Intel Corporation

Jim Beaney

Sebastian Gracias

Wesley Hamilton Smith

Karl I Nordling

Amir Hindie

Karl Leinfelder

David Pearce

Guozhu Long

A tone detector for a modem detects the presence of a tone, such as that sent during a retraining request, using a complex adaptive FIR filter of the form 1&minus;z . The filter will detect the tone regardless of symbol rate.

Tone detector for use in a modem

A plurality of modems or modem types can run on a host processor, a digital signal processor or both, either concurrently or selectively. Modules of more than one modem program can be swapped in and out of DSP memory space. Common modem code can be run on either a host processor or on a DSP using respective command libraries.

Multi-modem implementation with host based and digital signal processor based modems

An audio modem provides both the functionality needed for audio processing and that needed for implementing one or more modems. A digital signal processor utilizes a plurality of serial ports to interface with one or more codecs used for interfacing an analog audio channel and with one or more modem codecs used for interfacing an analog communications channel.

Integrated audio and modem device

According to an embodiment of the invention, a modem provides functionality for audio processing and for implementing a modem. A digital signal processor is connected to one or more audio codecs to interface with an analog audio channel, and is connected to one or more modem codecs and a data access arrangement to interface with a communications channel.

The taps of an equalizer are used as inputs to a discrete Fourier transform (DFT). Certain spectral components are extracted from the DFT and used to estimate the frequency difference. The frequency difference estimate is filtered using a phase locked loop and used to adjust one clock to synchronize the transmit and receive clocks.

Synchronization techniques using an interpolation filter

System for dedicating a host processor to running one of a plurality of modem programs and dedicating a DSP to running another one of the modem programs

Modem functionality is implemented on a digital signal processor running on a host. A plurality of program modules for executing modem functionality are stored in memory on the host and are selectively swapped in and out of the memory space of the DSP permitting complex modem functionality to be executed on a DSP that would otherwise not be possible.

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Raleigh, NC, United States of America

Jim Beaney