MULTI BAND AUDIO COMPRESSOR DYNAMIC LEVEL ADJUST IN A COMMUNICATIONS DEVICE

• US 20090254339A1
• Filed: 01/21/2009
• Published: 10/08/2009
• Est. Priority Date: 04/04/2008
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Seguin, Chad G.
• Granted Patent: US 8,781,820 B2
• Time in Patent Office: Days
• US Class Current: 704/212
• CPC Class Codes: H03G 9/005 of digital or coded signals
• CPC Class Codes: H03G 9/025 frequency-dependent volume compression or expansion, e.g. multiple-band systems H03G9/10, H03G9/18 take precedence

Abstract

An uplink or downlink audio processor contains a multi band compressor that receives an input, uplink or downlink, audio signal. The multi-band compressor has a band splitter that splits the input audio signal into a number of different band signals. Each band signal is input to a respective compressor block, which is independently programmable so that its audio frequency response (a) differs from a linear response in at least two non-overlapping windows of its input signal, and (b) differs from the frequency response of another one of the compressor blocks. Other embodiments are also described and claimed.

Claims

1. An audio communications device, comprising:

an uplink or downlink audio processor, the audio processor having

a multi band compressor to receive an input uplink or downlink audio signal, the multi-band compressor having a band splitter that is to split the input audio signal into a plurality of different band signals, and

a plurality of compressor blocks each to receive a respective one of the band signals as input, each of the compressor blocks having a plurality of input thresholds that are programmable and that include at least two of (1) a strong limit input threshold across which the compressor block strongly reduces gain applied to its input signal, (2) an expansion threshold across which the compressor block increases gain applied to the input signal, (3) a weak limit input threshold across which the compressor block weakly reduces gain to the input output signal, and (4) a no compression threshold across which gain applied to the input signal remains unchanged.

2. The audio communications device of claim 1 wherein the audio processor is an uplink processor and the input audio signal is an uplink signal.

3. The audio communications device of claim 1 wherein the audio processor is a downlink processor and the input audio signal is a downlink signal.

4. The audio communications device of claim 3 wherein the plurality of different band signals include a low band signal and a high band signal.

5. The audio communications device of claim 4 wherein the low band signal'"'"'s entire spectral content is below 1 kHz, and the high band signal'"'"'s entire spectral content is above 1 kHz.

6. The audio communications device of claim 3 further comprising a plurality of programmable linear gain blocks each to operate upon a respective one of the plurality of band signals.

7. An audio communications device, comprising:

an uplink or downlink audio processor, the audio processor having

a multi band compressor to receive an input, uplink or downlink, audio signal, the multi-band compressor having a band splitter that is to split the input audio signal into a plurality of different band signals, and

a plurality of compressor blocks each to receive a respective one of the band signals as input, each of the compressor blocks being independently programmable so that its audio frequency response (a) differs from a linear response in at least two non-overlapping windows of its input signal, and (b) differs from the frequency response of another one of the compressor blocks.

8. The audio communications device of claim 7 wherein the audio processor is an uplink processor and the input audio signal is an uplink signal.

9. The audio communications device of claim 7 wherein the audio processor is a downlink processor and the input audio signal is a downlink signal.

10. The audio communications device of claim 9 wherein the plurality of different band signals include a low band signal and a high band signal.

11. The audio communications device of claim 10 wherein the low band signal'"'"'s entire spectral content is below 1 kHz, and the high band signal'"'"'s entire spectral content is above 1 kHz.

12. The audio communications device of claim 9 further comprising a plurality of programmable linear gain blocks each to operate upon a respective one of the plurality of band signals.

13. The audio communications device of claim 7 wherein in the plurality of compressor blocks, strong attenuation is performed in one of the non-overlapping windows and weak attenuation is performed in another one of the non-overlapping windows.

14. The audio communications device of claim 13 wherein in the plurality of compressor blocks, expansion is performed in another one of the non-overlapping windows.

15. The audio communications device of claim 14 wherein in the plurality of compressor blocks, another one of the non-overlapping windows exhibits a linear response.

16. An audio communications device, comprising:

means for processing an input, uplink or downlink, audio signal, including

means for splitting the input audio signal into a plurality of different band signals,

first means for filtering one of the different band signals, the first filtering means being programmable so that its audio frequency response differs from a linear response in at least two non-overlapping windows of said one of the different band signals, and

second means for filtering another one of the different band signals, the second filtering means being independently programmable from the first filtering means so that its audio frequency response differs from that of the first filtering means.