Abstract: A method for processing a digital audio broadcast signal includes: separating an analog audio portion and a digital audio portion of the digital audio broadcast signal; determining the loudness of the analog audio portion and the digital audio portion over a first short time interval; using the loudness of the analog and digital audio portions to calculate a short term average gain; determining a long term average gain; converting one of the long term average gain or the short term average gain to dB; if an output has been blended to digital, adjusting a digital gain parameter by a preselected increment to produce a digital gain parameter; if an output has not been blended to digital, setting the digital gain parameter to the short term average gain; providing the digital gain parameter to an audio processor; and repeating the above steps using a second short time interval.

Abstract: A method includes: receiving an FM radio signal including an analog-modulated portion; digitally sampling an analog-modulated portion of the radio signal to produce a plurality of samples; using a ratio between an average magnitude and an RMS magnitude of a block of the samples to compute a signal quality metric; detecting sum and difference components of the baseband multiplex signal content; using the baseband content to produce an output signal; and blending the output signal from stereo to monaural as the signal quality metric falls below a threshold value.

Abstract: A method and apparatus are provided for blending analog and digital portions of a composite digital radio broadcast signal by processing compressed audio packets to compute corresponding digital audio quality indicator values, storing the compressed audio packets in an audio blend buffer, processing audio information from each compressed audio packet stored in the audio blend buffer with an audio decoder to generate decompressed digital audio signal samples, and using the digital audio quality indicator values to guide a blending process for combining analog audio signal samples with the digital audio signal samples to produce an audio output by preventing unnecessary blending back and forth between analog and digital if the digital audio quality indicator values indicate that the compressed audio packets are degraded or impaired.

Abstract: A method for detecting the digital quality of a radio signal includes: receiving a radio signal including an analog modulated portion; digitally sampling an analog modulated portion of the radio signal to produce a plurality of samples; using a ratio between an average magnitude and an RMS magnitude of a block of the samples to compute an analog signal quality metric. Receivers that implement the method are also provided.

Abstract: A method includes: constructing complementary low density parity check codewords by generating a first codeword having a first code rate; and partitioning the first codeword by assigning groups of bits of the first codeword to four quarter-partitions, wherein each of the quarter partitions includes bits in one half of one of four independently decodable semi-codewords each having a second code rate that is larger than the first code rate. Receivers that receive signals produced by the method are also disclosed.

Abstract: Systems and methods are described for rendering content at a digital radio broadcast receiver system. A digital radio broadcast signal comprises data for rendering content at the digital radio broadcast receiver. The digital radio broadcast signal is processed to determine whether the data from the digital radio broadcast transmission contains a data error. A portion of the data containing the data error is identified. A download request is transmitted to a computing system, where the download request requests duplicate data for the portion of the data containing the data error. The duplicate data is received at the digital radio broadcast receiver for the portion of the data containing the error via other wireless communication other than the digital radio broadcast. The duplicate data is processed to provide an uninterrupted rendering of the content.

Abstract: A translator includes: an input configured to receive a bit stream having a plurality of digitally encoded contents and control information; processing circuitry configured to select one of the digitally encoded contents, to use the selected digitally encoded content to produce an analog modulated signal, to use the digitally encoded contents to produce a digitally modulated signal, and to combine the analog modulated signal and the digitally modulated signal to produce a hybrid signal; and an output configured to output the hybrid signal. A method performed by the radio signal translator is also provided.

Abstract: Enhanced digital broad cast signals are transmitted on a digital radio broadcast signal by allocating spectral resources of the digital radio broadcast signal to simultaneously serve existing receivers (which can decode default content but not new content from the enhanced digital broadcast signal) and new receivers (which can decode default content and can decode new digital content from the enhanced digital broadcast signal) by modulating a first plurality of reference subcarriers with a first signal constellation, and modulating a second plurality of reference subcarriers with a second modified signal constellation such that a receiver processes the digital radio broadcast signal to produce a first coherent reference signal estimate for the first plurality of reference subcarriers to extract the default content for playback and to produce a second coherent reference signal estimate for the second plurality of reference subcarriers to disregard the new content.

Abstract: Methods and systems for transmitting and receiving large objects via digital radio broadcast involve retrieving an object and an object description; assigning a unique identifier to the object; segmenting the object into a plurality of fragments; generating at least one long message having selected ones of the fragments and a long header including the unique identifier and the object description; generating at least one short message having selected ones of the fragments and a short header including the unique identifier; and communicating the at least the long message or the short message to a digital radio broadcast transmitter. In accordance with certain embodiments, reassembly of the object can begin with either a long message or a short message.

Abstract: A method and apparatus are provided for smoothly blending analog and digital portions of a composite digital audio broadcast signal by using look ahead metrics computed from previously received audio frames to dynamically adjust either stereo separation or bandwidth or both of the digital audio portion of the digital audio broadcast signal to produce an adjusted digital audio portion that is blended with the analog audio portion.

Abstract: A method and apparatus are provided for recovering audio packet location fields and/or frame boundary information from a received digital radio broadcast signal frame in which there are detected errors in the signal frame header by using selected header elements and/or protocol data unit (PDU) structured data block parameters relating to minimum, maximum, and average packet length or PDU length in a scalable recovery process that may be throttled dynamically or configured statically based on available computation resources within a specific implementation and/or at a specific time.

Abstract: A method of block deinterleaving data received at a digital radio broadcast receiver is described. The method includes providing a block of memory having n×k addresses, wherein the block comprises a single table, receiving a digital radio broadcast signal at the receiver, and demodulating the digital radio broadcast signal into a plurality of interleaved data units. For at least one series of n×k data units a pointer step size is determined, and for each data unit in the series, an address in the block is calculated based on the pointer step size, and an output data unit is read from the block at the address, such that said output data units represent block deinterleaved data units. An input data unit from the plurality of interleaved data units is then written to the block at the address. Associated systems and computer readable storage media are presented.

Abstract: A method includes: receiving an FM radio signal including an analog-modulated portion; digitally sampling an analog-modulated portion of the radio signal to produce a plurality of samples; using a ratio between an average magnitude and an RMS magnitude of a block of the samples to compute a signal quality metric; detecting sum and difference components of the baseband multiplex signal content; using the baseband content to produce an output signal; and blending the output signal from stereo to monaural as the signal quality metric falls below a threshold value.

Abstract: A method for detecting the digital quality of a radio signal includes: receiving a radio signal including a digital portion modulated by a series of symbols each including a plurality of samples; computing correlation points between endpoint samples in cyclic prefix regions of adjacent symbols; and using the correlation points to produce a digital signal quality metric. Receivers that implement the method are also provided.

Abstract: A method for processing a radio signal includes: receiving an FM in-band on-channel radio signal including a plurality of digitally modulated subcarriers in upper and lower sidebands; sampling the FM in-band on-channel radio signal to produce an input signal including complex digital samples of a combination of a desired one the upper and lower sidebands and an FM interferer; removing FM interferer components from the first signal by notch filtering to produce a notch-filtered signal; weighting the notch-filtered signal to produce a weighted notch-filtered signal; using a parametric filter to filter the input signal to produce a parametric-filtered input signal; and combining the weighted notch-filtered signal and the parametric-filtered input signal to produce an output signal. A radio receiver that implements the method is also included.

Abstract: A peak-to-average power reduction method includes: (a) quadrature amplitude modulating a signal including a set of subcarriers with a set of data to produce an OFDM modulated symbol vector; (b) limiting the magnitude of the modulated symbol vector to produce a first limited OFDM modulated symbol; (c) demodulating the first limited OFDM modulated symbol to recover distorted QAM constellations; (d) constraining points in the distorted QAM constellations recovered from the first limited OFDM modulated symbol to produce constrained QAM constellations; (e) modulating an OFDM symbol vector with the constrained QAM constellations to produce a modified modulated OFDM symbol; and (f) output the modified modulated OFDM symbol. A transmitter that implements the method is also provided.

Abstract: A method of transmitting digital information includes: receiving a plurality of information bits representing audio information and/or data; encoding the information bits using complementary low density parity check coding to produce a composite codeword and a plurality of independently decodable semi-codewords; modulating at least one carrier signal with the forward error corrected bits; and transmitting the carrier signal(s). Transmitters that implement the method, and receivers that receive signals produced by the method, are also provided.

Abstract: A method and apparatus are provided for processing a received digital radio broadcast signal to efficiently remove signal interference artifacts from digital and/or analog signals by using signal quality information extracted from audio samples in one or more buffered audio frames to detect audio frames containing clipped noise artifacts and weaker noise artifacts and to selectively apply anti-interference processing to remove the signal interference artifacts.

Abstract: A data link manager includes a User Datagram Protocol (UDP) receiver for receiving HD Radio broadcast equipment communication protocol (HDP) data or non-HD Radio broadcast equipment communication protocol (non-HDP) data using a User Datagram Protocol/Internet Protocol (UDP/IP) protocol; a Transmission Control Protocol (TCP) receiver; and a router for receiving data from the UDP receiver and the TCP receiver, for searching for a destination route in a routing table, and for forwarding the data received from the from the UDP receiver and the TCP receiver to an identified destination route.

Abstract: A method for receiving and processing a digital radio broadcasting signal includes: receiving a digital radio broadcasting signal including encoded content in a first format; processing the encoded content to convert the encoded content into a second format; storing the encoded content in a second format; and decoding the stored encoded content to recover decoded content. A receiver that implements the method is also provided.