# US 2010/0167670 A1 · Detector with complementary response slope > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0167670 A1 - Document ID: US20100167670A1 - Status: Published application - Kind: A1 - Application number: 12/723,350 - Filed: 2010-03-12 - Published: 2010-07-01 - Earliest claimed: 2003-05-29 - Assignees: Analog Devices, Inc. - Inventors: Barrie Gilbert - Web page: https://patentgrep.com/patent/US20100167670A1 ## CPC - H03G 3/3047: {for intermittent signals, e.g. burst signals} - H03G: CONTROL OF AMPLIFICATION ## Abstract A measurement signal from a detector may have a complementary polarity. For example, an RF power detector may generate an output signal that decreases in magnitude in response to an increasing input signal. In one embodiment, the RF power detector may include a series of transconductance detector cells arranged to progressively turn off as the input signal becomes progressively larger. ## Claims ### Claim 1 A system comprising: a detector to generate a measurement signal responsive to an input signal; and a nulling circuit coupled to the detector to generate a control signal responsive to the difference between the measurement signal and a set-point signal; wherein the nulling circuit comprises a bandwidth compensation stage to maintain the overall control loop bandwidth at a substantially constant value. ### Claim 2 (depends on 1) A system according to claim 1 wherein the bandwidth compensation element corrects for nonlinearities in the AC domain. ### Claim 3 A system comprising: a detector to generate a measurement signal responsive to an input signal; and a nulling circuit coupled to the detector to generate a control signal responsive to the difference between the measurement signal and a set-point signal; wherein the nulling circuit has a bandwidth that can be varied responsive to a bandwidth compensation signal to maintain the overall control loop bandwidth at a substantially constant value. ### Claim 4 (depends on 3) A system according to claim 3 wherein the bandwidth varies exponentially responsive to the bandwidth compensation signal. ### Claim 5 A system comprising: a detector to generate a measurement signal responsive to an input signal; and a nulling circuit coupled to the detector to generate a control signal responsive to the difference between the measurement signal and a set-point signal; wherein the nulling circuit comprises a forward gain path having an error generator and an integrator; and wherein the forward gain path comprises a bandwidth compensation cell ahead of the integrator to maintain the overall control loop bandwidth at a substantially constant value. ### Claim 6 (depends on 5) A system according to claim 5 wherein the bandwidth compensation cell imparts an exponential correction to the control signal responsive to a bandwidth compensation signal. ### Claim 7 A system comprising: a detector to generate a measurement signal responsive to an input signal; and a nulling circuit coupled to the detector to generate a control signal responsive to the difference between the measurement signal and a set-point signal, wherein the nulling circuit comprises a forward gain path having an error generator and an integrator; wherein the forward gain path comprises a bandwidth compensation cell ahead of the integrator. ### Claim 8 A method comprising: generating a measurement signal responsive to an input signal; generating an error signal responsive to the difference between the measurement signal and a set-point signal; generating a control signal by integrating the error signal; and gain correcting the error signal prior to integrating the error signal. ### Claim 9 A method for controlling a system having a forward path including a detector, an error generator to receive a measured signal from the detector and a set-point signal, and an integrator, the method comprising varying the gain of the forward path prior to the integrator. ### Claim 10 A method for controlling a system having a forward path including a detector, an error generator to receive a measured signal from the detector and a set-point signal, and an integrator, the method comprising varying the bandwidth of the forward path. ### Claim 11 (depends on 1) A system according to claim 1 wherein the nulling circuit is constructed and arranged to hold the control signal responsive to a hold signal. ### Claim 12 (depends on 3) A system according to claim 3 wherein the nulling circuit is constructed and arranged to hold the control signal responsive to a hold signal. ### Claim 13 (depends on 5) A system according to claim 5 wherein the nulling circuit is constructed and arranged to hold the control signal responsive to a hold signal. ### Claim 14 (depends on 1) A system according to claim 1 wherein the nulling circuit comprises an error generator and an integrator. ### Claim 15 (depends on 14) A system according to claim 14 wherein the error generator and the bandwidth compensation stage comprise a variable gain amplifier having a first input coupled to receive the measurement signal, a second input coupled to receive the set-point signal, an output to provide an error signal in response to the measurement signal and the set-point signal, and an analog gain-control input to vary the gain of the amplifier in response to a gain control signal. ### Claim 16 (depends on 15) A system according to claim 15 wherein the integrator comprises a capacitor arranged to receive the error signal. ### Claim 17 (depends on 15) A system according to claim 15 wherein the gain-control input is coupled to the set-point signal. ### Claim 18 (depends on 15) A system according to claim 15 wherein the gain-control input is coupled to the control signal. ### Claim 19 (depends on 15) A system according to claim 15 wherein the gain-control input is coupled to receive an auxiliary signal. ### Claim 20 (depends on 15) A system according to claim 15 wherein the variable gain amplifier comprises an operational amplifier and an exponential signal generator.