Ladder filter, analog equalizer and signal readout system
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsShiro Dosho, Takashi Morie
Life of this patent
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Abstract
A ladder filter includes multiple inductor sections, each including voltage-controlled current sources and capacitors. A second signal input terminal is provided for the filter separately from an ordinary signal input terminal and a signal, which has been input through the second terminal, is supplied to one of the voltage-controlled current sources by way of a gain calculator. By adjusting the gain obtained by the gain calculator to an appropriate value, the ladder filter can make the numerator of its transfer function freely definable.
Claims7
A ladder filter comprising multiple inductor sections, each said inductor section being implemented by an equivalent circuit including voltage-controlled current sources and capacitors,
- wherein a signal input to the ladder filter is provided to at least one of the voltage-controlled current sources by way of gain adjusting means, and
- wherein a gain obtained by the gain adjusting means is set to such a value as realizing a desired transfer function for the ladder filter.
An analog equalizer comprising:
- a ladder filter including multiple inductor sections, each said inductor section being implemented by an equivalent circuit including voltage-controlled current sources and capacitors;
- means for detecting an error between an output signal of the ladder filter and a reference signal;
- and
- means for changing a filter characteristic of the ladder filter by reference to the error that has been detected by the detecting means,
- wherein a signal input to the ladder filter is provided to at least one of the voltage-controlled current sources by way of gain adjusting means, which obtains a variable gain, and
- wherein the changing means changes the gain, obtained by the gain adjusting means of the ladder filter, based on the error that has been detected by the detecting means.
Dependencies are inferred from the claim text.