Method and system for low bit rate voice encoding and decoding applicable for any reduced bandwidth requirements including wireless
First Claim
Patent Images
1. An apparatus, comprising:
- an encoder configured to generate and output zero crossings of a voice sample for a first formant in response to voice excitation in the first formant, and divide the output zero crossings of the voice sample for the first formant signal by two and sample at a frequency of the first formant thereby generating a plurality of frames that use no more than half of a bit rate for an excitation signal and a remainder of the bit rate for short term spectrum analysis;
a transmitter configured to transmit the plurality of frames;
a decoder configured to receive the plurality of frames and extract an excitation signal from the plurality of frames;
a signal processing module configured to convert the excitation signal into a Hanning modified sawtooth signal, and perform spectral flattening on the Hanning modified sawtooth signal to excite a spectrum generator; and
an output configured to output a waveform based on the Hanning modified sawtooth signal which produces both even and odd harmonics for both periodic and aperiodic frequencies.
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Abstract
A voice encoder/decoder (vocoder) may provide receiving a voice sample and generating zero crossings of the voice sample in response to voice excitation in a first formant and creating a corresponding output signal. Additional operations may include dividing the output signal by two, and sampling the output signal at a predefined frequency such that a resulting combination uses half of a bit rate for an excitation and a remainder for short term spectrum analysis.
7 Citations
18 Claims
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1. An apparatus, comprising:
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an encoder configured to generate and output zero crossings of a voice sample for a first formant in response to voice excitation in the first formant, and divide the output zero crossings of the voice sample for the first formant signal by two and sample at a frequency of the first formant thereby generating a plurality of frames that use no more than half of a bit rate for an excitation signal and a remainder of the bit rate for short term spectrum analysis; a transmitter configured to transmit the plurality of frames; a decoder configured to receive the plurality of frames and extract an excitation signal from the plurality of frames; a signal processing module configured to convert the excitation signal into a Hanning modified sawtooth signal, and perform spectral flattening on the Hanning modified sawtooth signal to excite a spectrum generator; and an output configured to output a waveform based on the Hanning modified sawtooth signal which produces both even and odd harmonics for both periodic and aperiodic frequencies. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 17, 18)
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10. A method comprising:
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generating zero crossings of a voice sample for a first formant in response to voice excitation in the first formant and creating a corresponding zero crossings output signal; dividing the zero crossings output signal by two; sampling the divided zero crossings output signal at a frequency of the first formant thereby generating a plurality of frames that use no more than half of a bit rate for an excitation signal and a remainder of the bit rate for short term spectrum analysis; transmitting the plurality of frames; receiving the plurality of frames and extracting an excitation signal therefrom; converting the excitation signal into a Hanning modified sawtooth signal, and perform spectral flattening on the Hanning modified sawtooth signal to excite a spectrum generator; and outputting a waveform based on the Hanning modified sawtooth signal which produces both even and odd harmonics for both periodic and aperiodic frequencies. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A non-transitory computer readable storage medium configured to store instructions that when executed cause a processor to perform:
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generating zero crossings of a voice sample for a first formant in response to voice excitation in the first formant and creating a corresponding zero crossings output signal; dividing the zero crossings output signal by two; sampling the divided zero crossings output signal at a frequency of the first formant thereby generating a plurality of frames that use no more than half of a bit rate for an excitation signal and a remainder of the bit rate for short term spectrum analysis; transmitting the plurality of frames; receiving the plurality of frames and extracting an excitation signal therefrom; converting the excitation signal into a Hanning modified sawtooth signal, and perform spectral flattening on the Hanning modified sawtooth signal to excite a spectrum generator; and outputting a waveform based on the Hanning modified sawtooth signal which produces both even and odd harmonics for both periodic and aperiodic frequencies.
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Specification