摘要:
A method for processing a digital audio broadcast signal in a radio receiver, includes: receiving a hybrid broadcast signal; demodulating the hybrid broadcast signal to produce an analog audio stream and a digital audio stream; and using a normalized cross-correlation of envelopes of the analog audio stream and the digital audio stream to measure a time offset between the analog audio stream and the digital audio stream. The time offset can be used to align the analog audio stream and the digital audio stream for subsequent blending of an output of the radio receiver from the analog audio stream to the digital audio stream or from the digital audio stream to the analog audio stream.
摘要:
A radio receiver comprises physical layer circuitry and processor circuitry. The physical layer circuitry receives quadrature amplitude modulation (QAM) symbols via a plurality of subcarriers included in a broadcast radio signal. Each received QAM symbol is a complex symbol comprising multiple bits of encoded source information. The processing circuitry demodulates the received data symbols, generates a constellation sample for each received QAM symbol, generates a soft metric for each bit of encoded information of the received QAM symbols using the constellation sample, and multiplies the soft metric by a channel state information (CSI) weight to produce a Log-likelihood Ratio (LLR) approximation for each bit of encoded information of the received QAM symbols.
摘要:
A method for processing a digital audio broadcast signal in a radio receiver, includes: receiving a hybrid broadcast signal; demodulating the hybrid broadcast signal to produce an analog audio stream and a digital audio stream; and using a normalized cross-correlation of envelopes of the analog audio stream and the digital audio stream to measure a time offset between the analog audio stream and the digital audio stream. The time offset can be used to align the analog audio stream and the digital audio stream for subsequent blending of an output of the radio receiver from the analog audio stream to the digital audio stream or from the digital audio stream to the analog audio stream.
摘要:
A method comprises performing iterations of a peak-to-average ratio (PAR) reduction algorithm on a modulated OFDM symbol, each of the iterations including: clipping the modulated OFDM symbol to produce a clipped modulated OFDM symbol; subtracting the clipped modulated OFDM symbol from the modulated OFDM symbol to produce a difference signal; weighting the difference signal using a weight that varies across the iterations, to produce a weighted difference signal that varies across the iterations; subtracting the weighted difference signal from the modulated OFDM symbol to produce a modified modulated OFDM symbol; and performing further PAR reduction operations on the modified modulated OFDM symbol to produce a PAR-reduced OFDM symbol for use in a next iteration.
摘要:
A method for processing audio signals in a radio transmitter, includes: receiving an analog audio sample stream and a digital audio sample stream; determining offsets in time between the analog audio stream and the digital audio stream using a normalized cross-correlation of audio envelopes of the analog audio sample stream and the digital audio sample stream; filtering the determined offsets in time to produce filtered offset values; determining an alignment slip adjustment value as a function of the filtered offset values; aligning the analog audio sample stream and the digital audio sample stream using the determined alignment slip adjustment value; and generating a hybrid radio signal for broadcast that includes time-aligned analog audio and digital audio.
摘要:
A method for processing audio signals in a radio transmitter, includes: receiving an analog audio sample stream and a digital audio sample stream; determining offsets in time between the analog audio stream and the digital audio stream using a normalized cross-correlation of audio envelopes of the analog audio sample stream and the digital audio sample stream; filtering the determined offsets in time to produce filtered offset values; determining an alignment slip adjustment value as a function of the filtered offset values; aligning the analog audio sample stream and the digital audio sample stream using the determined alignment slip adjustment value; and generating a hybrid radio signal for broadcast that includes time-aligned analog audio and digital audio.
摘要:
A method for processing a digital audio broadcast signal in a radio receiver includes: receiving a digital audio broadcast signal; demodulating the digital audio broadcast signal to produce an analog audio stream and a digital audio stream; determining a digital signal quality value for the digital audio stream; blending an output of the radio receiver from the analog audio stream to the digital audio stream when the digital signal quality value exceeds an adaptive analog-to-digital threshold value; and blending the output of the radio receiver from the digital audio stream to the analog audio stream when the digital signal quality value falls below an adaptive digital-to-analog threshold value, wherein the adaptive digital-to-analog threshold value is lower than the adaptive analog-to-digital threshold value.
摘要:
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.
摘要:
A radio transmitter comprises transmitting circuitry and processing circuitry. The transmitting circuitry broadcasts a frequency modulation (FM) in-band on-channel (IBOC) radio signal, wherein the FM IBOC radio signal includes multiple subcarriers grouped into multiple frequency partitions. The processing circuitry is configured to receive input bits for transmitting; encode and puncture the input bits using forward error correction (FEC) encoding; distribute encoded input bits between a main encoded component and a backup encoded component, wherein encoded bits of the backup encoded component are delayed for a specified duration relative to encoded bits of the main encoded component; allocate the encoded input bits of the main and backup encoded components into frequency diverse sidebands of the FM IBOC radio signal; and modulate the encoded input bits for transmitting using the frequency diverse sidebands of the FM IBOC radio signal, wherein the modulation is a type of quadrature amplitude modulation (QAM).
摘要:
A method for processing a digital audio broadcast signal in a radio receiver, includes: receiving a hybrid broadcast signal; demodulating the hybrid broadcast signal to produce an analog audio stream and a digital audio stream; and using a normalized cross-correlation of envelopes of the analog audio stream and the digital audio stream to measure a time offset between the analog audio stream and the digital audio stream. The time offset can be used to align the analog audio stream and the digital audio stream for subsequent blending of an output of the radio receiver from the analog audio stream to the digital audio stream or from the digital audio stream to the analog audio stream.