National Institute of Advanced Industrial Science and Technology

Yoichi Sato

Tetsuya Higuchi

Masahiro Murakawa

A serial-parallel converter/encoder unitinputs a transmission symbol data at a transmission symbol rate that is one-Nth of a base-point symbol rate. A precoder/collatorcreates a transmission symbol waveform at the base-point symbol rate. The transmission symbol waveform becomes a transmission signal after passing through a roll-off filterwith a band corresponding to the base-point symbol rate and a modulator. A reception signal demodulated by a demodulatoris input to a fractionally-spaced equalizerthat operates at the base-point symbol rate and is forcibly equalized at the transmission symbol rate by using a reference signal. A level of a signal output from the fractionally-spaced equalizerat the transmission symbol rate is determined by a level determining unitand becomes a reception symbol data by a sawtooth-function output unit

Data transmitting method and data transmitting apparatus

A signal transmission apparatus of the invention comprises: a correlatorfor shaping a spectrum of a signal; and a precoderdisposed on a previous stage of the correlator and including an adder which subtracts an output signal of a feedback filter from an input signal, a modulo arithmetic unit which inputs an output signal of the adder and executes modulo arithmetic operation, and the feedback filter which inputs an output signal of the modulo arithmetic unit and is provided with a transfer function obtained by subtracting 1 from a transfer function of the correlator. The correlator may be IIR filter means having a desired notch characteristic. By disposing a correlator which can freely shape a transmission signal spectrum containing a deep notch and suppress only a specified band on a receiving side, the suppression of an external noise can also be realized.

Growing community of inventors

Tsukuba, Japan

Yoichi Sato