A system and method for a frequency detector circuit includes: a transition detector configured to receive a data input and provide a first edge output based on transitions in the data input; a first circuit configured to generate a second edge output; a second circuit configured to generate a third edge output; and a combinational logic configured to output an UP output when at least two of the first edge output, the second edge output, and the third edge output are high and configured to output a DOWN output when the first edge output, the second edge output, and the third edge output are all low.

Enhancing the accuracy in compensating errors caused by a reference signal with unequal successive periods in a fractional-N phase locked loop (PLL). A compensation block generates a compensation factor, and is implemented based on a correction block and a filter. The correction block generates a correction signal containing a first frequency correction factor and a second frequency correction factor for a first period and a second period constituting each pair of successive periods, with the correction signal also containing a noise component at direct current (DC). The filter operates to remove the noise component at DC from the correction signal to generate a compensation factor containing the first frequency correction factor and the second frequency correction factor. The compensation factor thus generated may be provided as an input to a division factor generator of a frequency divider block of the PLL, potentially resulting in zero error frequency synthesis.

Apparatus and methods for clock synchronization and frequency translation are provided herein. Clock synchronization and frequency translation integrated circuits (ICs) generate one or more output clock signals having a controlled timing relationship with respect to one or more reference signals. The teachings herein provide a number of improvements to clock synchronization and frequency translation ICs, including, but not limited to, reduction of system clock error, reduced variation in clock propagation delay, lower latency monitoring of reference signals, precision timing distribution and recovery, extrapolation of timing events for enhanced phase-locked loop (PLL) update rate, fast PLL locking, improved reference signal phase shift detection, enhanced phase offset detection between reference signals, and/or alignment to phase information lost in decimation.

A division factor generator of a feedback divider block in a fractional-N phase locked loop (PLL). The division factor generator is enabled to operate with larger values of division factors without increased complexity of an internal modulator core implemented, for example, as a delta-sigma modulator (DSM) having a signal transfer function (STF), wherein the STF always generates only an integer value as an output in response to an integer value received as input.

An electronic device includes: a first input node configured to receive a dock signal; a second input node configured to receive an activation signal or a deactivation signal; a filter circuit responsive to: (a) the activation signal to activate the filter circuit to block the dock signal; or (b) the deactivation signal to deactivate the filter circuit to pass the dock signal; and an output node configured for coupling to a synchronous I/O interface of an integrated circuit to control operation of the synchronous I/O interface.

A frequency measurement circuit includes a counter circuit to receive a first digitally-controlled oscillator (DCO) clock signal corresponding to a first DCO input codeword and a measurement signal. The counter circuit is responsive to the measurement signal to generate a count representing a measured frequency of the first DCO clock signal. A control circuit is configured to selectively adjust a parameter of the measurement signal for generating a second count of a second DCO clock signal corresponding to a second DCO codeword. The control circuit selectively adjusts the parameter based on a received control signal.

A frequency counter circuit includes a first counter path to receive a digitally-controlled oscillator (DCO) clock signal and is configured to generate a first count corresponding to a first frequency of a first reduced clock signal corresponding to the DCO clock signal. A second counting path receives the DCO clock signal and generates a second count corresponding to a second frequency of a second reduced clock signal corresponding to the DCO clock signal. The first reduced clock signal is an integer multiple frequency of the second reduced clock signal. Detection circuitry detects a timing violation associated with the DCO clock signal based on a comparison between at least a portion of the first count and at least a portion of the second count.

An apparatus has a phase lock loop with an adaptive loop filter that has a reset circuit controlled by a power gating pulse circuit.

Disclosed herein are devices and methods to reduce unwanted CIM3 emission in a wireless communication device, such that the transmit (TX) power level applied in a RU can be increased without exceeding a regulatory emission requirement. In some aspects, unwanted emission may be reduced by shifting or changing local oscillator (LO) frequencies during TX operation. Some embodiments are directed to a fast-locking PLL with adjustable bandwidth that can be controlled to increase the PLL bandwidth during the RX to TX transition to provide a fast locking to a new LO frequency. Some aspects are directed to configuring an LO frequency shift amount for different RUs when multiple RUs are allocated within a frequency band.

A clock-and-data recovery circuit for serial receiver includes a jitter meter and an adaptive loop gain adjustment circuitry. The clock-recovery circuitry phase aligns a clock signal to the incoming data. A jitter meter provides a measure of jitter, while adaption circuitry uses the measure to adjust the clock-recovery circuity in a manner that reduces clock jitter. The jitter measure can be a ratio of errors associated with different inter-symbol slew rates.