Generating a signal with noise

Hi DAVE

I am trying to find the mean and variance for random generating function code shown below. I know how to calculate practically but not able to implement it can you please help me..

LIBRARY IEEE;

USE IEEE.STD_LOGIC_1164.ALL;

USE IEEE.NUMERIC_STD.ALL;

USE IEEE.STD_LOGIC_SIGNED.ALL;

ENTITY random IS ------> Interface

GENERIC (n : INTEGER := 16); -- Input bit width

PORT( clk : IN STD_LOGIC;

random_num : OUT STD_LOGIC_VECTOR(n-1 DOWNTO 0);

random_sum: OUT STD_LOGIC_VECTOR(n-1 DOWNTO 0)

);

END random;

ARCHITECTURE Behavioral of random is

BEGIN

PROCESS(clk)

VARIABLE rand_temp : STD_LOGIC_VECTOR(n-1 DOWNTO 0) := (n-1 => '1' , OTHERS => '0');

VARIABLE temp : STD_LOGIC := '0';

VARIABLE sum : STD_LOGIC_VECTOR(n-1 DOWNTO 0) :=( OTHERS => '0');

BEGIN

IF(RISING_EDGE(clk)) THEN

temp := rand_temp(n-1) XOR rand_temp(n-2);

rand_temp(n-1 DOWNTO 1) := rand_temp(n-2 DOWNTO 0);

rand_temp(0) := temp;

sum := sum + rand_temp;

END IF;

random_num <= rand_temp;

random_sum <= sum;

END PROCESS;

END;

--ADI