Patent ID: 8284856

Claim:
A data transmitting apparatus used for a data transmitting method including the steps of: inputting a transmission symbol data at a transmission symbol rate which is one-Nth (N is an integer of 2 or more) of a base-point symbol rate to create a transmission symbol waveform at the base-point symbol rate by a precoder and a correlator; transmitting the transmission symbol waveform through a roll-off filter having a band corresponding to the base-point symbol rate; inputting a reception signal to a fractionally-spaced equalizer that operates at the base-point symbol rate and is forcibly equalized at the transmission symbol rate by using a reference signal; determining a level of a signal output from the fractionally-spaced equalizer at the transmission symbol rate; and obtaining a sawtooth function output of a level-determined symbol data, thereby outputting a reception symbol data; wherein the precoder has a sawtooth-function output unit; wherein once in N times of a base-point symbol timing corresponding to the base-point symbol rate, another transmission symbol data is input to the sawtooth-function output unit, the another transmission symbol data is obtained by subtracting from the input transmission symbol data an output of the sawtooth-function output unit that is passed through a filter with a transmission function F 1 (D)−1; and an output of the sawtooth-function output unit is taken as an output symbol data of the precoder, wherein, in a base-point symbol timing that does not input the transmission symbol data, zero symbol data is output to the filter with the transmission function F 1 (D)−1 and zero symbol data is taken as the output symbol data of the precoder; the correlator adds the output symbol data of the precoder and a symbol data obtained by passing the output symbol data though a filter with the transmission function F 1 (D)−1 to take the addition result as an output symbol data of the correlator, thereby creating the transmission symbol waveform, and the transmission function F 1 (D) is set so that a channel passage rate of a spectrum energy of a transmission signal is increased.