Aspects of the disclosure relate to a local oscillator frequency divider for a receiver or transmitter. In this regard a frequency divider has a first frequency input coupled to a first oscillator frequency output, a second frequency input coupled to a complementary second oscillator frequency output, a first in-phase/quadrature (I/Q) divided frequency output, and a complementary second I/Q divided frequency output. The frequency divider further has a first alternating current (AC) coupling capacitor between the first frequency input and the first oscillator frequency output and a second AC coupling capacitor between the second frequency input and the second oscillator frequency output.

A power regulator provides current to a processing unit. A clock distribution network provides a clock signal to the processing unit. A level-based droop detector monitors a voltage of the current provided to the processing unit and provides a droop detection signal to the clock distribution network in response to the voltage falling below a first threshold voltage. The clock distribution network decreases a frequency of a clock signal provided to the processing unit in response to receiving the droop detection signal. The level-based droop detector interrupts the droop detection signal that is provided to the clock distribution network in response to the voltage rising above a second threshold voltage. The clock distribution network increases the frequency of the clock signal provided to the processing unit in response to interruption of the droop detection signal.

An apparatus can implement a frequency doubler with duty cycle correction in conjunction with, for instance, a phase-locked loop (PLL) to decrease phase noise. In an example aspect, an apparatus has a frequency doubler including a signal combiner, a first signal pathway, and a second signal pathway. The frequency doubler also includes a doubler input node and a doubler output node. The signal combiner is coupled to the doubler output node. The first signal pathway is coupled between the doubler input node and the signal combiner and includes a first adjustable delay cell. The second signal pathway is also coupled between the doubler input node and the signal combiner and includes a second adjustable delay cell.

A DLL circuit that has a programmable output frequency is provided. The DLL circuit uses a single delay line to produce the multiple frequencies. In various embodiments, the delay line is configured to receive an input clock defining an input clock period. The delay line comprises delay stages, each configured to generate a corresponding output clock having a phase relative to the input clock based on a delay of the delay line. In those embodiments, a control circuit is configured to change the delay of the delay line so as to cause a phase difference between the input clock and a sensed output clock to be substantially equal to the input clock period. An edge combiner is configured to generate a DLL output clock based on the output clocks of the delay stages and presents an equal schematic load for each of the output clocks of the delay stages.

In an embodiment a circuit includes frequency multiplier circuitry having input nodes configured to receive an input signal and an anti-phase version thereof, the input signal having a first frequency value, wherein the frequency multiplier circuitry is configured to produce a current signal at a second frequency value that is an even multiple of the first frequency value and a transformer including a primary side and a secondary side, wherein the primary side comprises a primary inductance coupled to the frequency multiplier circuitry to receive the current signal therefrom, wherein the secondary side is configured to provide a frequency multiplied voltage signal, and wherein the frequency multiplier circuitry and the transformer are cascaded between at least one first node and a second node, the at least one first node and the second node couplable to a supply node and ground.

The present invention provides a fractional frequency divider, wherein the fractional frequency divider includes a plurality of registers, a counter, a control signal generator and a clock gating circuit. Regarding the plurality of registers, at least a portion of the registers are set to have values The counter is configured to sequentially generate a plurality of counter values, wherein the plurality of counter values correspond to the at least a portion of the registers, respectively, and the plurality of counter values are generated repeatedly The control signal generator is configured to generate a control signal based on the received counter value and the value of the corresponding register. The clock gating circuit is configured to refer to the control signal to mask or not mask an input clock signal to generate an output clock signal.

A communication circuit is disclosed. The communication circuit includes a clock input, and a clock divider configured to generate an output clock signal having a fundamental frequency which is substantially equal to a fundamental frequency of an input clock signal received at the clock input divided by a factor of (2N+1)/2N, where the clock divider is configured to generate 2N+1 pre-aligned phase shifted clock signals based at least in part on the input clock signal, generate 2N unique phase shifted clock signals based at least in part on the 2N+1 pre-aligned phase shifted clock signals, where the 2N unique phase shifted clock signals are substantially separated in phase by 360/2N degrees, and generate the output clock signal based at least in part on the 2N unique phase shifted clock signals, and a mixer, configured to receive the output clock signal.

An odd harmonic generation device is provided. The odd harmonic generation device includes an even harmonic generation unit and a mixer. In this context, the even harmonic generation unit is configured to generate two even harmonic signals on the basis of a fundamental signal. In addition to this, the mixer is configured to mix the fundamental signal with the two even harmonic signals to generate a desired odd harmonic signal.

The present application discloses an interface transformer. The interface transformer includes a first clock generator, a combinational circuit, and a second clock generator. The first clock generator generates an intermediate clock signal according to an input clock signal. A rising edge of the input clock signal precedes a rising edge of the intermediate clock signal, and a falling edge of the intermediate clock signal precedes a falling edge of the input clock signal. The combinational circuit generates a mask clock signal by delaying the intermediate clock signal. The second clock generator generates a transformed clock signal according to the input clock signal and the mask clock signal. The transformed clock signal has two pulses within a cycle of the input clock signal.

Methods and apparatuses control the clock rate of a processing unit. The methods and apparatus control the clock rate by generating an output clock rate based on the determined frequency adjustment such that the processing unit maintains the overclocking. The methods include: receiving an analog voltage supply in response to detecting overclocking in the processing unit; dynamically sensing measurements of an output voltage from a voltage generator based on the received analog voltage supply; determining characteristics of a voltage droop in the output voltage based on the dynamically sensed output voltage measurements; determining a frequency adjustment for the clock rate of the processing unit based on the determined characteristics of the voltage droop; and generating an output clock rate based on the determined frequency adjustment such that the processing unit maintains the overclocking.