PURPOSE: To prevent interference with subordinate station data at a master station by stopping transmission from a subordinate station when a fault such as a step out, etc., occurs to a transmitted signal from the subordinate station.
CONSTITUTION: Output monitoring data (clock signal) from a receiving logical operation circuit 9 is supplied to one input of a step-out detecting circuit 22, and the output frame signal of a frame signal regenerating circuit 12 is supplied to the other input. When both signals differ in generation timing, a step-out signal is generated and applied to an OR circuit 21. On the basis of the frame signal, a transmission timing signal is generated and supplied to one input of a comparing circuit 26. Further, the transmission timing signal is generated from a transmitted signal inputted to an antenna 1 and supplied to the other input of the comparing circuit 26. When both signals differ in timing, the comparing circuit 26 generates and inputs a timing difference signal to the OR circuit 21. On the basis of an output signal of the OR circuit 21, the transmission of the subordinate station is stopped.
TAKENAKA NOBUO
NOMURA MASARU
