Hybrid audio delivery system and method therefor
Methods and systems to produce audio output signals from audio input signals. In one embodiment, a first portion of the audio input signals can be pre-processed, with the output used to modulate ultrasonic carrier signals, thereby producing modulated ultrasonic signals. The modulated ultrasonic signals can be transformed into a first portion of the audio output signals, which is directional. Based on a second portion of the audio input signals, a standard audio speaker can output a second portion of the audio output signals. Another embodiment further produces distortion compensated signals based on the pre-processed signals. The distortion compensated signals can be subtracted from the second portion of the audio input signals to generate inputs for the standard audio speaker to output the second portion of the audio output signals. In yet another embodiment, noise can be added during pre-processing of the first portion of the audio input signals.
1. An audio system to produce audio output signals comprising:
a filter configured to separate audio input signals into low frequency signals and high frequency signals;
a pre-processor operatively connected to the filter to receive the high frequency signals from the filter and to perform predetermined preprocessing on the high frequency signals to produce pre-processed signals;
a modulator operatively connected to the pre-processor to modulate ultrasonic carrier signals by the pre-processed signals thereby to produce modulated ultrasonic signals;
an ultrasonic speaker operatively connected to the modulator to receive the modulated ultrasonic signals and to output ultrasonic output signals to be transformed into high frequency portion of the audio output signals, which is directional; and
a standard audio speaker operatively connected to output low frequency portion of the audio output signals based on the low frequency signals.
2. An audio system as recited in claim 1 further comprising an audio signal generating device to generate the audio input signals.
3. An audio system as recited in claim 1 , wherein said audio system is portable.
4. An audio system as recited in claim 1 , wherein said audio system is wearable.
5. An audio system as recited in claim 1 , wherein said audio system is part of a portable electronic device.
6. An audio system as recited in claim 1 , wherein said audio system is integral with or coupled to a wireless communication device.
7. An audio system as recited in claim 6 , wherein the wireless communication device is a mobile phone.
8. An audio system to produce audio output signals from audio input signals, the audio input signals including at least low frequency signals and high frequency signals, the audio system comprising:
a modulator to modulate ultrasonic carrier signals by signals from the high frequency signals thereby to produce modulated ultrasonic signals;
an ultrasonic speaker operatively connected to the modulator to receive the modulated ultrasonic signals and to output ultrasonic output signals to be transformed into high frequency portion of the audio output signals, which is directional;
a standard audio speaker to output low frequency portion of the audio output signals at least based on the low frequency signals;
a pre-processor to perform predetermined processing on the high frequency signals to produce pre-processed signals;
a distortion compensation unit operatively connected to the pre-processor to produce distortion compensated signals at least based on the pre-processed signals; and
a combiner to modify at least the low frequency signals at least based on the distortion compensated signals to generate inputs for the standard audio speaker to output the low frequency portion of the audio output signals.
9. An audio system as recited in claim 8 ,
wherein the combiner to subtract the distortion compensated signals from the low frequency signals to generate the inputs for the standard audio speaker, and
wherein the distortion compensated signals to compensate for at least some of the non-linear distortion in the high frequency portion of the audio output signals produced from the transformation of the ultrasonic output signals.
10. An audio system as recited in claim 8 ,
wherein the combiner to subtract the distortion compensated signals from the low frequency signals to generate the inputs for the standard audio speaker, and
wherein the distortion compensation unit to substantially simulate non- linear distortion effect due to self-demodulation of ultrasonic signals in air.
11. A speaker arrangement as recited in claim 8 ,
wherein the combiner to subtract the distortion compensated signals from the low frequency signals to generate the inputs for the standard audio speaker, and
wherein the distortion compensation unit to twice differentiate at least a portion of the pre-processed signals thereby to produce distortion compensated signals.
12. An audio system as recited in claim 8 , wherein the pre-processor to add noise to the pre-processed signals to improve privacy.
13. An audio system to produce audio output signals comprising:
a pre-processor to receive at least a first portion of audio input signals and to perform predetermined preprocessing on the at least a portion of the audio input signals to produce pre-processed signals;
a distortion compensation unit operatively connected to the pre-processor to produce distortion compensated signals from the pre-processed signals;
a modulator operatively connected to the pre-processor to modulate ultrasonic carrier signals by the pre-processed signals thereby to produce modulated ultrasonic signals;
an ultrasonic speaker operatively connected to the modulator to receive the modulated ultrasonic signals to output ultrasonic output signals to be transformed into a first portion of the audio output signals, which is directional;
a standard audio speaker not to output ultrasonic signals; and
a combiner operatively connected to the distortion compensation unit to subtract the distortion compensated signals from at least a second portion of the audio input signals to generate inputs for the standard audio speaker to output a second portion of the audio output signals.
14. An audio system as recited in claim 13 , wherein the distortion compensated signals to compensate for at least some of the non-linear distortion in the first portion of the audio output signals produced from the transformation of the ultrasonic output signals.
15. An audio system to produce audio output signals comprising:
a filter to separate the audio input signals into at least low frequency signals and high frequency signals;
a pre-processor operatively connected to the filter to receive the high frequency signals and to perform predetermined preprocessing on the high frequency signals to produce pre-processed signals;
a distortion compensation unit operatively connected to the pre-processor to produce distortion compensated signals from the pre-processed signals;
a modulator operatively connected to the pre-processor to modulate ultrasonic carrier signals by the pre-processed signals thereby to produce modulated ultrasonic signals;
an ultrasonic speaker operatively connected to the modulator to receive the modulated ultrasonic signals to output ultrasonic output signals to be transformed into a first portion of the audio output signals, which is directional;
a standard audio speaker; and
a combiner operatively connected to the distortion compensation unit,
wherein the combiner is operatively connected to the filter to subtract the distortion compensated signals from the low frequency signals to generate inputs for the standard audio speaker to output a second portion of the audio output signals.
16. An audio system as recited in claim 15 further comprising an audio signal generating device to generate the audio input signals.
17. An audio system as recited in claim 15 , wherein said audio system is portable.
18. An audio system as recited in claim 17 , wherein said audio system is integral with or coupled to a wireless communication device.
19. An audio system to produce audio output signals comprising:
a pre-processor to receive at least a portion of audio input signals and to perform predetermined preprocessing on the at least a portion of the audio input signals to produce pre-processed signals;
a distortion compensation unit operatively connected to the pre-processor to produce distortion compensated signals from the pre-processed signals;
a modulator operatively connected to the pre-processor to modulate ultrasonic carrier signals by the pre-processed signals thereby to produce modulated ultrasonic signals;
an ultrasonic speaker operatively connected to the modulator to receive the modulated ultrasonic signals to output ultrasonic output signals to be transformed into a first portion of the audio output signals, which is directional;
a standard audio speaker; and
a combiner operatively connected to the distortion compensation unit to subtract the distortion compensated signals from at least a portion of the audio input signals to generate inputs for the standard audio speaker to output a second portion of the audio output signals,
wherein the pre-processor to add noise to the pre-processed signals to improve privacy.
20. A method to produce audio output signals from audio input signals comprising:
filtering the audio input signals into at least low frequency signals and high frequency signals;
modulating ultrasonic carrier signals by signals from the high frequency signals of the audio input signals to produce modulated ultrasonic signals;
outputting ultrasonic output signals by an ultrasonic speaker based on at least the modulated ultrasonic signals, the ultrasonic output signals being transformed into high frequency portion of the audio output signals, which is directional; and
outputting by a standard audio speaker a low frequency portion of the audio output signals based on signals from the low frequency signals of the audio input signals.
21. A method to produce audio output signals as recited in claim 20 further comprising:
processing signals from the high frequency signals of the audio input signals to produce pre-processed signals;
producing distortion compensated signals at least based on the pre- processed signals; and
subtracting the distortion compensated signals from the low frequency signals of the audio input signals to generate inputs for the standard audio speaker to output the low frequency portion of the audio output signals.