Abstract: An oscillator is provided. The oscillator is configured for generating an output signal which is phase locked to an input signal. The oscillator comprises a controlled oscillator configured for generating the output signal based on an oscillator input signal. Moreover, the oscillator comprises a frequency divider configured for dividing the frequency of the output signal, resulting in a frequency divided feedback signal. Also, the oscillator comprises a phase detector, which is configured for generating an error signal based upon the frequency divided feedback signal and the input signal. Also, the oscillator comprises an error signal pulse train modulator configured for generating the oscillator input signal by performing a pulse train modulation of the error signal) or a signal derived from the error signal based on the input signal.

Abstract: An oscillator is provided. The oscillator is configured for generating an output signal which is phase locked to an input signal. The oscillator comprises a controlled oscillator configured for generating the output signal based on an oscillator input signal. Moreover, the oscillator comprises a frequency divider configured for dividing the frequency of the output signal, resulting in a frequency divided feedback signal. Also, the oscillator comprises a phase detector, which is configured for generating an error signal based upon the frequency divided feedback signal and the input signal. Also, the oscillator comprises an error signal pulse train modulator configured for generating the oscillator input signal by performing a pulse train modulation of the error signal) or a signal derived from the error signal based on the input signal.

Abstract: A phase-locked loop having: an oscillator for forming an oscillating output signal; a frequency divider connected to receive the output of the oscillator and frequency divide it by a value dependent on a division control signal; and a phase comparator for comparing the phase of the divided signal and a reference signal to generate a control signal, the operation of the oscillator being dependent on the control signal; a first mode of operation in which the frequency divider is configured to operate in dependence on a first division control signal such that the resultant oscillating output signal has a first frequency and first phase, a second mode of operation in which the frequency divider is configured to operate in dependence on a second division control signal such that the resultant oscillating output signal has a second frequency and second phase, the first division control signal being generated independently of the oscillating output signal such that the first phase is maintained when the phase-locked

Abstract: A phase-locked loop having: an oscillator for forming an oscillating output signal; a frequency divider connected to receive the output of the oscillator and frequency divide it by a value dependent on a division control signal; and a phase comparator for comparing the phase of the divided signal and a reference signal to generate a control signal, the operation of the oscillator being dependent on the control signal; a first mode of operation in which the frequency divider is configured to operate in dependence on a first division control signal such that the resultant oscillating output signal has a first frequency and first phase, a second mode of operation in which the frequency divider is configured to operate in dependence on a second division control signal such that the resultant oscillating output signal has a second frequency and second phase, the first division control signal being generated independently of the oscillating output signal such that the first phase is maintained when the phase-locked

Abstract: A method of measuring a phase difference for use in a phase locked loop (PLL) that includes a binary phase detector (BPD), a time-to-digital converter (TDC) and a signal generator, the phase difference being that between a reference signal and a generated signal output from the signal generator. The method includes inputting the reference signal and the generated signal into the TDC; measuring the magnitude of the phase difference at the TDC; if the measured magnitude of the phase difference is less than a threshold value, operating the PLL according to a first operational mode in which the output of the BPD controls the signal generator; and if the measured magnitude of the phase difference is greater than the threshold value, operating the PLL according to a second operational mode in which the output of the TDC and the BPD controls the signal generator.

Abstract: A capacitive divider structure, comprising: a first plurality of capacitive devices, each being selectively controlled in accordance with a first input control signal so as to alter the effective capacitance of the capacitive divider structure by a first amount; a second plurality of capacitive devices coupled in parallel with the first plurality of capacitive devices, each being selectively controlled in accordance with a second input control signal so as to alter the effective capacitance of the capacitive divider structure by a second amount; and at least one series capacitive device arranged in series with the second plurality of capacitive devices, such that the second amount is less than the first amount.

Abstract: A phase-locked loop for generating an output signal including a signal generator arranged to generate an output, a comparison unit arranged to compare the output with a reference signal so as to provide a digital signal, and a loop filter arranged to generate a control signal for controlling the signal generator in dependence on the digital signal. The loop filter includes a proportional path having a digital filter arranged to generate a first component of the control signal for controlling the phase of the output generated by the signal generator, and an analogue integral path arranged to generate a second component of the control signal for controlling the frequency of the output generated by the signal generator.

Abstract: A phase-locked loop for generating an output signal including a signal generator arranged to generate an output, a comparison unit arranged to compare the output with a reference signal so as to provide a digital signal, and a loop filter arranged to generate a control signal for controlling the signal generator in dependence on the digital signal. The loop filter includes a proportional path having a digital filter arranged to generate a first component of the control signal for controlling the phase of the output generated by the signal generator, and an analogue integral path arranged to generate a second component of the control signal for controlling the frequency of the output generated by the signal generator.

Abstract: A method of measuring a phase difference for use in a phase locked loop (PLL) that includes a binary phase detector (BPD), a time-to-digital converter (TDC) and a signal generator, the phase difference being that between a reference signal and a generated signal output from the signal generator. The method includes inputting the reference signal and the generated signal into the TDC; measuring the magnitude of the phase difference at the TDC; if the measured magnitude of the phase difference is less than a threshold value, operating the PLL according to a first operational mode in which the output of the BPD controls the signal generator; and if the measured magnitude of the phase difference is greater than the threshold value, operating the PLL according to a second operational mode in which the output of the TDC and the BPD controls the signal generator.

Abstract: An apparatus for propagating local oscillator signals in a circuit, the apparatus comprising two pairs of lines carrying respectively differential in-phase and quadrature signals. The lines are arranged such that in at least one region along their length one of each pair of lines crosses the other of the pair to create a twist. The twist(s) in each respective pair of lines is offset from the twist(s) in the other pair of lines such that the portion of their length over which the in-phase lines magnetically couple to the quadrature lines with a positive coupling coefficient is substantially equal to the portion of their length over which the in-phase lines magnetically couple to the quadrature lines with a negative coupling coefficient.

Abstract: A phase-locked loop having: an oscillator for forming an oscillating output signal; a frequency divider connected to receive the output of the oscillator and frequency divide it by a value dependent on a division control signal; and a phase comparator for comparing the phase of the divided signal and a reference signal to generate a control signal, the operation of the oscillator being dependent on the control signal; the output data to form a divided signal a division ratio controller configured to, when clocked by an input signal, generate a series of output data for forming the division control signal; the phase-locked loop having: a first mode of operation in which the frequency divider is operable to frequency divide the output of the oscillator by a value dependent on the output of the division ratio controller; and a second mode of operation in which the frequency divider is not operable to frequency divide the output of the oscillator by a value dependent on the output of the division ratio controller

Abstract: A phase locked loop that includes a signal generator arranged to output a feedback signal, a first phase detector arranged to detect a phase difference between the feedback signal and a reference signal and to output a first phase detect signal in dependence on that detection, a second phase detector arranged to detect a phase difference between the feedback signal and a delayed version of the reference signal or between the reference signal and a delayed version of the feedback signal and to output a second phase detect signal in dependence on that detection, and an adjustor. The adjustor is arranged to determine which of the first and second phase detect signals commutes first and to alter the frequency of the feedback signal in dependence on the result of the determination.

Abstract: A phase-locked loop for generating an output signal that has a predetermined frequency relationship with a reference signal, the phase-locked loop comprising a signal generator arranged to generate the output signal, a charge pump arranged to generate current pulses for controlling the signal generator, two control units for controlling a duration of the current pulses generated by the charge pump and a selection unit arranged to select either the first control unit or the second control unit to control the charge pump, wherein a first one of the control units is arranged to continuously monitor a phase-difference between the reference signal and a feedback signal formed from the output signal and to, when selected by the selection unit, control the charge pump to output a current pulse having a duration that is dependent on that phase-difference and a second one of the control units is arranged to, when selected by the selection unit, control the charge pump to output a current pulse of predetermined duratio

Abstract: A phase-locked loop for generating an output signal that has a predetermined frequency relationship with a reference signal, the phase-locked loop comprising a signal generator arranged to generate the output signal, a charge pump arranged to generate current pulses for controlling the signal generator, two control units for controlling a duration of the current pulses generated by the charge pump and a selection unit arranged to select either the first control unit or the second control unit to control the charge pump, wherein a first one of the control units is arranged to continuously monitor a phase-difference between the reference signal and a feedback signal formed from the output signal and to, when selected by the selection unit, control the charge pump to output a current pulse having a duration that is dependent on that phase-difference and a second one of the control units is arranged to, when selected by the selection unit, control the charge pump to output a current pulse of predetermined duratio

Abstract: A current generator for a phase-locked loop arranged to generate an output signal having predetermined frequency-relationship with a reference signal, the phase-locked loop comprising a signal generator arranged to generate the output signal, a divider arranged to receive the output signal and divide the output signal to form a feedback signal, the divider being arranged to vary the divisor by which the output signal is divided, a comparison unit arranged to compare the feedback signal with the reference signal and output a first error signal indicative of the phase-difference between the feedback signal and the reference signal to the current generator and a loop filter arranged to filter a current signal output by the current generator to form a control signal for controlling the signal generator, the current generator being capable of receiving the first error signal and generating a current in dependence thereon, receiving a second error signal indicative of an error in the feedback signal caused by the v

Abstract: A phase-locked loop for generating an output signal that has a predetermined frequency relationship with a reference signal, the phase-locked loop comprising a signal generator arranged to generate the output signal, a charge pump arranged to generate current pulses for controlling the signal generator, two control units for controlling a duration of the current pulses generated by the charge pump and a selection unit arranged to select either the first control unit or the second control unit to control the charge pump, wherein a first one of the control units is arranged to continuously monitor a phase-difference between the reference signal and a feedback signal formed from the output signal and to, when selected by the selection unit, control the charge pump to output a current pulse having a duration that is dependent on that phase-difference and a second one of the control units is arranged to, when selected by the selection unit, control the charge pump to output a current pulse of predetermined duratio

Abstract: A loop filter for a phase-locked loop that generates an output signal having a predetermined phase relationship with a reference signal, the loop filter being arranged to control a signal generator that forms the output signal in dependence on a phase error between the output signal and the reference signal by outputting a control signal for controlling the signal generator in dependence thereon, the loop filter being arranged to form the control signal to comprise a proportional component representative of an instantaneous magnitude of the phase difference and an integral component representative of an integral of the phase difference, the loop filter comprising a proportional path arranged to receive a signal representative of the instantaneous magnitude of the phase difference and form the proportional component of the control signal in dependence thereon and an integral path arranged to receive a signal representative of the instantaneous magnitude of the phase difference and form the integral component o

Abstract: A loop filter for receiving an input signal indicative of a phase-difference between a reference signal and a signal output by a signal generator and forming a control signal for controlling the signal generator in dependence thereon, the loop filter comprising a plurality of filter components that determine the frequency response of the filter, said filter components being arranged so that a first set of said components determines one or more zeros of the filter's frequency response and a second set of said components determines one or more poles of the filter's frequency response, each of said first and second sets of filter components being independent of the other such that the zero(s) and pole(s) of the filter's frequency response may be selected independently.

Abstract: A charge pump circuit causes a current to flow either into or out of another circuit in dependence on a current output by first and second current paths, each including a current source and a current control device having two switched nodes, and a control node arranged to control a current flow between the first and second switched nodes. The charge pump further includes a capacitive element and a switching arrangement arranged such that, during a first time period, the capacitive element is in communication with a respective one of the current paths, whereby a current output by the first current path causes an electrical charge to be formed on a first capacitive plate and a current output by the second current path causes an electrical charge to be formed on a second capacitive plate, and during a second time period, the electrical charge formed on the first and second capacitive plates during the first time period is discharged to form a current at an output node.

Abstract: A phase-locked loop arranged to generate an output signal having a first frequency that is a static value times the frequency of a reference signal, the phase-locked loop comprising a signal generator arranged to generate the output signal, a divider arranged to receive the output signal and divide the output signal to form a feedback signal, the divider being arranged to vary the divisor by which the output signal is divided to cause the output signal to have a frequency that is said static value times the frequency of the reference signal, a comparison unit arranged to compare the feedback signal with the reference signal, one or more current generators arranged to output current pulses in dependence on said comparison, a summation unit arranged to receive the current pulses output by the current generator(s) and form a single current pulse therefrom and a loop filter arranged to filter the single current pulse to form a control signal for controlling the signal generator, the phase-locked loop being arrang