Method and apparatus for varying an impedance
AssigneeRFMicron, Inc.
InventorShahriar Rokhsaz
Life of this patent
Estimating the term…
Abstract
A method and apparatus for dynamically varying the impedance of a tank circuit whereby, over time, the response of the circuit to a received signal is maximized.
Claims125
A method for dynamically varying the impedance of a tank circuit comprising an inductor and a capacitor, the capacitance of which can be varied in a selected one of first and second directions, the method comprising the steps of:
- (1) selecting one of said first and second directions;
- (2) capturing a current response of the circuit to a received signal;
- (3) varying the capacitor in said selected direction;
- (4) comparing the captured response to the current response;
- (5) if the comparison made in step 4 indicates that the current response is weaker than the captured response, selecting the other of said directions;
- and
- (6) returning to step 2.
(canceled)
A tuning circuit for dynamically varying the impedance of a tank circuit comprising an inductor and a capacitor, the capacitance of which can be varied in a selected one of first and second directions, the tuning circuit comprising:
- a reference voltage generator, coupled to the tank circuit, to produce a reference voltage proportional to the response of the tank circuit to a received signal;
- a differentiator, coupled to the generator, to determine a polarity of the change in the reference voltage between a first point in time and a second point in time;
- a direction selector, coupled to the differentiator, to select one of said first and second directions in response to said polarity;
- and
- a ramp generator, coupled to the selector and to the capacitor, to selectively vary the capacitance of said capacitor in said selected direction.
(canceled)
(canceled)
A method for dynamically varying the impedance of a tank circuit comprising an inductor and a capacitor, the capacitance of which can be varied in a selected one of first and second directions, the method comprising the steps of:
- (1) selecting one of said first and second directions;
- (2) capturing a current response of the circuit to a signal received via said inductor;
- (3) varying the capacitor in said selected direction;
- (4) comparing the captured response to the current response;
- (5) if the comparison made in step 4 indicates that the current response is weaker than the captured response, selecting the other of said directions;
- and
- (6) returning to step 2.
A tuning circuit for dynamically varying the impedance of a tank circuit comprising an inductor and a capacitor, the capacitance of which can be varied in a selected one of first and second directions, the tuning circuit comprising:
- a reference voltage generator, coupled to the tank circuit, to produce a reference voltage proportional to the response of the tank circuit to a signal received via said inductor;
- a differentiator, coupled to the generator, to determine a polarity of the change in the reference voltage between a first point in time and a second point in time;
- a direction selector, coupled to the differentiator, to select one of said first and second directions in response to said polarity;
- and
- a ramp generator, coupled to the selector and to the capacitor, to selectively vary the capacitance of said capacitor in said selected direction.
A method for dynamically varying the impedance of a tank circuit comprising an inductor and a capacitor coupled in parallel with said inductor, the capacitance of which can be varied in a selected one of first and second directions, the method comprising the steps of:
- (1) selecting one of said first and second directions;
- (2) capturing a current response of the circuit to a received signal;
- (3) varying the capacitor in said selected direction;
- (4) comparing the captured response to the current response;
- (5) if the comparison made in step 4 indicates that the current response is weaker than the captured response, selecting the other of said directions;
- and
- (6) returning to step 2.
A tuning circuit for dynamically varying the impedance of a tank circuit comprising an inductor and a capacitor coupled in parallel with said inductor, the capacitance of which can be varied in a selected one of first and second directions, the tuning circuit comprising:
- a reference voltage generator, coupled to the tank circuit, to produce a reference voltage proportional to the response of the tank circuit to a received signal;
- a differentiator, coupled to the generator, to determine a polarity of the change in the reference voltage between a first point in time and a second point in time;
- a direction selector, coupled to the differentiator, to select one of said first and second directions in response to said polarity;
- and
- a ramp generator, coupled to the selector and to the capacitor, to selectively vary the capacitance of said capacitor in said selected direction.
A method for dynamically tuning a circuit comprising a coil antenna and a capacitor coupled in parallel with said antenna, the capacitance of which can be varied in a selected one of first and second directions, the method comprising the steps of:
- (1) selecting one of said first and second directions;
- (2) capturing a current response of the circuit to a signal magnetically coupled to said antenna;
- (3) varying the capacitor in said selected direction;
- (4) comparing the captured response to the current response;
- (5) if the comparison made in step 4 indicates that the current response is weaker than the captured response, selecting the other of said directions;
- and
- (6) returning to step 2.
A tuning circuit for dynamically tuning a circuit comprising a coil antenna and a capacitor coupled in parallel with said antenna, the capacitance of which can be varied in a selected one of first and second directions, the tuning circuit comprising:
- a reference voltage generator, coupled to the tank circuit, to produce a reference voltage proportional to the response of the tank circuit to a signal magnetically coupled to said antenna;
- a differentiator, coupled to the generator, to determine a polarity of the change in the reference voltage between a first point in time and a second point in time;
- a direction selector, coupled to the differentiator, to select one of said first and second directions in response to said polarity;
- and
- a ramp generator, coupled to the selector and to the capacitor, to selectively vary the capacitance of said capacitor in said selected direction.
A method for dynamically improving the voltage response of a tank circuit comprising an inductor and a capacitor, the capacitance of which can be varied in a selected one of first and second directions, the method comprising the steps of:
- (1) selecting one of said first and second directions;
- (2) capturing a current response of the circuit to a received signal;
- (3) varying the capacitor in said selected direction;
- (4) comparing the captured response to the current response;
- (5) if the comparison made in step 4 indicates that the current response is weaker than the captured response, selecting the other of said directions;
- and
- (6) returning to step 2.
A tuning circuit for dynamically improving the voltage response of a tank circuit comprising an inductor and a capacitor, the capacitance of which can be varied in a selected one of first and second directions, the tuning circuit comprising:
- a reference voltage generator, coupled to the tank circuit, to produce a reference voltage proportional to the response of the tank circuit to a received signal;
- a differentiator, coupled to the generator, to determine a polarity of the change in the reference voltage between a first point in time and a second point in time;
- a direction selector, coupled to the differentiator, to select one of said first and second directions in response to said polarity;
- and
- a ramp generator, coupled to the selector and to the capacitor, to selectively vary the capacitance of said capacitor in said selected direction.
A method for dynamically varying the impedance of a tank circuit comprising an inductor and a capacitor, the capacitance of which can be varied in a selected one of first and second directions, the method comprising the steps of:
- (1) selecting one of said first and second directions;
- (2) capturing a current voltage response of the circuit to a received signal;
- (3) varying the capacitor in said selected direction;
- (4) comparing the captured voltage response to the current voltage response;
- (5) if the comparison made in step 4 indicates that the current voltage response is weaker than the captured voltage response, selecting the other of said directions;
- and
- (6) returning to step 2.
A tuning circuit for dynamically varying the impedance of a tank circuit comprising an inductor and a capacitor, the capacitance of which can be varied in a selected one of first and second directions, the tuning circuit comprising:
- a reference voltage generator, coupled to the tank circuit, to produce a reference voltage proportional to the voltage response of the tank circuit to a received signal;
- a differentiator, coupled to the generator, to determine a polarity of the change in the reference voltage between a first point in time and a second point in time;
- a direction selector, coupled to the differentiator, to select one of said first and second directions in response to said polarity;
- and
- a ramp generator, coupled to the selector and to the capacitor, to selectively vary the capacitance of said capacitor in said selected direction.
A method for dynamically improving the voltage response of a tank circuit comprising an inductor and a capacitor, the capacitance of which can be varied in a selected one of first and second directions, the method comprising the steps of:
- (1) selecting one of said first and second directions;
- (2) capturing a current voltage response of the circuit to a received signal;
- (3) varying the capacitor in said selected direction;
- (4) comparing the captured voltage response to the current voltage response;
- (5) if the comparison made in step 4 indicates that the current voltage response is weaker than the captured voltage response, selecting the other of said directions;
- and
- (6) returning to step 2.
A tuning circuit for dynamically improving the voltage response of a tank circuit comprising an inductor and a capacitor, the capacitance of which can be varied in a selected one of first and second directions, the tuning circuit comprising:
- a reference voltage generator, coupled to the tank circuit, to produce a reference voltage proportional to the voltage response of the tank circuit to a received signal;
- a differentiator, coupled to the generator, to determine a polarity of the change in the reference voltage between a first point in time and a second point in time;
- a direction selector, coupled to the differentiator, to select one of said first and second directions in response to said polarity;
- and
- a ramp generator, coupled to the selector and to the capacitor, to selectively vary the capacitance of said capacitor in said selected direction.
A method for dynamically varying the reactance of a tank circuit leaving a resistive load comprising an inductor and a capacitor, the capacitance of which can be varied in a selected one of first and second directions, the method comprising the steps of:
- (1) selecting one of said first and second directions;
- (2) capturing a current response of the circuit to a received signal;
- (3) varying the capacitor in said selected direction;
- (4) comparing the captured response to the current response;
- (5) if the comparison made in step 4 indicates that the current response is weaker than the captured response, selecting the other of said directions;
- and
- (6) returning to step 2.
A tuning circuit for dynamically varying the reactance of a tank circuit leaving a resistive load comprising an inductor and a capacitor, the capacitance of which can be varied in a selected one of first and second directions, the tuning circuit comprising:
- a reference voltage generator, coupled to the tank circuit, to produce a reference voltage proportional to the response of the tank circuit to a received signal;
- a differentiator, coupled to the generator, to determine a polarity of the change in the reference voltage between a first point in time and a second point in time;
- a direction selector, coupled to the differentiator, to select one of said first and second directions in response to said polarity;
- and
- a ramp generator, coupled to the selector and to the capacitor, to selectively vary the capacitance of said capacitor in said selected direction.
Dependencies are inferred from the claim text.