A high performance, low complexity phase shift network may be created with one or more non-first-order all-pass recursive filters that are built on top of a plurality of first-order and/or second-order all-pass recursive filters and/or delay lines. A target time delay, whether large or small, may be specified as a constraint for a non-first-order all-pass recursive filter. A target phase response may be determined for the non-first-order all-pass recursive filter. Phase errors between the target phase response and a calculated phase response with filter coefficients of the non-first-order all-pass recursive filter may be minimized to yield a set of optimized values for the filter coefficients of the non-first-order all-pass recursive filter.

A high performance, low complexity phase shift network may be created with one or more non-first-order all-pass recursive filters that are built on top of a plurality of first-order and/or second-order all-pass recursive filters and/or delay lines. A target time delay, whether large or small, may be specified as a constraint for a non-first-order all-pass recursive filter. A target phase response may be determined for the non-first-order all-pass recursive filter. Phase errors between the target phase response and a calculated phase response with filter coefficients of the non-first-order all-pass recursive filter may be minimized to yield a set of optimized values for the filter coefficients of the non-first-order all-pass recursive filter.

An RF circuit and method for detecting the amount of phase shift applied to an RF signal. An RF heating apparatus including the RF circuit. The RF circuit includes a phase shifter operable to apply a phase shift to a reference signal to produce a phase shifted reference signal. The RF circuit also includes a phase detector operable to detect a phase difference between the phase shifted RF signal and the phase shifted reference signal. The phase detector has a reduced input range at a frequency of the phase shifted RF signal. The RF circuit further includes a controller operable to control the phase shifter to set the phase of the phase shifted reference signal so that the phase difference between the phase shifted RF signal and the phase shifted reference signal falls within the reduced input range of the phase detector.

An RF circuit and method for detecting the amount of phase shift applied to an RF signal. An RF heating apparatus including the RF circuit. The RF circuit includes a phase shifter operable to apply a phase shift to a reference signal to produce a phase shifted reference signal. The RF circuit also includes a phase detector operable to detect a phase difference between the phase shifted RF signal and the phase shifted reference signal. The phase detector has a reduced input range at a frequency of the phase shifted RF signal. The RF circuit further includes a controller operable to control the phase shifter to set the phase of the phase shifted reference signal so that the phase difference between the phase shifted RF signal and the phase shifted reference signal falls within the reduced input range of the phase detector.

A delay line is constructed by combining a phase generator and a fabric. The phase generator splits a digital input signal in multiple incrementally delayed versions, which are input to the fabric. The fabric has an array of node filters. Inputs of filters in the first array column are inputs of the fabric. A node filter has a delay element and a cross-coupling element, whose output signals are added or subtracted to form a filter output signal. A node filter in a row is concatenated to the previous filter in the row through its delay element. Inputs of cross-coupling elements are connected to other array rows. Outputs of node filters form the outputs of the fabric. Delay times of delay elements and cross-coupling elements are nominally equal. Drive strengths of cross-coupling elements may be lower than drive strengths of delay elements.

A phase shifter for altering the phase of a radio frequency signal is disclosed herein. A Lange coupler is used having reflective ports that are coupled to artificial transmission lines. The artificial transmission lines provide a reflection transmission path, the length of which can be determined by digital control lines. Transistors placed along the length of the central trace provide independent paths to ground that serve to shorten the electrical length of the ATL. Accordingly, by selectively turning the transistors on/off, the electrical length of the ATL can be selected and thus the amount of phase delay introduced by the phase shifter.

A phase shifter for altering the phase of a radio frequency signal is disclosed herein. A Lange coupler is used having reflective ports that are coupled to artificial transmission lines. The artificial transmission lines provide a reflection transmission path, the length of which can be determined by digital control lines. Transistors placed along the length of the central trace provide independent paths to ground that serve to shorten the electrical length of the ATL. Accordingly, by selectively turning the transistors on/off, the electrical length of the ATL can be selected and thus the amount of phase delay introduced by the phase shifter.

An alternating current signal transfer apparatus includes: a transmission line; a plurality of first phase shifters connected to the transmission line at a branching point; a plurality of resonator pairs including a power transmitting coil and a power receiving coil and each connected to each of the plurality of first phase shifters; and a plurality of second phase shifters each connected to each of the plurality of resonator pairs. The plurality of second phase shifters are connected at a connecting point.

An alternating current signal transfer apparatus includes: a transmission line; a plurality of first phase shifters connected to the transmission line at a branching point; a plurality of resonator pairs including a power transmitting coil and a power receiving coil and each connected to each of the plurality of first phase shifters; and a plurality of second phase shifters each connected to each of the plurality of resonator pairs. The plurality of second phase shifters are connected at a connecting point.

There is provided a phase shifter circuit of an optical encoder. The phase shifter circuit receives a first signal, a second signal, a third signal and a fourth signal sequentially having a 90-degree phase shift, and includes a first cascaded resistor string, a second cascaded resistor string, a third cascaded resistor string and a fourth cascaded resistor string. The first, second, third and fourth cascaded resistor strings respectively delay the first, third, second and fourth signals by selecting a switch connected at a tap-out node of the first, second, third and fourth cascaded resistor strings to correct phase deviations between incremental signals and an index signal and/or between incremental signals.