An apparatus includes a signal generator. The signal generator includes a voltage controlled oscillator (VCO) coupled to provide an output signal having a frequency. The signal generator further includes an asymmetric divider coupled to receive the output signal of the VCO and to provide an output signal. The output signal of the asymmetric divider has a frequency that is half the frequency of the output signal of the VCO. The asymmetric divider presents a balanced load to the VCO.

A multiplication injection locked oscillator (MIILO) circuitry includes a ring injection locked oscillator (ILO) circuitry that outputs clock signals, a first switching circuitry and a second switching circuitry. The ring ILO circuitry includes a first path having first delay stages, and a second path having a second delay stages. The first switching circuitry is connected to the first path and a voltage supply node. The first switching circuitry receives a first control signal and a second control signal and selectively connects the voltage supply node to the first path. The second switching circuitry is connected to the second path and a reference voltage node. The second switching circuitry receives the first control signal and the second control signal and selectively connects the reference voltage node to the second path.

A low-power voltage controlled oscillator is provided. The voltage controlled oscillator includes (2n+1) first circuit components (n is an integer of one or more). An output terminal of the first circuit component in a k-th stage (k is an integer of one or more and 2n or less) is connected to an input terminal of the first circuit component in a (k+1)-th stage. An output terminal of the first circuit component in a (2n+1)-th stage is connected to an input terminal of the first circuit component in a first stage. One of the first circuit components includes a second circuit component and a third circuit component whose input terminal is connected to an output terminal of the second circuit component. The third circuit component includes a first transistor and a second transistor whose source-drain resistance is controlled in accordance with a signal input to a gate through the first transistor.

A ring oscillator (200) comprises a feedback chain (110, 122) having a plurality of inverters (111-113). The ring oscillator (200) also comprises, for at least one of the inverters (111-113) of the chain (110, 122), a further inverter (211). Each of the at least one further inverter (211) is connected in parallel with the corresponding inverter (111-113) of the chain (110, 122) by means of a capacitor (250).

Clock generation circuitry includes quadrature locked loop circuitry having first injection locked oscillator circuitry, second injection locked oscillator circuitry, and XOR circuitry. The first injection locked oscillator circuitry receives a first input signal and a second input signal and outputs first clock signals. The first input signal and the second input signal correspond to a reference clock signal. The second injection locked oscillator circuitry is coupled to outputs of the first injection locked oscillator circuitry, and receives the first clock signals and generates second clock signals. The XOR circuitry receives the second clock signals and generates a first clock signal, a second clock signal, a third clock signal, and a fourth clock signal. The frequencies of the first clock signal, the second clock signal, the third clock signal, and the fourth clock signal are greater than the frequency of the reference clock signal.

The Direct Synthesis of a Receiver Clock (DSRC) contributes a method, system and apparatus for reliable and inexpensive synthesis of inherently stable local clock synchronized to a referencing signal received from an external source. Such local clock can be synchronized to a referencing frame or a data signal received from wireless or wired communication link and can be utilized for synchronizing local data transmitter or data receiver. Such DSRC can be particularly useful in OFDM systems such as LTE/WiMAX/WiFI or Powerline/ADSL/VDSL, since it can secure lower power consumption, better noise immunity and much more reliable and faster receiver tuning than those enabled by conventional solutions.

The present invention includes a voltage controlled oscillator circuit and a phase-locked loop device. The voltage controlled oscillator circuit comprises: a voltage-to-current conversion module, used for converting a control voltage of a voltage controlled oscillator into a control current as a linear function of the control voltage; and a current controlled oscillation module, used for outputting a low-amplitude oscillation signal based on the control current, so as to reduce power consumption. Further provided in the present invention is a phase-locked loop device comprising the voltage controlled oscillator circuit. According to the voltage controlled oscillator circuit, design parameters of low power consumption and high linearity may be achieved, thereby making a gain Kvco of the voltage controlled oscillator relatively stable, and it may be ensured that the voltage controlled oscillator and the phase-locked loop comprising the same have relatively excellent device performance.

Performance indicator circuitry is provided for characterizing performance of a phase locked loop (PLL) in a phase path of a polar modulator or polar transmitter that is used to generate a phase modulated RF signal. The PLL includes an oscillator, a high pass path, and a low pass path. The low pass path includes a loop filter. The performance indicator circuitry includes first input circuitry and parameter calculation circuitry. The first input circuitry is configured to input a loop filter signal from the loop filter. The parameter calculation circuitry is configured to compute a value for a performance indicator based on the loop filter signal and control or characterize an aspect of operation of the PLL based on the value.

A memory system in which a timing drift that would occur in distribution of a first timing signal for data transport in a memory device is determined by measuring the actual phase delays occurring in a second timing signal that has a frequency lower than that of the first timing signal and is distributed in one or more circuits mimicking the drift characteristics of at least a portion of distribution of the first timing signal. The actual phase delays are determined in the memory device and provided to a memory controller so that the phases of the timing signals used for data transport may be adjusted based on the determined timing drift.

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.