c       oscilloscope and saved as .TRC files.  These are to be first converted to
c       .FID files by using the program WF735.  Each .FID is compatible with
c       the .SPE standard, but is accompanied by a .TRC.INF file containing information
c       about the oscilloscope waveform and pulsing parameters.
c
C    2/ Binary FID files in the .FFT standard where microwave multi-pulsing per
C       single gas pulse has been coadded.  The FIDs can be:
C       (i) chirped pulse excitation files (multi Mpt files supported)
C      (ii) cavity FTMW files from single frequency conversion (typically to 20 MHz)
C     (iii) cavity FTMW files from double frequency conversion to zero IF (in this
C           case the display is treated as +ve sideband only)
C
C    3/ Two column ASCII FID files in (time,intensity) format, where time has to be
C       increasing in uniform increments.
C       This is the most general input option, but once in the FFT screen it is
C       recommended that the data is saved as a binary .FFT file since this is
C       a compact representation with 4-bytes used per point intensity, and little
C       additional overhead.
C
c    4/ .DAT files form the FTMW++ program of Jen-Uwe Grabow
c
C
C    On loading the .FID file the program first checks for the .TRC.INF file,
C    which should begin with a header similar to the examples further below
C    (the column of C's has been inserted at the beginning for use in this listing)
c
C+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
C
C   Version  27a.VIII.2023                        ----- Zbigniew KISIEL -----
C
C                          __________________________________________________
C                         | Institute of Physics, Polish Academy of Sciences |
C                         | Al.Lotnikow 32/46, Warszawa, POLAND              |
C                         |                             kisiel@ifpan.edu.pl  |
C                         |     http://info.ifpan.edu.pl/~kisiel/prospe.htm  |
C_________________________/--------------------------------------------------
C
C
C  Modification history:
C
C  25.09.12: hacked out of FTMW_20 by knocking out all routines relating
C            to experiment
C  19.02.13: more pruning and .CFG file
C  22.02.13: drag-and-drop file input, binary input + many small bugs
C  23.07.13: mods enforced by first chirped pulse spectra
C   1.08.13: more chirped-pulse tweaks
C  18.09.13: use of alternative FFT windowing functions
C  27.09.13: sorting out input, output and display issues and FFT snippets
C   9.10.13: incremental mods
C  29.11.13: autoscaling and R around the chirp region
C   2.12.13: solved n>0 problem and better interferogram display compression
c   9.12.13: f-domain compression, incremental mods and debugging
c  12.12.13: general sine wave subtraction and three types of input
c  15.12.13: further debugging of display and output
c  31.12.13: tweaks to ^V
c   4.02.14: tweaking and debugging of the V option
c  20.02.14: C option for inspection of the excitation part of the FID
c   6.04.14: The '=' option prints also intensity information
C  14.04.14: Major reworking of arrays so that all large ones are ALLOCATABLE
C  15.04.14: The Am display scheme
c  17.04.14: Many further incremental mods
c  17.11.14: Introduction of FFTS.LOG file and incremental mods
c  30.11.14: Subtraction of selected spurious peak with ^O + mods
C  12.03.15: More debugging+small mods
C   2.04.15: Many incremental mods+debugging: including pulse exclusion, comment at
C            the end of .TRC.INF, ^V blanking
C  23.04.15: consistent display of mV amplitudes, more debugging
C  13.05.15: debugging
C   4.03.16: debugging ctrlP option + enhancements
C  16.05.16: more tweaks
C  27.01.17: better dynamic range of output and tidier naming of output filenames
C  17.02.17: tidying up prior to public release
C  28.09.18: units of time on ASCII input + much debugging of outputs
C  22.01.20: debugging of RNREP flaw + enhancements
C  24.01.20: option to read .DAT files from FTMW++ of J-U.Grabow
C  11.06.20: mods to V option Y-scaling, Am mode + many other
C  18.06.20: experimental ctrl K opion (only relevant for local use)
C   2.07.20: mods to info saved in .FFT files
C  10.07.20: option to center on frequency difference+chirp display mod
C  28.09.20: graphics tweaks to avoid setting XP compatibility for Windows10
C  23.11.20: ctrl Z option for zeroing FID points
C  24.03.22: debugging display and input issues
C  14.04.22: automatic removal of predefined spurious constant amplitude components
C   4.07.23: better compatibility with .FFT files from VKIEL + small mods
C  25.08.23: n=6 tweak for WG-FTMW files, VS2015/IVF2016/W11 compatibility
C
C
C/////////////////////////////////////////////////////////////////////////////
c
c    Each .FID type waveform is to be accompanied by a .TRC.INF file
c    containing information on the scope waveform and on pulsing parameters.
c    The pulsing parameters are copied over from the PULSE2A.CFG file used by
c    the PULSE2A program, with examples given as below.
c
C
c    For supersonic chirped pulse operation with horns:
c
C================================================================================
CPulsing conditions:
C================================================================================
C!
C          Total FID time (microseconds) =     1000.000
C                     Number of MW shots =       20
C  Nozzle to first MW time, Tau.del (us) =      930.000
C Input PIN opening time, Tau.PINin (us) =        4.100
C   Output PIN blocking, Tau.PINout (us) =        6.100
C          Gas pulse spacing, IWAIT (ms) =      200
C!
C       Microwave centre frequency (MHz) =     7345.000
C                  ARB sweep range (MHz) =      100.000    -1120.0000000000
C
C================================================================================
C
C
C    For supersonic expansion operation with FP cavity (standard rectangular
C    pulse excitation):
C
C================================================================================
CPulsing conditions:
C================================================================================
C!
C          Total FID time (microseconds) =     1000.000
C                     Number of MW shots =        8
C  Nozzle to first MW time, Tau.del (us) =     1000.000
C Input PIN opening time, Tau.PINin (us) =        1.100
C   Output PIN blocking, Tau.PINout (us) =       10.100
C          Gas pulse spacing, IWAIT (ms) =      200
C!
C       Microwave centre frequency (MHz) =    11119.700
C       +- ARB sweep and signed IF (MHz) =        1.000      -20.2780090000
C
C================================================================================
C
C
C    For room-temperature chirped pulse operation with FP cavity:
C
C================================================================================
CPulsing conditions:
C================================================================================
C!
C          Total FID time (microseconds) =     5000.000
C                     Number of MW shots =      100
C  Nozzle to first MW time, Tau.del (us) =        0.000
C Input PIN opening time, Tau.PINin (us) =        1.500
C   Output PIN blocking, Tau.PINout (us) =       15.000
C          Gas pulse spacing, IWAIT (ms) =       40
C!
C       Microwave centre frequency (MHz) =    12200.630
C                  ARB sweep range (MHz) =        1.000      -20.2780090000
C
C================================================================================
C
C
C    For room-temperature chirped pulse operation with FP cavity maximising
C    the duty cycle (55.5% in this case):
C
C================================================================================
CPulsing conditions:
C================================================================================
C!
C          Total FID time (microseconds) =   200000.000
C                     Number of MW shots =     4000
C  Nozzle to first MW time, Tau.del (us) =      100.000
C Input PIN opening time, Tau.PINin (us) =        1.100
C   Output PIN blocking, Tau.PINout (us) =       10.100
C          Gas pulse spacing, IWAIT (ms) =      360
C!
C       Microwave centre frequency (MHz) =    12162.720
C       +- ARB sweep and signed IF (MHz) =        1.000      -20.2780090000
C
C================================================================================
C
C
C     When the program does not find such a .TRC.INF file then it will check
C     in the C:\FFT_CHIRPED directory for the FFTS.CFG file, which can look as follows
C     (leading C column inserted for this listing):
C
C!------------------------------------------------------------------------------
C!
C!   Multipulse compression options for FFTS
C!
C!----------------------------------------......................................
C!
C            Intermediate frequency /MHz:    -20.278014
C              number of microwave shots:     100
C                 Carrier frequency /MHz:   12200.630
C                                 nskips:     100
C                                 nskipe:     100
C!
C!------------------------------------------------------------------------------
C
C
C/////////////////////////////////////////////////////////////////////////////
C
C-----------------------------------------------------------------------------
C    C O M P I L A T I O N:
C-----------------------------------------------------------------------------
C
c     NOTE: Since character casing wasn't important in MSF5 it is useful to ensure
c           case uniformity - (in VISUAL STUDIO) this is done by setting in
c           PROJECT SETTINGS->FORTRAN->FORTRAN LANGUAGE
c           Name interpretation = lower case this is equivalent to command line
c           option /names:lowercase
c           (this is actually the same option that is set in the
c            EXTERNAL PROCEDURES section)
c
c
C    This version compiles with Intel Visual Fortran 9.0 to 12.x, although
C    only the most recent Fortran version is used routinely.
C    Module names in USE statements have been changed from the Compaq DF names
C    (which still work) to IF names:
C
C    DFLIB->IFQWIN,  DFWIN->IFWIN,  DFMT->IFMT,  DFPORT->IFPORT
C
C    1. DFWINTY not necessary since USE IFWIN seems sufficient
C    2. GETCHARQQ requires USE IFCORE instead of USE IFQWIN
C    3. The USE of a module which USEs some IF modules eliminates the need to
C       specify those modules again in a given program segment
c
c
C     Compilation options for Intel Visual Fortran XE 2011:
C
C     /nologo /arch:IA32 /fpscomp:filesfromcmd /warn:unused /Qsave
C     /names:uppercase /iface:cref /iface:mixed_str_len_arg
C     /module:"Debug/" /object:"Debug/" /traceback /ccdefault:fortran
C     /libs:qwin /c
C
C     Linker options:
C
C     /OUT:"Debug/ftmw_20.exe" /NOLOGO /MANIFEST:NO /SUBSYSTEM:WINDOWS
C     /MACHINE:IX86 kernel32.lib ieee_32m.lib
C
C     Note that some compiler options have changed and the key ones are
C     in the 'External procedures' tag. ccdefault is in 'runtime' tag
C
C
C     Legacy Compilation options for Compaq Visual Fortran 6:
C
C     /ccdefault:fortran /check:bounds /compile_only /debug:full
C     /fpscomp:filesfromcmd /iface:cref /libs:qwin /nologo /traceback
C     /warn:argument_checking /warn:nofileopt /module:"debug/"
C     /object:"debug/" /pdbfile:"debug/DF60.PDB"
C
C     Linker options:
C
C     kernel32.lib ieee_32m.lib /nologo /subsystem:windows /pdb:none
C     /machine:IX86 /out:"debug/ftmw.exe"
C
C
C--------------------------------------------------------
C    Migration to Visual Studio 2015 and Visual Fortran 2016 (Intel Parallel Studio XE Professional)
C--------------------------------------------------------
C
C    In order to migrate a solution from IVF2011 make a suitable new work directory, copy to it
C    the latest .FOR file and the files:
C         .vfproj
C         .ico
C         .rc
C         .h
C         .sln
C    Compilation also compiles resources placing a .res file in the DEBUG directory.
c
C    On kisiel4/W10 but with VS2015/IVF2016 it was necessary to amend the 
C    linker->general->additional library directories to
C                 c:\Program Files (x86)\Windows Kits\10\Lib\10.0.18362.0\um\x86\;
C                 c:\Program Files (x86)\Microsoft Visual Studio 14.0\lib\
C
C/////////////////////////////////////////////////////////////////////////////