According to an aspect, a tri-level digital to analog converter (DAC) comprises a first set of switches turned on to cause a first analog value with a first error as an output for a first digital value, a second set of switches turned on to cause a second analog value with a second error as the output for a second digital value, wherein, both the first set of switches and the second set of switches are turned on to cause a third analog value, proportional to the first error and the second error, as the output for a digital value equal to zero, and both the first set of switches and the second set of switches are turned off to cause a fourth analog value equal to zero as the output for a fourth digital value representing a reset state.

A matching circuit comprising: an input-terminal configured to be connected to an active-circuit; an output-terminal configured to be connected to a downstream component; a current-source configured to provide a disabled-current; one or more diode-modules, each comprising a diode and a biasing-resistor in parallel with each other; and a reactive-matching-component that has a reactive impedance. The current source is configured to pass the disabled-current through the one or more diode-modules and the reactive-matching-component when the matching circuit is in a disabled-mode of operation such that they contribute to the impedance of the matching circuit between the input-terminal and the output-terminal.

A matching circuit comprising: an input-terminal configured to be connected to an active-circuit; an output-terminal configured to be connected to a downstream component; a current-source configured to provide a disabled-current; one or more diode-modules, each comprising a diode and a biasing-resistor in parallel with each other; and a reactive-matching-component that has a reactive impedance. The current source is configured to pass the disabled-current through the one or more diode-modules and the reactive-matching-component when the matching circuit is in a disabled-mode of operation such that they contribute to the impedance of the matching circuit between the input-terminal and the output-terminal.

An active digital electronic tuner (AET) uses a digital PIN diode electronic tuner, an adjustable directional coupler, two circulators and a power amplifier to create a compact load pull tuner device able of generating octave frequency band virtual reflection factors |Gamma|1 at milli-second tuning speed.

An active digital electronic tuner (AET) uses a digital PIN diode electronic tuner, an adjustable directional coupler, two circulators and a power amplifier to create a compact load pull tuner device able of generating octave frequency band virtual reflection factors |Gamma|1 at milli-second tuning speed.

An attenuator having an impedance that is controllable by a first setpoint signal is coupled to a transmission line. A matching circuit having an impedance that is controllable by a second setpoint signal is also coupled to the transmission line. A transformer circuit block also coupled to the transmission line has a complex impedance. A control circuit sets the first and second setpoint signals so as to control a conjugate impedance relationship between the variable impedances presented by the attenuator and matching circuit relative to the complex impedance of the transformer circuit.

An attenuator having an impedance that is controllable by a first setpoint signal is coupled to a transmission line. A matching circuit having an impedance that is controllable by a second setpoint signal is also coupled to the transmission line. A transformer circuit block also coupled to the transmission line has a complex impedance. A control circuit sets the first and second setpoint signals so as to control a conjugate impedance relationship between the variable impedances presented by the attenuator and matching circuit relative to the complex impedance of the transformer circuit.

An impedance matching device includes: a variable capacitor; a calculation unit that calculates a reflection coefficient on the load side; a storage unit that stores the reflection coefficient calculated within a predetermined period so as to be associated with ON/OFF states of the semiconductor switches; a determination unit that determines ON/OFF states to be taken by the semiconductor switches using a calculation result within the predetermined period; a control unit that turns on or off the semiconductor switches based on the determined ON/OFF states; and a counting unit that counts the number of times the determined ON/OFF states have changed. In a case where the counted number of times is larger than a predetermined number of times, the control unit turns on or off the semiconductor switches so as to match ON/OFF states associated with a reflection coefficient closer to 0, among the stored reflection coefficients, and then prohibits ON/OFF switching.

An impedance matching device includes: a variable capacitor; a calculation unit that calculates a reflection coefficient on the load side; a storage unit that stores the reflection coefficient calculated within a predetermined period so as to be associated with ON/OFF states of the semiconductor switches; a determination unit that determines ON/OFF states to be taken by the semiconductor switches using a calculation result within the predetermined period; a control unit that turns on or off the semiconductor switches based on the determined ON/OFF states; and a counting unit that counts the number of times the determined ON/OFF states have changed. In a case where the counted number of times is larger than a predetermined number of times, the control unit turns on or off the semiconductor switches so as to match ON/OFF states associated with a reflection coefficient closer to 0, among the stored reflection coefficients, and then prohibits ON/OFF switching.

An impedance matching device includes: a variable capacitor in which a plurality of series circuits of capacitors and semiconductor switches are connected in parallel; a calculation unit that calculates an impedance or a reflection coefficient on the load side using information regarding impedance acquired from the outside; and a control unit that determines ON/OFF states to be taken by the semiconductor switches included in the variable capacitor using the impedance or the reflection coefficient calculated by the calculation unit and turns on or off the semiconductor switches based on the determined states. The control unit changes an ON/OFF control timing between one and another of the semiconductor switches.