# US 2021/0333357 A1 · Digital compensation for mismatches in a radar system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0333357 A1 - Document ID: US20210333357A1 - Status: Published application - Kind: A1 - Application number: 17/368,319 - Filed: 2021-07-06 - Published: 2021-10-28 - Earliest claimed: 2016-01-22 - Assignees: Texas Instruments Incorporated - Applicants: Texas Instruments Incorporated - Inventors: Sriram Murali; Karthik Subburaj; Karthik Ramasubramanian - Web page: https://patentgrep.com/patent/US20210333357A1 ## CPC - G01S 7/352: {Receivers} - G01S 7/4021: {of receivers} - G01S 13/931: of land vehicles - G01S 7/358: {using I/Q processing} - G01S 7/406: {using internally generated reference signals, e.g. via delay line, via RF or IF signal injection or via integrated reference reflector or transponder} - 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 radar system is provided that includes a receive channel configured to receive a reflected signal and to generate a first digital intermediate frequency (IF) signal based on the reflected signal, a reference receive channel configured to receive a reflected signal and to generate a second digital IF signal based on the reflected signal, and digital mismatch compensation circuitry coupled to receive the first digital IF signal and the second digital IF signal, the digital mismatch compensation circuitry configured to process the first digital IF signal and the second digital IF signal to compensate for mismatches between the receive channel and the reference receive channel. ## Claims ### Claim 1 A device comprising: a first receive channel configured to couple to a first receive antenna; a second receive channel configured to couple to a second receive antenna that includes a compensation filter; and a control circuit coupled to the first receive channel and the second receive channel and configured to: receive, via the first receive channel, a first signal associated with a reflection from a target, wherein the first signal has a first frequency; receive, via the second receive channel, a second signal associated with the reflection from the target, wherein the second signal has a second frequency; determine a difference between the first frequency and the second frequency; and configure the compensation filter to apply a frequency shift based on the difference between the first frequency and the second frequency. ### Claim 2 (depends on 1) The device of claim 1 further comprising a digital front end that includes: the compensation filter; a first frequency generator of the first receive channel; a first mixer of the first receive channel coupled to the first frequency generator; a second frequency generator of the second receive channel; and a second mixer of the second receive channel coupled between the second frequency generator and the compensation filter. ### Claim 3 (depends on 2) The device of claim 2, wherein: the reflection is a first reflection; the target is a first target; and the control circuit is further configured to: receive, via the first receive channel, a third signal associated with a second reflection from a second target, wherein the third signal has a first phase; receive, via the second receive channel, a fourth signal associated with the second reflection from the second target, wherein the fourth signal has a second phase; determine a difference between the first phase and the second phase; and configure at least one of the first frequency generator and the second frequency generator based on the difference between the first phase and the second phase. ### Claim 4 (depends on 1) The device of claim 1, wherein: the control circuit is further configured to: receive, via the first receive channel, a third signal; receive, via the second receive channel, a fourth signal; determine a gain mismatch between the third signal and the fourth signal; and configure a gain of the compensation filter based on the gain mismatch between the third signal and the fourth signal. ### Claim 5 (depends on 1) The device of claim 1, wherein the control circuit is configured to provide to the compensation filter, a gain mismatch factor, a pole parameter, and a frequency shift parameter. ### Claim 6 (depends on 1) The device of claim 1, wherein: the first receive channel includes: a first mixer configured to couple to the first receive antenna; and a first bandpass filter coupled to the first mixer such that the first signal is a first intermediate frequency signal; the second receive channel includes: a second mixer configured to couple to the second receive antenna; and a second bandpass filter coupled to the second mixer such that the second signal is a second intermediate frequency signal; and the compensation filter is an intermediate frequency compensation filter. ### Claim 7 (depends on 6) The device of claim 6, wherein: the first receive channel includes a first analog-to-digital converter coupled to the first mixer such that the first signal is a first digital intermediate frequency signal; the second receive channel includes a second analog-to-digital converter coupled to the second mixer such that the second signal is a second digital intermediate frequency signal; and the compensation filter is a digital intermediate frequency compensation filter. ### Claim 8 (depends on 1) The device of claim 1, wherein the compensation filter is a complex coefficient infinite impulse response filter. ### Claim 9 (depends on 1) The device of claim 1 further comprising an integrated circuit that includes the first receive channel, the second receive channel, and the control circuit. ### Claim 10 (depends on 1) The device of claim 1 further comprising a transmit channel, wherein: the control circuit is configured to cause the transmit channel to provide a chirp; and the reflection from the target is associated with the chirp. ### Claim 11 (depends on 10) The device of claim 10, wherein the chirp is a radar chirp. ### Claim 12 A method comprising: receiving, from a first channel coupled to a first antenna, a first signal in response to a reflection from a target, wherein the first signal has a first frequency; receiving, from a second channel coupled to a second antenna, a second signal in response to the reflection from the target, wherein: the second channel includes a compensation filter; and the second signal has a second frequency; determining a difference between the first frequency and the second frequency; and providing a configuration for the compensation filter based on the difference between the first frequency and the second frequency. ### Claim 13 (depends on 12) The method of claim 12, wherein the configuration is configured to cause the compensation filter to apply a frequency shift that is based on the difference between the first frequency and the second frequency. ### Claim 14 (depends on 12) The method of claim 12, wherein the configuration specifies a gain mismatch factor, a pole parameter, and a frequency shift parameter of the compensation filter. ### Claim 15 (depends on 12) The method of claim 12, wherein: the first channel includes a first frequency generator; the second channel includes a second frequency generator; and the method further comprises: receiving, from the first channel, a third signal, wherein the third signal has a first phase; receiving, from the second channel, a fourth signal, wherein the fourth signal has a second phase; determining a difference between the first phase and the second phase; and configuring at least one of the first frequency generator and the second frequency generator based on the difference between the first phase and the second phase. ### Claim 16 (depends on 12) The method of claim 12 further comprising: receiving, via the first channel, a third signal; receiving, via the second channel, a fourth signal; determining a gain mismatch between the third signal and the fourth signal; and configuring a gain of the compensation filter based on the gain mismatch between the third signal and the fourth signal. ### Claim 17 (depends on 12) The method of claim 12, wherein: the first signal is a first intermediate frequency signal; the second signal is a second intermediate frequency signal; and the compensation filter is an intermediate frequency filter. ### Claim 18 (depends on 17) The method of claim 17, wherein the determining of the difference between the first frequency and the second frequency includes: performing a first Fourier transform on the first intermediate frequency signal to determine the first frequency; and performing a second Fourier transform on the first intermediate frequency signal to determine the second frequency. ### Claim 19 (depends on 12) The method of claim 12 further comprising causing a transmit channel to transmit a chirp, wherein the reflection is in response to the chirp. ### Claim 20 (depends on 19) The method of claim 19, wherein the chirp is a radar chirp.