The R2 signal information communicating between two exchangers follows the continuous confirmation procedure so that ther direction of receiving multi-frequency signal could be acknowledged in advance. A digital signal processor (DSP) as a digital filter calculates six frequency spectrums selected from the forward and backward directions after receiving the directional information from the superior microprocessor. The calculated signal and the preset reference value are compared to detect the proper signal so that the processing capability of the digital filter is extended up to 50% and the signal detecting time is improved.
展开▼
