AUDIO CONTROL SIGNAL DETECTOR OF SATELLITE BROADCASTING SIGNAL

摘要

PURPOSE: To precisely decode a received sound control signal by checking the occurrence of errors by discriminating whether or not the state of the corresponding bit is constant for many frames by a prescribed number of times or more upon detecting the received voice control signal. CONSTITUTION: A synchronization detecting section 7a generates a synchronizing signal upon detecting the input of the first 16 bits of one frame and the synchronizing signal is inputted to an internal clock generator 7b and generates first to twelfth clock signals. A control bit detecting section 7b detects the corresponding control bit to the input to a descrambler C and the next majority discriminating section 7e checks the state of the input and discriminates whether or not the eight or more bits in the first 16 bits of each frame are in constant state 1 for 16 frames. The signal of the section 7e is supplied to an output selecting section 71 where time constant elongation is controlled in order to eliminate a difference in restoring time zone due to different mode-wise sampling time. The signal of a signal outputting section 7f controls the time base elongation for accurate control signal detection.