# US 2014/0191812 A1 · Integrated circuit with calibrated pulling effect correction > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191812 A1 - Document ID: US20140191812A1 - Status: Published application - Kind: A1 - Application number: 13/802,395 - Filed: 2013-03-13 - Published: 2014-07-10 - Earliest claimed: 2013-01-09 - Assignees: Broadcom Corporation - Applicants: Broadcom Corporation - Inventors: Ahmad MIRZAEI; Hooman DARABI - Web page: https://patentgrep.com/patent/US20140191812A1 ## CPC - H03L 7/099: concerning mainly the controlled oscillator of the loop - H03L 7/06: using a reference signal applied to a frequency- or phase-locked loop - H03L 7/085: concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal (H03L7/10 takes precedence; circuits for comparing the phase or frequency of two mutually-independent oscillations H03D13/00) - H03L 7/101: {using an additional control signal to the controlled loop oscillator derived from a signal generated in the loop (H03L7/113, H03L7/187 take precedence)} - H03L 7/18: using a frequency divider or counter in the loop (H03L7/20, H03L7/22 take precedence) - H03L 2207/14: Preventing false-lock or pseudo-lock of the PLL - H04B 1/0475: {with means for limiting noise, interference or distortion (H04B1/0483 takes precedence)} - H04B 1/525: with means for reducing leakage of transmitter signal into the receiver - H04B 2001/0491: {with frequency synthesizers, frequency converters or modulators} - H03L: AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES (generation of oscillations H03B) - H04B: TRANSMISSION ## Abstract A frequency-control circuit includes a phase frequency detector configured to receive a reference frequency signal and generate an output detection signal. The phase frequency detector can be configured to detect a difference in phase and frequency between the reference frequency signal and a feedback of the output frequency signal. The frequency-control circuit also includes a current source applied to the output detection signal to form a correction voltage that is a function of a pulling signal having one or more unwanted frequency components. The frequency-control circuit also includes a loop filter configured to filter the output detection signal including the correction voltage and generate a control voltage signal. The frequency-control circuit also includes a voltage-controlled oscillator configured to receive the control voltage signal and generate an output frequency signal. ## Claims ### Claim 1 A frequency-control circuit for reducing interference from a pulling signal having one or more unwanted frequency components, the frequency-control circuit comprising: a phase frequency detector (PFD) configured to receive a reference frequency signal and generate an output detection signal; a current source coupled to an output of the PFD, the current source configured to receive a baseband signal that is a function of the pulling signal and output a current source signal; a loop filter coupled to an output of the current source and the output of the PFD, the loop filter configured to receive the output detection signal including the current source signal and generate a control voltage signal having a correction voltage that corrects for the one or more unwanted frequency components of the pulling signal; and a voltage-controlled oscillator (VCO) coupled to an output of the loop filter, the VCO configured to receive the control voltage signal with the correction voltage and generate an output frequency signal having a reduced number of the one or more unwanted frequency components of the pulling signal, wherein the PFD is further configured to detect a difference in phase and frequency between the reference frequency signal and a feedback of the output frequency signal. ### Claim 2 (depends on 1) The frequency-control circuit of claim 1, wherein the output current signal is combined with the output detection signal through the loop filter to form the correction voltage at an input of the VCO. ### Claim 3 (depends on 1) The frequency-control circuit of claim 1, further comprising: a processor configured to generate one or more components of the baseband signal based on a calibration of the output frequency signal, wherein the processor is further configured to compute one or more components of the baseband signal that correspond to the one or more unwanted frequency components; and a digital-to-analog converter configured to convert the baseband signal from the analog domain to the digital domain for output to the current source. ### Claim 4 (depends on 1) The frequency-control circuit of claim 1, wherein the correction voltage comprises phase and magnitude components associated with the one or more unwanted frequency components. ### Claim 5 (depends on 4) The frequency-control circuit of claim 4, wherein the pulling signal comprises second-order frequency components associated with a transmitted baseband signal. ### Claim 6 (depends on 5) The frequency-control circuit of claim 5, wherein the second-order frequency components of the transmitted baseband signal are greater than a magnitude threshold. ### Claim 7 (depends on 1) The frequency-control circuit of claim 1, wherein the pulling signal is generated by another frequency-control circuit. ### Claim 8 (depends on 1) The frequency-control circuit of claim 1, further comprising a frequency divider inserted in a feedback loop from the VCO to the PFD and configured to increase the feedback of the output frequency signal by N times the reference frequency signal, where N is a positive integer. ### Claim 9 (depends on 1) The frequency-control circuit of claim 1, further comprising a sigma-delta modulator inserted in a feedback loop from the VCO to the PFD and configured to increase the feedback of the output frequency signal by a fractional divide ratio of N/N+1 times the reference frequency signal, where N is a positive integer. ### Claim 10 (depends on 1) The frequency-control circuit of claim 1, further comprising: calibration circuitry coupled to an output of the VCO, wherein the calibration circuitry adjusts the VCO during a calibration state to vary the output frequency signal according to the correction voltage. ### Claim 11 An apparatus for reducing interference from a pulling signal having one or more unwanted frequency components, the apparatus comprising: means for receiving a reference frequency signal and generating an output detection signal; means for receiving a baseband signal that is a function of the pulling signal and outputting an output current signal; means for receiving the output detection signal including the output current signal and generating a control voltage signal having a correction voltage that corrects for the one or more unwanted frequency components of the pulling signal; and means for receiving the control voltage signal with the correction voltage and generating an output frequency signal having a reduced number of the one or more unwanted frequency components of the pulling signal. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein the means for receiving the reference frequency signal comprises means for detecting a difference in phase and frequency between the reference frequency signal and a feedback of the output frequency signal. ### Claim 13 (depends on 11) The apparatus of claim 11, further comprising: means for generating the baseband signal based on a calibration of the output frequency signal; and means for converting the baseband signal from the analog domain to the digital domain for output to the means for receiving the baseband signal. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein the means for generating the baseband signal comprises means for computing one or more components of the baseband signal that correspond to the one or more unwanted frequency components. ### Claim 15 (depends on 11) The apparatus of claim 11, wherein the correction voltage comprises phase and magnitude components associated with the one or more unwanted frequency components. ### Claim 16 (depends on 11) The apparatus of claim 11, wherein the pulling signal is generated by another frequency-control circuit operating at a center frequency that is proximate to a center frequency of the frequency-control circuit. ### Claim 17 (depends on 11) The apparatus of claim 11, further comprising a frequency divider inserted in a feedback loop from the VCO to the PFD and configured to increase the feedback of the output frequency signal by N times the reference frequency signal, where N is a positive integer. ### Claim 18 (depends on 11) The apparatus of claim 11, further comprising a sigma-delta modulator inserted in a feedback loop from the VCO to the PFD and configured to increase the feedback of the output frequency signal by a fractional divide ratio of N/N+1 times the reference frequency signal, where N is a positive integer. ### Claim 19 (depends on 11) The apparatus of claim 11, further comprising: means for calibrating the means for generating the output frequency signal. ### Claim 20 (depends on 19) The apparatus of claim 19, wherein the means for calibrating comprises means for adjusting the means for generating the output frequency signal during a calibration state to vary the output frequency signal according to the correction voltage.