Sigma-Delta Analog-Digital Converter For An Xdsl Multistandard Input Stage
First Claim
1. A sigma delta analog/digital converter for an xDSL multi standard input stage for converting an xDSL signal into a digital output signal, wherein the sigma delta analogue/digital converter (1) comprises:
- (a) an analog loop filter (6) which filters an analog difference signal between the xDSL signal to be converted and a feedback signal in order to produce a filter output signal;
(b) a quantizer which quantizes the filter output signal from the analog loop filter (6) in order to produce the digital output signal; and
(c) a first digital/analog converter (16) which converts the digital output signal into the analog feedback signal,and further wherein the analog loop filter (6)has at least two resonator filter stages (6a, 6b) which respectively comprises a first integrator (6a 1;
6b 1) and a second integrator (6a 2;
6b 2) connected in series thereto,wherein the second integrator (6a 2;
6b 2) can be connected to the first integrator (6a 1, 6b 1) by means of a controllable feedback switch (6a 3, 6b 3) adapted to close a local feedback loop, andthe integrator outputs can respectively be connected by means of a controllable switch (25) to a signal input of an adder (27) which adds the output signals from the integrators in order to produce the filter output signal.
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Abstract
The invention relates to a sigma-delta analogue/digital converter for an xDSL multi-standard input stage for converting an xDSL signal into a digital output signal, where the sigma-delta analogue/digital converter (1) has: an analogue loop filter (6) which filters an analogue difference signal between the xDSL signal to be converted and a feedback signal in order to produce a filter output signal; a quantizer which quantizes the filter output signal from the analogue loop filter (6) in order to produce the digital output signal; a first digital/analogue converter (16) which converts the digital output signal into the analogue feedback signal; where the analogue loop filter (6) has at least two resonator filter stages (6a, 6b) which respectively comprise a first integrator (6a-1; 6b-1) and a second integrator (6a-2; 6b-2) connected in series therewith, where the second integrator (6a-2; 6b-2) can be connected to the first integrator (6a-1, 6b-1) by means of a controllable feedback switch (6a-3, 6b-3) in order to close a local feedback loop, where the integrator outputs can respectively be connected by means of a controllable switch (25) to a signal input of an adder (27) which adds the output signals from the integrators in order to produce the filter output signal.
16 Citations
29 Claims
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1. A sigma delta analog/digital converter for an xDSL multi standard input stage for converting an xDSL signal into a digital output signal, wherein the sigma delta analogue/digital converter (1) comprises:
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(a) an analog loop filter (6) which filters an analog difference signal between the xDSL signal to be converted and a feedback signal in order to produce a filter output signal; (b) a quantizer which quantizes the filter output signal from the analog loop filter (6) in order to produce the digital output signal; and (c) a first digital/analog converter (16) which converts the digital output signal into the analog feedback signal, and further wherein the analog loop filter (6) has at least two resonator filter stages (6a, 6b) which respectively comprises a first integrator (6a 1;
6b 1) and a second integrator (6a 2;
6b 2) connected in series thereto,wherein the second integrator (6a 2;
6b 2) can be connected to the first integrator (6a 1, 6b 1) by means of a controllable feedback switch (6a 3, 6b 3) adapted to close a local feedback loop, andthe integrator outputs can respectively be connected by means of a controllable switch (25) to a signal input of an adder (27) which adds the output signals from the integrators in order to produce the filter output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification