Embodiments of an integrated circuit (IC) comprising circuitry to determine settings for an injection-locked oscillator (ILO) are described. In some embodiments, an injection signal is generated based on a first clock edge of a reference clock signal, and is injected into an ILO. Next, one or more output signals of the ILO are sampled based on a second clock edge of the reference clock signal, and settings for the ILO are determined based on the samples. In some embodiments, a sequence of two or more time-to-digital (TDC) codes is generated based on a reference clock signal and a free-running ILO. In some embodiments, the TDC circuitry that is already present in a delay-locked loop is reused for determining the sequence of two or more TDC codes. The ILO settings can then be determined based on the sequence of two or more

A random number generator includes a ring oscillator, an inversion selecting circuit, and controller. The ring oscillator includes an inverter chain having at least one inverter and generates an output signal. The inversion selecting circuit controlling a phase inverter configured to invert a signal of the inverter chain. The controller is configured to operate the inversion selecting circuit to provide an output of the first phase inverter to the inverter chain during a first operation mode to measure a frequency of the ring oscillator and operate the inversion selecting circuit to not provide the output of the phase inverter during a second operation mode for generating a random number.

A random number generator includes a ring oscillator, an inversion selecting circuit, and controller. The ring oscillator includes an inverter chain having at least one inverter and generates an output signal. The inversion selecting circuit controlling a phase inverter configured to invert a signal of the inverter chain. The controller is configured to operate the inversion selecting circuit to provide an output of the first phase inverter to the inverter chain during a first operation mode to measure a frequency of the ring oscillator and operate the inversion selecting circuit to not provide the output of the phase inverter during a second operation mode for generating a random number.

A tuning array selection circuit, together with a decoder and a voltage controlled oscillator (VCO), can be employed to overcome some disadvantages of previous methods of phase locked loops. For example, a VCO can include a coarse tuning array and a fine tuning array. A coarse tuning array can be used to tune a VCO to generate a signal within a wide frequency range. A fine tuning array can be used to tune a VCO to generate a signal within a narrow frequency range. In one embodiment, the narrow frequency range is within the wide frequency range. The tuning array selection circuit can coordinate selection of appropriate fine tuning devices and narrow tuning devices to reduce transition jitter and the risk of fail locking of phase locked loops.

A clock synthesizer is provided. The Clock synthesizer includes a Phase Locked Loop (PLL) configured to generate a clock signal based on a reference signal. A clock buffer is connected to the PLL. The clock buffer stores the clock signal. A Duty Cycle Controller and Phase Interpolator (DCCPI) circuit is connected to the clock buffer. The DCCPI circuit receives the clock signal from the clock buffer, adjusts a duty cycle of the clock signal to substantially equal to 50%, performs phase interpolation on the clock signal, and provides the clock signal as an output after adjusting the duty cycle substantially equal to 50% and performing the phase interpolation.

A clock synthesizer is provided. The Clock synthesizer includes a Phase Locked Loop (PLL) configured to generate a clock signal based on a reference signal. A clock buffer is connected to the PLL. The clock buffer stores the clock signal. A Duty Cycle Controller and Phase Interpolator (DCCPI) circuit is connected to the clock buffer. The DCCPI circuit receives the clock signal from the clock buffer, adjusts a duty cycle of the clock signal to substantially equal to 50%, performs phase interpolation on the clock signal, and provides the clock signal as an output after adjusting the duty cycle substantially equal to 50% and performing the phase interpolation.

Provided are a clock signal production circuit, a clock signal production method, and an electronic device, relating to the technical field of communications. In the clock signal production circuit, by digital circuits such as a control word generation circuit, an initial clock generation circuit, and a spread spectrum clock generation circuit, a frequency control word is first generated on the basis of spread spectrum parameters, an initial clock signal of a target duty cycle is then generated on the basis of the frequency control word, and spread spectrum processing is finally performed on the basis of the target duty cycle of the initial clock signal and the frequency control word to obtain a spread spectrum clock signal, i.e., the entire spread spectrum process is executed by the digital circuits. Therefore, it is not necessary to control the electronic device comprising the clock signal production circuit to stop working, i.e., the normal operation of the electronic device is not affected. Moreover, according to the clock signal production circuit, real-time adjustment of spread spectrum parameters (such as spread spectrum depth) that affect a spread spectrum result can be implemented, and the spread spectrum flexibility is relatively high.

Provided are a clock signal production circuit, a clock signal production method, and an electronic device, relating to the technical field of communications. In the clock signal production circuit, by digital circuits such as a control word generation circuit, an initial clock generation circuit, and a spread spectrum clock generation circuit, a frequency control word is first generated on the basis of spread spectrum parameters, an initial clock signal of a target duty cycle is then generated on the basis of the frequency control word, and spread spectrum processing is finally performed on the basis of the target duty cycle of the initial clock signal and the frequency control word to obtain a spread spectrum clock signal, i.e., the entire spread spectrum process is executed by the digital circuits. Therefore, it is not necessary to control the electronic device comprising the clock signal production circuit to stop working, i.e., the normal operation of the electronic device is not affected. Moreover, according to the clock signal production circuit, real-time adjustment of spread spectrum parameters (such as spread spectrum depth) that affect a spread spectrum result can be implemented, and the spread spectrum flexibility is relatively high.

Described herein are a method and apparatus for a selective SYSREF (SYStem REFerence signal) scheme that is driven by an external SYSREF source for a system that may include, for example, analog blocks, such as analog-to-digital converters (ADCs), digital-to-analog converters (DACs), radio frequency (RF) arrays, as well as digital blocks, which may include JESD serializer/deserializer (SERDES) Transport and Link Layer circuitry, all of which can be operating at different clock frequencies. In one aspect, synchronization of the components is achieved when an internal SYSREF for the analog blocks is keyed off the external SYSREF, but the internal SYSREF pulse used by the digital blocks is programmatically keyed off one of the periodic internal SYSREF pulses. Additionally, a mechanism is provided for synchronization of the programmatically selected internal SYSREF across different clock domains in the digital blocks.

Described herein are a method and apparatus for a selective SYSREF (SYStem REFerence signal) scheme that is driven by an external SYSREF source for a system that may include, for example, analog blocks, such as analog-to-digital converters (ADCs), digital-to-analog converters (DACs), radio frequency (RF) arrays, as well as digital blocks, which may include JESD serializer/deserializer (SERDES) Transport and Link Layer circuitry, all of which can be operating at different clock frequencies. In one aspect, synchronization of the components is achieved when an internal SYSREF for the analog blocks is keyed off the external SYSREF, but the internal SYSREF pulse used by the digital blocks is programmatically keyed off one of the periodic internal SYSREF pulses. Additionally, a mechanism is provided for synchronization of the programmatically selected internal SYSREF across different clock domains in the digital blocks.