# US 12,120,622 B2 · Radio apparatus for communicating digital audio streams > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,120,622 B2 - Document ID: US12120622B2 - Status: Granted - Kind: B2 - Application number: 17/637,224 - Filed: 2020-08-20 - Published: 2022-09-08 - Granted: 2024-10-15 - Earliest claimed: 2019-08-23 - Assignees: Nordic Semiconductor ASA - Applicants: Nordic Semiconductor ASA - Inventors: Nils Strøm; Anders Nore; Rolf Ambühl - Web page: https://patentgrep.com/patent/US12120622B2 ## CPC - H04J 3/0632: {Synchronisation of packets and cells, e.g. transmission of voice via a packet network, circuit emulation service [CES] (queuing arrangements in packet switching elements H04L49/90; synchronising systems for the synchronous transmission of a pulse code modulated video signal with one or more other pulse code modulated signals H04N7/56)} - H04W 56/002: {Mutual synchronization} - G06F 3/162: {Interface to dedicated audio devices, e.g. audio drivers, interface to CODECs} - H04R 1/025: {Arrangements for fixing loudspeaker transducers, e.g. in a box, furniture} - H04R 3/00: Circuits for transducers (arrangements for producing a reverberation or echo sound G10K15/08; amplifiers H03F) - H04S 1/007: {in which the audio signals are in digital form (data reduction aspects thereof based on psychoacoustics G10L19/02)} - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) - H04S: STEREOPHONIC SYSTEMS ## Abstract A radio receiver apparatus comprises radio circuitry for receiving a sequence of radio data packets, transmitted at regular intervals, wherein the sequence of radio data packets encodes a digital audio stream and each radio data packet encodes a respective number of audio samples from the digital audio stream. The apparatus also comprises a digital audio interface for outputting audio samples from the received digital audio stream, a controllable oscillator arranged to control an output rate at which the audio samples are output from the digital audio interface, and a timer. The apparatus also comprises control logic, configured to use the timer to measure an interval between receiving each of a pair of the radio data packets, and to control the oscillator to vary the output rate incrementally, in a number of steps, while outputting the audio samples from one radio data packet. The number of steps, or the size of each step, or both, depends on the measured interval. ## Claims ### Claim 1 A radio receiver apparatus comprising: radio circuitry for receiving a sequence of radio data packets, transmitted at regular intervals, the sequence of radio data packets encoding a digital audio stream, wherein each radio data packet encodes a respective number of audio samples from the digital audio stream; a digital audio interface for outputting audio samples from the received digital audio stream; a controllable oscillator arranged to control an output rate at which the audio samples are output from the digital audio interface; a timer; and control logic configured to use the timer to measure a reception interval between receiving each of a pair of the radio data packets, and, for at least one radio data packet of the sequence, to control the oscillator to vary said output rate incrementally, in a respective number of steps of non-zero size, while outputting the audio samples from the respective radio data packet, wherein the respective number of steps is at least two steps, and wherein the respective number of steps, or the respective size of each step, or both, depends on said measured reception interval and is such that the output rate is always positive. ### Claim 2 (depends on 1) The radio receiver apparatus of claim 1, wherein the control logic is configured to adjust the variable output rate incrementally, in at least a hundred steps, while outputting the audio samples from one radio data packet. ### Claim 3 (depends on 1) The radio receiver apparatus of claim 1, wherein the control logic is configured to determine a respective step size for outputting the audio samples of each successive radio data packet of the sequence. ### Claim 4 (depends on 1) The radio receiver apparatus of claim 1, wherein the control logic is configured to use the timer to measure the reception intervals between receiving every adjacent pair of radio data packets within the sequence. ### Claim 5 (depends on 1) The radio receiver apparatus of claim 1, wherein the control logic is further configured to measure an output interval between outputting each of a pair of output frames of audio samples, where each output frame consists of the audio samples contained in a respective radio data packet, and is configured to determine the number of steps, or the size of each step, or both, additionally based on said measured output interval between a pair of output frames. ### Claim 6 (depends on 1) The radio receiver apparatus of claim 1, wherein the controllable oscillator provides an interface for receiving data, from the control logic, that is representative of the step size, and for receiving data, from the control logic, that is representative of the number of steps, and comprises circuitry for making incremental changes to a periodic output of the oscillator in dependence on the received data representative of the step size and further in dependence on the received data representative of the number of steps. ### Claim 7 (depends on 1) The radio receiver apparatus of claim 1, further comprising a digital-to-audio converter for receiving the audio samples from the digital audio interface. ### Claim 8 (depends on 7) The radio receiver apparatus of claim 7, further comprising an amplifier and an acoustic transducer for outputting the digital audio stream as sound. ### Claim 9 (depends on 1) The radio receiver apparatus of claim 1, further comprising radio transmission circuitry and being configured to transmit a sequence of outgoing radio data packets encoding an outgoing digital audio stream. ### Claim 10 (depends on 9) The radio receiver apparatus of claim 9, comprising: an outgoing digital audio interface for receiving audio samples for transmission in the outgoing digital audio stream; a buffer memory for buffering the audio samples received at the outgoing digital audio interface; the controllable oscillator, or a further controller oscillator, configured to control a buffering rate at which audio samples for transmission are input to the buffer memory; and control logic configured, for at least one radio data packet of the sequence of outgoing radio data packets, to control the controllable oscillator to vary said buffering rate incrementally, in a respective number of steps of non-zero size, while inputting the audio samples for the respective radio data packet to the buffer memory, wherein the respective number of steps is at least two steps, and wherein the respective number of steps, or the respective size of each step, or both, depends on said measured reception interval and is such that the buffering rate is always positive. ### Claim 11 (depends on 1) A radio communication system comprising a radio transmitter apparatus and the radio receiver apparatus of claim 1, wherein the radio transmitter apparatus is configured to transmit the sequence of radio data packets to the radio receiver apparatus at regular intervals, the sequence of radio data packets encoding the digital audio stream. ### Claim 12 (depends on 11) The radio communication system of claim 11, further comprising a second radio receiver apparatus, wherein the radio transmitter apparatus is configured to transmit a second sequence of radio data packets to the second radio receiver apparatus at regular intervals, the second sequence of radio data packets encoding a second digital audio stream, wherein each radio data packet of the second sequence encodes a respective number of audio samples from the second digital audio stream, and wherein the second radio receiver apparatus comprises: radio circuitry for receiving the second sequence of radio data packets; a digital audio output for outputting audio samples from the received second digital audio stream; a controllable oscillator arranged to control an output rate at which the audio samples from the second digital audio stream are output from the digital audio output; a timer; and control logic configured to use the timer to measure a second receiver reception interval between receiving each of a pair of the radio data packets of the second sequence, and, for at least one radio data packet of the second sequence, to control the oscillator to vary said output rate incrementally, in a respective number of steps of non-zero size, while outputting the audio samples from the respective radio data packet of the second sequence, wherein the respective number of steps is at least two steps, and wherein the number of steps, or the size of each step, or both, depends on said measured second receiver reception interval and is such that the output rate is always positive. ### Claim 13 (depends on 12) The radio communication system of claim 12, wherein the first and second audio streams are left and right audio streams of a stereo audio stream. ### Claim 14 (depends on 1) The radio receiver apparatus of claim 1, wherein the digital audio interface is an external port of the radio receiver apparatus or is a connection to a bus of the radio receiver apparatus. ### Claim 15 A method of processing a digital audio stream, the method comprising: receiving a sequence of radio data packets, transmitted at regular intervals, the sequence of radio data packets encoding a digital audio stream, wherein each radio data packet encodes a respective number of audio samples from the digital audio stream; outputting audio samples from the received digital audio stream at a variable output rate; measuring a reception interval between receiving each of a pair of the radio data packets; and for at least one radio data packet of the sequence, adjusting the variable output rate incrementally, in a respective number of steps of non-zero size, while outputting the audio samples from the respective radio data packet, wherein the respective number of steps is at least two steps, and wherein the number of steps, or the size of each step, or both, depends on said measured reception interval and is such that the output rate is always positive. ### Claim 16 (depends on 15) The method of claim 15, comprising adjusting the variable output rate incrementally, in at least a hundred steps, while outputting the audio samples from one radio data packet. ### Claim 17 (depends on 15) The method of claim 15, comprising determining a respective step size for outputting the audio samples of each successive radio data packet of the sequence. ### Claim 18 (depends on 15) The method of claim 15, comprising measuring reception intervals between receiving every adjacent pair of radio data packets within the sequence. ### Claim 19 (depends on 15) The method of claim 15, comprising measuring an output interval between outputting each of a pair of output frames of audio samples, where each output frame consists of the audio samples contained in a respective radio data packet, and wherein the number of steps, or the size of each step, or both, depends additionally on said measured output interval between a pair of output frames. ### Claim 20 A radio transceiver apparatus comprising: radio reception circuitry for receiving a sequence of incoming radio data packets, transmitted at regular intervals; radio transmission circuitry for transmitting a sequence of outgoing radio data packets encoding an outgoing digital audio stream, wherein each respective outgoing radio data packet of the sequence of outgoing radio data packets corresponds to a respective incoming radio data packet of the sequence of incoming radio data packets; a digital audio interface for receiving audio samples for transmission in the outgoing digital audio stream; a buffer memory for buffering the audio samples received at the digital audio interface; a controllable oscillator configured to control a buffering rate at which audio samples are input to the buffer memory; a timer; and control logic configured to use the timer to measure a reception interval between receiving each of a pair of the incoming radio data packets, and, for at least one radio data packet of the sequence of outgoing radio data packets, to control the oscillator to vary said buffering rate incrementally, in a respective number of steps of non-zero size, while inputting the audio samples for the respective radio data packet to the buffer memory, wherein the respective number of steps is at least two steps, and wherein the number of steps, or the size of each step, or both, depends on said measured reception interval and is such that the buffering rate is always positive.