Ruby decimal / frational to binary conversion

The following function can be used to convert decimal (fractional) numbers to binary format:

def dec2bin(number, int_bits, frac_bits, decimal_mark)
  negative = false
  if (number < 0)
   negative = true
   number = -number
  end
  
  ## Create Integer only number
  number_int = Integer(number);

  ## Create Fractional only number
  number_frac = number - number_int;

  ## Create Integer Binary String
  ret_bin_int = "";

  ## Create Fractional Binary String
  ret_bin_frac = "";

   ##Integer
   ret_bin_int = number_int.to_s(2) ;
   padding_bits = int_bits - ret_bin_int.length ;
   begin
      ret_bin_int =  Array.new(padding_bits, "0").join + ret_bin_int ;
   rescue
      puts "ERROR not enough integer bits to represent #{number}";
      return -1;
   end

   ## Fractional
   ret_bin_frac = ""
   fractional   = 0
   if (frac_bits > 0)
      ret_bin_frac = Integer(number_frac * 2**frac_bits).to_s(2);
      padding_bits = frac_bits - ret_bin_frac.length ;
      ret_bin_frac =  Array.new(padding_bits, "0").join + ret_bin_frac ;
      fractional = ret_bin_frac.to_i(2).to_f / (2**frac_bits)
   end
   
   if (negative == true)
      number = (ret_bin_int + ret_bin_frac).to_i(2)
      #Perforrm this binary operation number = -number + 1
      #In an integer number space
      number = 2**(int_bits+frac_bits) - number
      ret_bin_int  = number.to_s(2)[0,int_bits]
      ret_bin_frac = number.to_s(2)[int_bits, frac_bits]
   end
   
   binary = ret_bin_int +  decimal_mark + ret_bin_frac;
  
  ## ret_bin Add decimal marker
   return {
      :binary => binary,
      :int    => number_int,
      :frac   => fractional,
      :real   => (fractional+number_int)
   }
end

Example using the function:

intBits = 6
fracBits =4
converted = dec2bin(10.5, intBits, fracBits, "_")
puts converted[:binary]

NOTE:
Since first post I have fixed a fracbits=0 bug and now works with negative numbers (converting to a twos complement format)