A method for startup of a crystal oscillator (XO) with aid of external clock injection, associated XO and a monitoring circuit therein are provided. The XO includes an XO core circuit, an external oscillator, and an injection switch, where a quality factor of the external oscillator is lower than a quality factor of the XO core circuit. The method includes: utilizing the external oscillator to generate an injected signal; turning on the injection switch to make energy of the injected signal be injected into the XO core circuit, where an amplitude modulation (AM) signal is generated according to combination of the injected signal and an intrinsic oscillation signal from the XO core circuit; and controlling the external oscillator to selectively change an injection frequency of the injected signal according to the AM signal. More particularly, the injection switch is not turned off until the startup process is completed.

Oscillators and methods for realignment of an oscillator are provided. An oscillator includes an inductor having first and second terminals and a capacitor electrically coupled in parallel to the inductor at the first and second terminals. A first transistor of a first conductivity type is electrically coupled to the first terminal and a voltage source. The first transistor includes a gate configured to receive a first realignment signal. When the first realignment signal is in a realignment state, the first transistor is turned on and a voltage of the first terminal is increased from a low level to a high level in order to align a phase of a waveform of the oscillator.

Disclosed is a radar. The radar comprises a transmitter configured to radiate an output signal to an outside. The transmitter includes the phase shifter including a first oscillator configured to generate a first signal, based on a first external signal and a second oscillator configured to generate a second signal, based on a second external signal having a phase different from that of the first external signal, and wherein the first oscillator further receives the second signal to generate the first signal and the second oscillator further receives the first signal to generate the second signal, and configured to generate an oscillation signal of which phase is shifted based on the first signal and the second signal, and the signal amplifier configured to amplify the phase-shifted oscillation signal to generate the output signal.

Systems and methods for integrating injection-locked oscillators into transceiver arrays are disclosed. In one aspect, there is provided an injection-locked oscillator (ILO) distribution system including a master clock generator configured to generate a master clock signal. The ILO distribution system also includes an ILO distribution circuit including an ILO and configured to receive the master clock signal. The ILO is configured to generate a reference clock signal based on the master clock signal. The ILO distribution circuit is further configured to generate an output signal indicative of an operating frequency of the ILO. The ILO distribution system further includes an injection-locked detector (ILD) configured to receive the master clock signal and the output signal. The ILD is further configured to determine whether the ILO is in a locked state or in an unlocked state based on the master clock signal and the output signal.

Systems and methods for integrating injection-locked oscillators into transceiver arrays are disclosed. In one aspect, there is provided an injection-locked oscillator (ILO) distribution system including a master clock generator configured to generate a master clock signal. The ILO distribution system also includes an ILO distribution circuit including an ILO and configured to receive the master clock signal. The ILO is configured to generate a reference clock signal based on the master clock signal. The ILO distribution circuit is further configured to generate an output signal indicative of an operating frequency of the ILO. The ILO distribution system further includes an injection-locked detector (ILD) configured to receive the master clock signal and the output signal. The ILD is further configured to determine whether the ILO is in a locked state or in an unlocked state based on the master clock signal and the output signal.

Networks of superharmonic injection-locked (SHIL) electronic oscillators can be used to emulate Ising machines for solving difficult computational problems. The oscillators can be simulated or implemented in hardware (e.g., with LC oscillators) and are coupled to each other with links whose connection strengths are weighted according to the problem being solved. The oscillators' phases may be measured with respect to reference signal(s) from one or more reference oscillators, each of which emits a reference signal but does not receive input from any other oscillator. Sparsely connected networks of SHIL oscillators and reference oscillators can be used as Viterbi decoders that do not suffer from the information bottleneck between logic computational blocks and memory in digital computing systems. Sparsely connected networks of SHIL oscillators and reference oscillators can also be programmed to act as Boolean logic gates that operate in both forward and backward directions, enabling multipliers that can factor numbers.

A quadrature voltage-controlled oscillator circuit with phase shift includes two voltage-controlled oscillators with the same structure, wherein the two voltage-controlled oscillators are connected to each other through input and output ports, and the two voltage-controlled oscillators respectively include a cross-coupled oscillating circuit, an injection locking circuit, a resonant circuit and a voltage-controlled current source circuit which are electrically connected to each other; and signals are injected through the injection locking circuit and coupled with the oscillating circuit, so as to output a quadrature signal. An oscillator is enabled to operate stably in one mode by means of a simple circuit structure, and a good phase shift can be provided for the resonant circuit in a lower frequency band; and meanwhile, a tuning range of the oscillator is improved without increasing phase noise.

An oscillator calibration circuit is presented. The oscillator calibration includes a first frequency locking circuit (FLC) coupled to a first oscillator, wherein the first FLC calibrates the frequency of the first oscillator using an over-the-air reference signal, wherein the first FLC calibrates the first oscillator prior to a data transmission session and remains free running during the data transmission session; and a second FLC coupled to a second oscillator, wherein the second FLC calibrates the frequency of the second oscillator using the over-the-air reference signal, wherein the second FLC calibrates the second oscillator immediately prior to a data transmission session and remains free running during the data transmission session.

The disclosure provides an apparatus including: a pair of signal injection transistors each having a gate terminal coupled to a differential reference signal, and a pair of cross-coupled amplifier transistors configured to amplify a voltage of the differential reference signal to yield a voltage-amplified reference signal at a local oscillator (LO) port of a mixer; an electronic oscillator having an oscillation output node coupled to the LO port of the mixer in parallel with the injection-locked buffer, and configured to generate an oscillator output for transmission to the output node based on a back gate bias voltage applied to the electronic oscillator; and an access transistor having a gate coupled to a switching node, and a back gate terminal coupled to the back gate bias voltage, wherein the access transistor is configured to enable or disable current flow through the electronic oscillator in parallel with the injection-locked buffer.

A method for startup of a crystal oscillator (XO) with aid of external clock injection, associated XO and a monitoring circuit therein are provided. The XO includes an XO core circuit, an external oscillator, and an injection switch, where a quality factor of the external oscillator is lower than a quality factor of the XO core circuit. The method includes: utilizing the external oscillator to generate an injected signal; turning on the injection switch to make energy of the injected signal be injected into the XO core circuit, where an amplitude modulation (AM) signal is generated according to combination of the injected signal and an intrinsic oscillation signal from the XO core circuit; and controlling the external oscillator to selectively change an injection frequency of the injected signal according to the AM signal. More particularly, the injection switch is not turned off until the startup process is completed.