Data processing: speech signal processing – linguistics – language – Audio signal bandwidth compression or expansion
Reexamination Certificate
1999-06-28
2002-02-19
Dorvil, Richemond (Department: 2741)
Data processing: speech signal processing, linguistics, language
Audio signal bandwidth compression or expansion
C704S504000
Reexamination Certificate
active
06349285
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to data processing and in particular, to audio bass management and methods and circuits and systems using the same.
2. Description of the Related Art
The ability to process audio information has become increasingly important in the personal computer (PC) environment. Among other things, audio is important in many multimedia applications, such as gaming and telecommunications. Audio functionality is therefore typically available on most conventional PCs, either in the form of an add-on audio board or as a standard feature provided on the motherboard itself. In fact, PC users increasingly expect not only audio functionality but high quality sound capability. Additionally, digital audio plays a significant role outside the traditional PC realm, such as in compact disk players, VCRs and televisions. As the audio technology progresses, digital applications are increasingly sophisticated as improvements in sound quality and sound effects are sought.
One of the key components in many digital audio information processing systems is the decoder. Generally, the decoder receives data in a compressed form and converts that data into a decompressed digital form. The decompressed digital data is then passed on for further processing, such as filtering, expansion or mixing, conversion into analog form, and eventually conversion into audible tones. In other words the decoder must provide the proper hardware and software interfaces to communicate with the possible compressed (and decompressed) data sources, as well as the destination digital and/or audio devices. In addition, the decoder must have the proper interfaces required for overall control and debugging by a host microprocessor or microcontroller. Further, the decoder must also perform additional functions appropriate to the decoder subsystem of a digital audio system, such as the mixing of various received digital and/or audio data streams.
During processing of streaming data, such as audio data (compressed or decompressed), it is essential that the processing device or system be capable of throughputting data accurately and with the requisite speed. One way of insuring this is by providing efficient communications between the various processing blocks within the given system or device. This is especially true when multiple processors are utilized. Thus, the need has arisen for circuits and methods of maintaining efficient communication between processing blocks, for use in such applications as advanced audio decoders.
In addition, advanced audio decoders should also be capable of performing post processing functions on the multichannel audio. These could include tasks such as bass management to accommodate the program content to the particular setup, tone control, graphic or parametric equalization, etc.
SUMMARY OF THE INVENTION
Disclosed is a method of managing the bass in multiple channels of audio data in an audio system having multiple speakers of different bass capabilities. A first channel signal is selectively passed through a software high-pass filter to selectively drive a first one of the speakers. A plurality of channel signals are selectively summed in software to generate a composite signal and a composite signal is selectively passed through a software low-pass filter to selectively drive a second one of the speakers.
The principles of the present invention provide numerous advantages over the prior art. Among other things, bass management can be fully implemented on a single chip audio processing device instead of an entire circuit board of analog components. Additionally, a significant number of possible speaker and filter configurations, both standard and custom, can be supported by the hardware and software described herein.
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Dokic Miroslav
Liu Pu
Rao Raghunath
Cirrus Logic Inc.
Dorvil Richemond
Murphy James J.
Winstead Sechrest & Minick
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