There is provided an interpolation circuit of an optical encoder including a phase shifter circuit, two multiplexers, two digital circuits and four comparators. The phase shifter circuit receives signals sequentially have a 90 degrees phase shift and outputs multiple phase shifted signals. Each of the two multiplexers receives a half of the multiple phase shifted signals and outputs two pairs of phase shifted signals, each pair having 180 degrees phase difference, respectively to two comparators connected thereto. Each of the two digital circuits controls the corresponding multiplexer to select the two pairs of phase shifted signals from the half of the multiple phase shifted signals.

Apparatuses and methods for adjusting a phase mixer circuit are disclosed. An example apparatus includes a shift register that includes a plurality of registers coupled in series to one another. The plurality of registers are grouped into a first group of registers and a second group of registers. The first group of registers includes first and second registers. The second group of registers includes a third register. The first and second registers of the first group of registers are configured to receive in common an output of the third register of the second group of registers so that both the first and second registers store the output of the third register responsive to a shift clock.

An apparatus for generating a plurality of phase-shifted clock signals is provided. The apparatus comprises a first input node configured to receive a first reference clock signal. Further, the apparatus comprises a second input node configured to receive a second reference clock signal. The apparatus comprises a plurality of output nodes each configured to output one of the plurality of phase-shifted clock signals. Additionally, the apparatus comprises a cascade of coupled clock generation circuits configured to generate the plurality of phase-shifted clock signals based on the first reference clock signal and the second reference clock signal. Input nodes of the first clock generation circuit of the cascade of clock generation circuits are coupled to the first input node and the second input node. Output nodes of the last clock generation circuit of the cascade of clock generation circuits are coupled to the plurality of output nodes. At least one of the plurality of clock generation circuits is an active circuit, and at least one of the plurality of clock generation circuits is a passive circuit.

A multiphase signal generator includes an input port. Furthermore, the multiphase signal generator includes a plurality of phase shifters. Each phase shifter of the plurality of phase shifters is configured to provide an identical phase shift Δφ. At least one phase shifter is connected to the input port. Furthermore, the multiphase signal generator includes a first phase interpolator and at least a second phase interpolator. Each phase interpolator has a respective output terminal. Each phase interpolator is configured to weight a phase of a signal at a respective first input terminal of the phase interpolator with a respective first weighting factor w.sub.i,1 and to weight a phase of another signal at a respective second input terminal of the phase interpolator with a respective second weighting factor w.sub.i,2 to generate an interpolated phase signal at the respective output terminal of the phase interpolator. A first subset of the plurality of phase shifters includes n>1 serially connected phase shifters. The first subset of phase shifters is coupled between the first input terminal and the second input terminal of the first phase interpolator. A different second subset of the plurality of phase shifters includes n serially connected phase shifters. The second subset of phase shifters is coupled between the first input terminal and the second input terminal of the second phase interpolator.

Embodiments of a device and method are disclosed. In an embodiment, a Doherty amplifier module includes a first amplifier die with a first output terminal, a second amplifier die with a second output terminal, and a wideband impedance inverter circuit electrically coupled between the first and second output terminals. The wideband impedance inverter circuit includes a network of capacitors, the network of capacitors including at least a series capacitor having a positive capacitance, a first shunt circuit having a first negative capacitance, and a second shunt circuit having a second negative capacitance.

There is provided an interpolation circuit of an optical encoder including a phase shifter circuit, two multiplexers, two digital circuits and four comparators. The phase shifter circuit receives signals sequentially have a 90 degrees phase shift and outputs multiple phase shifted signals. Each of the two multiplexers receives a half of the multiple phase shifted signals and outputs two pairs of phase shifted signals, each pair having 180 degrees phase difference, respectively to two comparators connected thereto. Each of the two digital circuits controls the corresponding multiplexer to select the two pairs of phase shifted signals from the half of the multiple phase shifted signals.

A compensation signal generator generates a compensation signal for canceling an electromagnetic noise on a connection line on the basis of a detection signal of a noise detector. A compensation signal injector injects the compensation signal into the connection line. A compensation signal detector outputs a detection signal of the compensation signal. A low-frequency component subtraction unit amplifies a component in a predetermined first frequency region of the detection signal and negatively feeds back the amplified component to the compensation signal generator. An intermediate frequency component addition unit positively feeds back a component of a predetermined second frequency that is higher than the first frequency region in the detection signal to the compensation signal generator.

A phase rotator control circuit is provided. The phase rotator control circuit is coupled to a phase rotator core and includes a first set of transistors coupled to receive digital control signals. The first set of transistors is coupled to a second set of transistors configured and arranged to form a filtered current mirror. An output of the filtered current mirror is coupled to provide an analog phase control signal to the phase rotator core.

A phase mixing circuit for a multi-phase signal includes a jitter cancellation circuit configured to mix phases of a signal input to a first node and a signal input to a second node to produce signals at a third node and a fourth node; and a delay adjustment circuit configured to adjust delays of the signals output from the third node and the fourth node to produce signals at a fifth node and a sixth node.

Apparatuses and methods for adjusting a phase mixer circuit are disclosed. An example apparatus includes a shift register that includes a plurality of registers coupled in series to one another. The plurality of registers are grouped into a first group of registers and a second group of registers. The first group of registers includes first and second registers. The second group of registers includes a third register. The first and second registers of the first group of registers are configured to receive in common an output of the third register of the second group of registers so that both the first and second registers store the output of the third register responsive to a shift clock.