Analogue-to-digital converter
AssigneeNokia Corporation
InventorKimmo Koli
Life of this patent
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Abstract
An analogue to digital converter uses charge sampling in combination with a successive approximation conversion technique in order to combine anti-alias filtering and quadrature downconversion functions into the data converter. The conversion method is an energy-efficient realization for wide-band radio systems with moderate resolution specifications such as 4G or ultra-wideband radio (UWB). The converter uses two capacitor matrices, one to perform charge sampling, and one to be used simultaneously in the successive approximation technique, so that full use of an input signal is made and efficiency is maximized.
Claims31
A method of converting an analogue signal to a digital signal, comprising:
- converting an input analogue voltage signal to a current signal;
- alternately applying the current signal to a first charge-storage and a second charge storage during a sampling period;
- performing approximation of a voltage derived from charge stored in the first charge storage while the current signal is applied to the second charge storage during the sampling period by determining one of a successively smaller range of voltages which corresponds to the derived voltage;
- and
- outputting a digital signal corresponding to the approximated voltage.
An apparatus for performing analogue-to-digital conversion, comprising:
- one or more transconductance amplifiers for converting an input analogue voltage signal to a current signal;
- a first charge storage for storing charge carried by the current signal during a sampling period;
- a second charge storage for storing charge carried by the current signal during the sampling period;
- a voltage approximator for performing approximation of a voltage derived from the charge stored in the charge storage while the current is applied to the second charge storage during the sampling period by determining one of a successively smaller range of voltage levels which corresponds to the derived voltage;
- and
- an output for outputting a digital signal corresponding to the approximated voltage.
Dependencies are inferred from the claim text.