Abstract: Reproduction accuracy of, for example a digital stereo audio signal, is improved by transmitting sample data as sub-signals such as frequency subband signals. In one or more subbands, corresponding components such as left and right stereo channels are combined so that only one composite signal is transmitted per subband. An indicator signal is transmitted, indicating which subbands are combined. Scale factor signals for all subbands, and for the relative intensity of the respective subband signals which were combined, may also be transmitted. In the receiver a subband signal is derived for each channel from the composite signal, before synthesis of the full channel signals which will be reproduced.

Abstract: A transmission channel may be utilized for a combination of wide-band signals and auxiliary signals, while still providing improved reproduction accuracy. Digital sub-signals or subband signals representing at least first and second data-reduced components are combined with at least one auxiliary digital signal in defined frame portions before transmission. The auxiliary signal may be user-discernible information such as third and fourth audio channels, so that a four channel surround sound signal is transmitted; or teletext or video or picture information may be provided. Sampling reduction and filtering into subbands may be applied to the auxiliary signal as well as to the first and second signal components.