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.

Disclosed is a Serializer/Deserializer physical layer circuit (SerDes PHY) for receiving and transmitting data in a half-duplex manner, the SerDes PHY including: a clock multiplication unit including a phase frequency detector (PFD), a charge pump (CP), a low pass filter, a voltage-controlled oscillator (VCO) and a loop divider; a sampling circuit sampling a received signal according to clocks from the VCO in a receive mode; a phase detector (PD) operating according to outputs of the sampling circuit; a multiplexer connecting the PD with the CP and disconnecting the PFD from the CP in the receive mode, and connecting the PFD with the CP and disconnecting the PD from the CP in a transmission mode; a parallel-to-serial converter converting parallel data into serial data according a clock from the VCO in the transmission mode; and a transmission driver outputting a transmission signal according to the serial data in the transmission mode.

A semiconductor device includes a delay code generation circuit configured to adjust a shifting code for delaying a first internal clock, by comparing phases of a second internal clock and a delayed clock, the delayed clock generated by delaying the first internal clock, and configured to generate a first delay code and a second delay code from the shifting code.

A phase-detecting method for testing an under-test circuit under control of a testing station includes the steps of receiving input and output signals of the under-test circuit, combining the input and output signals with each other and accordingly generating a frequency-doubled signal, comparing the frequency-doubled signal with a reference clock signal at a same clock rate and accordingly generating a difference signal, filtering the difference signal and accordingly generating a filtered signal, and determining whether the filtered signal is in an acceptable range and accordingly report a result to the testing station.

A method of making an atomic vapor source includes positioning a glass base of a vapor cell in a vacuum chamber, providing an alkaline-earth metal in the glass base, and positioning a linear motion feedthrough mechanism adjacent the vacuum chamber in line with the glass base. The method includes sealing and evacuating the vacuum chamber, and positioning, using a linear motion actuator of the linear motion feedthrough mechanism, a glass lid to contact the glass base of the vapor cell to form an optical contact bond therebetween.

A communication technique for converging internet of everything (IoT) technology with a 5.sup.th generation (5G) communication system for supporting a higher data transfer rate beyond a 4G system is provided. The communication technique can be applied to intelligent services, based on 5G communication technology and IoT-related technology. In an embodiment, an electronic device includes a first processor configured to output a first signal for generating a first frequency signal, a second processor configured to output a second signal for generating a second frequency signal, a first radio frequency (RF) chip configured to output the first frequency signal, based on the first signal received from the first processor and a baseband signal, and a second RF chip configured to output the second frequency signal, based on the second signal received from the second processor and the first frequency signal outputted from the first RF chip.

Clock signal control circuitry comprises a clock selector to output a current clock signal selected from two or more candidate clock signals and to execute a clock signal change operation to select a different one of the two or more candidate clock signals for output as the current clock signal; a counter to generate a count value by counting clock pulses of the current clock signal multiplied by a scaling value; and control logic to execute a scaling value change operation to change the scaling value in response to initiation of a clock signal change operation; in which the clock selector and the control logic are configured to cooperate to inhibit the output of the current clock signal during a scaling value change operation.

Detecting the health of a phase-lock loop (PLL) generating a feedback clock signal based on a reference clock signal, includes providing, by a delay line, the feedback clock signal to a plurality of latches clocked by the reference clock signal; providing, based on an output of the plurality of latches, an input to a plurality of sticky latches, the input indicating whether an edge of the feedback clock signal was detected; determining, based on a number of asserted sticky latches of the plurality of sticky latches, a phase error metric; comparing the phase error metric to a threshold; and outputting, based on the comparison, an indication of a lock state.

The subject technology provides for removing a source of delay in a phase-locked loop (PLL) by causing the output rising edge to occur at the same time as the input rising edge. The subject technology replicates the amount of delay experienced along an input reference signal path to the PLL as close as possible using a same circuit configuration and bias circuits as in the input reference signal path. For example, a timing alignment circuit containing a replica circuit adds compensation delay to a negative feedback loop signal to match the feedback loop delay with the reference path delay. The delay of the reference signal path is estimated and added into the replica circuit. The delay characteristics of these two paths negate one another such that the phases of the input reference signal and the feedback loop signal become phase-locked at the input to the PLL.

Oscillator calibration circuits and wireless transmitters including oscillator calibration circuits. An oscillator calibration circuit includes a first frequency locking circuit (FLC) coupled to a first oscillator, wherein the first FLC calibrates the frequency of the first oscillator using an over-the-air reference signal, wherein the first FLC calibrates the first oscillator prior to a data transmission session and remains free running during the data transmission session.