Band extending apparatus and method
First Claim
1. A band extending apparatus receiving at least an input signal of a preset frequency band to output a band extended signal corresponding to said input signal extended in a frequency band thereof, said apparatus comprising:
- a spectral parameter calculating unit for calculating spectral parameters representing spectrum characteristics of said input signal of said preset frequency band;
a noise generating circuit for generating a noise signal; and
a coefficient calculating unit for shifting the frequency of said spectral parameters to then find filter coefficients;
said band extended signal being generated based on said noise signal, filer coefficients and said input signal.
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Accused Products
Abstract
A band extending apparatus includes a spectral parameter calculating circuit for calculating spectral parameters of a narrow-band input signal, a coefficient calculating circuit supplied with the spectral parameters to convert the spectral parameters into coefficients of a band extended signal, and a gain circuit supplied with a gain from a gain adjustment circuit and multiplying an output signal of a noise generating circuit with the gain to output the resulting signal to a synthesis filter circuit. The synthesis filter circuit forms a filter by receiving coefficients from the coefficient calculating circuit. The signal from the gain circuit is passed through the filter. The synthesis filter circuit outputs a high band signal for band extension. The band extending apparatus also includes a sampling frequency converting circuit, supplied with the narrow-band input signal to output a signal up-sampled to a preset sampling frequency, and an adder for summing the high band signal to the up sampled signal to output a band extended signal.
18 Citations
38 Claims
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1. A band extending apparatus receiving at least an input signal of a preset frequency band to output a band extended signal corresponding to said input signal extended in a frequency band thereof, said apparatus comprising:
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a spectral parameter calculating unit for calculating spectral parameters representing spectrum characteristics of said input signal of said preset frequency band;
a noise generating circuit for generating a noise signal; and
a coefficient calculating unit for shifting the frequency of said spectral parameters to then find filter coefficients;
said band extended signal being generated based on said noise signal, filer coefficients and said input signal. - View Dependent Claims (14, 15)
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2. A band extending apparatus comprising:
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a spectral parameter calculating unit, receiving at least an input signal of a preset frequency band to calculate spectral parameters representing spectral characteristics;
a noise generating unit for generating a noise signal;
a coefficient calculating unit for shifting the frequency of said spectral parameters to then find filter coefficients;
a gain unit for supplying a gain to an output of said noise generating unit;
a synthesis filter unit for passing an output signal of said gain unit through a synthesis filter, formed using said filter coefficients, to reproduce a signal for band extension; and
means for adding a signal corresponding to said input signal converted in a sampling frequency thereof to an output signal of said synthesis filter unit to generate a band extended signal. - View Dependent Claims (3, 13, 16, 18, 19)
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4. A band extending apparatus comprising:
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a spectral parameter calculating unit, receiving at least an input signal of a preset frequency band to calculate spectral parameters representing spectral characteristics;
an adaptive codebook unit, calculating a pitch period at least from said input signal to generate an adaptive codebook component based on said pitch period and a past sound source signal;
a noise generating unit for generating a noise signal;
a coefficient calculating unit for shifting the frequency of said spectral parameters to find filter coefficients;
a gain unit for supplying a gain to at least one of an output signal of said noise generating unit and an output signal of said adaptive codebook unit, and for summing the output signals to output a sound source signal;
a synthesis filter unit, receiving said sound source signal from said gain unit to a synthesis filter formed using said filter coefficients to reproduce a signal for band extension; and
means for summing a signal corresponding to said input signal converted in a sampling frequency thereof to an output signal of said synthesis filter unit to produce a band extended signal. - View Dependent Claims (5, 12, 17)
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6. A band extending apparatus comprising:
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a spectral parameter calculating unit, receiving at least with an input signal of a preset frequency band to calculate spectral parameters representing spectral characteristics;
an adaptive codebook unit for calculating a pitch period at least from said input signal to generate an adaptive codebook component based on said pitch period and past sound source signal;
a noise generating unit for generating a noise signal;
a coefficient calculating unit for shifting the frequency of said spectral parameters to then find filter coefficients;
a gain unit for supplying a gain to at least one of an output of said noise generating unit and an output signal of said adaptive codebook unit and for summing the resulting signals to output a sound source signal;
a pitch pre-filter for filtering said sound source signal from said gain unit, using said pitch period;
a synthesis filter unit for supplying an output signal of said pitch pre-filter to a synthesis filter formed using said filter coefficients to generate band-expanding signal; and
means for summing a signal corresponding to said input signal converted in a sampling frequency thereof to an output signal of said synthesis filter unit to generate a band extended signal. - View Dependent Claims (7)
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8. A band extending apparatus comprising:
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a spectral parameter calculating unit, receiving at least with an input signal of a preset frequency band to calculate spectral parameters representing spectral characteristics;
a pitch generating unit, calculating a pitch period at least from said input signal to generate a period signal using said pitch period;
a noise generating unit for generating a noise signal;
a coefficient calculating unit for shifting the frequency of said spectral parameters to find filter coefficients;
a gain unit for supplying a proper gain to at least one of an output signal of said noise generating unit and an output signal of said pitch generating unit, and for summing the resulting output signals to output a sound source signal;
a synthesis filter unit, receiving said sound source signal from said gain unit to a synthesis filter, formed using said filter coefficients, to reproduce a signal for band extension; and
means for summing a signal corresponding to said input signal converted in a sampling frequency thereof to an output signal of said synthesis filter unit, to produce a band extended signal. - View Dependent Claims (9)
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10. A band extending apparatus comprising:
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a spectral parameter calculating unit, receiving at least an input signal of a preset frequency band to calculate spectral parameters representing spectral characteristics;
a pitch generating unit for calculating a pitch period at least from said input signal to generate a period signal using said pitch signal;
a noise generating unit for generating a noise signal;
a coefficient calculating unit for shifting the frequency of said spectral parameters to then find filter coefficients;
a gain unit for supplying a gain to at least one of an output signal of said noise generating unit and an output signal of said pitch generating unit and for summing the resulting output signals to output a sound source signal;
a pitch pre-filter for filtering said sound source signal from said gain unit, using said pitch period;
a synthesis filter unit, receiving an output signal of said pitch pre-filter to reproduce a signal for band extension; and
means for summing a signal corresponding to said input signal converted in a sampling frequency thereof to an output signal of said synthesis filter unit to obtain a band extended signal. - View Dependent Claims (11)
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20. A band extending method in which at least an input signal of a preset band is input and the frequency range of said input signal is extended, said method comprising:
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calculating spectral parameters representing spectral characteristics of the input signal of said preset band entered;
shifting the frequency of said spectral parameters and then finding filter coefficients;
generating a noise signal; and
generating a band extended signal, using said noise signal and said filter coefficients, generated in said steps, and the input signal. - View Dependent Claims (33, 34)
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21. A band extending method comprising:
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receiving at least an input signal of a preset frequency band to calculate spectral parameters representing spectral characteristics;
shifting the frequency of said spectral parameters to then find filter coefficients;
supplying a gain to a noise signal generated by a noise generating unit;
passing a signal, added by said gain, through a synthesis filter, formed using said filter coefficients, to reproduce a signal for band extension; and
summing a signal corresponding to said input signal converted in a sampling frequency thereof to an output signal of said synthesis filter unit to generate a band extended signal. - View Dependent Claims (22, 32, 35, 37, 38)
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23. A band extending method comprising:
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receiving at least an input signal of a preset frequency band to calculate spectral parameters representing spectral characteristics;
calculating a pitch period at least from said input signal to generate an adaptive codebook component based on said pitch period and a past sound source signal;
shifting the frequency of said spectral parameters to find filter coefficients;
supplying a gain to at least one of a noise signal from a noise generating unit and to said adaptive codebook component and for summing the resulting output signals to output a sound source signal;
receiving said sound source signal from said gain unit to a synthesis filter formed using said filter coefficients to reproduce a signal for band extension; and
summing a signal corresponding to said input signal converted in a sampling frequency thereof to an output signal of said synthesis filter unit to obtain a band extended signal. - View Dependent Claims (24, 31, 36)
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25. A band extending method comprising:
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receiving at least an input signal of a preset frequency band to calculate spectral parameters representing spectral characteristics;
calculating a pitch period at least from said input signal to generate an adaptive codebook component based on said pitch period and the past sound source signal;
shifting the frequency of said spectral parameters to then find filter coefficients;
supplying a gain to at least one of a noise signal from a noise generating unit and said adaptive codebook component and for summing the resulting signals to output a sound source signal;
pre-filtering said sound source signal, using said pitch period;
supplying the results of processing of said pitch pre-filter to a synthesis filter formed using said filter coefficients to generate a signal for band extension; and
summing a signal corresponding to said input signal converted in a sampling frequency thereof to an output signal of said synthesis filter unit to generate a band extended signal. - View Dependent Claims (26)
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27. A band extending method comprising:
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receiving at least an input signal of a preset frequency band to calculate spectral parameters representing spectral characteristics;
calculating a pitch period at least from said input signal to generate a period signal using said pitch period;
shifting the frequency of said spectral parameters to find filter coefficients;
supplying a gain to at least one of a noise signal of said noise generating unit and said period signal and for summing the resulting output signals to output a sound source signal;
receiving said sound source signal to a synthesis filter formed using said filter coefficients to reproduce a signal for band extension; and
summing a signal, corresponding to said input signal converted in a sampling frequency thereof to an output signal of said synthesis filter unit to obtain a band extended signal. - View Dependent Claims (28)
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29. A band extending method comprising:
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receiving at least an input signal of a preset frequency band and calculating spectral parameters representing spectral characteristics;
calculating a pitch period at least from said input signal to generate a period signal using said pitch signal;
shifting the frequency of said spectral parameters to then find filter coefficients;
supplying a gain to at least one of an output signal of said noise generating unit and said pitch signal and for summing the resulting output signals to output a sound source signal;
pre-filtering said sound source signal using said pitch period;
receiving a signal representing the result of processing by said pitch pre-filter to a synthesis filter formed using said pitch period to reproduce a signal for band extension; and
summing a signal corresponding to said input signal converted in a sampling frequency thereof to an output signal of said synthesis filter unit to produce a band extended signal. - View Dependent Claims (30)
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Specification