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US 6,184,747 B2Granted
Differential filter with gyrator
AssigneeHoneywell International Inc.
InventorsMichael A. Helgeson, Keith R. Maile
Life of this patent
Estimating the term…
Abstract
A differential gyrator based filter is disclosed that preferably has a first gyrator connected to the positive input signal of the differential input signal and a second gyrator connected to the negative input signal of the differential input signal. A load capacitor is connected between the load terminals of the first gyrator and second gyrator, which minimizes the total load capacitance required for the gyrator based filter. This implementation is believed to increase the overall density, reliability, yield, signal-to-noise ratio and dynamic range of the gyrator based filter and related circuitry.
Claims29
A differential gyrator filter for receiving a differential mode input signal comprising:
- load means having an admittance;
- and
- a differential gyrator having a positive input terminal and a negative input terminal with an input impedance therebetween for receiving the differential mode input signal, said differential gyrator coupled to said load means and providing an input impedance that is proportional to the admittance of said load means.
A differential filter having a positive filter input terminal and a negative filter input terminal, comprising:
- first capacitance means having a first terminal and a second terminal;
- second capacitance means having a first terminal and a second terminal;
- first gyrator means having an input terminal and a load terminal, the input terminal of the first gyrator means coupled to the positive filter input terminal of the filter, and the load terminal of the first gyrator means coupled to the first terminal of said first capacitance means;
- and
- second gyrator means having an input terminal and a load terminal, the input terminal of the second gyrator means coupled to the negative filter input terminal of the filter, and the load terminal of the second gyrator means coupled to the first terminal of said second capacitance means;
- said second terminal of said first capacitance means and said second terminal of said second capacitance means coupled to a reference voltage.
3 more elements
A differential filter having a positive filter input terminal and a negative filter input terminal, comprising:
- capacitance means having a first terminal and a second terminal;
- first gyrator means having an input terminal and a load terminal, the input terminal of the first gyrator means coupled to the positive filter input terminal of the filter, and the load terminal of the first gyrator means coupled to the first terminal of said capacitance means;
- and
- second gyrator means having an input terminal and a load terminal, the input terminal of the second gyrator means coupled to the negative filter input terminal of the filter, and the load terminal of the second gyrator means coupled to the second terminal of said capacitance means.
1 more element
A filter having a number of cascaded filter stages, wherein each filter stage has a positive filter input terminal and a negative filter input terminal, each filter stage comprising:
- one or more capacitors, each having a first terminal and a second terminal;
- a first gyrator having an input terminal, an output terminal and one or more load terminals, the input terminal of the first gyrator coupled to the positive filter input terminal of the corresponding filter stage, and the one or more load terminals of the first gyrator coupled to the first terminals of the one or more capacitors;
- a second gyrator having an input terminal, an output terminal and one or more load terminals, the input terminal of the second gyrator coupled to the negative filter input terminal of the corresponding filter stage, and the one or more load terminals of the second gyrator coupled to the second load terminals of the one or more capacitors;
- and
- the output terminal of the first gyrator and the output terminal of the second gyrator being coupled to the positive filter input terminal and the negative filter input terminal, respectively, of the next succeeding filter stage.
2 more elements
A differential filter having a positive filter input terminal and a negative filter input terminal, comprising:
- capacitance means having a first terminal and a second terminal;
- first gyrator means having an input terminal and a load terminal, the input terminal of the first gyrator means coupled to the positive filter input terminal of the filter, and the load terminal of the first gyrator means coupled to the first terminal of said capacitance means, said first gyrator means including:
- a first differential amplifier having a positive input terminal, a negative input terminal, a positive output terminal and a negative output terminal;
- a second differential amplifier having a positive input terminal, a negative input terminal, a positive output terminal and a negative output terminal;
- the positive input terminal of the first differential amplifier of the first gyrator means and the negative output terminal of the second differential amplifier of the first gyrator means are coupled to the input terminal of the first gyrator means;
- the negative input terminal of the first differential amplifier of the first gyrator means is coupled to the positive output terminal of the second differential amplifier of the first gyrator means;
- the positive output terminal of the first differential amplifier of the first gyrator means is coupled to the positive input terminal of the second differential amplifier of the first gyrator means;
- the negative output terminal of the first differential amplifier of the first gyrator means is coupled to the negative input terminal of the second differential amplifier of the first gyrator means;
- second gyrator means having an input terminal and a load terminal, the input terminal of the second gyrator means coupled to the negative filter input terminal of the filter, and the load terminal of the second gyrator means coupled to the second terminal of said capacitance means, said second gyrator means including:
- a first differential amplifier having a positive input terminal, a negative input terminal, a positive output terminal and a negative output terminal;
- a second differential amplifier having a positive input terminal, a negative input terminal, a positive output terminal and a negative output terminal;
- the positive input terminal of the first differential amplifier of the second gyrator means and the negative output terminal of the second differential amplifier of the second gyrator means are coupled to the input terminal of the second gyrator means;
- the negative input terminal of the first differential amplifier of the second gyrator means is coupled to the positive output terminal of the second differential amplifier of the second gyrator means;
- the positive output terminal of the first differential amplifier of the second gyrator means is coupled to the positive input terminal of the second differential amplifier of the second gyrator means;
- and
- the negative output terminal of the first differential amplifier of the second gyrator means is coupled to the negative input terminal of the second differential amplifier of the second gyrator means.
13 more elements
A differential filter having a positive filter input terminal and a negative filter input terminal comprising:
- capacitance means having at least two first terminals and at least two second terminal;
- first gyrator means having an input terminal and at least two load terminals, the input terminal of the first gyrator means coupled to the positive filter input terminal of the filter, and each of the at least two load terminals of the first gyrator means coupled to a corresponding one of the at least two first terminals of said capacitance means;
- and
- second gyrator means having an input terminal and at least two load terminals, the input terminal of the second gyrator means coupled to the negative filter input terminal of the filter, and each of the at least two load terminals of the second gyrator means coupled to a corresponding one of the at least two second terminals of said capacitance means.
1 more element
Dependencies are inferred from the claim text.