| 摘要 |
PURPOSE:To reduce the influence of harmonic noise and to improve considerably a bit error rate by setting the transmission signal frequency to an integer-fold of system fundamental frequency and analyzing high frequencies on a basis of a system voltage in the reception side and performing always overall discrimination with stray higher harmonics to receive bits. CONSTITUTION:After confirming that there are no accidents or the like in the system, an address calling a transmission terminal is transmitted. After confirming that signals transmitted from the other slave stations do not exist, a master station starts reading with a voltage and a current in its own end as the input and defines the point of zero voltage as zero of the reference time in accordance with these voltage and current and obtains Fourier coefficients cm and dm of the signal frequency and Fourier coefficients cn and dn corresponding to another signal frequency near said signal frequency if said signal frequency is about m-fold fundamental wave. The slave station obtains Fourier coefficients of higher harmonics of the M-th order and the N-th order of the slave station current on a basis of zero voltage similarly to the master station and transmits them as data. The master station compares this data with cm, dm, cn, and dn measured in its own end to discriminate whether they are different or not; and if the result is within a determined range, it is judged to be normal, and transmission of regular data is requested to the slave station. |
