Wireless cellular telephone with audio codec
View Patent ↗A wireless cellular telephone with an audio codec for converting digital audio signals to analog audio signals. The audio codec comprises two digital audio bus interfaces for coupling to respective digital audio buses, and a digital-only signal path between the two digital audio bus interfaces, such that no analog processing of the audio signals occurs in the digital-only signal path.
1. A wireless cellular telephone comprising:
a communications processor for processing a telephony call;
an applications processor for processing digital audio signals;
a wireless codec for wirelessly communicating audio data with a wireless peripheral device;
an audio codec for converting digital audio signals to analog audio signals;
a first digital audio bus between the audio codec and the communications processor, for carrying digital audio signals from the communications processor to the audio codec and carrying digital audio signals from the audio codec to the communications processor;
a second digital audio bus between the audio codec and the applications processor, for carrying digital audio signals from the applications processor to the audio codec and carrying digital audio signals from the audio codec to the applications processor; and
a third digital audio bus, separate from the first digital audio bus, between the audio codec and the wireless codec, for carrying digital audio signals from the wireless codec to the audio codec and carrying digital audio signals from the audio codec to the wireless codec.
2. A wireless cellular telephone according to claim 1 wherein the first and third digital audio buses share a clock line.
3. A wireless cellular telephone according to claim 1 wherein the audio codec comprises a digital signal mixer operable to mix a digital audio signal received from the communications processor over the first digital audio bus with a digital audio signal received from the applications processor over the second digital audio bus and output the resulting mixed digital audio signal to the wireless codec over the third digital audio bus.
4. A wireless cellular telephone according to claim 1 wherein the second digital audio bus is operable to carry (i) a first digital audio signal from the applications processor to the audio codec, (ii) a second digital audio signal from the applications processor to the audio codec, and (iii) a third digital audio signal from the audio codec to the applications processor wherein digital audio data of the first and second digital audio signals are carried in respective time-divided slots of a time division multiplex scheme.
5. A wireless cellular telephone according to claim 4 wherein the audio codec is operable to receive the first digital audio signal over the second digital audio bus from the applications processor and transmit it over the first digital audio bus to the communications processor and while receiving the second digital audio signal over the second digital audio bus from the applications processor and transmitting it over the third digital audio bus to the wireless codec.
6. A wireless cellular telephone according to claim 1 wherein the second digital audio bus is operable to carry (i) a first digital audio signal to the applications processor from the audio codec, (ii) a second digital audio signal to the applications processor from the audio codec, and (iii) a third digital audio signal to the audio codec from the applications processor wherein digital audio data of the first and second digital audio signals are carried in respective time-divided slots of a time division multiplex scheme.
7. A wireless cellular telephone according to claim 6 wherein the audio codec is operable to receive the first digital audio signal over the first digital audio bus from the communications processor and transmit it over the second digital audio bus to the applications processor while receiving the second digital audio signal over the third digital audio bus from the wireless codec and transmitting it over the second digital audio bus to the applications processor.
8. A method of operating a wireless cellular telephone, said wireless cellular telephone comprising a communications processor for processing a telephony call, an applications processor for processing digital audio signals, a wireless codec for wirelessly communicating audio data with a wireless peripheral device, and an audio codec for converting digital audio signals to analog audio signals;
wherein said method comprises:
carrying digital audio signals from the communications processor to the audio codec and carrying digital audio signals from the audio codec to the communications processor on a first digital audio bus between the audio codec and the communications processor;
carrying digital audio signals from the applications processor to the audio codec and carrying digital audio signals from the audio codec to the applications processor on a second digital audio bus between the audio codec and the applications processor; and
carrying digital audio signals from the wireless codec to the audio codec and carrying digital audio signals from the audio codec to the wireless codec on a third digital audio bus, separate from the first digital audio bus, between the audio codec and the wireless codec.
9. A method according to claim 8 comprising carrying digital audio signals on the first and third digital audio buses synchronously using a common clock signal.
10. A method according to claim 8 comprising:
transmitting a first digital audio signal from the communications processor to the audio codec over the first digital audio bus;
transmitting a second digital audio signal received from the applications processor to the audio codec over the second digital audio bus;
mixing the first and second digital audio signals digitally in the audio codec; and
outputting the resulting mixed digital audio signal to the wireless codec over the third digital audio bus.
11. A method according to claim 8 comprising carrying on the second digital audio bus (i) a first digital audio signal from the applications processor to the audio codec, (ii) a second digital audio signal from the applications processor to the audio codec, and (iii) a third digital audio signal from the audio codec to the applications processor, wherein the first and second digital audio signals are carried on the second digital audio bus in respective time-divided slots of a time division multiplex scheme.
12. A method according to claim 11 comprising transmitting the first digital audio signal over the first digital audio bus from the audio codec to the communications processor while transmitting the second digital audio signal over the third digital audio bus from the audio codec to the wireless codec.
13. A method according to claim 8 comprising carrying on the second digital audio bus (i) a first digital audio signal to the applications processor from the audio codec, (ii) a second digital audio signal to the applications processor from the audio codec, and (iii) a third digital audio signal to the audio codec from the applications processor, wherein the first and second digital audio signals are carried on the second digital audio bus in respective time-divided slots of a time division multiplex scheme.
14. A method according to claim 13 comprising transmitting the first digital audio signal over the first digital audio bus to the audio codec from the communications processor while transmitting the second digital audio signal over the third digital audio bus to the audio codec from the wireless codec.