step simulation

Hi all,

I'm stuck on a simple issue but can't get out of it: I would like to generate severals waveform signals for my future testbench but the frequency of my signals are not correct.

Below is the code I want to simulate:

library ieee;
use ieee.std_logic_1164 .all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
use ieee.math_real.all;

entity triangle_generator is

 generic(AMP: real;
  OFFSET: real;
  FREQ: real;
  PHASE :real);
 
 port(wave1: out real);
       
end triangle_generator;

architecture archi of triangle_generator is

signal tmp1 : real := 0.0;

begin

 P1:process
 
 constant delta   : real := 1000.0e-12;
 constant fin  : time := 1000 ps;
 
 variable angle   : real := 0.0;
 variable t    : real := 0.0;
 variable PHASE_RAD : real := 0.0;
 
 begin
 
   PHASE_RAD := (math_2_pi * PHASE)/360.0;

  loop
   angle   := math_2_pi * FREQ * t;
   t := t + delta;
   
   tmp1 <= OFFSET+(AMP/2.0)*(2.0/math_pi)*arcsin(sin(angle));

   wait for fin;
  
  end loop;
  
  wait;
  
 end process P1;
 
 wave1 <= tmp1;
 
end archi;

When I simule this code with FREQ=100 000 000 Hz I get the waveform in attachment, not really what I wanted. So I was thinking, if I write delta = 1000.0e-15 maybe it will be right, but absolutly not. When I change the value of delta, the frequency of the waveform is wrong.

So can you help me to get through this please?