A first clock signal is generated from a reference clock signal. A first frequency associated with the first clock signal is less than a reference clock frequency associated with the reference clock signal. The first clock signal is propagated towards a first component of an integrated circuit through a clock tree. A second clock signal having a second frequency is generated from the first clock signal at a terminal point of the clock tree. The second clock signal is provided to the first component.

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.

Circuits, controllers, and techniques are provided for reducing non-linearities in a phase rotator. A circuit, according to one implementation, includes a single Phase-Locked Loop (PLL) circuit having a main path and a return path forming a feedback loop. The circuit also includes one or more phase rotators connected to an output of the single PLL circuit outside the feedback loop and one or more adaptable Look-Up Tables (LUTs) populated with operating code to be provided to the one or more phase rotators for defining operating characteristics of the one or more phase rotators. Furthermore, the circuit includes a control device configured to receive phase response characteristics from the one or more phase rotators. The control device is further configured to modify the operating code of the one or more adaptable LUTs based on the phase response characteristics to reduce non-linearities of the one or more phase rotators.

Clock circuits, components, systems and signal processing methods enabling digital communication are described. A phase locked loop device derives an output signal locked to a first reference clock signal in a feedback loop. A common phase detector is employed to obtain phase differences between a copy of the output signal and a second reference clock signal. The phase differences are employed in an integral phase control loop within the feedback loop to lock the phase locked loop device to the center frequency of the second reference signal. The phase differences are also employed in a proportional phase control loop within the feedback loop to reduce the effect of imperfect component operation. Cascading the integral and proportional phase control within the feedback loop enables an amount of phase error to be filtered out from the output signal.

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 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.

In one embodiment, a phase lock loop circuit includes a control circuit, wherein the control circuit is configured to input an estimation having a second frequency and a second phase. The second frequency is selected from a range of frequencies including a first frequency from an acquired signal. A numerically controlled oscillator is coupled to the control circuit, wherein the control circuit is configured to control an output response of the numerically controlled oscillator. The numerically controlled oscillator is configured to receive the estimation from the control circuit and generate an output signal in response to the estimation. A phase detector is coupled to the control circuit and the numerically controlled oscillator, wherein the phase detector is configured to compare the first signal and the output signal and produce a comparison output, the comparison output indicative of a phase difference between the first signal and the estimation.

A method of operation in a locked-loop circuit. The locked-loop circuit includes a loop filter and a digitally-controlled oscillator (DCO). The loop filter includes a first input to receive a digital word representing a difference between a reference clock frequency and a DCO output frequency. The loop filter includes internal storage. The method includes selecting a desired DCO output frequency that is generated in response to a calibration DCO codeword. A start value is retrieved from the loop filter internal storage. The start value corresponds to the calibration DCO codeword. The locked-loop circuit is then started with the retrieved start value.

A method of operation in a locked-loop circuit. The locked-loop circuit includes a loop filter and a digitally-controlled oscillator (DCO) coupled to the output of the loop filter. The loop filter includes a first input to receive a digital word representing a difference between a reference clock frequency and a DCO output frequency. The method includes determining a calibration DCO codeword representing a calibration operating point for the locked-loop circuit; determining a scaling factor based on the calibration operating point, the scaling factor based on a ratio of an actual DCO gain to a nominal DCO gain; and applying the scaling factor to operating parameters of the loop filter.

A method for implementing an efficient clock recovery for multilane high-speed Serializer/Deserializer (SerDes) system having M interleaved lanes, has a non-recursive architecture.