# US 2014/0192852 A1 · Equalizer device, receiver device and equalization method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192852 A1 - Document ID: US20140192852A1 - Status: Published application - Kind: A1 - Application number: 14/237,135 - Filed: 2012-02-22 - Published: 2014-07-10 - Earliest claimed: 2011-10-14 - Assignees: Mitsubishi Electric Corporation - Inventors: Naosuke Ito; Jun Ido - Web page: https://patentgrep.com/patent/US20140192852A1 ## CPC - H04L 27/01: Equalisers {(baseband equalizers at the transmitter end H04L25/03343; in analogue transmission systems H04B3/04, H04B7/005)} - H04B 3/06: by the transmitted signal - H04L 25/0212: {of impulse response} - H04L 25/03159: {operating in the frequency domain (H04L25/03165, H04L25/03178 take precedence)} - H04L 2025/03382: {Single of vestigal sideband} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION ## Abstract The present invention is provided with: a CIR generating unit which generates an channel impulse response from a received signal; a CIR variation detection unit which uses a plurality of channel impulse responses generated from a plurality of different sections of the received signal by the CIR generating unit to detect an amount of variation in the channel impulse response; an equivalent width control unit which determines an equivalent width corresponding to a signal length used in equalization of the received signal such that the equivalent width is shortened as the amount of variation in the channel impulse response increases; and a waveform equalization unit which uses the channel impulse response generated by the CIR generating unit to equalize the received signal over the equivalent width determined by the equivalent width control unit and generate a demodulated signal. ## Claims ### Claim at position 1 1-23. (canceled) ### Claim 24 An equalizer device comprising: a CIR generating unit for generating an channel impulse response from a received signal; a CIR variation detection unit for using a plurality of channel impulse responses generated from a plurality of different sections of the received signal by the CIR generating unit to detect an amount of variation in the channel impulse response; an equivalent width control unit for determining an equivalent width corresponding to a signal length used in equalization of the received signal such that the equivalent width is shortened as the amount of variation in the channel impulse response increases; and a waveform equalization unit for using the channel impulse response generated by the CIR generating unit to equalize the received signal over the equivalent width determined by the equivalent width control unit and generate a demodulated signal. ### Claim 25 (depends on 24) The equalizer device of claim 24, wherein: the received signal includes a known signal; the CIR generating unit generates a first channel impulse response from the known signal and a first section of the received signal corresponding to the known signal, and generates a second channel impulse response from a second section of the demodulated signal generated by the waveform equalization unit and a section of the received signal corresponding to the second section, the second section excluding the known signal; and the CIR variation detection unit uses a plurality of channel impulse responses including at least one of the first channel impulse response and the second channel impulse response to detect the amount of variation in the channel impulse response. ### Claim 26 (depends on 25) The equalizer device of claim 25, wherein the CIR generating unit generates the one of the first channel impulse response and the second channel impulse response in correspondence to a Fourier transform interval used when the waveform equalization unit equalizes the received signal over the equivalent width determined by equivalent width control unit. ### Claim 27 (depends on 25) The equalizer device of claim 25, wherein the CIR generating unit generates one of the first channel impulse response, the second channel impulse response, and a third channel impulse response in correspondence to a Fourier transform interval used when the waveform equalization unit equalizes the received signal over the equivalent width determined by equivalent width control unit, the third channel impulse response being generated by interpolation or extrapolation using a plurality of channel impulse responses including at least one of the first channel impulse response and the second channel impulse response. ### Claim 28 (depends on 24) The equalizer device of claim 24, wherein the equivalent width control unit both shortens the equivalent width as the amount of variation in the channel impulse response increases and lengthens the equivalent width with increasing magnitude of long delay components included in the received signal. ### Claim 29 (depends on 28) The equalizer device of claim 28, wherein the equivalent width control unit identifies, among coefficients included in the channel impulse response that are disposed in tap positions more delayed than a predetermined tap position, coefficients having values exceeding a predetermined threshold value, and determines that the long delay components have increasing magnitude as the values of the identified coefficients increase. ### Claim 30 (depends on 24) The equalizer device of claim 24, wherein the equivalent width control unit both shortens the equivalent width as the amount of variation in the channel impulse response increases and lengthens the equivalent width with increasing delay of long delay components included in the received signal. ### Claim 31 (depends on 30) The equalizer device of claim 30, wherein the equivalent width control unit identifies, among coefficients included in the channel impulse response that are disposed in tap positions more delayed than a predetermined tap position, coefficients having values exceeding a predetermined threshold value, and determines that the long delay components have increasing delay as the tap positions of the identified coefficients have increasing amounts of delay. ### Claim 32 (depends on 24) The equalizer device of claim 24, wherein the waveform equalization unit: generates a reconstructed signal by equalizing the received signal after making a width of a window function by which the received signal is multiplied correspond to the equivalent width determined by the equivalent width control unit; and generates the demodulated signal by overlapping the reconstructed signal at overlap intervals corresponding to the equivalent width determined by the equivalent width control unit. ### Claim 33 (depends on 24) A receiver device comprising: the equalizer device of claim 24; and a signal processing device for generating the received signal by converting a broadcast signal to a prescribed frequency band. ### Claim 34 An equalization method comprising: a CIR generating step for generating an channel impulse response from a received signal; a CIR variation detection step for using a plurality of channel impulse responses generated from a plurality of different sections of the received signal in the CIR generating step to detect an amount of variation in the channel impulse response; an equivalent width control step for determining an equivalent width corresponding to a signal length used in equalization of the received signal such that the equivalent width is shortened as the amount of variation in the channel impulse response increases; and a waveform equalization step for using the channel impulse response generated in the CIR generating step to equalize the received signal over the equivalent width determined in the equivalent width control step and generate a demodulated signal. ### Claim 35 (depends on 34) The equalization method of claim 34, wherein: the received signal includes a known signal; the CIR generation step generates a first channel impulse response from the known signal and a first section of the received signal corresponding to the known signal, and generates a second channel impulse response from a second section of the demodulated signal generated in the waveform equalization step, and a section of the received signal corresponding to the second section, the second section excluding the known signal; and the CIR variation detection step uses a plurality of channel impulse responses including at least one of the first channel impulse response and the second channel impulse response to detect the amount of variation in the channel impulse response. ### Claim 36 (depends on 35) The equalization method of claim 35, wherein the CIR generation step generates the one of the first channel impulse response and the second channel impulse response in correspondence to a Fourier transform interval used when the waveform equalization step equalizes the received signal over the equivalent width determined in the equivalent width control step. ### Claim 37 (depends on 35) The equalization method of claim 35, wherein the CIR generation step generates one of the first channel impulse response, the second channel impulse response, and a third channel impulse response in correspondence to a Fourier transform interval used when the waveform equalization step equalizes the received signal over the equivalent width determined in the equivalent width control step, the third channel impulse response being generated by interpolation or extrapolation using a plurality of channel impulse responses including at least one of the first channel impulse response and the second channel impulse response. ### Claim 38 (depends on 34) The equalization method of claim 34, wherein the equivalent width control step both shortens the equivalent width as the amount of variation in the channel impulse response increases and lengthens the equivalent width with increasing magnitude of long delay components included in the received signal. ### Claim 39 (depends on 38) The equalization method of claim 38, wherein the equivalent width control step identifies, among coefficients included in the channel impulse response that are disposed in tap positions more delayed than a predetermined tap position, coefficients having values exceeding a predetermined threshold value, and determines that the long delay components have increasing magnitude as the values of the identified coefficients increase. ### Claim 40 (depends on 34) The equalization method of claim 34, wherein the equivalent width control step both shortens the equivalent width as the amount of variation in the channel impulse response increases and lengthens the equivalent width with increasing delay of long delay components included in the received signal. ### Claim 41 (depends on 40) The equalization method of claim 40, wherein the equivalent width control step identifies, among coefficients included in the channel impulse response that are disposed in tap positions more delayed than a predetermined tap position, coefficients having values exceeding a predetermined threshold value, and determines that the long delay components have increasing delay as the tap positions of the identified coefficients have increasing amounts of delay. ### Claim 42 (depends on 34) The equalization method of claim 34, wherein the waveform equalization step: generates a reconstructed signal by equalizing the received signal after making a width of a window function by which the received signal is multiplied correspond to the equivalent width determined in the equivalent width control step; and generates the demodulated signal by overlapping the reconstructed signal at overlap intervals corresponding to the equivalent width determined in the equivalent width control step.