Provided are embodiments for monitoring clock drift. Embodiments may include an XOR gate that is configured to receive a first clock signal from a first clock source and a second clock signal from a second clock source, wherein the XOR logic gate is further configured to generate a switching output based on an XOR operation of the first clock signal and the second clock signal, and a rising edge detector and a falling edge detector that are configured to detect a rising edge and a falling edge of the switching output. Embodiments may also include an AND gate that is configured to threshold compare the rising edge to a configurable threshold to determine if a fault condition exists indicating clock drift between the first clock signal and the second clock signal and provide an indication of the fault condition based at least in part on the comparison.

A ring oscillator system for characterizing substrate strain including, a substrate including a through-substrate-via, at least two ring oscillators, wherein a first ring oscillator is closer to the through-substrate-via than a second ring oscillator, and a logic difference circuit that is configured to receive an input from at least the first ring oscillator and the second ring oscillator, and detect a difference between the signal frequency of the first ring oscillator and the signal frequency of the second ring oscillator.

A ring oscillator system for characterizing substrate strain including, a substrate including a through-substrate-via, at least two ring oscillators, wherein a first ring oscillator is closer to the through-substrate-via than a second ring oscillator, and a logic difference circuit that is configured to receive an input from at least the first ring oscillator and the second ring oscillator, and detect a difference between the signal frequency of the first ring oscillator and the signal frequency of the second ring oscillator.

A device for generating first clock signals includes first circuits, each including a ring oscillator delivering one of the first clock signals and being connected to a first node configured to receive a first current. A circuit selects one the first clock signals, and a phase-locked loop delivers a second signal which is a function of a difference between a frequency of the first selected clock signal and a set point frequency. Each first circuit supplies the first node with a compensation current determined by the second signal, when this first circuit delivers the selected clock signal and operates in controlled mode.

A device for generating first clock signals includes first circuits, each including a ring oscillator delivering one of the first clock signals and being connected to a first node configured to receive a first current. A circuit selects one the first clock signals, and a phase-locked loop delivers a second signal which is a function of a difference between a frequency of the first selected clock signal and a set point frequency. Each first circuit supplies the first node with a compensation current determined by the second signal, when this first circuit delivers the selected clock signal and operates in controlled mode.

A semiconductor device includes: a data sampler configured to receive a data signal having a first frequency and to sample the data signal with a clock signal having a second frequency, higher than the first frequency, to output data for a time corresponding to a unit interval of the data signal; an error sampler configured to sample the data signal with an error clock signal having the second frequency and a phase, different from a phase of the clock signal, to output a plurality of pieces of error data for the time corresponding to the unit interval; and an eye-opening monitor (EOM) circuit configured to compare the data with each of the plurality of pieces of error data to obtain an eye diagram of the data signal in the unit interval.

A semiconductor device includes: a data sampler configured to receive a data signal having a first frequency and to sample the data signal with a clock signal having a second frequency, higher than the first frequency, to output data for a time corresponding to a unit interval of the data signal; an error sampler configured to sample the data signal with an error clock signal having the second frequency and a phase, different from a phase of the clock signal, to output a plurality of pieces of error data for the time corresponding to the unit interval; and an eye-opening monitor (EOM) circuit configured to compare the data with each of the plurality of pieces of error data to obtain an eye diagram of the data signal in the unit interval.

Methods and systems are described for receiving N phases of a local clock signal and M phases of a reference signal, wherein M is an integer greater than or equal to 1 and N is an integer greater than or equal to 2, generating a plurality of partial phase error signals, each partial phase error signal formed at least in part by comparing (i) a respective phase of the M phases of the reference signal to (ii) a respective phase of the N phases of the local clock signal, and generating a composite phase error signal by summing the plurality of partial phase error signals, and responsively adjusting a fixed phase of a local oscillator using the composite phase error signal.

Methods and systems are described for receiving N phases of a local clock signal and M phases of a reference signal, wherein M is an integer greater than or equal to 1 and N is an integer greater than or equal to 2, generating a plurality of partial phase error signals, each partial phase error signal formed at least in part by comparing (i) a respective phase of the M phases of the reference signal to (ii) a respective phase of the N phases of the local clock signal, and generating a composite phase error signal by summing the plurality of partial phase error signals, and responsively adjusting a fixed phase of a local oscillator using the composite phase error signal.

Time folding power combining circuits convert a continuous wave into a pulsed wave of greater peak power. Such a circuit may comprise: a switch which receives a continuous wave signal as input, and outputs first and second pulsed wave signals along first and second signal paths, respectively, said switch being configured to repeatedly switch connection back and forth between the input and the outputs of the first and second signal paths in a plurality of time frames; a delay line in the second signal path configured to introduce a time delay to the second pulsed wave signal in the second signal path such that the first pulsed wave signal in the first signal path and the time-delayed second pulsed wave signal in the second signal path substantially align in the same time frames; and a combiner, which receives the first pulsed wave signal in the first signal path and the time-delayed pulsed second wave signal in the second signal path as inputs, and combines them into a single combined pulsed wave signal as output.