Patent ID: 8761231

Claim:
A frequency modulating apparatus, comprising: a transmission rate controller configured to control a data transmission rate and a number of repetitive transmission times according to a communication channel environment; a data generator controlled by the transmission rate controller and configured to output serial data repetitively based on the number of repetitive transmission times; a serial-to-parallel converter configured to convert the serial data outputted from the data generator into parallel data; and a frequency selective spreader configured to select and output a frequency selective spread code corresponding to the parallel data, under the control of the transmission rate controller, wherein the transmission rate controller is configured to control the frequency selective spreader to select one of a plurality of spread code groups obtained by dividing 2 N spread codes used for performing frequency spreading on the parallel data by 2 M spread codes, using N−M frequency selective control bits, each spread code group including 2 M spread codes, N being a natural number greater than 1, and M being a natural number smaller than N, and wherein the selected and outputted frequency selective spread code is selected from spread codes of the selected spread code group.