# US 2017/0285172 A1 · Method and apparatus for second order intercept point (ip2) calibration > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0285172 A1 - Document ID: US20170285172A1 - Status: Published application - Kind: A1 - Application number: 15/207,995 - Filed: 2016-07-12 - Published: 2017-10-05 - Earliest claimed: 2016-03-31 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Daniel BABITCH; Andrea Y. CHEN; Chung LAU; Bhaskar NALLAPUREDDY - Web page: https://patentgrep.com/patent/US20170285172A1 ## CPC - G01S 19/235: {Calibration of receiver components} - G01S 19/21: Interference related issues {; Issues related to cross-correlation, spoofing or other methods of denial of service} - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract A method and apparatus is provided. The apparatus a processor configured to generate a first square wave, generate a second square wave, wherein the first square wave and the second square wave are driven by a reference frequency oscillator, modulate a radio frequency wave with the first square wave, downconvert the modulated radio frequency wave to an intermediate frequency, filter the downconverted modulated radio frequency wave, convert the filtered downconverted modulated radio frequency wave to a digital signal, and integrate the digital signal. ## Claims ### Claim 1 An electronic device comprising: a processor configured to: generate a first square wave; generate a second square wave, wherein the first square wave and the second square wave are driven by a reference frequency oscillator; modulate a radio frequency wave with the first square wave; downconvert the modulated radio frequency wave to an intermediate frequency; filter the downconverted modulated radio frequency wave; convert the filtered downconverted modulated radio frequency wave to a digital signal; and integrate the digital signal. ### Claim 2 (depends on 1) The electronic device of claim 1, wherein downconverting the modulated radio frequency wave comprises providing a DC bias voltage from a digital to analog converter (DAC) to a mixer. ### Claim 3 (depends on 2) The electronic device of claim 2, further comprising determining DAC codes for a first DAC providing a first DC bias voltage to a first mixer and a second DAC providing a second bias voltage to a second mixer, wherein the determined DAC codes minimize the imbalances in the first mixer and the second mixer. ### Claim 4 (depends on 3) The electronic device of claim 3, wherein determining the DAC codes for the first DAC and the second DAC which minimizes the imbalances in the first mixer and the second mixer comprises performing a global search. ### Claim 5 (depends on 3) The electronic device of claim 3, wherein determining the first and second DAC codes comprises: setting the first and second DAC codes to zero, measuring and storing the mixer imbalance value; incrementing the first and second DAC codes by an integer value of at least one; repeating the setting, measuring and storing until the maximum DAC code is reached; determining a DAC code range that results in a minimized mixer imbalance; repeating the setting, measuring and storing within the determined DAC code range using an increment of one; and determining the first and second DAC codes associated with the minimum mixer imbalance value. ### Claim 6 (depends on 3) The electronic device of claim 3, wherein the electronic device is a global navigation satellite system (GNSS) receiver and the GNSS receiver is calibrated using the determined DAC codes. ### Claim 7 (depends on 6) The electronic device of claim 6, further comprising a temperature measuring device, wherein the calibration method of the GNSS receiver is executed when a temperature of the GNSS receiver changes more than a predefined threshold. ### Claim 8 (depends on 6) The electronic device of claim 6, wherein the frequency of the radio frequency wave is outside the band of the GNSS receiver radio frequency input signal. ### Claim 9 (depends on 1) The device of claim 1, wherein driving the first square wave and the second square wave by the reference frequency oscillator decreases a pin count on at least one of a baseband integrated circuit (BBIC) and a radio frequency integrated circuit (RFIC). ### Claim 10 (depends on 1) The electronic device of claim 1, wherein the first square wave and the second square wave are out of phase with one another. ### Claim 11 A method comprising: generating a first square wave by a reference frequency oscillator; amplitude modulating a radio frequency wave with the first square wave; downconverting the modulated radio frequency wave to an intermediate frequency; filtering the downconverted modulated radio frequency wave; converting the filtered downconverted modulated radio frequency wave to a digital signal; and integrating the digital signal. ### Claim 12 (depends on 11) The method of claim 11, wherein downconverting the modulated radio frequency wave comprises providing a DC bias voltage from a digital to analog converter (DAC) to a mixer. ### Claim 13 (depends on 12) The method of claim 12, further comprising determining DAC codes for a first DAC providing a first DC bias voltage to a first mixer and a second DAC providing a second DC bias voltage to a second mixer, wherein the determined DAC codes minimize the imbalances in the first mixer and the second mixer. ### Claim 14 (depends on 13) The method of claim 13, wherein determining the first and second DAC codes comprises: setting the first and second DAC codes to zero, measuring and storing the mixer imbalance value; incrementing the first and second DAC codes by an integer value of at least one; repeating the setting, measuring and storing until the maximum DAC code is reached; determining a DAC code range that results in a minimized mixer imbalance; repeating the setting, measuring and storing within the determined DAC code range using an increment of one; and determining the first and second DAC codes associated with the minimum mixer imbalance. ### Claim 15 (depends on 14) The method of claim 14, wherein a global navigation satellite system (GNSS) receiver is calibrated using the determined DAC codes. ### Claim 16 (depends on 15) The method of claim 15, wherein the calibration of the GNSS receiver is executed when a temperature of the GNSS receiver changes more than a predefined threshold. ### Claim 17 (depends on 15) The method of claim 15, wherein the frequency of the radio frequency wave is outside the band of the GNSS receiver radio frequency input signal. ### Claim 18 (depends on 11) The method of claim 11, wherein the first square wave is generated on a radio frequency integrated circuit (RFIC) and a second square wave is generated on a baseband integrated circuit (BBIC), wherein the first and second square waves are generated by the reference frequency oscillator, and the first and second square waves are out of phase with one another. ### Claim 19 (depends on 11) The method of claim 11, wherein integrating the digital signal comprises accumulating the digital signal over a programmable period of time. ### Claim 20 A chipset for receiving global navigation satellite system (GNSS) signals, the chipset configured to: generate a square wave; modulate a radio frequency wave with the square wave; downconvert the modulated radio frequency wave to an intermediate frequency; filter the downconverted modulated radio frequency wave; convert the filtered downconverted modulated radio frequency wave to a digital signal; and integrate the digital signal. ### Claim 21 (depends on 1) The electronic device of claim 1, wherein the processor is configured to generate the first square wave in a first integrated circuit, and generate the second square wave in a second integrated circuit.