# US 2008/0304673 A1 · Multipoint communication apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0304673 A1 - Document ID: US20080304673A1 - Status: Published application - Kind: A1 - Application number: 12/155,828 - Filed: 2008-06-10 - Published: 2008-12-11 - Earliest claimed: 2007-06-11 - Assignees: Fujitsu Limited - Inventors: Takeshi Otani - Web page: https://patentgrep.com/patent/US20080304673A1 ## CPC - H03G 9/025: {frequency-dependent volume compression or expansion, e.g. multiple-band systems (H03G9/10, H03G9/18 take precedence)} - H04M 1/6016: {in the receiver circuit} - H04M 3/56: Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities (video conference systems H04N7/15) - H03G: CONTROL OF AMPLIFICATION - H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08) ## Abstract According to an aspect of an embodiment, a multipoint communication apparatus comprises: a receiving unit for receiving a plurality of signals containing voice signal elements and noise signal elements from the plurality of other communication apparatuses, respectively; a noise estimating unit for estimating the plurality of noise signal elements in the plurality of received signals, respectively; a gain control unit for adjusting gains of the plurality of signals passing therethrough so as to equalize the levels of the plurality of noise signal elements outputted from the gain element on the basis of the estimated levels of the noise signal elements ; a combining unit for combining the plurality of signals passed through the gain control unit; and an output unit for outputting a sound signal on the basis of the a combined signal by the combining unit. ## Claims ### Claim 1 A multipoint communication apparatus for controlling and outputting a signal by combining a plurality of signals receiving from a plurality of other communication apparatuses, comprising: a receiving unit for receiving a plurality of signals containing voice signal elements and noise signal elements from the plurality of other communication apparatuses, respectively; a noise estimating unit for estimating the plurality of noise signal elements in the plurality of received signals, respectively; a gain control unit for adjusting gains of the plurality of signals passing therethrough so as to equalize the levels of the plurality of noise signal elements outputted from the gain element on the basis of the estimated levels of the noise signal elements ; a combining unit for combining the plurality of signals passed through the gain control unit; and an output unit for outputting a sound signal on the basis of the a combined signal by the combining unit. ### Claim 2 (depends on 1) The multipoint communication apparatus according to claim 1, wherein the gain control unit adjusts a gain of the voice signal elements in the controlled signal to a target gain. ### Claim 3 (depends on 1) The multipoint communication apparatus according to claim 1, further comprising: a noise superimposing unit for superimposing low level noise elements to the plurality of signals. ### Claim 4 (depends on 1) The multipoint communication apparatus according to claim 1, wherein the gain control unit replaces the plurality of noise volume elements respectively to an upper limit value when the noise volume elements is larger than the upper limit value and replaces the plurality of noise volume elements respectively to a lower limit value when the noise volume elements is smaller than the lower limit value. ### Claim 5 (depends on 1) The multipoint communication apparatus according to claim 1, further comprising: a plurality of second gain control units for controlling a gain of the controlled signal outputted out of the control unit respectively; wherein the each second gain control unit comprises: a spectrum generating unit for dividing the controlled signal outputted out of the control unit into a plurality of bands and generating an input spectrum representing a signal level of the each band; a noise spectrum estimating unit for finding a noise spectrum representing a noise level of the each band from the signal level of the each band; a signal-to-noise ratio estimating unit for finding a signal-to-noise ratio of the each band from a ratio between the input spectrum and the noise spectrum; a gain calculating unit for finding a gain of the each band from a target gain and the signal-to-noise ratio of the each band; and a multiplier for finding an output level of the each band by multiplying the signal level of the each band with the gain of each band. ### Claim 6 (depends on 5) The multipoint communication apparatus according to claim 5, wherein the plurality of gain control units further comprises: a target gain calculating unit for finding the target gain from a target volume and the volume of the controlled signal inputted from the control unit. ### Claim 7 (depends on 5) The multipoint communication apparatus according to claim 5, wherein the plurality of gain control units further comprises: a target gain calculating unit for finding the target gain from a target volume and the signal level of each band. ### Claim 8 A multipoint communication apparatus for controlling and outputting a signal by combining a plurality of signals receiving from a plurality of other communication apparatuses, comprising: a receiving unit for receiving a plurality of signals containing voice volume elements and noise volume elements from the plurality of other communication apparatuses respectively; a noise volume estimating unit for calculating the plurality of noise volume elements in the plurality of received signals respectively; a signal-to-noise ratio estimating unit for finding the plurality of signal-to-noise ratios of the plurality of receiving signals in accordance with the estimated noise volume elements respectively; a control unit for finding the largest signal-to-noise ratio of the receiving signal in the plurality of signal-to-noise and finding a target noise volume from the largest signal-to-noise ratio of the receiving signal and controlling the plurality of signals to adjust to the target noise volume. a combining unit for combining the plurality of controlled signals; and an output unit for outputting a combined signal. ### Claim 9 A multipoint communication apparatus for controlling and outputting a signal by combining a plurality of signals receiving from a plurality of other communication apparatuses, comprising: a receiving unit for receiving a plurality of signals containing voice volume elements and noise volume elements from the plurality of other communication apparatuses respectively; a noise volume estimating unit for calculating the plurality of noise volume elements in the plurality of received signals respectively; a control unit for controlling the plurality of signals to adjust the plurality of noise volume elements of the plurality of signals to a predetermined noise volume respectively; a combining unit for combining the plurality of controlled signals; and an output unit for outputting a combined signal. ### Claim 10 A volume control unit comprising: a spectrum generating unit for dividing a input signal containing voice volume elements and noise volume elements into a plurality of bands and generating a plurality of input spectra representing a signal level of the each band respectively; a noise spectrum estimating unit for finding a plurality of noise spectra representing a noise level of the each band from the signal level of the each band respectively; a signal-to-noise ratio estimating unit for finding a plurality of signal-to-noise ratios of the each band from a ratio between the input spectrum and the noise spectrum respectively; a gain calculating unit for finding a plurality of gains of the each band from a target gain and the signal-to-noise ratio of the each band respectively; and a multiplier for finding a plurality of output levels of the each band by multiplying the signal level of the each band with the gain of each band respectively. ### Claim 11 (depends on 10) The volume control unit according to claim 10 further comprising: a target gain calculating unit for finding the target gain from a target volume the volume of the input signal. ### Claim 12 (depends on 10) The volume control unit according to claim 10, further comprising: a target gain calculating unit for finding the target gain from the target volume and the signal level of each band. ### Claim 13 (depends on 10) The volume control unit according to claim 10, wherein the target gain calculating unit sets the target gain as an upper limit value when the target gain is larger than the upper limit value and sets the target gain as a lower limit value when the target gain is smaller than the lower limit value. ### Claim 14 A multipoint communication apparatus for controlling and outputting a signal by combining a plurality of signals receiving from a plurality of other communication apparatuses, comprising: a receiving unit for receiving a plurality of signals containing voice signal elements and noise signal elements from the plurality of other communication apparatuses, respectively; a processor for performing a process of adjusting gains of the plurality of signals comprising the steps of: estimating the plurality of noise signal elements in the plurality of received signals, respectively; adjusting gains of the plurality of signals passing therethrough so as to equalize the levels of the plurality of noise signal elements outputted from the gain element on the basis of the estimated levels of the noise signal elements combining the plurality of signals passed through the gain control unit; and an output unit for outputting a sound signal on the basis of the a combined signal by the combining unit.