A frequency generator is disclosed. The frequency generator is for generating an oscillator clock according to a reference clock, and the frequency generator is used in a frequency hopping system that switches a carrier frequency among a plurality of channels, and the carrier frequency further carries a modulation frequency for data transmission. The frequency generator includes: a frequency hopping and modulation control unit, arranged for generating a current channel according to a channel hopping sequence and a frequency command word (FCW) based on the reference clock, a digital-controlled oscillator (DCO), arranged for to generating the oscillator clock according to an oscillator tuning word (OTW) obtained according to the estimated DCO normalization value. An associated method is also disclosed.

A frequency generator for generating a controlled signal having a controlled frequency uses a frequency ratio generator with an input; a frequency divider for dividing the controlled frequency by a frequency ratio signal to generate a divided signal having a divided frequency; a converter for generating an excitation signal having the divided frequency, the excitation signal exciting a resonator for generating a resonance signal having a resonance frequency; a frequency phase detector of a phase difference between the divided frequency and the resonance frequency; an inner loop filter for generating the frequency ratio signal and filtering the phase difference signal to prevent instability of two frequency ratio generator loops; an output configured for providing the frequency ratio signal based on a ratio between the controlled frequency and the resonance frequency; a controlled oscillator circuit for connecting an oscillator generating an oscillating signal having an oscillator frequency; and a PLL (Phase Locked Loop) for generating the controlled signal based on the oscillator frequency, which is adapted based on comparison of the frequency ratio with a target ratio.

Determining the ratio between two frequencies can be a useful electronic building block in different electronic circuits with very divers functionalities. The invention comprises a circuit for determining a frequency ratio between a first input signal having a first frequency and a second input signal having a second frequency, wherein the circuit comprises: a controlled fractional frequency divider arranged for generating a divided signal having a divided frequency being substantially the first frequency divided by a control signal; a frequency phase detector arranged for generating a phase difference signal based on a frequency phase difference between the divided frequency of the divided signal and the second frequency of the second input signal; and a loop filter arranged for generating the control signal based on the phase difference signal; wherein a loop is formed by the controlled fractional frequency divider, the divided signal, the frequency phase detector, the phase difference signal, the loop filter and the control signal; wherein the loop filter filters the phase difference signal such that instability of the loop is prevented; and wherein the control signal, preferably the magnitude of the control signal, is indicative of the frequency ratio.

A clock oscillator includes a first resonator, a second resonator, and a frequency synthesis module, where an output frequency of the first resonator is higher than an output frequency of the second resonator, the frequency synthesis module is configured to generate a synthesis frequency based on the output frequency of the first resonator and the output frequency of the second resonator, and the synthesis frequency is used as a clock frequency output by the clock oscillator. The clock oscillator uses both of the two resonators with the different output frequencies as clock signal sources, and generates a synthesized clock signal by using the frequency synthesis module.

Embodiments of the present disclosure provide systems and methods for realizing phase synchronization updates based on an input system reference signal SYSREF without the need to synchronously distribute the SYSREF signal on a high-speed domain. In particular, phase synchronization mechanisms of the present disclosure are based on keeping a first phase accumulator in the device clock domain and using a second phase accumulator in the final digital clock domain to asynchronously transmit phase updates to the final digital clock domain. Arrival of a new SYSREF pulse may be detected based on the counter value of the first phase accumulator, which value is asynchronously transferred and scaled to the second phase accumulator downstream. In this manner, even though the SYSREF signal itself is not synchronously transferred to the second phase accumulator, the phase updates from the SYSREF signal may be transferred downstream so that the final phase may be generated deterministically.

A time-to-digital converter (TDC) circuit includes self-referenced delay cell circuits each including: a first inverter coupled with a second inverter, the first inverter receiving a positive time signal representative of an incoming up signal; a third inverter coupled with a fourth inverter, the third inverter receiving a negative time signal representative of an incoming down signal; a first bank of capacitors coupled to a first node between the first/second inverters; and a second bank of capacitors coupled to a second node between the third/fourth inverters. Control logic generates first control signals, each with an up value, to selectively control the first bank of capacitors. Control logic generates second control signals, each with a down value, to selectively control the second bank of capacitors. The up values vary relative to the down values across the first control signals and the second control signals.

A method for operating a clock product includes selectively coupling a first output divider and a second output divider based on a determination of whether the first divider value is integrally related to the second divider value. In response to the first divider value being integrally related to the second divider value, the selectively coupling includes cascading the first output divider with the second output divider. In in response to the first divider value being non-integrally related to the second divider value, the selectively coupling includes configuring the second output divider to be cascaded with a first phase-locked loop and in parallel with the first output divider and to be responsive to an error correction signal based on a difference in response times of the first output divider and the second output divider to a change in a filtered phase difference signal of the first phase-locked loop.

The present disclosure relates to a method for up-converting a clock signal, a clock circuit and a digital processing device. More specifically, provided is a method for up-converting a clock signal, comprising: employing a first clock sub-circuit to provide a clock signal having a first frequency to a chip; receiving an instruction to up-convert the clock signal having the first frequency to a clock signal having a second frequency; in response to receiving the instruction, causing a second clock sub-circuit to output the clock signal having the second frequency; and after the second clock sub-circuit outputs the clock signal having the second frequency, employing the second clock sub-circuit to provide the clock signal having the second frequency to the chip in place of the first clock sub-circuit.

A method, providing an oscillator output signal to reference inputs of a PLL and an output clock circuit; providing a first divisor value to a control input of the PLL to regulate a closed loop that includes a physics cell, a receiver, and the PLL; providing a second divisor value to a control input of the output clock circuit to control an output frequency of an output clock signal; shifting the first divisor value in a first direction to cause a perturbation in the closed loop; shifting the second divisor value in an opposite second direction to counteract a response of the closed loop to the perturbation and to regulate the output frequency of the output clock signal; and based on the receiver output signal, analyzing the response of the closed loop to the perturbation.

According to a clock generator, an oscillator outputs source oscillation clocks which are trimmed according to a trimming code. A first frequency divider generates X frequency division clocks by frequency-dividing the source oscillation clocks by a first frequency division ratio X. A trimming controller changes the trimming code within a period of the X frequency division clocks and supplies the changed trimming code to the oscillator.