US 7,612,617 B2Granted

Voltage-controlled oscillator gain calibration for two-point modulation in a phase-locked loop

AssigneeSkyworks Solutions, Inc.

InventorsRajasekhar Pullela, Morten Damgaard, Shahrzad Tadjpour, John E. Vasa, Hoon Lee

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Abstract

A phase-locked loop (PLL) is arranged to receive high-pass data at a first input and low-pass data at a second input. A first digital input is coupled to a primary path through a digital-to-analog converter (DAC) and a second digital input is coupled to a feedback path of the PLL. The controller provides the first input and the second input during a calibration procedure. The controller adjusts first and second control inputs in an attempt to keep the input voltage to a voltage-controlled oscillator (VCO) in the PLL constant while determining the gain of the VCO in Hz/LSB.

Claims20

Dependent claims

A method for measuring gain of a voltage-controlled oscillator (VCO), comprising:

applying a first control signal to a phase-locked loop (PLL);
allowing the PLL to settle;
recording a first voltage at the input to the VCO in the PLL;
applying a second control signal different from the first control signal to the PLL;
adjusting the feedback path to compensate for an expected change in the voltage at the input to the VCO;
recording a second voltage at the input to the VCO;
determining if time is available to compare the measured change in voltage with a threshold value, wherein when time is unavailable proceeding to calculate the gain of the VCO and terminating the method, otherwise when time is available;
determining whether a difference between the second voltage and the first voltage at the input to the VCO is within a specified tolerance;
when the difference between the second voltage and the first voltage is not within a specified tolerance, further adjusting the feedback path in response to the difference;
repeating the recording, determining and further adjusting steps until the difference between the second voltage and the first voltage at the input to the VCO is within the specified tolerance;
and
calculating the gain of the VCO.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/040,875Filed 1 Mar 2008
Published: US 2009/0219100 A13 Sep 2009
Granted: 3 Nov 2009
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

H03C 3/0925
With frequency divider or counter in the loop: applying frequency modulation at the divider in the feedback loop
H03C 3/0933
With frequency divider or counter in the loop: using fractional frequency division in the feedback loop of the phase locked loop
H03C 3/0941
Using a phase locked loop: applying frequency modulation at more than one point in the loop
H03C 3/095
Using a phase locked loop: applying frequency modulation to the loop in front of the voltage controlled oscillator

Family

US 2009/0219100 A1Pre-grant publication · published 3 Sep 2009
US 7,612,617 B2This patent

From the US filing history. Foreign family members aren’t listed.

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