公开(公告)号：US11107485B2

公开(公告)日：2021-08-31

申请号：US16530798

申请日：2019-08-02

Applicant: Cirrus Logic International Semiconductor Ltd.

Inventor： Shafagh Kamkar ,  Dylan A. Hester ,  Bruce E. Duewer

IPC: H03M5/08 ,  G10L19/16 ,  H03M5/14 ,  G06F3/16 ,  G10L19/02 ,  G10L19/032 ,  G10L19/26

Abstract: A single-bit audio stream can be converted to a modified single-bit audio stream with a constant edge rate while maintaining a modulation index of the original audio stream using direct mapping. With direct mapping, a pre-filter bank may be combined with a multi-bit symbol mapper to select symbols for the modified audio stream with a constant edge rate per symbol and the same modulation index as the original audio stream. The output of the pre-filter bank may be an audio stream with no consecutive full-scale symbols. Using the output of the pre-filter bank, a multi-bit symbol mapper may use the symbol selector to output a symbol with a constant edge rate per symbol and the same modulation index as the original signal. The symbols may be converted to an analog signal for reproduction of audio content using a transducer.

公开(公告)号：US11050971B2

公开(公告)日：2021-06-29

申请号：US16694362

申请日：2019-11-25

Applicant: Cirrus Logic International Semiconductor Ltd.

Inventor： Shafagh Kamkar ,  Bruce E. Duewer ,  Dylan A. Hester

IPC: H04N9/80 ,  H04N5/926 ,  H03M13/47 ,  H03M13/09 ,  G11B20/18 ,  G11B20/10 ,  H03M13/29

Abstract: An encoding for data in an audio data stream may be indicated in the data stream using a footer stored in low-order bits of data frames in the audio data stream. When the audio data stream may include either Pulse Code Modulation (PCM) or Direct Stream Digital (DSD) data, PCM data may be marked with a footer to indicate the encoding as PCM. The footer may be a fixed value, an alternating fixed value, a predetermined sequence of values, or a value computed based on the PCM data. Examples of computed values for the footer marker may include an error code, an error correction code (ECC), and a scrambled code.

公开(公告)号：US10522155B2

公开(公告)日：2019-12-31

申请号：US15693900

申请日：2017-09-01

Applicant: Cirrus Logic International Semiconductor Ltd.

Inventor： Shafagh Kamkar ,  Bruce E. Duewer ,  Dylan A. Hester

IPC: G10L19/00 ,  G10L19/005 ,  H04L1/00 ,  G10L19/16 ,  G10L19/22 ,  G11B20/00 ,  G11B20/10

Abstract: An encoding for data in an audio data stream may be indicated in the data stream using a footer stored in low-order bits of data frames in the audio data stream. When the audio data stream may include either Pulse Code Modulation (PCM) or Direct Stream Digital (DSD) data, PCM data may be marked with a footer to indicate the encoding as PCM. The footer may be a fixed value, an alternating fixed value, a predetermined sequence of values, or a value computed based on the PCM data. Examples of computed values for the footer marker may include an error code, an error correction code (ECC), and a scrambled code.

公开(公告)号：US20180240464A1

公开(公告)日：2018-08-23

申请号：US15693900

申请日：2017-09-01

Applicant: Cirrus Logic International Semiconductor Ltd.

Inventor： Shafagh Kamkar ,  Bruce E. Duewer ,  Dylan A. Hester

IPC: G10L19/005 ,  H04L1/00 ,  G10L19/16 ,  G10L19/22

Abstract: An encoding for data in an audio data stream may be indicated in the data stream using a footer stored in low-order bits of data frames in the audio data stream. When the audio data stream may include either Pulse Code Modulation (PCM) or Direct Stream Digital (DSD) data, PCM data may be marked with a footer to indicate the encoding as PCM. The footer may be a fixed value, an alternating fixed value, a predetermined sequence of values, or a value computed based on the PCM data. Examples of computed values for the footer marker may include an error code, an error correction code (ECC), and a scrambled code.

公开(公告)号：US20180218744A1

公开(公告)日：2018-08-02

申请号：US15706093

申请日：2017-09-15

Applicant: Cirrus Logic International Semiconductor Ltd.

Inventor： Shafagh Kamkar ,  Bruce Duewer ,  Dylan Hester

IPC: G10L19/16 ,  G06F3/16 ,  G10L19/22 ,  G10L19/008

Abstract: An audio processing circuit may have a first path for processing multi-bit audio signals in parallel with a second path for processing single-bit audio signals. The parallel paths may share a common input node for receiving audio data and a common output node for reproducing audio at a transducer. Each path may have a volume control for adjusting an output of the path. The audio processing circuit may determine a type of an audio signal received at the input. The path not corresponding to the detected type of the audio signal is muted, and the path corresponding to the detected type of audio signal is unmuted.

公开(公告)号：US20180166088A1

公开(公告)日：2018-06-14

申请号：US15373745

申请日：2016-12-09

Applicant: Cirrus Logic International Semiconductor Ltd.

Inventor： Bruce E. Duewer ,  Dylan A. Hester ,  Shafagh Kamkar

IPC: G10L19/16 ,  G10L19/22 ,  G06F3/16

CPC classification number: G10L19/167 ,  G06F3/165 ,  G10L19/22

Abstract: A data encoding may be determined by examining the data itself. By examining the data, such as by identifying characteristics of the data, the data encoding may be identified and the substantive information extracted from the data by decoding the data according to the identified data encoding. The data encoding may be identified without extra control or header information separate from the encoded data itself. The identification of data encoding may be determined by a plurality of detectors examining different characteristics of the data and determining an encoding of the data based on each of those individual characteristics. The output of the detectors may be collected and used to decide the encoding of the data. One example application involves determining if audio data is DSD- or PCM-encoded audio data by examining only the data itself.