Patents by Inventor John Robert Stuart
John Robert Stuart 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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Publication number: 20240029749Abstract: Encoding and decoding systems are described for the provision of high quality digital representations of audio signals with particular attention to the correct perceptual rendering of fast transients at modest sample rates. This is achieved by optimising downsampling and upsampling filters to minimise the length of the impulse response while adequately attenuating alias products that have been found perceptually harmful.Type: ApplicationFiled: June 9, 2023Publication date: January 25, 2024Inventors: Peter Graham Craven, John Robert Stuart
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Patent number: 11710493Abstract: Encoding and decoding systems are described for the provision of high quality digital representations of audio signals with particular attention to the correct perceptual rendering of fast transients at modest sample rates. This is achieved by optimising downsampling and upsampling filters to minimise the length of the impulse response while adequately attenuating alias products that have been found perceptually harmful.Type: GrantFiled: December 14, 2020Date of Patent: July 25, 2023Assignee: MQA LIMITEDInventors: Peter Graham Craven, John Robert Stuart
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Publication number: 20210193157Abstract: Encoding and decoding systems are described for the provision of high quality digital representations of audio signals with particular attention to the correct perceptual rendering of fast transients at modest sample rates. This is achieved by optimising downsampling and upsampling filters to minimise the length of the impulse response while adequately attenuating alias products that have been found perceptually harmful.Type: ApplicationFiled: December 14, 2020Publication date: June 24, 2021Inventors: Peter Graham Craven, John Robert Stuart
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Publication number: 20200395918Abstract: Methods and devices are described for reducing the audible effect of pre-responses in an audio signal. The pre-responses are effectively delayed by employing a digital non-minimum-phase filter, which includes a zero lying outside the unit circle in its z-transform response. This zero is not paired with another zero at a reciprocal position inside the unit circle, as this would linearise the phase modification. The filtering can introduce a greater group delay at the pre-response frequency than at a low frequency, such as 500 Hz or even 0 Hz. The technique can be used to reduce pre-responses in an existing audio signal and also to pre-empt pre-responses that would be introduced to the audio signal by subsequent processing.Type: ApplicationFiled: August 28, 2020Publication date: December 17, 2020Inventors: Peter Graham Craven, John Robert Stuart
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Patent number: 10867614Abstract: Encoding and decoding systems are described for the provision of high quality digital representations of audio signals with particular attention to the correct perceptual rendering of fast transients at modest sample rates. This is achieved by optimising downsampling and upsampling filters to minimise the length of the impulse response while adequately attenuating alias products that have been found perceptually harmful.Type: GrantFiled: October 2, 2018Date of Patent: December 15, 2020Assignee: MQA LimitedInventors: Peter Graham Craven, John Robert Stuart
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Patent number: 10763828Abstract: Methods and devices are described for reducing the audible effect of pre-responses in an audio signal. The pre-responses are effectively delayed by employing a digital non-minimum-phase filter, which includes a zero lying outside the unit circle in its z-transform response. This zero is not paired with another zero at a reciprocal position inside the unit circle, as this would linearise the phase modification. The filtering can introduce a greater group delay at the pre-response frequency than at a low frequency, such as 500 Hz or even 0 Hz. The technique can be used to reduce pre-responses in an existing audio signal and also to pre-empt pre-responses that would be introduced to the audio signal by subsequent processing.Type: GrantFiled: December 3, 2015Date of Patent: September 1, 2020Inventors: Peter Graham Craven, John Robert Stuart
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Patent number: 10224950Abstract: Devices and methods for digital to analog conversion (DAC) are provided, in which the analog outputs of an even number of digital to analog converters are combined. The individual converters operate on the same data but there is a relative time delay between the input digital signal received by one or more of the converters and the input digital signal received by other of the converters, wherein the delay is a fraction of the data sample period. Moreover, the data signal fed to half of the converters has an inverse relationship with the data signal fed to the other half of the converters and their analog outputs are subtracted. Dither and filtering techniques may also be employed.Type: GrantFiled: May 26, 2016Date of Patent: March 5, 2019Assignee: REINET S.A.R.L.Inventor: John Robert Stuart
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Publication number: 20190057709Abstract: Encoding and decoding systems are described for the provision of high quality digital representations of audio signals with particular attention to the correct perceptual rendering of fast transients at modest sample rates. This is achieved by optimising downsampling and upsampling filters to minimise the length of the impulse response while adequately attenuating alias products that have been found perceptually harmful.Type: ApplicationFiled: October 2, 2018Publication date: February 21, 2019Inventors: Peter Graham Craven, John Robert Stuart
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Patent number: 10115410Abstract: Encoding and decoding systems are described for the provision of high quality digital representations of audio signals with particular attention to the correct perceptual rendering of fast transients at modest sample rates. This is achieved by optimizing downsampling and upsampling filters to minimize the length of the impulse response while adequately attenuating alias products that have been found perceptually harmful.Type: GrantFiled: June 10, 2014Date of Patent: October 30, 2018Inventors: Peter Graham Craven, John Robert Stuart
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Publication number: 20180167081Abstract: Devices and methods for digital to analogue conversion (DAC) are provided, in which the analogue outputs of an even number of digital to analogue converters are combined. The individual converters operate on the same data but there is a relative time delay between the input digital signal received by one or more of the converters and the input digital signal received by other of the converters, wherein the delay is a fraction of the data sample period. Moreover, the data signal fed to half of the converters has an inverse relationship with the data signal fed to the other half of the converters and their analogue outputs are subtracted. Dither and filtering techniques may also be employed.Type: ApplicationFiled: May 26, 2016Publication date: June 14, 2018Inventor: John Robert Stuart
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Publication number: 20170346465Abstract: Methods and devices are described for reducing the audible effect of pre-responses in an audio signal. The pre-responses are effectively delayed by employing a digital non-minimum-phase filter, which includes a zero lying outside the unit circle in its z-transform response. This zero is not paired with another zero at a reciprocal position inside the unit circle, as this would linearise the phase modification. The filtering can introduce a greater group delay at the pre-response frequency than at a low frequency, such as 500 Hz or even 0 Hz. The technique can be used to reduce pre-responses in an existing audio signal and also to pre-empt pre-responses that would be introduced to the audio signal by subsequent processing.Type: ApplicationFiled: December 3, 2015Publication date: November 30, 2017Inventors: Peter Graham Craven, John Robert Stuart
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Patent number: 9763007Abstract: Methods are provided for equalizing the group delay of a sound reproduction system, in particular a system comprising acoustic transducers with at least one crossover between a lower-frequency and a higher-frequency range. A correction is applied to a signal in the lower-frequency range, including the crossover region, to substantially equalize the group delay for the lower-frequency range, and a signal delay is applied to a signal in the higher-frequency range to bring it into closer alignment with the equalized lower-frequency range signal. The methods may be implemented in the design of an acoustic transducer system and also via a computer program product, which can be implemented as an update or enhancement to an existing digital signal processor loudspeaker system.Type: GrantFiled: January 7, 2014Date of Patent: September 12, 2017Assignee: Meridian Audio LimitedInventors: Michael D. Capp, John Robert Stuart, Alan S. J. Wood, Richard J. Hollinshead
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Publication number: 20170110141Abstract: Encoding and decoding systems are described for the provision of high quality digital representations of audio signals with particular attention to the correct perceptual rendering of fast transients at modest sample rates. This is achieved by optimising downsampling and upsampling filters to minimise the length of the impulse response while adequately attenuating alias products that have been found perceptually harmful.Type: ApplicationFiled: June 10, 2014Publication date: April 20, 2017Inventors: Peter Graham Craven, John Robert Stuart
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Patent number: 9548055Abstract: An encoder for digital audio signals at a higher sample rate creates a stream for consumer distribution at a lower sampling rate, with compatibility for standard PCM players without a decoder. In conjunction with a suitable decoder, two enhanced playback options are supported, the first option allowing full lossless reconstruction of a noise-shaped higher sampling rate signal, the second option allowing lossy bandwidth extension even if an intervening transmission chain has truncated the least-significant-bits of the encoder's output signal.Type: GrantFiled: June 12, 2013Date of Patent: January 17, 2017Inventors: Peter Graham Craven, Malcolm Law, John Robert Stuart
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Publication number: 20160005411Abstract: Methods and devices are described whereby a representation of an original PCM signal may be reversibly degraded in a controlled manner and information losslessly embedded to produce a streamable PCM signal, which provides a controlled audio quality when played on standard players and conditional access to a lossless presentation of the original PCM signal. Using such techniques allows control over the level of degradation of the signal and also flexibility in the type information of information embedded. Some methods require a song key, which is employed in one or both of the degrading and embedding steps and for creating a token. These methods may further require a user key, which is used to encrypt the song key before creating the token.Type: ApplicationFiled: February 13, 2014Publication date: January 7, 2016Inventors: John Robert Stuart, Richard J. Hollinshead, Peter Graham Craven, Malcolm Law
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Publication number: 20150350786Abstract: Methods are provided for equalising the group delay of a sound reproduction system, in particular a system comprising acoustic transducers with at least one crossover between a lower-frequency and a higher-frequency range. A correction is applied to a signal in the lower-frequency range, including the crossover region, to substantially equalise the group delay for the lower-frequency range, and a signal delay is applied to a signal in the higher-frequency range to bring it into closer alignment with the equalised lower-frequency range signal. The methods may be implemented in the design of an acoustic transducer system and also via a computer program product, which can be implemented as an update or enhancement to an existing digital signal processor loudspeaker system.Type: ApplicationFiled: January 7, 2014Publication date: December 3, 2015Inventors: Michael D. Capp, John Robert Stuart, Alan S. J. Wood, Richard J. Hollinshead
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Publication number: 20150154969Abstract: An encoder for digital audio signals at a higher sample rate creates a stream for consumer distribution at a lower sampling rate, with compatibility for standard PCM players without a decoder. In conjunction with a suitable decoder, two enhanced playback options are supported, the first option allowing full lossless reconstruction of a noise-shaped higher sampling rate signal, the second option allowing lossy bandwidth extension even if an intervening transmission chain has truncated the least-significant-bits of the encoder's output signal.Type: ApplicationFiled: June 12, 2013Publication date: June 4, 2015Inventors: Peter Graham Craven, Malcolm Law, John Robert Stuart
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Patent number: 7193538Abstract: A lossless encoder and decoder are provided for transmitting a multichannel signal on a medium such as DVD-Audio. The encoder accepts additionally a downmix specification and splits the encoded stream into two substreams, such that a two-channel decoder of meagre computational power can implement the downmix specification by decoding one substream, while a multichannel decoder can decode the original multichannel signal losslessly using both substreams. Further features provide for efficient implementation on 24-bit processors, for confirmation of lossless reproduction to the user, and for benign behaviour in the case of downmix specifications that result in overload. The principle is also extended to mixed-rate signals, where for example some input channels are sampled at 48 kHz and some are sampled at 96 kHz.Type: GrantFiled: August 5, 2004Date of Patent: March 20, 2007Assignee: Dolby Laboratories Licensing CorporationInventors: Peter Graham Craven, Malcolm James Law, John Robert Stuart
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Patent number: 6774820Abstract: A lossless encoder and decoder are provided for transmitting a multichannel signal on a medium such as DVD-Audio. The encoder accepts additionally a downmix specification and splits the encoded stream into two substreams, such that a two-channel decoder of meagre computational power can implement the downmix specification by decoding one substream, while a multichannel decoder can decode the original multichannel signal losslessly using both substreams. Further features provide for efficient implementation on 24-bit processors, for confirmation of lossless reproduction to the user, and for benign behaviour in the case of downmix specifications that result in overload. The principle is also extended to mixed-rate signals, where for example some input channels are sampled at 48 kHz and some are sampled at 96 kHz.Type: GrantFiled: August 18, 2003Date of Patent: August 10, 2004Assignee: Dolby Laboratories Licensing CorporationInventors: Peter Graham Craven, Malcolm James Law, John Robert Stuart
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Publication number: 20040070523Abstract: A lossless encoder and decoder are provided for transmitting a multichannel signal on a medium such as DVD-Audio. The encoder accepts additionally a downmix specification and splits the encoded stream into two substreams, such that a two-channel decoder of meagre computational power can implement the downmix specification by decoding one substream, while a multichannel decoder can decode the original multichannel signal losslessly using both substreams. Further features provide for efficient implementation on 24-bit processors, for confirmation of lossless reproduction to the user, and for benign behaviour in the case of downmix specifications that result in overload.Type: ApplicationFiled: August 18, 2003Publication date: April 15, 2004Inventors: Peter Graham Craven, Malcolm James Law, John Robert Stuart