Voltage controlled oscillator comprising an injection pulling compensation circuit
AssigneeSTMicroelectronics S.r.l.
InventorPeter Nayler
Life of this patent
Estimating the term…
Abstract
The present invention relates to a method for stabilising the operation of a voltage controlled oscillator driven by a phase locked loop, the voltage controlled oscillator delivering an RF signal and receiving through at least one spurious path a harmonic component of a frequency equal or proximate to that of the RF signal, capable of disturbing its operation by injection pulling. According to the present invention, the method comprises a step of injecting into the voltage controlled oscillator an injection pulling compensation signal, the phase and the amplitude of which are adjusted so as to neutralise the effects of the spurious harmonic component. Application particularly to phase modulation IQ circuits in radiotelephony.
Claims47
An RF circuit comprising:
- a voltage controlled oscillator to deliver an RF signal;
- a phase locked loop to control the voltage controlled oscillator;
- a modulation circuit to receive the RF signal and to deliver a modulated signal having at least one harmonic component of a frequency equal or proximate to that of the RF signal delivered by the voltage controlled oscillator, the harmonic component being capable of disturbing operation of the voltage controlled oscillator by injection pulling;
- an injection pulling compensation circuit, having one input to receive at least the disturbing harmonic component and means for modifying a phase and an amplitude of the harmonic component to deliver an injection pulling compensation signal;
- and
- means for injecting the compensation signal into the voltage controlled oscillator.
A method for stabilizing operation of a voltage controlled oscillator that sends an RF signal and is driven by a phase locked loop, the method comprising:
- receiving through at least one spurious path a harmonic component of a frequency equal or proximate to that of the RF signal sent, said harmonic component being capable of disturbing the operation of the voltage controlled oscillator by injection pulling;
- and
- injecting, into a core of the voltage controlled oscillator, an injection pulling compensation signal, a frequency of which is within a bandwidth of the voltage controlled oscillator and a phase and an amplitude of which are adjustable so as to neutralize disturbing effects of the harmonic component.
A method for stabilizing operation of a voltage controlled oscillator that sends an RF signal and is driven by a phase locked loop, the method comprising:
- receiving through at least one spurious path a harmonic component of a frequency equal or proximate to that of the RF signal sent, said harmonic component being capable of disturbing the operation of the voltage controlled oscillator by injection pulling;
- and
- injecting, into the voltage controlled oscillator, an injection pulling compensation signal having a phase and an amplitude that are adjustable so as to neutralize disturbing effects of the harmonic component,
- wherein said injecting the compensation signal includes injecting said compensation signal having two components at two different points of the voltage controlled oscillator.
A method for stabilizing operation of a voltage controlled oscillator that sends an RF signal and is driven by a phase locked loop, the method comprising:
- receiving through at least one spurious path a harmonic component of a frequency equal or proximate to that of the RF signal sent, said harmonic component being capable of disturbing the operation of the voltage controlled oscillator by injection pulling;
- injecting, into the voltage controlled oscillator, an injection pulling compensation signal having a phase and an amplitude that are adjustable so as to neutralize disturbing effects of the harmonic component;
- and
- adjusting said phase of the compensation signal using a phase-shift circuit.
Dependencies are inferred from the claim text.