What does this do ?

Hi,

Can anyone tell me what this bit of code is doing ?

-- declarations

------------------------------------------------------------------------------------------- signal phase : std_logic_vector(6 downto 0);

type INTEGER_ARRAY is array ( natural range ) of integer;

constant NUMERATOR : INTEGER_ARRAY(7 downto 0) := (7,30,7,7, 30, 30,

variable phase_next : std_logic_vector(6 downto 0);

--------------------------------------------------------------------------------------------

-- **** problem code **********

phase_next := phase + NUMERATOR(conv_integer(std));

Obviously the conv_integer(std) part of the code is being used to access the array NUMERATOR but I don't understand exactly how since no number value is being specified to key into the array ie. what is the value of 'std' that is being converted to an integer by the function 'conv_integer' ?

Thanks