# US 10,770,085 B2 · Encoding method, decoding method, encoding apparatus, and decoding apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,770,085 B2 - Document ID: US10770085B2 - Status: Granted - Kind: B2 - Application number: 16/238,797 - Filed: 2019-01-03 - Published: 2019-05-09 - Granted: 2020-09-08 - Earliest claimed: 2013-01-15 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Bin Wang; Zexin Liu; Lei Miao - Web page: https://patentgrep.com/patent/US10770085B2 ## CPC - G10L 19/03: Spectral prediction for preventing pre-echo; Temporary noise shaping [TNS], e.g. in MPEG2 or MPEG4 - G10L 19/12: the excitation function being a code excitation, e.g. in code excited linear prediction [CELP] vocoders - G10L 19/26: Pre-filtering or post-filtering - G10L 19/265: {Pre-filtering, e.g. high frequency emphasis prior to encoding} - G10L 21/038: using band spreading techniques - G10L 19/0204: {using subband decomposition} - G10L 19/107: Sparse pulse excitation, e.g. by using algebraic codebook - G10L 2019/0016: {Codebook for LPC parameters} - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING ## Abstract An encoding method, a decoding method, an encoding apparatus, a decoding apparatus, a transmitter, a receiver, and a communications system, where the encoding method includes dividing a to-be-encoded time-domain signal into a low band signal and a high band signal, performing encoding on the low band signal to obtain a low frequency encoding parameter, performing encoding on the high band signal to obtain a high frequency encoding parameter, obtaining a synthesized high band signal; performing short-time post-filtering processing on the synthesized high band signal to obtain a short-time filtering signal, and calculating a high frequency gain based on the high band signal and the short-time filtering signal. ## Claims ### Claim 1 An encoding method for encoding a speech signal, comprising: obtaining a low band signal of the speech signal and a high band signal of the speech signal; encoding the low band signal to obtain a low frequency encoding parameter; encoding the high band signal to obtain a linear predictive coding (LPC) parameter; obtaining an excitation signal according to the low frequency encoding parameter; obtaining a synthesized high band signal according to the excitation signal and the LPC parameter; and performing filtering processing on the synthesized high band signal, using a pole-zero filter, wherein a coefficient of the pole-zero filter is set based on the LPC parameter. ### Claim 2 (depends on 1) The encoding method of claim 1, wherein the method further comprises: performing, using a first-order filter, filtering processing on the synthesized high band signal that has been processed by the pole-zero filter, wherein a z-domain transfer function of the first-order filter is Ht(z)=1−μz−1, and wherein μ is a preset constant. ### Claim 3 (depends on 1) The encoding method of claim 1, wherein the method further comprises: performing, using a first-order filter, filtering processing on the synthesized high band signal that has been processed by the pole-zero filter, wherein a z-domain transfer function of the first-order filter is Ht(z)=1−μz−1, and wherein μ is a value obtained by calculation performed according to the LPC parameter and the synthesized high band signal. ### Claim 4 (depends on 1) The encoding method of claim 1, wherein encoding the high band signal to obtain the LPC parameter comprises: encoding, using an LPC technology, the high band signal to obtain an LPC coefficient; setting the LPC coefficient as the LPC parameter; and wherein a z-domain transfer function of the pole-zero filter is calculated using the following formula: H s ⁡ ( z ) = 1 - a 1 ⁢ β ⁢ ⁢ z - 1 - a 2 ⁢ β 2 ⁢ z - 2 - … - a M ⁢ β M ⁢ z - M 1 - a 1 ⁢ γ ⁢ ⁢ z - 1 - a 2 ⁢ γ 2 ⁢ z - 2 - … - a M ⁢ γ M ⁢ z - M , wherein a1, a2, . . . aM is the LPC coefficient, wherein M represents a quantity of the LPC coefficient, and wherein β and γ satisfy a condition 0<β<γ<1. ### Claim 5 (depends on 4) The encoding method of claim 4, wherein the β=0.5 and the γ=0.8. ### Claim 6 A decoding method for decoding a speech signal, comprising: obtaining a low frequency encoding parameter, a linear predictive coding (LPC) parameter, and a high frequency gain from encoded information corresponding to the speech signal; obtaining a low band signal of the speech signal according to the low frequency encoding parameter; obtaining an excitation signal according to the low frequency encoding parameter; obtaining a synthesized high band signal according to the excitation signal and the LPC parameter; performing filtering processing on the synthesized high band signal using a pole-zero filter, wherein a coefficient of the pole-zero filter is set based on the LPC parameter, to obtain a short-time filtered signal; adjusting the short-time filtered signal using the high frequency gain to obtain a high band signal; and combining the low band signal of the speech signal and the high band signal to obtain a decoded signal. ### Claim 7 (depends on 6) The decoding method of claim 6, wherein the method further comprises: performing, using a first-order filter, filtering processing on the synthesized high band signal that has been processed by the pole-zero filter to obtain the short-time filtered signal, wherein a z-domain transfer function of the first-order filter is Ht(z)=1−μz−1, and wherein μ is a preset constant. ### Claim 8 (depends on 6) The decoding method of claim 6, wherein the method further comprises: performing, using a first-order filter, filtering processing on the synthesized high band signal that has been processed by the pole-zero filter to obtain the short-time filtered signal, wherein a z-domain transfer function of the first-order filter is Ht(z)=1−μz−1, and wherein μ is a value obtained by calculation performed according to the LPC parameter and the synthesized high band signal. ### Claim 9 (depends on 6) The decoding method of claim 6, wherein the LPC parameter is an LPC coefficient obtained by encoding using an LPC technology, and wherein a z-domain transfer function of the pole-zero filter being calculated using the following formula: H s ⁡ ( z ) = 1 - a 1 ⁢ β ⁢ ⁢ z - 1 - a 2 ⁢ β 2 ⁢ z - 2 - … - a M ⁢ β M ⁢ z - M 1 - a 1 ⁢ γ ⁢ ⁢ z - 1 - a 2 ⁢ γ 2 ⁢ z - 2 - … - a M ⁢ γ M ⁢ z - M , wherein a1, a2, . . . aM is the LPC coefficient, wherein M represents a quantity of the LPC coefficient, and wherein β and γ satisfy a condition 0<β<γ<1. ### Claim 10 (depends on 9) The decoding method of claim 9, wherein the β=0.5 and the γ=0.8. ### Claim 11 An encoding apparatus for encoding a speech signal, comprising: a memory comprising instructions; and at least a processor coupled to the memory, the instructions causing the at least processor to be configured to: obtain a low band signal of the speech signal and a high band signal of the speech signal; encode the low band signal to obtain a low frequency encoding parameter; encode the high band signal to obtain a linear predictive coding (LPC) parameter; obtain an excitation signal according to the low frequency encoding parameter; obtain a synthesized high band signal according to the excitation signal and the LPC parameter; and perform filtering processing on the synthesized high band signal using a pole-zero filter, wherein a coefficient of the pole-zero filter is set based on the LPC parameter. ### Claim 12 (depends on 11) The encoding apparatus of claim 11, wherein the instructions further cause the processor to be configured to perform, using a first-order, filtering processing on the synthesized high band signal that has been processed by the pole-zero filter, wherein a z-domain transfer function of the first-order filter is Ht(z)=1−μz−1, and wherein μ is a preset constant. ### Claim 13 (depends on 11) The encoding apparatus of claim 11, wherein the instructions further cause the processor to be configured to perform, using a first-order filter, filtering processing on the synthesized high band signal that has been processed by the pole-zero filter, wherein a z-domain transfer function of the first-order filter is Ht(z)=1−μz−1, and wherein μ is a value obtained by adaptive calculation performed according to the LPC parameter and the synthesized high band signal. ### Claim 14 (depends on 11) The encoding apparatus of claim 11, wherein the instructions further cause the processor to be configured to: encode the high band signal using an LPC technology to obtain an LPC coefficient; set the LPC coefficient as the LPC parameter; and wherein a z-domain transfer function of the pole-zero filter being calculated using the following formula: H s ⁡ ( z ) = 1 - a 1 ⁢ β ⁢ ⁢ z - 1 - a 2 ⁢ β 2 ⁢ z - 2 - … - a M ⁢ β M ⁢ z - M 1 - a 1 ⁢ γ ⁢ ⁢ z - 1 - a 2 ⁢ γ 2 ⁢ z - 2 - … - a M ⁢ γ M ⁢ z - M , wherein a1, a2, . . . aM is the LPC coefficient, wherein M represents a quantity of the LPC coefficient, and wherein β and γ satisfy a condition 0<β<γ<1. ### Claim 15 (depends on 14) The encoding apparatus of claim 14, wherein the β=0.5 and the γ=0.8. ### Claim 16 A decoding apparatus for decoding a speech signal, comprising: a memory comprising instructions; and at least one processor coupled to the memory, the instructions causing the at least one processor to be configured to: obtain a low frequency encoding parameter, a linear predictive coding (LPC) parameter, and a high frequency gain from encoded information corresponding to the speech signal; obtain a low band signal of the speech signal according to the low frequency encoding parameter; obtain an excitation signal according to the low frequency encoding parameter; obtain a synthesized high band signal according to the excitation signal and the LPC parameter; perform filtering processing on the synthesized high band signal using a pole-zero filter, wherein a coefficient of the pole-zero filter is set based on the LPC parameter, to obtain a short-time filtered signal; adjust the short-time filtered signal using the high frequency gain to obtain a high band signal; and combine the low band signal of the speech signal and the high band signal to obtain a decoded signal. ### Claim 17 (depends on 16) The decoding apparatus of claim 16, wherein the instructions further cause the at least one processor to be configured to perform, using a first-order filter, filtering processing on the synthesized high band signal that has been processed by the pole-zero filter, wherein a z-domain transfer function of the first-order filter is Ht(z)=1−μz−1, and wherein μ is a preset constant. ### Claim 18 (depends on 16) The decoding apparatus of claim 16, wherein the instructions further cause the at least one processor to be configured to perform, using a first-order filter, filtering processing on the synthesized high band signal that has been processed by the pole-zero filter, wherein a z-domain transfer function of the first-order filter is Ht(z)=1−μz−1, and wherein μ is a value obtained by adaptive calculation performed according to the LPC parameter and the synthesized high band signal. ### Claim 19 (depends on 16) The decoding apparatus of claim 16, wherein the LPC parameter is an LPC coefficient obtained using an LPC technology, wherein a z-domain transfer function of the pole-zero filter is calculated using the following formula: H s ⁡ ( z ) = 1 - a 1 ⁢ β ⁢ ⁢ z - 1 - a 2 ⁢ β 2 ⁢ z - 2 - … - a M ⁢ β M ⁢ z - M 1 - a 1 ⁢ γ ⁢ ⁢ z - 1 - a 2 ⁢ γ 2 ⁢ z - 2 - … - a M ⁢ γ M ⁢ z - M , wherein a1, a2, . . . aM is the LPC coefficient, wherein M represents a quantity of the LPC coefficient, wherein β and γ satisfy a condition 0<β<γ<1. ### Claim 20 (depends on 19) The decoding apparatus of claim 19, wherein the β=0.5 and the γ=0.8.