Switched-capacitor filter
AssigneesFujitsu Limited, Nippon Telegraph & Telephone Public Corporation
InventorsNorio Ueno, Seiji Kato, Atsushi Iwata
Life of this patent
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Abstract
A switched capacitor filter having at its input, a signal converter for creating so-called 100% sample and hold signals. The signal converter comprises a plurality of switched capacitors. The switched capacitors, connected in parallel with each other, receive the same successive input signals and supply the so-called 100% sample and hold input signals to the switched-capacitor filter. The switched capacitors, on one hand, charge each of said input signals sequentially and, on the other hand, alternately discharge the respective stored input signals one by one.
Claims13
A signal converter for receiving a succession of input signals and converting same for transfer to a switched capacitor filter, said converter being driven by constant frequency clock pulses and comprising:
- a plurality of switched capacitors connected in parallel with each other, each said switched capacitor comprising a capacitor and associated switching means connected in series,
- wherein each of the switched capacitors receives the same successive input signals to be transferred, each of said input signals comprising both a holding term for transferring the input signal and a non-holding term for not transferring the input signal,
- wherein said switched capacitors store said input signals during the holding term in synchrony with said clock pulses,
- and wherein the switched capacitors discharge respective stored input signals sequentially, during both said holding term and said non-holding term, in synchrony with said clock pulses.
A signal converter, comprising:
- input means for receiving an input signal which comprises both a holding term and a non-holding term;
- means for receiving a clock signal;
- an output terminal;
- first switched-capacitor means, operatively connected to said input means, for sampling said input signal synchronously with said clock signal during said holding term of said input signal, and for transferring to said output terminal during said holding term of said input signal an output signal proportional to said input signal;
- and
- one or more other switched-capacitor means operatively connected to said input means and to said output terminal, for sampling said input signals during said holding term thereof, and for transferring to said output terminal successively, in synchrony with successive clock pulses during said non-holding term of said input signal, respective output signals proportional to the value of said input signal during said holding term in which said input signal was sampled by said respective one or more other switched-capacitor means.
A signal converter, comprising:
- input means for receiving an input signal, said input signal comprising both a holding term and a non-holding term;
- an output terminal;
- and
- a plurality of switched capacitors connected in parallel, each said respective switched capacitor comprising:
- a capacitor;
- and
- means for connecting said capacitor to said input means at the beginning of each said holding term of said input signal, and for connecting said capacitor of each said respective switched capacitor to said output terminal sequentially during the remainder of said holding term and the succeeding non-holding term of said input signal.
Dependencies are inferred from the claim text.