SOFTWARE BASED AUDIO TIMING AND SYNCHRONIZATION

• US 20180192385A1
• Filed: 01/05/2018
• Published: 07/05/2018
• Est. Priority Date: 02/21/2014
• Status: Active Grant

• Current Assignee: WISA Technologies Incorporated
• Original Assignee: Summit Semiconductor, LLC
• Granted Patent: US 10,582,461 B2
• Time in Patent Office: Days
• CPC Class Codes: 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
• CPC Class Codes: H04J 3/0664 unidirectional timestamps
• CPC Class Codes: H04J 3/0667 Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays arrangements for monitoring round trip delays in packet switching networks H04L43/0864
• CPC Class Codes: H04N 21/43072 of multiple content streams on the same device
• CPC Class Codes: H04N 21/43637 involving a wireless protocol, e.g. Bluetooth, RF or wireless LAN [IEEE 802.11] arrangements for wireless networking or broadcasting of information in indoor or near-field type systems H04B10/114
• CPC Class Codes: H04R 2420/07 Applications of wireless loudspeakers or wireless microphones
• CPC Class Codes: H04R 5/04 Circuit arrangements, e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments combinations of amplifiers H03F3/68; stereophonic systems H04S
• CPC Class Codes: H04W 56/001 Synchronization between nodes

Abstract

Synchronization of plural outputs of data transported by a wireless network is facilitated by bandlimiting a sample clock signal controlling a rate at which data is processed by the network'"'"'s devices and/or bandlimiting wall time data controlling the real time for presenting a datum.

Claims

1. An audio system comprising:

(a) a first listener including;

(i) a wall clock maintaining a wall time for occurrence of an event, said wall time updated by data transmitted by a master clock and received by said first listener;

(ii) a sample clock recoverer retrieving a sample clock from data received by said first listener from a talker, said sample clock regulating a processing rate for a datum included in said data received from said talker; and

(iii) a frequency filter bandlimiting said sample clock output by said sample clock recoverer, wherein said frequency filter comprises an estimator connected to receive said sample clock output by said sample clock recoverer; and

(iv) a transmitter transmitting said bandlimited sample clock; and

(b) a second listener arranged to receive said transmitted bandlimited sample clock and use said bandlimited sample clock to regulate processing data received from said talker.

2. The audio system of claim 1 wherein the first listener further comprises a frequency filter attenuating a frequency of said updating data received from said master clock.

3. The audio system of claim 2 wherein said updating data received from said master clock comprises a timing synchronization function datum.

4. The audio system of claim 2 wherein said updating datum received from said master clock comprises a precision time protocol datum.

5. An audio system comprising:

(a) a first listener including;

(i) a wall clock maintaining a wall time for occurrence of an event, said wall time updated by a data transmitted by a master clock and received by said first listener;

(ii) a frequency filter bandlimiting said updating data received from said master clock and said wall time, wherein said frequency filter comprises an estimator connected to receive said updating data by said sample clock recoverer; and

(iii) a sample clock recoverer retrieving a sample clock from data received by said first listener from a talker, said sample clock regulating a processing rate for a datum included in said data received from said talker; and

(iv) a transmitter transmitting said bandlimited wall time; and

(b) a second listener arranged to receive said bandlimited wall time and to use said bandlimited wall time to recover a sample clock from data received from said talker.

6. The audio system of claim 5 wherein said updating data received from said master clock comprises a timing synchronization function datum.

7. The audio system of claim 5 wherein said updating datum received from said master clock comprises a precision time protocol datum.

8. A method of recovering a sample clock in a network, the method comprising the steps of:

(a) generating a raw sample clock signal oscillating at a frequency determined by a datum included in a data packet; and

(b) bandlimiting the raw sample clock signal about the mean frequency of the raw sample clock signal by estimating the raw sample clock signal.

9. A method of recovering a sample clock in a network, the method comprising the steps of:

(a) bandlimiting a raw wall time signal about a mean frequency of said raw wall time signal by estimating the raw wall time signal; and

(b) generating a sample clock signal oscillating at a frequency determined by a datum included in a data packet and the bandlimited raw wall time signal.

10. A method of recovering audio timing in a network, the method comprising the steps of:

(a) bandlimiting a raw wall time signal about a mean frequency of the raw wall time signal by estimating the frequency and delay of the raw wall time signal to a talker transmitter audio clock; and

(b) including timing datum in a data packet about the mean frequency of said timing signal from the estimate of the frequency and delay of said timing signal and an audio playtime at the transmitter; and

(c) bandlimiting said raw wall time signal about the mean frequency of said raw wall time signal by estimating the frequency and delay of said raw wall time signal to a listener receiver audio clock; and

(d) combining both wall time estimation and received timing datum estimation from a packet to generate audio play time at the receiver; and

(e) using the playtime to generate coefficients for a polynomial interpolator that resamples the audio to the receiver audio clock.

11. A method of recovering audio timing in a network, the method comprising the steps of:

(a) bandlimiting a raw wall time signal about a mean frequency of the raw wall time signal by estimating the frequency and delay of the raw wall time signal to the listener receiver audio clock;

(b) estimating the frequency and delay of this wall time signal to the transmitter audio clock by the talker transmitter requesting a copy of the wall time signal from the receiver and bandlimiting about a mean frequency of this wall time signal by;

(c) including timing datum in a data packet about the mean frequency of said timing signal from the estimate of the frequency and delay of said timing signal and an audio playtime at the transmitter; and

(d) combining both wall time estimation and received timing datum estimation from a packet to generate audio play time at the receiver; and

(e) using the playtime to generate coefficients for a polynomial interpolator that resamples the audio to the receiver audio clock.

12. A method of recovering audio timing in a network, the method comprising the steps of:

(a) bandlimiting a raw wall time signal about a mean frequency of the raw wall time signal by estimating the frequency and delay of the raw wall time signal to the talker transmitter audio clock;

(b) including timing datum in a data packet about the mean frequency of said timing signal from the estimate of the frequency and delay of said timing signal and an audio playtime at the transmitter;

(c) estimating the frequency and delay of this wall time signal to the receiver audio clock by the listener receiver requesting a copy of the wall time signal from the transmitter and bandlimiting about a mean frequency of this wall time signal; and

(d) combining both wall time estimation and received timing datum estimation from a packet to generate audio play time at the receiver; and

(e) using the playtime to generate coefficients for a polynomial interpolator that resamples the audio to the receiver audio clock.

13. A method of recovering audio timing in a network, the method comprising the steps of:

(a) bandlimiting a raw wall time signal about a mean frequency of the raw wall time signal by estimating the frequency and delay of the raw wall time signal to a talker transmitter audio clock; and

(b) including timing datum in a data packet about the mean frequency of said timing signal from the estimate of the frequency and delay of said timing signal and an audio playtime at the transmitter; and

(c) bandlimiting said raw wall time signal about the mean frequency of said raw wall time signal by estimating the frequency and delay of said raw wall time signal to a listener receiver audio clock; and

(d) combining both wall time estimation and received timing datum estimation from a packet to generate audio play time at the receiver; and

(e) using the playtime to generate coefficients for a fractional delay filter that resamples the audio to the receiver audio clock.

14. A method of recovering audio timing in a network, the method comprising the steps of:

(a) bandlimiting a raw wall time signal about a mean frequency of the raw wall time signal by estimating the frequency and delay of the raw wall time signal to the listener receiver audio clock;

(b) estimating the frequency and delay of this wall time signal to the transmitter audio clock by the talker transmitter requesting a copy of the wall time signal from the receiver and bandlimiting about a mean frequency of this wall time signal by;

(c) including timing datum in a data packet about the mean frequency of said timing signal from the estimate of the frequency and delay of said timing signal and an audio playtime at the transmitter; and

(d) combining both wall time estimation and received timing datum estimation from a packet to generate audio play time at the receiver; and

(e) using the playtime to generate coefficients for a fractional delay filter that resamples the audio to the receiver audio clock.

15. A method of recovering audio timing in a network, the method comprising the steps of:

(a) bandlimiting a raw wall time signal about a mean frequency of the raw wall time signal by estimating the frequency and delay of the raw wall time signal to the talker transmitter audio clock;

(b) including timing datum in a data packet about the mean frequency of said timing signal from the estimate of the frequency and delay of said timing signal and an audio playtime at the transmitter;

(c) estimating the frequency and delay of this wall time signal to the receiver audio clock by the listener receiver requesting a copy of the wall time signal from the transmitter and bandlimiting about a mean frequency of this wall time signal; and

(d) combining both wall time estimation and received timing datum estimation from a packet to generate audio play time at the receiver; and

(e) using the playtime to generate coefficients for a fractional delay filter that resamples the audio to the receiver audio clock.