Abstract: A method and system for analytically and dynamically generating a repeatable digital probing signal representing an answer tone. The probing signal may conveniently be used by a modem to determine whether characteristics of the communication path between the modem and another end are sufficiently similar to these of a previous communication path, such that a shortened training sequence can be employed between two ends. When the modem initiates communication, the modem applies a predefined algorithm to dynamically generate a sequence of samples representing an answer tone signal. Next, the modem encodes the generated sequence of samples into a sequence of codewords and sends it to a second modem via a transmission path. When the second modem receives each codeword of the sequence, the second modem dynamically generates a respective codeword and compares it to the received codeword.

Abstract: A communications receiver is provided that includes a first and second compensators 64 and 68, a pilot tracker 60, and a demodulator 66. The first compensator 64 is operable to adjust an input signal based on both a coarse frequency offset and a fine frequency offset to produce an adjusted input signal. The pilot tracker 60 determines an estimated residual frequency offset based on at least a portion of the adjusted input signal. The demodulator 66 determines at least a first symbol sequence and a second symbol sequence based on the adjusted input signal. The second compensator 68 is operable to adjust the first symbol sequence and the second symbol sequence based on the estimate residual frequency offset.

Abstract: A method and apparatus permit a wireless communication device to be calibrated during manufacturing and subsequently re-calibrated while in use to correct for the effects of temperature changes on transmit power.

Abstract: The subject invention defines the details of packet based DSL modulation. The invention claims a method for minimizing crosstalk generation by specifying a duty cycle for bursted carrier data traffic and a method of providing opportunistic echo canceller training. In this way the present invention minimizes power and interference while maximizing the peak capacity of a transceiver used in ADSL communication systems.

Abstract: Improved data communication for modems having digital identification information capability.

Abstract: A system and method for user information transfer before modem connection. The invention makes high-speed modems more efficient, particularly for transaction and Internet applications, by providing for transmission of pre-connection user data during modem training. A training sequence for a modem in accordance with the invention may be summarized as follows: beginning training of the modem at a first data rate using a defined training sequence; after a selected amount of training, transmitting pre-connection user data from the modem at up to the first data rate while continuing training of the modem; ending training; and enabling transmission of user data at a full connected data rate of the modem.

Abstract: A system and method for generating and repetitively transmitting a single modulated symbol during idle periods in user data in a digital subscriber line (DSL) communication system. The modulated symbol to be transmitted is selected such that its spectral properties match those of user data modulated symbols. For an asynchronous DSL system, and variants thereof, a preferred idle symbol is the "superframe" synchronization symbol. A separate modulated symbol would indicate the end of the idle state. In the preferred embodiment, the end-of-idle symbol is the idle symbol shifted by a 180.degree. phase shift. In a preferred embodiment, the transmitter in a DSL modem would calculate the idle state modulated symbol once at the start of the idle period and then simply repeat this symbol until the end of the idle period, in which case the transmitter would invert the final idle symbol. At the receiver, an idle state modulated symbol detector and phase detector are implemented.