Abstract: This invention provides a method of detecting time alignment of an analog audio signal and a digital audio signal in a hybrid radio system. The method comprises the steps of filtering the analog audio signal to produce a filtered analog audio signal, filtering the digital audio signal to produce a filtered digital audio signal, and using the filtered analog audio signal and the filtered digital audio signal to calculate a plurality of correlation coefficients, wherein the correlation coefficients are representative of time alignment between the analog audio signal and the digital audio signal. An apparatus for performing the method is also provided.

Abstract: Methods and systems for recovering a DC component in a zero-IF radio receiver are disclosed that involve receiving a frequency modulated radio frequency broadcast signal, down-converting the frequency modulated radio frequency broadcast signal directly to an original baseband frequency signal, wherein the original baseband frequency signal includes an original DC component, filtering the original baseband signal to obtain a filtered baseband signal, wherein the original DC component is removed, analyzing modulus values of the filtered baseband signal to determine an estimated quantity for the original DC component, and adding the estimated quantity for the original DC component to the filtered baseband signal to compensate for removal of the original DC component such that a reconstructed baseband signal is obtained.

Abstract: A method is provided for receiving and processing a digital radio broadcasting signal. The method includes the steps of receiving a digital radio broadcasting signal including content, storing encoded content, and decoding the stored encoded content to recover decoded content. The stored encoded content can include protocol data units or packets. The stored encoded content can be recovered by decoding the encoded content according to a logical protocol stack.

Abstract: An apparatus includes first and second speakers, and an antenna including a first pair of wires connected to the first speaker, a second pair of wires connected to the second speaker, and a conductive sleeve surrounding portions of the first and second pairs of wires, the sleeve forming a coaxial capacitor with the first and second pairs of wires. The apparatus can further include an inductor connected between the first and second pairs of wires and the sleeve, to form a resonant circuit with the coaxial capacitor.

Abstract: A signal generator includes a memory for storing content information in the form of vectors including in-phase and quadrature elements of an orthogonal frequency division multiplexing waveform, a processor for converting the vectors to a radio frequency signal, and a logic device for controlling the operation of the memory and the processor. The in-phase and quadrature elements represent baseband content of the orthogonal frequency-division multiplexing waveform.

Abstract: A method for detecting a digital radio signal includes the steps of receiving the digital radio signal, developing a correlation waveform having a peak that corresponds to a symbol boundary, normalizing the correlation waveform, calculating a peak value of the normalized correlation waveform, and dwelling on the received digital radio signal when the peak value exceeds a predetermined threshold. A receiver that performs the method is also provided.

Abstract: A method for detecting a digital radio signal includes the steps of receiving the digital radio signal including a series of symbols, developing a correlation waveform having a peak that corresponds to a symbol boundary, normalizing the correlation waveform, and calculating a peak value of the normalized correlation waveform, wherein the peak value represents the quality of the received digital radio signal. A receiver that performs the method is also provided.

Abstract: Systems, methods, and processor readable media are disclosed for encoding and transmitting first media content, second media content and triggering instructions to a digital radio broadcast receiver such that the triggering instructions arrive for immediate execution to trigger immediate rendering of the second media content in synchronization with the first media content.

Abstract: A digital radio broadcast system includes a processing system that receives first audio content, first program data identifying a first item for the first audio content, second audio content, and second program data identifying a second item for the second audio content such that a start of the first program data is received at the processing system within 0.5 seconds of a start of the first audio content. A digital radio broadcast signal including the audio content and the program data is processed for digital radio broadcast transmission via a transmitter. The processing system stops delivery of the first program data to the transmitter upon receipt of the second program data, the first program data thereby being truncated, and begins delivery of the second program data to the transmitter. A digital radio broadcast receiver can tag content of interest based on a user command registered at the receiver.

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 of broadcasting an AM compatible digital audio broadcasting signal includes: producing an analog modulated carrier signal centrally positioned in a radio channel, wherein the analog modulated carrier signal is modulated by an analog signal, producing a plurality of digitally modulated subcarrier signals in the radio channel, wherein the digitally modulated subcarrier signals are modulated using complementary pattern-mapped trellis code modulation (CPTCM) including a code mapped to overlapping partitions including an upper main partition, a lower main partition, an upper backup partition and a lower backup partition, and a non-overlapping tertiary partition, and transmitting the analog modulated carrier signal and the plurality of digitally modulated subcarrier signals. Transmitters that broadcast the signal and receivers that receive the signal, and the reception method are also included.

Abstract: Systems, methods, and processor readable media are disclosed for encoding and transmitting first media content and second media content using a digital radio broadcast system, such that the second media content can be rendered in synchronization with the first media content by a digital radio broadcast receiver. The disclosed systems, methods, and processor-readable media determine when a receiver will render audio and data content that is transmitted at a given time by the digital radio broadcast transmitter, and adjust the media content accordingly to provide synchronized rendering. In exemplary embodiments, these adjustments can be provided by: 1) inserting timing instructions specifying playback time in the secondary content based on calculated delays; or 2) controlling the timing of sending the primary or secondary content to the transmitter so that it will be rendered in synchronization by the receiver.

Abstract: A method is provided for equalizing OFDM symbol vectors received on AM in-band on-channel radio signal including a main carrier and first and second BPSK modulated subcarriers. The method comprises the steps of: computing a BPSK magnitude signal; filtering the BPSK magnitude signal; filtering complex samples received on the main carrier; using the filtered BPSK magnitude signal and the filtered complex samples received on the main carrier to compute a plurality of flat fade equalization coefficients; and multiplying the OFDM symbol vectors by the flat fade equalization coefficients. A receiver that includes an equalizer, which operates in accordance with the method is also provided.

Abstract: Methods and systems for advancing to another service from a plurality of services in a digital radio broadcast receiver are described. The methods and systems include the steps of receiving an instruction to advance to another service from a man-machine interface of the digital radio broadcast receiver, selecting an entry from a set of entries stored in a memory of the digital radio broadcast receiver responsive to the instruction, wherein each entry identifies a service, and wherein at least some of said services correspond to services identified as receivable, tuning to a first service identified by the selected entry, rendering content received on the first service at the digital radio broadcast receiver, and updating the set of entries stored in the memory of the digital radio broadcast receiver based on at least one criteria.

Abstract: A broadcasting method includes: using a first transmitter to send a signal including a plurality of frames of data synchronized with respect to a first GPS pulse signal, receiving the signal at a first remote transmitter, synchronizing the frames to a second GPS pulse signal at the first remote transmitter, and transmitting the synchronized frames from the remote transmitter to a plurality of receivers. A system that implements the method is also provided.

Abstract: A method of tuning an antenna circuit includes: (a) receiving a signal on an antenna, (b) producing a received signal strength indication based on the received signal, (c) using the received signal strength indication to produce a control voltage, (d) using the control voltage to control a capacitance in an antenna matching circuit, (e) changing the control voltage to minimize a ratio of a change in the received signal strength indication to a change in the control voltage and (f) repeating steps (a), (b), (c), (d) and (e). An apparatus that implements the method is also provided.

Abstract: A method for symbol tracking in AM in-band on-channel radio receivers comprises the steps of: receiving a stream of time domain samples; assembling a set of the time domain samples equal to a symbol time plus a half symbol delay in response to a symbol timing adjustment value for each symbol period; interpolating the time domain samples; partitioning the interpolated time domain samples into a first group of samples representing half-off symbols and a second group of samples representing on-time symbols; processing the first and second groups of samples to produce the symbol timing adjustment value; and outputting the second group of samples representing on-time symbols at a symbol rate. An apparatus that performs the method is also included.

Abstract: A method is provided for coherently tracking a radio signal including a plurality of digitally modulated reference subcarriers. The method comprises the steps of receiving symbols transmitted on the reference subcarriers, combining the reference subcarrier symbols with a known reference sequence conjugate to produce a plurality of samples, median filtering the samples to produce filtered samples, and smoothing the samples for each of the reference subcarriers over the plurality of reference subcarriers to produce a coherent reference signal estimate for each of the subcarriers. A receiver for coherently tracking a radio signal including at least one digitally modulated reference carrier is also provided.

Abstract: Digital pre-downloading of high bandwidth digital data is performed through a system gateway based on selective filtering, scheduling, and end user device requirements. Digital broadcasting systems are used to push large bandwidth data during non-peak periods (e.g., in the early AM hours) or during times of other relative network or end user device inactivity. Digital data, such as background images, song compilations, artist compilations, newspapers, e-books, digital purchases of other data, maps of local areas based on, for example, GPS based location detection, etc., are pre-downloaded and stored in the end user (client) device, e.g., a car digital radio or other consumer electronic device with display flag turned off. The device is subscriber preconfigured to selectively filter and retain (e.g., in local cache memory) a desired portion of the data broadcast. Later, a command is sent to activate the contents for subscriber presentation. Delta updates, if received, are pushed in real-time.

Abstract: A method of broadcasting an AM compatible digital audio broadcasting signal includes: producing an analog modulated carrier signal centrally positioned in a radio channel, wherein the analog modulated carrier signal is modulated by an analog signal, producing a plurality of digitally modulated subcarrier signals in the radio channel, wherein the digitally modulated subcarrier signals are modulated using complementary pattern-mapped trellis code modulation (CPTCM) including a code mapped to overlapping partitions including an upper main partition, a lower main partition, an upper backup partition and a lower backup partition, and a non-overlapping tertiary partition, and transmitting the analog modulated carrier signal and the plurality of digitally modulated subcarrier signals. Transmitters that broadcast the signal and receivers that receive the signal, and the reception method are also included.