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US 6,611,175 B2Granted
Frequency synthesizer and method of providing a mixing oscillator signal to a mixer
AssigneeInfineon Technologies AG
InventorRoland Heymann
Life of this patent
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Abstract
A frequency synthesizer for generating an oscillator signal with a desired frequency includes a first phase locked loop and a second phase locked loop, which is connected in a cascaded manner to the first phase locked loop, such that the second phase locked loop receives, as a reference frequency, a frequency generated by the first phase locked loop. The second phase locked loop outputs the desired oscillator signal at the output of a divider provided in the feedback path of the second phase locked loop. A method of supplying a mixing oscillator signal to a mixer is also provided.
Claims14
A frequency synthesizer for generating an oscillator signal of a desired frequency, comprising:
- a first phase locked loop for generating a signal with a given frequency from a reference frequency signal;
- a second phase locked loop connected in a cascaded manner to said first phase locked loop such that said second phase locked loop receives the given frequency of the signal generated by said first phase locked loop as a reference frequency;
- said first phase locked loop having a reference voltage source for generating the reference frequency signal, a reference frequency divider, a first phase detector, a first voltage-controlled oscillator and a first main frequency divider;
- said first phase detector comparing a frequency of the reference frequency signal with a frequency supplied by said first main frequency divider and, as a function thereof, driving said first voltage-controlled oscillator;
- said second phase locked loop having a second phase detector, a second voltage-controlled oscillator, a second main frequency divider, a further reference frequency divider, and an additional frequency divider;
- said second phase detector comparing a frequency, supplied by said first voltage-controlled oscillator of said first phase locked loop, with a frequency supplied by said second main frequency divider and, as a function thereof, driving said second voltage-controlled oscillator;
- said second main frequency divider of said second phase locked loop and said first main frequency divider of said first phase locked loop receiving a signal dependent on an output signal from said second voltage-controlled oscillator;
- said second phase detector of said second phase locked loop receiving, via said further reference frequency divider, the frequency supplied by said first further voltage-controlled oscillator;
- said second main frequency divider of said second phase locked loop and said first main frequency divider of said first phase locked loop receiving, via said additional frequency divider, the frequency supplied by said second voltage-controlled oscillator of said second phase locked loop;
- said additional frequency divider providing, as an output signal, the oscillator signal with the desired frequency;
- said first main frequency divider, said second main frequency divider, said reference frequency divider, said further reference frequency divider, and said additional frequency divider having respective divider ratios;
- and
- said first main frequency divider, said second main frequency divider, said reference frequency divider, said further reference frequency divider, said additional frequency divider and said reference voltage source being configured to select the divider ratios of said first main frequency divider, said second main frequency divider, said reference frequency divider, said further reference frequency divider, and said additional frequency divider, and a reference frequency of said reference voltage source to cause said second voltage-controlled oscillator of said second phase locked loop to receive a frequency corresponding to four times a value of the desired frequency of the oscillator signal, and to cause said additional frequency divider to have a divider ratio of 1:4.
10 more elements
A frequency synthesizer for generating an oscillator signal of a desired frequency, comprising:
- a first phase locked loop for generating a signal with a given frequency from a reference frequency signal;
- a second phase locked loop connected in a cascaded manner to said first phase locked loop to cause said second phase locked loop to receive the given frequency of the signal generated by said first phase locked loop as a reference frequency;
- said first phase locked loop having a reference voltage source for generating the reference frequency signal, a reference frequency divider, a first phase detector, a first voltage-controlled oscillator and a first main frequency divider;
- said first phase detector comparing a frequency of the reference frequency signal with a frequency supplied by said first main frequency divider and, as a function thereof, driving said first voltage-controlled oscillator;
- said second phase locked loop having a second phase detector, a second voltage-controlled oscillator, a second main frequency divider, a further reference frequency divider, and an additional frequency divider;
- said second phase detector comparing a frequency, supplied by said first voltage-controlled oscillator of said first phase locked loop, with a frequency supplied by said second main frequency divider and, as a function thereof, driving said second voltage-controlled oscillator;
- said second main frequency divider of said second phase locked loop and said first main frequency divider of said first phase locked loop receiving a signal dependent on an output signal from said second voltage-controlled oscillator;
- said second phase detector of said second phase locked loop receiving, via said further reference frequency divider, the frequency supplied by said first voltage-controlled oscillator;
- said second main frequency divider of said second phase locked loop and said first main frequency divider of said first phase locked loop receiving, via said additional frequency divider, the frequency supplied by said second voltage-controlled oscillator of said second phase locked loop;
- said additional frequency divider providing, as an output signal, the oscillator signal with the desired frequency;
- and
- said second phase locked loop having two second voltage-controlled oscillators with respectively different frequency ranges, said second phase locked loop being configured to switch between said two second voltage-controlled oscillators as a function of the desired frequency of the oscillator signal.
9 more elements
A method of providing a mixing oscillator signal to a mixer, the method which comprises:
- providing a mixing oscillator including a first phase locked loop for generating a signal with a given frequency from a reference frequency signal and including a second phase locked loop connected in a cascaded manner to the first phase locked loop such that the second phase locked loop receives the given frequency of the signal generated by the first phase locked loop as a reference frequency, the first phase locked loop having a reference voltage source for generating the reference frequency signal, a first phase detector, a first voltage-controlled oscillator and a first main frequency divider, the first phase detector comparing a frequency of the reference frequency signal with a frequency supplied by the first frequency divider and, as a function thereof, driving the first voltage-controlled oscillator, the second phase locked loop having a second phase detector, a second voltage-controlled oscillator, a second main frequency divider, a reference frequency divider, and an additional frequency divider, the second phase detector comparing a frequency, supplied by the first voltage-controlled oscillator of the first phase locked loop, with a frequency supplied by the second main frequency divider and, as a function thereof, driving the second voltage-controlled oscillator, the second main frequency divider of the second phase locked loop and the first main frequency divider of the first phase locked loop receiving a signal dependent on an output signal from the second voltage-controlled oscillator, the second phase detector of the second phase locked loop receiving, via the reference frequency divider, the frequency supplied by the first voltage-controlled oscillator, the second main frequency divider of the second phase locked loop and the first main frequency divider of the first phase locked loop receiving, via the additional frequency divider, the frequency supplied by the second voltage-controlled oscillator of the second phase locked loop, and the additional frequency divider providing, as an output signal, the mixing oscillator signal with a desired frequency;
- and
- providing the mixing oscillator signal with the desired frequency to the mixer.
Dependencies are inferred from the claim text.