Method and apparatus for symmetrical DMT X-DSL communications
Granted: July 11, 2006
Patent Number:
7075998
A method and apparatus for communicating multi-tone modulated upstream and downstream channels of communication data between a pair of communication devices utilizing a common set of tones for the upstream and downstream channels. The pair of communication devices each include a digital stage configured to assign mutually orthogonal code sequences for encoding and decoding the upstream and downstream channel respectively. The transmit path of the digital stage of each communication…
Method and apparatus for an X-DSL modem supporting multiple X-DSL line codes
Granted: October 25, 2005
Patent Number:
6959036
An X-DSL modem supporting multiple X-DSL line codes including discrete multi-tone (DMT) and carrierless phase and amplitude (CAP). The modem includes: components coupled to one another to form a transmit path and a receive path. The components include an encoder component and a Fourier transform component. The encoder component encodes data associated with a CAP communication channel into QAM symbols and encodes data associated with a DMT communication channel into DMT sub-symbols. The…
Method and apparatus for compensating an amplifier
Granted: August 2, 2005
Patent Number:
6924701
A method and apparatus for compensating an amplifier is disclosed which significantly improves the unity gain bandwidth of the amplifier. In an embodiment of the invention the amplifier includes at least one compensated pair of cascode coupled transistors including: an input transistor, a cascode transistor, and a bypass element. The input transistor exhibits a first transition frequency. The cascode transistor is cascode coupled to the input transistor. The cascode transistor exhibits a…
Method and apparatus for synchronizing a packet based modem supporting multiple X-DSL protocols
Granted: January 11, 2005
Patent Number:
6842429
The current invention provides a digital signal processor which supports multiple X-DSL protocols and a multiplicity of channels on a single chip. Each channel is packetized and each packet includes control information for controlling the performance of the components/modules on the transmit and receive path. Further flexibility is derived from an architecture which incorporates discrete and shared modules on the transmit path and the receive path. The transmit path and receive path…
Dual impedance hybrid
Granted: July 6, 2004
Patent Number:
6760434
A method and apparatus for coupling an xDSL transceiver with a subscriber line is disclosed. A hybrid circuit is disclosed which exhibits a different relative gain factor for transmitted signals and received signals. The difference in gain factors results in part from a combined balance circuit and transformer which exhibit a different coupling ratio between the primary and secondary coils on the receive path and the transmit path. The hybrid circuit may be used to isolate the receive…
Method and apparatus for wireline characterization
Granted: April 6, 2004
Patent Number:
6718019
The current invention provides a method and apparatus for wireline characterization is disclosed. The method may be implemented with any modulation protocol but is particularly suited for multi-carrier modulation protocols such as discrete multi-tone (DMT). The apparatus may be incorporated into physical or logical modems. In an embodiment of the invention an apparatus for wireline characterization in a modem with a transmit path and a receive path each configured to couple with a remote…
Method and apparatus for insertion loss estimation in wireline communications
Granted: February 4, 2003
Patent Number:
6516049
The current invention provides a method and apparatus for determining insertion loss in wireline communication systems. The method may be implemented with any modulation protocol but is particularly suited for multi-carrier modulation protocols such as discrete multi-tone (DMT). The method for calculation of the insertion loss uses a received signal and a discrete subset of frequency ranges, e.g. DMT tones, within that signal. For each of the subset of frequency ranges the average…
Method and apparatus for down conversion within an X-DSL receiver
Granted: January 28, 2003
Patent Number:
6512739
The current invention provides a method and apparatus for downconverting received digital data from the elevated frequencies at which the data is modulated. Various multi-tone communications systems (such as DMT in wire-line communication or OFDM in wireless communication) operate by up-converting output of the modulated signal at the output of the IFFT from baseband to a higher center frequency. Therefore, at the receiver, the inverse operation is required. At the receiver the signal…
Method and apparatus for multi-channel X-DSL line driver
Granted: October 15, 2002
Patent Number:
6466088
An apparatus and method for reducing power requirements in X-DSL and other communication protocols is disclosed. The apparatus may be applied with equal advantage in wired and wireless media Power is supplied selectively to input lines in which input signals exceed selected threshold levels. The apparatus is configured to support statistical multiplexing of the input signal lines across a plurality of amplification means which support amplification at up to either of at least two power…
A/D multi-channel pipeline architecture
Granted: October 16, 2001
Patent Number:
6304205
An apparatus and method for A/D conversion is provided. The apparatus provides for multi-path multi-channel (MPMC) pipelined A/D conversion. Unlike prior art designs in which the handling of multiple channels requires a linear increase in the associated circuitry and components, the current design scales for multiple channel A/D conversion with less than linear scalability. The A/D converter comprises a plurality of stages and interfaces between adjacent columns of the stages. The stages…
