program testsig3
c
c   Generation of triangular test signals. 
c
      parameter(ndim= 66000 )
c
      real*4 x(ndim)
      character name*10,par*20,text*35,noisfi*10,ja
      character*50 prolog(64)
      data par/'                    '/
      text='     Test signal'
      write(6,*) text
    6 write(6,*) 'Filename for the test signal?'
      read(5,'(a)') name
      write(6,*) 'Number of samples?'
      read(5,*) n
      if(n.gt.ndim) stop
      write(6,*) 'Sampling interval?'
      read(5,*) dt
      zpi=8.*atan(1.)
      npro=0
      do 4 j=1,n
    4 x(j)=0.
    1 write(6,*) 'Triangle. Period? [0=no more]:'
      read(5,*) per
      write(6,*) 'Amplitude?'
      read(5,*) amp
      npro=npro+1
      write(prolog(npro),5) per,amp
    5 format('% triangle  per=',f10.3,' amp=',f10.3)
      np=nint(per/dt)
      nh=nint(per/dt/2.)
      nv=nint(per/dt/4.)
      do 3 j=1,nv
      t=(j-1)*dt
    3 x(j)=amp*t/per*4.
      do 8 j=nv+1,n
        m=mod(j+np-nv,np)
        if(m.le.nh) then
          x(j)=amp*(1.-2.*m/nh)
        else
          x(j)=amp*(2.*m/nh-3.)
        endif
    8 continue
    7 write(6,'(a)') 'format? <cr>=(8f9.3):'
      read(5,'(a20)') par
      call output(name,prolog,npro,par,text,n,dt,x)
      write(6,'(a)') 'Done. Another signal? (y/n)'
      read(5,'(a)') ja
      if(ja.eq.'y') goto 6
      stop
      end

      subroutine output(name,prolog,npro,par,text,n,dt,x)
      real*4 x(n)
      character name*10,text*35,par*20,iform*20
      character*50 prolog(64)
      iform='(5f12.3)            '
      if(par(1:1).eq.'(') read(par,'(a20)') iform
      write(6,5) name,iform
    5 format('Signal is written into file ',a10/' format: ',a20)
      open(8,file=name)
      write(8,'(a)') text
      do j=1,npro
      write(8,'(a)') prolog(j)
      enddo
      write(8,1) n,iform,dt
    1 format(i10,a20,3f10.3,2i5,a10)
      write(8,iform) (x(j),j=1,n)
      close(8)
      return
      end