A digital data transmitting system comprises a first circuit for transmitting digital data related to an information signal data in terms of sectors each having k words with respect to each channel, where k is a natural number. The transmission of the digital data is performed within a predetermined transmission time period once or a plurality of times according to a tolerance of data error rate for an information content of the digital data. The information signal data are among digital data related to a plurality of channels of information signals which are subjected to a digital modulation, and the plurality of channels of information signals are made up of a combination at least including the information signal data among three kinds of information signals. The three kinds of information signals are a non-compressed audio signal, a video signal, and the information signal data other than the non-compressed audio signal and the video signal. The system also comprises a second circuit for adding a code and a synchronizing signal to the digital data which are obtained from the first circuit, and for transmitting the digital data having the first code and the first synchronizing signal added thereto. The first code is at least indicative of a number of times the digital data are repeatedly transmitted within the predetermined transmission time period.