An apparatus includes a sampling circuit, a sense circuit, and a tuning circuit. The sampling circuit samples an input signal according to a sampling clock signal to produce a sampled signal. The sense circuit determines a scaling factor based on a distortion in the sampled signal caused by the sampling clock signal. The tuning circuit generates an offset signal based on the sampling clock signal and the scaling factor. The offset signal reduces the distortion in the sampled signal caused by the sampling clock signal.

A circuit and corresponding method control cycle time of an output clock used to clock at least one other circuit. The circuit comprises an agile ring oscillator (ARO) and ARO controller. The ARO includes at least one instance of a first ring oscillator (RO) and second RO that generate high and low phases, respectively, of cycles of the output clock. The ARO controller controls durations of the high and low phases, independently, via first and second control words output to the ARO, respectively. In a present cycle of the output clock, the ARO controller effects a change to the high or low phase, or a combination thereof, in a next cycle of the output clock by updating the first or second control word, or a combination thereof, based on an indication of expected usage of the at least one other circuit in the next cycle. The change improves a performance-to-power ratio of the at least one other circuit.

A circuit and corresponding method control cycle time of an output clock used to clock at least one other circuit. The circuit comprises an agile ring oscillator (ARO) and ARO controller. The ARO includes at least one instance of a first ring oscillator (RO) and second RO that generate high and low phases, respectively, of cycles of the output clock. The ARO controller controls durations of the high and low phases, independently, via first and second control words output to the ARO, respectively. In a present cycle of the output clock, the ARO controller effects a change to the high or low phase, or a combination thereof, in a next cycle of the output clock by updating the first or second control word, or a combination thereof, based on an indication of expected usage of the at least one other circuit in the next cycle. The change improves a performance-to-power ratio of the at least one other circuit.

A level shifter includes a pre-level shifter and a selector. The selector is coupled to the pre-level shifter. The pre-level shifter shifts an input digital voltage to a first digital voltage and a second digital voltage. The levels of the first digital voltage and the second digital voltage transition sequentially in time when the level of the input digital voltage transitions from one logic to the other. The selector selects and outputs the first digital voltage whose level transitions earlier in time compared to the transition of the level of the second digital voltage.

An electronic device comprises a first feedback circuit operatively connected to an amplitude detector and a first control input of an oscillator. The first feedback circuit is configured to control an amplitude of an output of the oscillator by continuously applying a first control signal to the first control input in response to an amplitude detected by the amplitude detector. The electronic device further comprises a second feedback circuit operatively connected to the amplitude detector and a second control input of the oscillator. The second feedback circuit is configured to modify one or more amplitude regulating parameters of the oscillator by providing a second control signal in response to the amplitude being beyond an upper or lower amplitude threshold, and refrain from modifying the one or more amplitude regulating parameters when the amplitude is within the upper and lower amplitude thresholds.

An electronic device comprises a first feedback circuit operatively connected to an amplitude detector and a first control input of an oscillator. The first feedback circuit is configured to control an amplitude of an output of the oscillator by continuously applying a first control signal to the first control input in response to an amplitude detected by the amplitude detector. The electronic device further comprises a second feedback circuit operatively connected to the amplitude detector and a second control input of the oscillator. The second feedback circuit is configured to modify one or more amplitude regulating parameters of the oscillator by providing a second control signal in response to the amplitude being beyond an upper or lower amplitude threshold, and refrain from modifying the one or more amplitude regulating parameters when the amplitude is within the upper and lower amplitude thresholds.

A bias-current-control circuit is provided. The bias-current-control circuit includes a transconductance circuit, a constant-current source, and a current-mirror circuit. The transconductance circuit is connected to a node and detects a voltage signal to generate a first current. The constant-current source is connected to the node and generates a tail current. The current-mirror circuit includes a reference current terminal and a bias current terminal, and the reference current terminal is coupled to the node. A second current which flows through the reference current terminal is determined by a current difference between the tail current and the first current. A bias current which flows through the bias current terminal is generated based on the second current. Furthermore, the second current and the bias current are in a predetermined ratio.

A crystal oscillator device is disclosed. The crystal oscillator device includes a casing; a crystal piece; a pair of excitation electrodes; a transmission antenna electrically coupled to one of the excitation electrodes; a reception antenna configured to receive a radio wave from the transmission antenna; and an alarm generator configured to generate an alarm based on a signal whose amplitude is equal to or less than a reference value, the signal being received by the reception antenna.

A crystal oscillator device is disclosed. The crystal oscillator device includes: a crystal oscillator including a casing, a crystal piece, a pair of excitation electrodes configured to excite a main vibration, and a pair of sub vibration electrodes configured to excite a sub-vibration; and an alarm generator configured to generate an alarm based on a signal whose amplitude is equal to or less than a reference value, the signal being generated in the sub vibration electrodes.

A crystal oscillator device is disclosed. The crystal oscillator device includes: a casing; a crystal piece provided in the casing; a pair of excitation electrodes provided on the crystal piece; a magnetic flux generating member provided on the crystal piece; a coil through which magnetic flux from the magnetic flux generating member passes; and an alarm generator configured to generate an alarm based on a signal whose amplitude is equal to or less than a reference value, the signal being generated in the coil.