Time spread transmission system using block conversion

In the digital transmission of non‐telephone signals, impulse noise interference, such as switching machine noise, interruptions, etc., become problematic and it has become necessary to suppress them. to suppress impulse noise interference efficiently, this paper presents a time spread transmission system, which transmits digital signals spread on the time axis through a block conversion, and discusses the system construction and the noise attenuation characteristic. First, the requirements for the time spread matrix in a general communication channel with impulse noises and random noises, such as thermal noise, crosstalk, etc., are described. It is clarified that for the matrix a cyclic orthogonal one is most suitable. For a single impulse noise interference, noise amplitude attenuation characteristics of the system are improved by 3 dB, compared with those of the conventional smearing‐desmearing filter method. Finally, the bit error rate is estimated for burst noise interference channel on a statistical noise model and it is shown that the bit error rate reduction of two decimals is achieved for the case of transmission rate 64 Kb/s and spread time 8 ms.