Conexant Systems, Inc.

Sandeep Rajpal

Sverrir Olafsson

Olafur Orn Jonsson

Ramin A Nobakht

Jonathan H Ta

Stanley C Hsieh

Samuel T Wong

A non-coherent frequency shift keying detection scheme. The invention has been applied to the special case of capturing caller ID information when the voice-band modem is in the low power mode. The technique provides the capability for capturing and decoding enough of the caller ID information transmitted by the telephone company while the computer is in the sleep or low power mode, and upon awakening the computer can use this captured information to decode the actual caller ID information. Additionally, this invention automatically accommodates both the Bell 202 or V.23 transmission standards by utilizing a threshold concept in which the time that has elapsed between the zero crossings of an FSK tone half cycle are measured. The elapsed times may be used as an indication of which FSK tone has been transmitted thus allowing capture of caller ID information. The bit output of the caller ID capture circuit is output for storage by RAM thus allowing use by the computer when it wakes up.

Non-coherent frequency shift keying detection scheme

A method is disclosed for encoding and modulating bits of an information stream and transmitting them over a designated channel in a high speed communication system. The method includes the steps of dividing a set of the entire constellation of available points into a finite plurality of zero parity vectors defined by two criteria, namely that (1) the column vectors have odd parity and (2) a group of a predefined integer number of column vectors have a 0 modulus (i.e. be divisible by a given number). Column vectors forming only a partially dimensioned portion of the code (e.g. 4D) corresponding to one discrete baud interval are preferably transmitted in a systematic form and with sufficient coding gain for adaptive DFE equalization and whereby a group of column vectors corresponding to an integer number of successive baud intervals that form the fully dimensioned code (e.g. 16D) are transmitted with correlation to one another to achieve an even greater amount of coding gain suitable for high reliability data transmission with error correction and subsequent detection that yield a low bit error rate.

4 x 4 dimensional block modulation code for a PAM-5 constellation

A methodology for a modem control channel is disclosed. The channel allows faster seamless rate change and precoder tap exchange than the baseline procedure for seamless rate change, allowing for more robust transmission of control information. It can also be use to convey side-information in the case of multiple data applications, serving the purpose of mode switching. Thus, with a single control channel both the needs for seamless rate change and transmitting control information for multiple data applications can be met.

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Irvine, CA, United States of America

Sandeep Rajpal