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: A radio receiver includes a first signal path including a first tuner configured to receive a first signal from a first antenna, and a first demodulator configured to demodulate symbols from an output of the first tuner to produce first branch metrics derived from the demodulated symbols; a second signal path including a second tuner configured to receive a second signal from a second antenna, and a second demodulator configured to demodulate symbols from an output of the second tuner to produce second branch metrics derived from the demodulated symbols; a combiner for maximum ratio combining the first branch metrics and the second branch metrics; and processing circuitry to process the combined first and second branch metrics to produce an output signal.

Abstract: A method for specifying content of interest using a digital radio broadcast receiver is described. A digital radio broadcast signal includes first audio content and first program data, wherein the first program data includes information identifying a first item, and includes second audio content and second program data, wherein the second program data includes information identifying a second item. A user command entered at a user interface during reception of audio content is registered, indicating a user's interest in either the first or second audio content. It is determined whether there is an ambiguity in the content of interest. If there is an ambiguity, a first data structure is stored for the first audio content, and a second data structure is stored for the second audio content. The first data structure includes the information identifying the first item, and the second data structure includes the information identifying the second item.

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 specifying content of interest using a digital radio broadcast receiver is described. A digital radio broadcast signal includes first audio content and first program data, wherein the first program data includes information identifying a first item, and includes second audio content and second program data, wherein the second program data includes information identifying a second item. A user command entered at a user interface during reception of audio content is registered, indicating a user's interest in either the first or second audio content. It is determined whether there is an ambiguity in the content of interest. If there is an ambiguity, a first data structure is stored for the first audio content, and a second data structure is stored for the second audio content. The first data structure includes the information identifying the first item, and the second data structure includes the information identifying the second item.

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: 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 includes: (a) modulating a set of subcarriers with a set of data to produce a modulated OFDM symbol vector; (b) modulating a FM carrier signal with the set of data to produce a modulated FM symbol; (c) combining the modulated OFDM symbol and the modulated FM symbol to produce a modulated hybrid symbol; (d) limiting the magnitude of the modulated hybrid symbol to produce a first limited modulated hybrid symbol; (e) demodulating the first limited modulated hybrid symbol to recover distorted QPSK constellations; (f) constraining the distorted QPSK constellations to values greater than or equal to a minimum threshold value to produce constrained QPSK constellations; (g) demodulating the modulated hybrid symbol to produce a demodulated hybrid symbol vector; (h) subtracting the demodulated FM symbol vector from the Hybrid symbol vector to produce modified OFDM symbol vector; (i) applying a mask to inactive subcarriers in the plurality of subcarriers of the OFDM symbol vector; (j) modulating an OFDM symbol

Abstract: Systems, methods, and processor readable media are disclosed for scheduling and delivering content for digital radio broadcast transmission. To overcome the inefficiencies of conventional scheduling and delivery techniques, the present disclosure describes a novel multiport synchronous-asynchronous client for receiving content from multiple sources and then scheduling and delivering that content to an importer.

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: Methods and systems lor temporally aligning audio samples of digital and analog portions ol a radio broadcast signal involve receiving a radio broadcast signal having analog and digital portions; separating the analog and digital portions; retrieving a stored first time interval of an approximate time for a sample of the digital portion to travel through a digital signal path in a receiver including a digital demodulator: measuring a second time lor the sample of the digital portion to travel from an input of the digital signal path to an input of the digital demodulator; generating a delay amount by adding the first time to the second time; delaying second audio samples of the digital portion by tho delay amount relative to first audio samples of tho analog portion such that the second audio samples are temporally aligned with the first audio samples; and combining ihe first and second audio samples.

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 for rendering an alert message on a digital radio broadcast receiver is described. A digital radio broadcast signal is received at the digital radio broadcast receiver. Data corresponding to an alert message comprising type information for identifying a type of the alert message and message information is detected. If the type information satisfies a triggering condition for a type of alert message pre-selected by a user of the digital radio broadcast receiver, the message information is rendered at the digital radio broadcast receiver. A digital radio broadcast receiver that performs the method is also described.

Abstract: A data unit for transmitting data in a digital broadcasting system includes a first payload field, and a first byte code field having a value indicating an offset of data in the first payload field with respect to an absent value. A method for formatting the data unit includes: providing data for a payload field for a data unit, wherein the data includes an absent byte value, determining an offset between an absent byte value and other data in the payload field, shifting the data in the payload field by the offset to produce shifted bytes, and inserting a byte code in the data unit, wherein the byte code indicates the offset. A transmitter for transmitting the data units, and a receiver for receiving the data units are also provided.

Abstract: Methods and systems for correcting a frequency error in a digital portion of a radio broadcast signal are disclosed. The methods and systems include the steps of receiving a radio broadcast signal having an analog portion and a digital portion, separating the analog portion of the radio broadcast signal and the digital portion of the radio broadcast signal, determining a coarse frequency offset of the analog portion of the radio broadcast signal, generating an error signal for adjusting a frequency of the digital portion of the radio broadcast signal, wherein the error signal is based on the coarse frequency offset of the analog portion of the radio broadcast signal, and adjusting the frequency of the digital portion of the radio broadcast signal with the error signal that is based on the coarse frequency offset of the analog portion of the radio broadcast signal, such that a frequency error in the digital portion of the radio broadcast signal is reduced below a predetermined amount.

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 receiving and processing a digital radio broadcasting signal includes: receiving a digital radio broadcasting signal comprised of two or more multicast contents, playing a first one of the multicast contents, and concurrently storing a second one of the multicast contents. A receiver that implements the method is also provided.

Abstract: An apparatus includes a network receiver for receiving an over-the-air in-band on-channel broadcast signal and extracting broadcast content from the broadcast signal, and an output for delivering the content by way of a first receiver output signal to a plurality of network player devices. A method performed by the apparatus is also included.

Abstract: Methods and systems for adjusting a sampling rate of a digital radio receiver are disclosed that comprise the steps of receiving from a decoder a first frame of data having a first number of samples; determining at the digital radio receiver a phase difference between a receiver clock and a transmitter clock; generating at the digital radio receiver a second frame of data having a second number of samples, wherein the second number of samples depends on the phase difference between the receiver clock and the transmitter clock such that the second number of samples is less than the first number of samples if the transmitter clock is ahead of the receiver clock, and the second number of samples is greater than the first number of samples if the receiver clock is ahead of the transmitter clock; outputting the second frame of data having the second number of samples; and requesting a next frame of data from the decoder at a time that is earlier than a processing time for the first number of samples if the transmi