Described are apparatus and methods for high frequency clock generation. A circuit includes a phase frequency detector (PFD) which outputs differential error clocks based on comparison of differential reference clocks and differential feedback clocks, which are at a first frequency. A controlled oscillator (CO) connected to the PFD, which adjusts a frequency of the CO based on the differential error clocks to generate differential clocks at a second frequency, which is a multiple of the first frequency. A quadrature clock generator connected to the CO, which generates differential quadrature clocks at the second frequency from the differential clocks, where the differential feedback clocks are generated from the differential clocks and one pair of the differential quadrature clocks. A frequency doubler which doubles each pair of the differential quadrature clocks and outputs fully differential and balanced clocks at a third frequency for distribution, which is a multiple of the second frequency.

A pulse density modulation method includes the following steps: S01, obtaining a number of bits n of a binary density value d, setting a number of bits of a counter as n, an initial value of the counter is 0 or 1; S02, searching for a rightmost 1: obtaining a number of bits j of the rightmost 1 of a current value i of the counter counted from right to left; a number in the counter is a binary number; a minimum value of j is 1; S03, determining whether corresponding bits are equal; S04, adding the value i of the counter by 1, proceeding to a next period, and turning to the step S02.

One embodiment includes a clock distribution system. The system includes at least one resonator spine that propagates a clock signal and at least one resonator rib conductively coupled to the at least one resonator spine and being arranged as a standing wave resonator. At least one of the at least one resonator rib has a thickness that varies along a length of the respective one of the at least one resonator rib. The system also includes at least one transformer-coupling line. Each of the at least one transformer-coupling line can be conductively coupled to an associated circuit and being inductively coupled to the at least one resonator rib to inductively generate a clock current corresponding to the clock signal to provide functions for the associated circuit.

A pulse density modulation method includes the following steps: S01, obtaining a number of bits n of a binary density value d, setting a number of bits of a counter as n, an initial value of the counter is 0 or 1; S02, searching for a rightmost 1: obtaining a number of bits j of the rightmost 1 of a current value i of the counter counted from right to left; a number in the counter is a binary number; a minimum value of j is 1; S03, determining whether corresponding bits are equal; S04, adding the value i of the counter by 1, proceeding to a next period, and turning to the step S02.

A gated tri-state (G3S) inverter includes: first, second and third transistors of a first dopant type (D1 transistors) and first, second and third transistors of a second dopant type (D2 transistors) serially connected between a first reference voltage and second reference voltage, the second dopant type being different than the first dopant type; gate terminals of an alpha one of the noted D1 transistors and an alpha one of the noted D2 transistors being configured to receive an input signal; gate terminals of a beta one of the noted D1 transistors and a beta one of the noted D2 transistors being configured to receive a gating signal; a gate terminal of a gamma one of the noted D2 transistors being configured to receive an enable signal; and a gate terminal of a gamma one of the noted D1 transistors being configured to receive an enable_bar signal.

One embodiment includes a clock distribution system. The system includes at least one resonator spine that propagates a sinusoidal clock signal and at least one resonator rib conductively coupled to the at least one resonator spine and arranged as a standing wave resonator. The system further includes at least one coupling capacitor. Each of the at least one coupling capacitor can interconnect at least one of the at least one resonator rib and a respective circuit to capacitively provide a clock current corresponding to the sinusoidal clock signal to the respective circuit to provide functions for the respective circuit.

A duty cycle conversion circuit portion comprises N inverters, wherein N is an integer greater than two. The duty cycle conversion circuit is arranged to receive N input signals each having a duty cycle between 1/N and 2/N. Each of the N input signals is applied to a respective input terminal of one of the N inverters such that each inverter receives a different input signal. Each of the N input signals is applied to a respective power terminal of one of the N inverters such that each inverter is powered by a different input signal. Each inverter receives different input signal at its respective input terminal to the input signal applied to its respective power terminal.

Aspects of the disclosure include an apparatus that has a first clock generator and a second clock generator. The first clock generator is configured to drive a first circuit, causing the first circuit to (i) receive a signal corresponding to an audio input, and (ii) determine whether an energy level of the signal exceeds a predetermined threshold. The second clock generator is activated when the first circuit determines that the energy level of the signal exceeds the predetermined threshold. The second clock generator is configured to drive a second circuit, causing the second circuit to determine whether the signal matches a predetermined pattern. A third circuit is activated when the second circuit determines that the signal matches the predetermined pattern.

A circuit for providing a fractional divider/multiplier using harmonic recombination may include a power amplifier, an oscillator coupled to the power amplifier, and a divider coupled to the oscillator. In one or more implementations, the divider is configured to generate one or more phases of a harmonic from the oscillator to reduce signal interference from the power amplifier. In one or more implementations, the divider includes a divide-by-M divider, where M is a positive integer, and an array of transconductance cells coupled to the output of the divide-by-M divider. In one or more implementations, the divider includes an inductor or a filter coupled to the output of the array of transconductance cells. In one or more implementations, the oscillator includes a logical gate and a resistor-capacitor circuit coupled in series feedback with a multi-stage ring oscillator. The oscillator may include a divider coupled to the multi-stage ring oscillator.

Apparatuses and methods for providing multiphase clock signals are described. An example apparatus includes first, second, third and fourth clocked inverters, first and second clock terminals, and first and second latch circuits. An input node and an output node of the first clocked inverter is coupled respectively to an output node of the fourth clocked inverter and an input node of the second clocked inverter. An input node and an output node of the third clocked inverter is coupled to an output node of the second clocked inverter and an input node of the fourth clocked inverter. The first and second clock terminals are supplied respectively with first and second clock signals. The first latch is coupled between the output nodes of the first and third clocked inverters, and the second latch circuit is coupled between the output nodes of the second and fourth clocked inverters.