A method and apparatus are disclosed for generating a quadrature signal that may be used to modulate and/or demodulate communication signals transmitted between communication devices. A quadrature signal generator may include a control block, a mixer, and a filter. The control block may generate a reference signal and a filter control signal based on an input clock signal. The mixer may generate a mixer output signal based on the input clock signal and the reference signal. The filter, controlled by the filter control signal, may filter the mixer output signal to suppress a band of frequencies within the mixer output signal.

A method and apparatus are disclosed for generating a quadrature signal that may be used to modulate and/or demodulate communication signals transmitted between communication devices. A quadrature signal generator may include a control block, a mixer, and a filter. The control block may generate a reference signal and a filter control signal based on an input clock signal. The mixer may generate a mixer output signal based on the input clock signal and the reference signal. The filter, controlled by the filter control signal, may filter the mixer output signal to suppress a band of frequencies within the mixer output signal.

A high-frequency oscillator comprises a reference-frequency generator and a high-frequency generator. The reference-frequency generator generates a variable reference frequency and supplies it to the high-frequency generator. The high-frequency generator comprises a phase-locked loop and generates a high-frequency signal from the variable reference frequency. The phase-locked loop comprises at least one first mixer, a second mixer and several switches. The first mixer, the second mixer and the switches are connected in series. The mixers are connected into the phase-locked loop individually in a selective manner by means of the switches.

A high-frequency oscillator comprises a reference-frequency generator and a high-frequency generator. The reference-frequency generator generates a variable reference frequency and supplies it to the high-frequency generator. The high-frequency generator comprises a phase-locked loop and generates a high-frequency signal from the variable reference frequency. The phase-locked loop comprises at least one first mixer, a second mixer and several switches. The first mixer, the second mixer and the switches are connected in series. The mixers are connected into the phase-locked loop individually in a selective manner by means of the switches.

An apparatus comprising a first electrical oscillator, a second electrical oscillator, at least one ferroelectric capacitor coupled between the first electrical oscillator and the second electrical oscillator, a ferroelectric capacitor of the at least one ferroelectric capacitor comprising a first terminal, a second terminal, and a ferroelectric material between the first terminal and the second terminal; and a detector coupled to the first electrical oscillator and second electrical oscillator, the detector to produce an output based on a state of the first electrical oscillator and the second electrical oscillator.

An apparatus comprising a first electrical oscillator, a second electrical oscillator, at least one ferroelectric capacitor coupled between the first electrical oscillator and the second electrical oscillator, a ferroelectric capacitor of the at least one ferroelectric capacitor comprising a first terminal, a second terminal, and a ferroelectric material between the first terminal and the second terminal; and a detector coupled to the first electrical oscillator and second electrical oscillator, the detector to produce an output based on a state of the first electrical oscillator and the second electrical oscillator.

A reservoir computer. In some embodiments, the reservoir computer includes a Duffing oscillator, and a readout circuit, and the readout circuit is configured to calculate a plurality of products, each of the products being calculated by multiplying a sample, of a plurality of samples of a signal from the Duffing oscillator, by a respective weight of a plurality of weights.