Method for tuning feed-forward canceller
First Claim
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1. A method for tuning an electronic circuit to cancel a leaked transmitter signal under changeable impedance of a transmission medium, the method comprising:
- determining, by a control device, a setting of variable components in the electronic circuit to achieve a desirable cancelation level at an impedance of the transmission medium;
determining a value of a reflection coefficient of the transmission medium; and
changing the setting of the variable components in the electronic circuit, based on the determined value of the reflection coefficient, in proportion to a change between the determined value and an old value of the reflection coefficient, both in amplitude and phase, to maintain the desirable cancelation level, wherein the electronic circuit comprises two or more variable attenuators, two or more variable phase shifters, and a circuitry or circuit element to achieve a signal cancelation.
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Abstract
A method for maintaining good cancelation in a passive feed-forward cancelation circuit is disclosed. The feed-forward cancelation circuit may include at least one path which may comprise a phase-shifter and a variable attenuator. This method uses the complex value of the reflection coefficient at the point where the communication device is connected to a transmission medium, such as an antenna, to determine the values for the phase shifter(s) and the variable attenuator(s).
154 Citations
19 Claims
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1. A method for tuning an electronic circuit to cancel a leaked transmitter signal under changeable impedance of a transmission medium, the method comprising:
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determining, by a control device, a setting of variable components in the electronic circuit to achieve a desirable cancelation level at an impedance of the transmission medium; determining a value of a reflection coefficient of the transmission medium; and changing the setting of the variable components in the electronic circuit, based on the determined value of the reflection coefficient, in proportion to a change between the determined value and an old value of the reflection coefficient, both in amplitude and phase, to maintain the desirable cancelation level, wherein the electronic circuit comprises two or more variable attenuators, two or more variable phase shifters, and a circuitry or circuit element to achieve a signal cancelation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A feed-forward cancelation system, comprising:
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an input port corresponding to a transmitter; an output port corresponding to a receiver; a cancelation circuit coupled to the input port and the output port and configured to substantially cancel a leaked transmitter signal at the receiver; a discriminator that couples a transmission medium with changeable impedance to the receiver and the transmitter; and a control device coupled to the cancelation circuit and configured to; determine a setting of variable components in the cancelation circuit to achieve a desirable cancelation level of the transmitter signal at the receiver under an impedance of the transmission medium, determine a value of a reflection coefficient of the transmission medium, and change the setting of the variable components in the cancelation circuit, based on the determined value of the reflection coefficient, in proportion to a change between the determined value and an old value of the reflection coefficient, both in amplitude and phase, to maintain the desirable cancelation level. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification