Analogue-to-digital converters
AssigneeGEC-Marconi Limited
InventorAndrew Mark Thurston
Life of this patent
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Abstract
An analog-to-digital converter includes an input for analog signals, a quantizer for producing a digital signal output, a feedback loop for feeding a signal derived from the digital output to be combined in analog form with the analog input for input to a filter. The output of the filter is fed to the quantizer. The filter comprises at least three filter stages. The filtered signal is derived using the output of at least one stage, other than the first stage, which is representative only of the response of the corresponding filter order and not of other filter orders. The output of the third stage is representative only of the third order response. A limiter is provided in the output of the third stage of the filter.
Claims6
An analogue-to-digital converter, comprising:
- an input for analogue signals, quantizing means for producing a digital output, a feedback loop for feeding a signal derived from the digital output to be combined in analogue form with the analogue input for input to a filter means, the filtered signal being fed to the quantizing means, the filter means comprising at least three filter stages, the filtered signal being derived using the output of at least one stage, other than the first, which is representative only of the response of the corresponding filter order and not of other filter orders, the output of the third stage being representative only of a third order response, and there is provided a limiter in the output of the third stage of the filter.
An analog-to-digital converter, comprising:
- an input for analog signals;
- quantizing means for producing a digital output;
- a feedback loop coupled to the digital output and including means for converting the digital output to an analog feedback signal;
- means for summing the analog signals at the input with the analog feedback signal to form a combined analog signal;
- filter means receiving the combined analog signal, the filter means including at least first, second and third filter stages, the filter stages having outputs corresponding to different order responses, wherein the third stage has an output that is representative only of a third order response and the filter means includes a limiter connected to the output of the third stage;
- and
- means for summing the outputs of the filter stages to produce a filtered signal that is fed to the quantizing means.
Dependencies are inferred from the claim text.