Abstract:
Implementations provide a phase locked loop (PLL) device that includes: a phase and frequency detector (PFD) and charge pump (CP) portion; a low pass filter; a voltage controlled oscillator (VCO) driven by the low pass filter to generate a VCO clock signal, multiple divider configured to receive the VCO clock signal and frequency divide the VCO clock signal in stages to generate a series statically divided VCO clock signals and a dynamically divided VCO clock signal; a feedback portion including a first component configured to receive the dynamically divided VCO clock signal and generate indicator signals; and a second component configured to multiplex from the indicator signals to generate the feedback clock signal set for the PFD and CP portion; and a master phase/frequency control engine configured to assert a division control over at least one divider and a multiplex control over the multiplex network.
Abstract:
Techniques and circuits are proposed to increase averaging in the clock recovery band based on an amount of channel overlap in receivers using excess bandwidth for clock recovery, to mitigate the impact of spectral energy leaking into an active channel of interest from an adjacent active channel and to improve the accuracy of the phase estimate of the received transmitted clock.
Abstract:
Certain aspects of the present disclosure provide methods and apparatus for implementing a fully differential charge pump circuit that eliminates a source of noise and power consumption by using a low-noise switched-capacitor common-mode feedback (CMFB) circuit, rather than a continuous-time amplifier-based CMFB circuit. The fully differential charge pump circuit presented in this disclosure includes the switched-capacitor CMFB (SC-CMFB) unit connected to differential output nodes of the charge pump and provides a feedback signal to the charge pump to control a common-mode voltage of the differential signals based on a reference common-mode voltage. In certain aspects, a replica phase-frequency detector (PFD), a frequency divider, and a non-overlapping clock generator provides control signals for the SCCMFB circuit.
Abstract:
A digital phased lock loop includes a digital controlled oscillator configured to produce an output signal at a frequency. A phase comparator compares the output signal, or a signal derived therefrom, with a reference signal to produce a phase error signal. A first loop filter produces a first control signal for the digital controlled oscillator from an output of the phase comparator. A frequency error measuring circuit coupled to the output of the phase comparator produces a frequency error signal. A second loop filter produces a second control signal for the digital controlled oscillator from an output of the frequency error measuring circuit. A circuit combines the first and second control signals and provides the combined control signals to the digital controlled oscillator.
Abstract:
An apparatus and method for operating a frequency synthesizer wherein a value of an first control signal associated with a fine frequency feedback loop connected to a signal generator is monitored, and a second control signal associated with a medium or coarse frequency feedback loop connected to the signal generator is adjusted based on the monitoring. The first and second control signals are then output to control the frequency synthesizer.
Abstract:
A Digital Calibration System for a Phase Locked Loop, wherein the PLL comprise a PLL controller used to output a tuning voltage in response to a phase difference between a reference signal and a feedback signal, a voltage controlled oscillator used to output the feedback signal in response to the tuning voltage; comprising: a Tuning V oltage Controller configured to set the tuning voltage to a value; a Phase Difference Quantizer configured to output a phase difference after comparing a phase of the reference signal with a phase of the feedback signal; a Digital Controller configured to receive the phase difference of the PDQ and control a coarse tuning signal such that an average phase difference of the PDQ is 0; and a Frequency Calibration Logic configured to calibrate the feedback signal in response to the output of the DC. As such, the calibration system can be calibrated fast.
Abstract:
Disclosed is a clock and data recovery circuit. The clock and data recovery circuit according to one embodiment of the present invention uses a hybrid phase detector which is composed of a linear phase detector and a binary phase detector. The clock and data recovery circuit has a phase detector gain irrespective of received data and jitters of recovered clocks by basically including the linear phase detector, a charge pump, a loop filter, a voltage-controlled oscillator, and a D flipflop to recover the clocks and the data, and simultaneously compensates phase offsets among the received data and the recovered clocks by finely adjusting the amount of up/down current of the charge pump using the binary phase detector and a charge pump controller.
Abstract:
A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator (33) configured to generate an output signal (F 0 ) having a frequency controlled by an input digital control word (DCW); a feedback loop (35-38) connected between an output and an input of the digital controlled oscillator, the feedback loop configured to provide the digital control word to the input of the digital controlled oscillator from an error derived from an input frequency control word (FCW) and the output signal; and a duty cycle module (32) connected to the digital controlled oscillator and the feedback loop, the duty cycle module configured to generate a plurality of control signals to periodically enable and disable the digital controlled oscillator for a set fraction of clock cycles of an input reference clock signal (RefClock).