Abstract: In a satellite broadcasting receiver for receiving and decoding pulse code modulation (PCM) audio frame data having a plurality of channels, the logical state of charged flags (FD) included in the data of each channel is detected and the charged flags detected at a channel-related period are stored. Then the charged flags of a previous frame are simultaneously gated at the start time of a frame. A plurality of pulses clocking individual frame periods are counted and a multiframe signal spanning a given period is generated. In this case, the logical values of the charged flags gated at multiframe periods are accumulated, and an audio mute signal is generated when charged flags exceeding a given number are detected during a multiframe signal period.

Abstract: A sound control signal detecting circuit for a satellite broadcasting signals comprises a detecting portion for detecting control bits by carrying out shiftings for a predetermined number of times after the pulse code modulation sound signals are provided and a majority logic deciding portion for providing A/B mode signals, first and second TV sound signals, and first and second extra sound signals after verifying whether a certain state of relevant bits is maintained over a predetermined number of times in a plurality of frames so that a precise decoding operation can be accomplished. The detecting portion comprises a first shift register, a second shift register, and a first control signal generating section. The majority logic deciding portion comprises a period converting section, a state judging section, a second control signal generating section and a latch section.