Patents by Inventor Masayuki Iwamatsu
Masayuki Iwamatsu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8483407Abstract: A noise reducing circuit includes a variable low-cut filter disposed at an upstream of a sound signal switching section and has a variable cutoff frequency, and a control circuit which controls the cutoff frequency of the variable low-cut filter to a first cutoff frequency lower than a cutoff frequency of a low-cut filter disposed at downstream of the variable low-cut filter when a switching instruction is not issued from a switching instructing section, and increases the cutoff frequency of the variable low-cut filter to a second cutoff frequency higher than the first cutoff frequency when the switching instruction is issued. The switching of the sound signal switching section is executed after a predetermined period elapses since the switching instruction is issued, and the control section decreases the cutoff frequency of the variable low-cut filter to the first cutoff frequency after the switching of the sound signal switching section is completed.Type: GrantFiled: July 29, 2010Date of Patent: July 9, 2013Assignee: Yamaha CorporationInventor: Masayuki Iwamatsu
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Patent number: 8265283Abstract: An acoustic processing device, includes an inputting section which receives a first audio signal and a second audio signal, a first input signal amplifying section which amplifies the first audio signal at an amplification factor, a second input signal amplifying section which amplifies the second audio signal at an amplification factor, a first initial delayed amplifying section, a first adding section which adds the first audio signal amplified by the first amplifying portion and the first audio signal amplified by the first input signal amplifying section, a second adding section which adds the first audio signal amplified by the second amplifying portion and the second audio signal amplified by the second input signal amplifying section, a first supplying section which supplies an audio signal output from the first adding section to a first sound emitting section, and a second supplying section which supplies an audio signal output from the second adding section to a second sound emitting section differenType: GrantFiled: November 26, 2008Date of Patent: September 11, 2012Assignee: Yamaha CorporationInventor: Masayuki Iwamatsu
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Patent number: 8164388Abstract: An amplifying apparatus amplifies an input signal supplied to an input terminal and outputs an output signal from an output terminal. The apparatus includes a high-potential power supply line through which a high voltage is supplied; a low-potential power supply line through which a low voltage is supplied; a control unit; and a power supply in which one of the high and low voltages is a fixed voltage, and which generates, as the other of the high and low voltages, one of a first voltage in which a polarity of the fixed voltage is inverted, and a second voltage which is closer to the ground potential than the first voltage is. The control unit controls the power supply to cause the other of the high and low voltages to be switched between the first voltage and the second voltage in accordance with a signal level of the output signal.Type: GrantFiled: September 15, 2010Date of Patent: April 24, 2012Assignee: Yamaha CorporationInventor: Masayuki Iwamatsu
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Patent number: 8149057Abstract: A signal processing circuit includes a waveform shaping section that applies a first gain to an input signal and generates a first signal when an absolute value of a level of the input signal falls within a first input range from a first level to a second level, a variable gain section that adjusts an amplitude of the first signal and amplifies the first signal by a gain to generate an output signal, and a control section that reduces the gain of the variable gain section so that the output signal is prevented from occurrence of clipping when the amplitude of the first signal falls within a second input range. The second input range includes a range of the level of the first signal output from the waveform shaping section corresponding to the first input range of the input signal.Type: GrantFiled: January 25, 2011Date of Patent: April 3, 2012Assignee: Yamaha CorporationInventor: Masayuki Iwamatsu
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Patent number: 8050425Abstract: An audio signal supplying device includes a connection terminal which is connected to a speaker unit and which outputs an audio signal to the speaker unit, a specifying section which specifies a type of the speaker unit connected to the connection terminal, an acquiring section which acquires a parameter corresponding to the type of the speaker unit specified by the specifying section from an outside, a storing section which stores the parameter acquired by the acquiring section, an inputting section into which the audio signal is input, an acoustic characteristic controlling section which adjusts an acoustic characteristic of the audio signal input into the inputting section based on the parameter stored in the storing section, and a supplying section which supplies the audio signal whose acoustic characteristic is adjusted by the acoustic characteristic controlling section to the connection terminal.Type: GrantFiled: November 22, 2008Date of Patent: November 1, 2011Assignee: Yamaha CorporationInventor: Masayuki Iwamatsu
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Publication number: 20110181362Abstract: A signal processing circuit includes a waveform shaping section that applies a first gain to an input signal and generates a first signal when an absolute value of a level of the input signal falls within a first input range from a first level to a second level, a variable gain section that adjusts an amplitude of the first signal and amplifies the first signal by a gain to generate an output signal, and a control section that reduces the gain of the variable gain section so that the output signal is prevented from occurrence of clipping when the amplitude of the first signal falls within a second input range. The second input range includes a range of the level of the first signal output from the waveform shaping section corresponding to the first input range of the input signal.Type: ApplicationFiled: January 25, 2011Publication date: July 28, 2011Applicant: Yamaha CorporationInventor: Masayuki Iwamatsu
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Patent number: 7961044Abstract: An amplifier includes: a variable gain unit that adjusts an amplitude of an input signal and outputs a first signal; an amplitude limiting unit that limits an amplitude of the first signal and outputs a second signal set to have an amplitude of a first amplitude value or less; an amplifying unit that amplifies the second signal to output the amplified second signal as an output signal; and a control unit that detects when the first signal has an amplitude of a second amplitude value or more to control a gain of the variable gain unit so that the amplitude of the first signal becomes less than the second amplitude value, the second amplitude value being larger than the first amplitude value.Type: GrantFiled: November 23, 2009Date of Patent: June 14, 2011Assignee: Yamaha CorporationInventor: Masayuki Iwamatsu
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Patent number: 7961011Abstract: An amplifier includes: an operation amplifier including a positive input terminal and a negative input terminal; and a detector which detects that a difference between a voltage of the positive input terminal and a voltage of the negative input terminal is equal to or exceeds a predetermined value and outputs a detection signal.Type: GrantFiled: October 3, 2008Date of Patent: June 14, 2011Assignee: Yamaha CorporationInventors: Masayuki Iwamatsu, Hirotoshi Tsuchiya
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Publication number: 20110068872Abstract: An amplifying apparatus amplifies an input signal supplied to an input terminal and outputs an output signal from an output terminal. The apparatus includes a high-potential power supply line through which a high voltage is supplied; a low-potential power supply line through which a low voltage is supplied; a control unit; and a power supply in which one of the high and low voltages is a fixed voltage, and which generates, as the other of the high and low voltages, one of a first voltage in which a polarity of the fixed voltage is inverted, and a second voltage which is closer to the ground potential than the first voltage is. The control unit controls the power supply to cause the other of the high and low voltages to be switched between the first voltage and the second voltage in accordance with a signal level of the output signal.Type: ApplicationFiled: September 15, 2010Publication date: March 24, 2011Applicant: Yamaha CorporationInventor: Masayuki Iwamatsu
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Publication number: 20110026735Abstract: A noise reducing circuit includes a variable low-cut filter disposed at an upstream of a sound signal switching section and has a variable cutoff frequency, and a control circuit which controls the cutoff frequency of the variable low-cut filter to a first cutoff frequency lower than a cutoff frequency of a low-cut filter disposed at downstream of the variable low-cut filter when a switching instruction is not issued from a switching instructing section, and increases the cutoff frequency of the variable low-cut filter to a second cutoff frequency higher than the first cutoff frequency when the switching instruction is issued. The switching of the sound signal switching section is executed after a predetermined period elapses since the switching instruction is issued, and the control section decreases the cutoff frequency of the variable low-cut filter to the first cutoff frequency after the switching of the sound signal switching section is completed.Type: ApplicationFiled: July 29, 2010Publication date: February 3, 2011Applicant: Yamaha CorporationInventor: Masayuki Iwamatsu
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Publication number: 20100127778Abstract: An amplifier includes: a variable gain unit that adjusts an amplitude of an input signal and outputs a first signal; an amplitude limiting unit that limits an amplitude of the first signal and outputs a second signal set to have an amplitude of a first amplitude value or less; an amplifying unit that amplifies the second signal to output the amplified second signal as an output signal; and a control unit that detects when the first signal has an amplitude of a second amplitude value or more to control a gain of the variable gain unit so that the amplitude of the first signal becomes less than the second amplitude value, the second amplitude value being larger than the first amplitude value.Type: ApplicationFiled: November 23, 2009Publication date: May 27, 2010Applicant: Yamaha CorporationInventor: Masayuki Iwamatsu
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Patent number: 7551031Abstract: The amplifier comprises an inverting negative feedback amplifier circuit using an operational amplifier, a comparator for comparing the potential of the negative phase input terminal of the operational amplifier with the reference potential Vref of the comparator, and a low-pass filter. The imaginary short state of the operational amplifier is lost when clipping occurs on the output signal. It is thus possible to detect clipping by monitoring the potential of the negative phase input terminal.Type: GrantFiled: May 28, 2008Date of Patent: June 23, 2009Assignee: Yamaha CorporationInventor: Masayuki Iwamatsu
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Publication number: 20090147134Abstract: An audio signal supplying device includes a connection terminal which is connected to a speaker unit and which outputs an audio signal to the speaker unit, a specifying section which specifies a type of the speaker unit connected to the connection terminal, an acquiring section which acquires a parameter corresponding to the type of the speaker unit specified by the specifying section from an outside, a storing section which stores the parameter acquired by the acquiring section, an inputting section into which the audio signal is input, an acoustic characteristic controlling section which adjusts an acoustic characteristic of the audio signal input into the inputting section based on the parameter stored in the storing section, and a supplying section which supplies the audio signal whose acoustic characteristic is adjusted by the acoustic characteristic controlling section to the connection terminal.Type: ApplicationFiled: November 22, 2008Publication date: June 11, 2009Applicant: YAMAHA CORPORATIONInventor: Masayuki Iwamatsu
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Publication number: 20090141911Abstract: An acoustic processing device, includes an inputting section which receives a first audio signal and a second audio signal, a first input signal amplifying section which amplifies the first audio signal at an amplification factor, a second input signal amplifying section which amplifies the second audio signal at an amplification factor, a first initial delayed amplifying section, a first adding section which adds the first audio signal amplified by the first amplifying portion and the first audio signal amplified by the first input signal amplifying section, a second adding section which adds the first audio signal amplified by the second amplifying portion and the second audio signal amplified by the second input signal amplifying section, a first supplying section which supplies an audio signal output from the first adding section to a first sound emitting section, and a second supplying section which supplies an audio signal output from the second adding section to a second sound emitting section differenType: ApplicationFiled: November 26, 2008Publication date: June 4, 2009Applicant: Yamaha CorporationInventor: Masayuki Iwamatsu
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Publication number: 20090115514Abstract: A class D amplifier includes: an amplifier that generates a digital signal for driving a load based on an input signal; an attenuator that attenuates the input signal according to an attenuation command signal; and a clip prevention controller that outputs the attenuation command signal to intermittently attenuate the input signal when the digital signal is brought into a clip state or a near-clip state.Type: ApplicationFiled: December 23, 2008Publication date: May 7, 2009Applicant: YAMAHA CORPORATIONInventors: Toshio Maejima, Masayuki Iwamatsu
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Publication number: 20090091355Abstract: An amplifier includes: an operation amplifier including a positive input terminal and a negative input terminal; and a detector which detects that a difference between a voltage of the positive input terminal and a voltage of the negative input terminal is equal to or exceeds a predetermined value and outputs a detection signal.Type: ApplicationFiled: October 3, 2008Publication date: April 9, 2009Applicant: Yamaha CorporationInventors: Masayuki Iwamatsu, Hirotoshi Tsuchiya
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Publication number: 20090052696Abstract: An electroacoustic transducer includes a single package, a microphone provided in the single package, an amplifier provided in the single package, and a controller provided in the single package. The microphone converts an acoustic pressure into an electrical signal. The amplifier amplifies the electrical signal that is output from the microphone. The amplifier is configured to allow the gain to be adjustable. The controller controls the gain of the amplifier, with reference to the level of an output signal from the amplifier, so as to prevent the output signal from being clipped.Type: ApplicationFiled: June 11, 2008Publication date: February 26, 2009Applicant: Yamaha CorporationInventor: Masayuki Iwamatsu
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Patent number: 7482870Abstract: A class D amplifier includes: an amplifier that generates a digital signal for driving a load based on an input signal; an attenuator that attenuates the input signal according to an attenuation command signal; and a clip prevention controller that outputs the attenuation command signal to intermittently attenuate the input signal when the digital signal is brought into a clip state or a near-clip state.Type: GrantFiled: September 28, 2006Date of Patent: January 27, 2009Assignee: Yamaha CorporationInventors: Toshio Maejima, Masayuki Iwamatsu
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Publication number: 20080297257Abstract: The amplifier comprises an inverting negative feedback amplifier circuit using an operational amplifier, a comparator for comparing the potential of the negative phase input terminal of the operational amplifier with the reference potential Vref of the comparator, and a low-pass filter. The imaginary short state of the operational amplifier is lost when clipping occurs on the output signal. It is thus possible to detect clipping by monitoring the potential of the negative phase input terminal.Type: ApplicationFiled: May 28, 2008Publication date: December 4, 2008Applicant: Yamaha CorporationInventor: Masayuki Iwamatsu
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Publication number: 20070103234Abstract: A class D amplifier includes: an amplifier that generates a digital signal for driving a load based on an input signal; an attenuator that attenuates the input signal according to an attenuation command signal; and a clip prevention controller that outputs the attenuation command signal to intermittently attenuate the input signal when the digital signal is brought into a clip state or a near-clip state.Type: ApplicationFiled: September 28, 2006Publication date: May 10, 2007Applicant: YAMAHA CORPORATIONInventors: Toshio Maejima, Masayuki Iwamatsu