Tuning range enhancement by negative resistance
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorsUfuk Özdemir, Peter Caputa, Mustafa Özen, Ahmed Mahmoud
Life of this patent
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Abstract
A tank circuit (200) includes a tunable resonator subcircuit (210) having a first control input and having an effective parallel resistance that varies with tuning of the tunable resonator subcircuit (210). The tank circuit (200) further comprises a variable negative-resistance subcircuit (250) having a second control input and coupled in parallel to the tunable resonator subcircuit (210), where the variable negative-resistance subcircuit (250) is configured to provide a variable negative resistance, responsive to the control input, so as to increase the effective parallel resistance of the tank circuit (200).
Claims21
A tank circuit, comprising:
- a tunable resonator subcircuit having a first control input for tuning the resonant frequency of the tunable resonator subcircuit, the tunable resonator subcircuit having an effective parallel resistance that varies with tuning of the tunable resonator subcircuit;
- a variable negative-resistance subcircuit having a second control input and coupled in parallel to the tunable resonator subcircuit, wherein the variable negative-resistance subcircuit is configured to provide a variable negative resistance, responsive to the second control input, so as to increase the effective parallel resistance of the tank circuit;
- and
- a control circuit coupled to the first control input and the second control input, wherein the control circuit is configured to control the second control input so as to increase the negative resistance presented by the variable negative-resistance subcircuit in response to a change in the tunable resonator subcircuit that lowers the resonant frequency of the tunable resonator subcircuit.
A method for providing a variable resonance in a tank circuit comprising a tunable resonator subcircuit and a variable negative-resistance subcircuit coupled in parallel to the tunable resonator subcircuit, the method comprising:
- controlling the tunable resonator subcircuit to tune a resonant frequency of the tunable resonator subcircuit, via a control input of the tunable resonator subcircuit, the tunable resonator subcircuit having an effective parallel resistance that varies with tuning of the tunable resonator subcircuit;
- and
- controlling the variable negative-resistance subcircuit, via a control input of the variable negative-resistance subcircuit, wherein the variable negative-resistance subcircuit is configured to provide a variable negative resistance responsive to the control input of the negative-resistance subcircuit, so as to increase the effective parallel resistance of the tank circuit, and wherein controlling the variable negative-resistance subcircuit comprises controlling the variable negative-resistance subcircuit so as to increase the negative resistance presented by the switchable negative-resistance subcircuit in response to a change in the tunable resonator subcircuit that lowers the resonant frequency of the tunable resonator subcircuit.
A method of enhancing the tuning range of a transceiver that comprises an amplifier stage and a tank circuit, the tank circuit comprising a tunable resonator subcircuit and a variable negative-resistance subcircuit coupled in parallel to the tunable resonator subcircuit, wherein the method comprises:
- controlling the tunable resonator subcircuit of the tank circuit in the transceiver to tune a resonant frequency of the tunable resonator subcircuit, via a control input of the tunable resonator subcircuit, the tunable resonator subcircuit having an effective parallel resistance that varies with tuning of the tunable resonator subcircuit;
- and
- controlling the variable negative-resistance subcircuit, via a control input of the variable negative-resistance subcircuit, wherein the variable negative-resistance subcircuit is configured to provide a variable negative resistance responsive to the control input of the negative-resistance subcircuit, so as to increase the effective parallel resistance of the tank circuit in the transceiver, and wherein controlling the variable negative-resistance subcircuit comprises controlling the variable negative-resistance subcircuit so as to increase the negative resistance presented by the switchable negative-resistance subcircuit in response to a change in the tunable resonator subcircuit that lowers the resonant frequency of the tunable resonator subcircuit.
Dependencies are inferred from the claim text.