A passive equalizer is provided. The passive equalizer includes a first resistive element, a first inductive element, a second resistive element, and a first variable capacitor. The first resistive element is coupled between an input node and an output node. The first inductive element and the second resistive element are coupled in series between the output node and a first voltage supply node. The first variable capacitor is coupled between the input node and a first node located between the first inductive element and the second resistive element.

Systems, devices, and methods for determining and establishing frequency-dependent gain compensation in wide bandwidth communication systems are disclosed. Variable frequency-dependent gain compensation circuits, or variable equalizers, have settings that configure them to establish discrete frequency-dependent gain compensation. The frequency-dependent gain compensation can include various types and levels of gain slope and/or ripple. The settings of the variable equalizers can be set by control signals established a control circuit in response to signals from an external computer. The variable equalizers are coupled to other circuits or devices and the frequency-dependent gain of the combined circuit are measured. The settings of the variable equalizer are then changed to establish an optimal frequency-dependent gain profile or frequency-dependent gain that is closest to a predetermined frequency-dependent target gain profile. The settings can then be saved in a memory or register.

An equalizer circuit includes: a pair of input terminals: a differential amplification circuit outputs, to a pair of output terminals, first signals obtained by amplifying a difference in levels of input signals supplied to the pair of input terminals; and a differential differentiation amplification circuit that outputs, to the pair of output terminals, second signals obtained by amplifying a time-varying change in the difference in the levels of the input signals supplied to the pair of input terminals.

Systems, devices, and methods for determining and establishing frequency-dependent gain compensation in wide bandwidth communication systems are disclosed. Variable frequency-dependent gain compensation circuits, or variable equalizers, have settings that configure them to establish discrete frequency-dependent gain compensation. The frequency-dependent gain compensation can include various types and levels of gain slope and/or ripple. The settings of the variable equalizers can be set by control signals established a control circuit in response to signals from an external computer. The variable equalizers are coupled to other circuits or devices and the frequency-dependent gain of the combined circuit are measured. The settings of the variable equalizer are then changed to establish an optimal frequency-dependent gain profile or frequency-dependent gain that is closest to a predetermined frequency-dependent target gain profile. The settings can then be saved in a memory or register.

In accordance with an embodiment, a device includes a directional coupler having an input port, a transmitted port, a coupled port and an isolated port. The device also includes a first passive equalizer having a first terminal coupled to a first one of a coupled port and an isolated port of the directional coupler. The first passive equalizer includes a resonator having a first inductor and a first capacitor, the resonator coupled between the first terminal and a second terminal of the first passive equalizer. The first passive equalizer also includes a first resistor and a second resistor serially connected between the first and the second terminals of the first passive equalizer, the first resistor connected to the second resistor at a first node. The first equalizer further includes a shunt network coupled between a reference terminal and the first node.

An inspection apparatus for use in wellbores in the oil and gas industries relates in general to the field of transmission of data between downhole module in a wellbore and a controlling module at the surface. The invention provides a method and apparatus for determining analogue filter parameters for an analogue front end comprising a plurality of filter stages receiving signals from a telemetry module, by repeating the steps of; receiving a signal of a known frequency and processing said signal by determining the magnitude of the frequency of the received signal until a plurality of signals have been received and processed; calculating an optimum set of filter parameters in dependence upon the measured frequency magnitudes and a predefined set of filter stage frequency responses.

Systems and methods for improving data communication over less than perfect power lines or transmission lines are described. The systems and methods allow for pushing out electrically any null within a frequency range of interest and/or for lossless transmission by providing impedance matching between communication devices and the transmission line. This is achieved by implementing line equalizing modules within the transceivers, at the transmitter side and/or the receiver side, or by plugging, as a stand-alone module, into an electrical outlet within a building. The line equalizing module includes multiple inductor-capacitor cells coupled in cascade where multiple switches allow for selective and concurrent connection between the inductor-capacitor cells. In another embodiment, the line equalizing module includes variable inductor-capacitor cells. The line equalizing module provides a variable propagation delay that allows for stretching electrically the transmission line. Further improvement may achieve by adjusting the operational frequency using an up-conversion or down-conversion operation.

Systems and methods for improving data communication over less than perfect power lines or transmission lines are described. The systems and methods allow for pushing out electrically any null within a frequency range of interest and/or for lossless transmission by providing impedance matching between communication devices and the transmission line. This is achieved by implementing line equalizing modules within the transceivers, at the transmitter side and/or the receiver side, or by plugging, as a stand-alone module, into an electrical outlet within a building. The line equalizing module includes multiple inductor-capacitor cells coupled in cascade where multiple switches allow for selective and concurrent connection between the inductor-capacitor cells. In another embodiment, the line equalizing module includes variable inductor-capacitor cells. The line equalizing module provides a variable propagation delay that allows for stretching electrically the transmission line. Further improvement may achieve by adjusting the operational frequency using an up-conversion or down-conversion operation.

In accordance with an embodiment, a device includes a directional coupler having an input port, a transmitted port, a coupled port and an isolated port. The device also includes a first passive equalizer having a first terminal coupled to a first one of a coupled port and an isolated port of the directional coupler. The first passive equalizer includes a resonator having a first inductor and a first capacitor, the resonator coupled between the first terminal and a second terminal of the first passive equalizer. The first passive equalizer also includes a first resistor and a second resistor serially connected between the first and the second terminals of the first passive equalizer, the first resistor connected to the second resistor at a first node. The first equalizer further includes a shunt network coupled between a reference terminal and the first node.

An integrated circuit equalizes a data signal expressed as a series of symbols. The symbols form data patterns with different frequency components. By considering these patterns, the integrated circuit can experiment with equalization settings specific to a subset of the frequency components, thereby finding an equalization control setting that optimizes equalization. Optimization can be accomplished by setting the equalizer to maximize symbol amplitude.