write_delay_line.F90
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! This file is part of SACAMOS, State of the Art CAble MOdels in Spice.
! It was developed by the University of Nottingham and the Netherlands Aerospace
! Centre (NLR) for ESA under contract number 4000112765/14/NL/HK.
!
! Copyright (C) 2016-2017 University of Nottingham
!
! SACAMOS is free software: you can redistribute it and/or modify it under the
! terms of the GNU General Public License as published by the Free Software
! Foundation, either version 3 of the License, or (at your option) any later
! version.
!
! SACAMOS is distributed in the hope that it will be useful, but
! WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
! or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
! for more details.
!
! A copy of the GNU General Public License version 3 can be found in the
! file GNU_GPL_v3 in the root or at <http://www.gnu.org/licenses/>.
!
! SACAMOS uses the EISPACK library (in /SRC/EISPACK). EISPACK is subject to
! the GNU Lesser General Public License. A copy of the GNU Lesser General Public
! License version can be found in the file GNU_LGPL in the root of EISPACK
! (/SRC/EISPACK ) or at <http://www.gnu.org/licenses/>.
!
! The University of Nottingham can be contacted at: ggiemr@nottingham.ac.uk
!
! File Contents:
! SUBROUTINE write_delay_line
!
! NAME
! write_delay_line
!
! AUTHORS
! Chris Smartt
!
! DESCRIPTION
! Write a delay line element to the spice subcircuit file
! This will either be a simple delay line (T element) or LTRA transmission line
! with zero resistance dependent on the use_LTRA flag
!
! INPUTS REQUIRED
! 1. spice_model_name ! component name
! 2. node_1_in ! controlling node number 1
! 3. node_2_in ! controlling node number 2
! 4. node_1_out ! controlled node number 1
! 5. node_2_out ! controlled node number 2
! 6. Z0 ! characteristic impedance
! 7. delay ! transmission delay
! 8. length ! transmission line length
!
! OUTPUTS
! 1. components written to the spice subcircuit file
!
!
! COMMENTS
!
!
!
! HISTORY
!
! started 20/10/2017 Try out robustness of LTRA as opposed to T elements for Ngspice transient analysis
! 16/11/2017 CJS Include network synthesis process to replace s-domain transfer functions
!
!
SUBROUTINE write_delay_line(spice_model_name,node_1,node_2, &
node_3,node_4,Z0,TD,length)
USE type_specifications
USE general_module
USE filter_module
IMPLICIT NONE
! variables passed to the subroutine
character(LEN=spice_name_length),intent(IN) :: spice_model_name ! component name
integer,intent(IN) :: node_1 ! delay line node number 1
integer,intent(IN) :: node_2 ! delay line node number 2
integer,intent(IN) :: node_3 ! delay line node number 3
integer,intent(IN) :: node_4 ! delay line node number 4
real(dp),intent(IN) :: Z0 ! characteristic impedance
real(dp),intent(IN) :: TD ! delay
real(dp),intent(IN) :: length ! length
! local variables
real(dp) :: velocity
real(dp) :: L_local
real(dp) :: C_local
! START
if (.NOT.use_LTRA) then
! write the delay line (T type) element
write(spice_model_file_unit,'(A30,4I6,A4,ES16.6,A4,ES16.6)')spice_model_name, &
node_1,node_2,node_3,node_4, &
' Z0=',Z0,' TD=',TD
else
! use the LTRA transmission line model
velocity=length/TD
C_local=1.0/(Z0*velocity)
L_local=Z0/velocity
! write the LTRA element
if (spice_version.EQ.Pspice) then
write(spice_model_file_unit,'(A30,4I6,A5,ES16.6)')spice_model_name, &
node_1,node_2,node_3,node_4, &
' LEN=',length
write(spice_model_file_unit,'(A10,ES16.6,A9,ES16.6)')'+ R=0.0 L=',L_local,' G=0.0 C=',C_local
else ! Ngspice or LTspice
write(spice_model_file_unit,'(A32,4I6,A36)')'O_'//spice_model_name, &
node_1,node_2,node_3,node_4, &
' LTRA_'//spice_model_name
! write the associated .model
write(spice_model_file_unit,'(A42,A15,ES16.6,A3,ES16.6,A5,ES16.6,A2)')'.MODEL LTRA_'//spice_model_name, &
' LTRA( R=0.0 L=',L_local,' C=',C_local,' LEN=',length,' )'
end if ! spice version
end if ! use_LTRA
END SUBROUTINE write_delay_line