Analog and digital audio alignment in the HD radio exciter engine (exgine)

Patent metadata

Field	Value
Publication number	US-10484115-B2
Application number	US-201816108355-A
Country	US
Kind code	B2
Filing date	Aug 22, 2018
Priority date	Feb 9, 2018
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

An apparatus comprises a digital input port configured to receive digital audio packets of main program service (MPS) audio; a modem operatively coupled to the digital port; an analog input port configured to receive an audio engineer society format (AES) audio signal that is a digitized version of the analog signal component of the frequency modulation (FM) hybrid radio signal; and an alignment unit configured to time-align the AES audio signal with the digital audio packets at the modem; wherein the modem is configured to generate the FM hybrid radio signal using the digital audio packets and the time-aligned AES audio signal.

First claim

What is claimed is:

1. An apparatus for generating a frequency modulation (FM) hybrid radio signal for broadcast, the apparatus comprising:
a digital input port configured to receive digital audio packets of main program service (MPS) audio;
a modem operatively coupled to the digital port;
an analog input port configured to receive an audio engineer society format (AES) audio signal that is a digitized version of the analog signal component of the FM hybrid radio signal; and
an alignment unit configured to time-align the AES audio signal with the digital audio packets at the modem; wherein the modem is configured to generate the FM hybrid radio signal using the digital audio packets and the time-aligned AES audio signal.

2. The apparatus of claim 1 , including:
an audio decoder configured to decode the received digital audio packets and generate a digital audio signal;
wherein the alignment unit is configured to determine an offset between the digital audio signal and the AES audio signal, and includes a delay circuit configured to delay arrival of one or more digitized samples of the AES audio signal at the modem according to the determined offset.

3. The apparatus of claim 2 , wherein the alignment unit includes a correlation unit configured to perform an alignment correlation algorithm to determine the offset between audio data of the digital audio signal and the digitized samples of the AES audio signal.

4. The apparatus of claim 1 , including a timing module and a sampling circuit, the sampling circuit configured to resample the AES audio signal using a clock signal of the timing module to produce a clock-restored AES audio signal and the alignment unit is configured to time-align the clock-restored AES audio signal with the digital audio packets at the modem.

5. The apparatus of claim 4 , including:
an audio decoder configured to decode the received digital audio packets and generate a digital audio signal; and
a rate adjustment circuit configured to change the sampling rate of the sampling circuit to reduce a sample rate difference between the clock-restored AES audio signal and the digital audio signal.

6. The apparatus of claim 1 , wherein the digital port is an Ethernet port, and the analog port is operatively coupled to a studio transmitter link of radio broadcast studio equipment.

7. The apparatus of claim 1 , wherein the modem is configured to generate an FM in-band on-channel (IBOC) radio signal that includes the time-aligned AES audio signal in an analog FM signal of the FM IBOC radio signal and the time-aligned digital audio in subcarriers of the FM IBOC radio signal.

8. The apparatus of claim 1 , wherein the AES audio signal is an FM composite AES audio signal.

9. A method for controlling operation of a hybrid radio exciter engine, the method comprising:
receiving digital audio packets of main program service (MPS) audio at a digital port of the hybrid radio exciter engine and providing the digital audio packets to a modem of the hybrid radio exciter engine;
receiving an audio engineer society format (AES) audio signal of the MPS audio at an analog port of the hybrid radio exciter engine, wherein the AES audio signal is a digitized version of an analog audio signal of the MPS audio;
aligning the AES audio signal in time with corresponding digital audio packets at the modem; and
generating a frequency modulated (FM) hybrid radio signal for broadcast that includes time-aligned analog MPS audio and digital MPS audio.

10. The method of claim 9 , wherein aligning the audio samples includes:
decoding the digital audio packets to produce a digital audio signal;
determining an offset between audio data of the digital audio signal and audio data of the AES audio signal; and
delaying digitized samples of the AES audio signal modem according to the determined offset before transferring the digitized samples to the modem.

11. The method of claim 10 , wherein determining the offset includes determining the offset between the between audio data of the digital audio signal and the audio data of the audio samples using an alignment correlation algorithm.

12. The method of claim 9 , including:
resampling the AES audio signal to produce a clock-restored AES audio signal at hybrid radio exciter engine;
wherein aligning the AES audio signal includes aligning the clock-restored AES audio signal in time with the digital audio packets at the modem.

13. The method of claim 9 , including:
decoding the digital audio packets to produce a digital audio signal; and
changing the sampling rate of the AES audio signal to reduce a sample rate difference between the clock-restored AES audio signal and the digital audio signal.

14. The method of claim 9 ,
wherein receiving digital audio packets includes receiving the digital audio packets of the MPS audio from an Ethernet network; and
wherein receiving the AES audio signal includes receiving an AES audio signal of MPS audio from radio broadcast studio equipment.

15. The method of claim 9 , wherein generating the FM hybrid radio signal includes generating an FM in-band on-channel (IBOC) radio signal that includes the time-aligned AES audio signal in an analog FM signal of the FM IBOC radio signal and the time-aligned digital audio in subcarriers of the FM IBOC radio signal.

16. An apparatus for generating a frequency modulation (FM) hybrid radio signal for broadcast, the apparatus comprising:
a digital input port configured to receive digital audio packets of main program service (MPS) audio;
a modem operatively coupled to the digital input port;
an analog input port configured to receive an audio engineer society format (AES) audio signal that is a digitized version of the analog signal component of the FM hybrid radio signal;
a sampling circuit configured to resample the AES audio signal to produce a clock-restored AES audio signal; and
a rate adjustment circuit configured to determine a sampling rate of digital audio information included in the digital audio packets and adjust a rate of resampling of the AES audio signal to reduce a sample rate difference between an audio sample of the clock-restored AES audio signal and a digital audio packet corresponding to the audio sample;
wherein the modem is configured to generate the FM hybrid radio signal using time-aligned AES audio samples and digital MPS audio.

17. The apparatus of claim 16 , including:
an audio decoder configured to decode the received digital audio packets and generate a digital audio signal;
wherein the rate adjustment circuit is configured to determine the sample rate of the digital audio information using the generated digital audio signal and reduce a difference between the sample rate of the clock-restored AES audio signal and the sample rate of the digital audio information.

18. The apparatus of claim 16 , wherein the digital port is an Ethernet port, and the analog port is operatively coupled to a studio transmitter link of radio broadcast studio equipment.

19. The apparatus of claim 16 , wherein the modem is configured to generate an FM in-band on-channel (IBOC) radio signal that includes the time-aligned analog audio in an analog FM signal of the FM IBOC radio signal and the time-aligned digital audio in subcarriers of the FM IBOC radio signal.

20. The apparatus of claim 16 , wherein the analog port is configured to receive an FM composite AES audio signal.

Assignees

• Ibiquity Digital Corp

Inventors

• Iannuzzelli Russell
• Horowitz Adam
• Detweiler Jeffrey R
• Snelling William E

Classifications

• H04H20/18 Primary

  Arrangements for synchronising broadcast or distribution via plural systems · CPC title

• H04H20/30

  by a single channel · CPC title

• H04H2201/20

  digital audio broadcasting [DAB] · CPC title

• H04H2201/183

  FM digital or hybrid · CPC title

• H04H20/48

  for FM stereophonic broadcast systems · CPC title