摘要:
The present invention provides a method of hierarchically modulating first and second digital data streams in a broadcast system such as an SDAR system that is compatible with legacy receivers. The second digital data stream, but not the first, is provided with a non-binary pseudo-random encoding. A carrier is first modulated, e.g. QPSK, by the first digital data stream; and a second modulation is performed with the encoded second digital data stream. The encoding includes a multiplication of a matrix formed of 2, 3 or 4 consecutive bits of the secondary data stream by a matrix, e.g. a Hadamard matrix to form a product matrix having non-binary values that are used to modify consecutive symbols of the first modulation. The second modulation appears as Gaussian noise to legacy receivers over time.
摘要:
A technique for demodulating secondary data from a hierarchically modulated signal includes a number of steps. A gray coded eight phase shift key (8-PSK) hierarchically modulated signal is received that includes primary data and secondary data. An imaginary portion of the signal is determined and a real portion of the signal is determined. An absolute value of the real portion of the signal may then be subtracted from an absolute value of the imaginary portion of the signal to provide the secondary data. The gray coded 8-PSK hierarchically modulated signal may be a uniform gray coded 8-PSK hierarchically modulated signal or a non-uniform gray coded 8-PSK hierarchically modulated signal.
摘要:
Additional data may be added to the current SDARS satellite signals as a phase and/or amplitude offset from the legacy quadrature phase shift keying (QPSK) modulated data and transmitted by the SDAR terrestrial repeaters. However, in the case where a legacy receiver architecture for a differential modulation system outputs angular/phase differences between carriers, the phase and/or amplitude information appears as distortion to the legacy receiver. The present invention provides a method for optimizing the SDARS infrastructure more efficiently by allowing independent adjustment of the phase and/or amplitude offset (610) at each terrestrial site. The present invention provides a method for adjusting the performance of each signal together or separately as needed.
摘要:
A system and method of communicating sub-synchronization information into a transmitted digital audio stream and extracting sub-synchronization information from a received digital audio stream is provided. The method includes the steps of having a transmitter introduce sub-synchronization information into a data stream at a period less than that of existing transmitter pre-amble signals, and transmitting that data to a receiver. The method further includes the steps of receiving the transmitted data stream in the receiver circuitry, extracting the synchronization information, and using the synchronization information to accurately decode the received audio data.
摘要:
A method and system of communicating sub-synchronization information into a transmitted digital audio stream and extracting sub-synchronization information from a received digital audio stream is provided. The method includes the steps of having a transmitter introduce sub-synchronization information into a data stream at a period less than that of existing pre-amble signals, and transmitting that data to a receiver. The method further includes the steps of receiving the transmitted data stream in the receiver, extracting the synchronization information, and using the synchronization information to accurately decode the received audio data.
摘要:
The present invention involves a media player and method for providing digital audio data in satellite digital audio radio (SDAR) format. The media player includes a satellite radio receiver, audio circuitry for reproducing sound from signals provided by the satellite radio receiver, and a computer interface circuit configured for accessing audio information files. The media player may have an antenna for receiving satellite radio broadcasts, and another antenna for a wireless connection. The media player may further have a control and display for interfacing with a source of digital audio files, such as through a network connection. The invention also includes a converter for providing audio files from digital audio files that are formatted for satellite digital audio radio (SDAR), with a source interface adapted to connect to a source of audio files, a translator adapted to create an SDAR formatted digital audio file, and a media player interface adapted to connect to a media player. The method of providing satellite digital audio radio (SDAR) formatted digital audio files to a SDAR enabled media player includes accessing a source of digital audio files with an interface of the media player, and playing a SDAR formatted digital audio file with the media player.