# US 2017/0285140 A1 · Dynamic iq mismatch correction in fmcw radar > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0285140 A1 - Document ID: US20170285140A1 - Status: Published application - Kind: A1 - Application number: 15/088,566 - Filed: 2016-04-01 - Published: 2017-10-05 - Earliest claimed: 2016-04-01 - Assignees: Texas Instruments Incorporated - Applicants: Texas Instruments Incorporated - Inventors: PANKAJ GUPTA; SRIRAM MURALI; KARTHIK RAMASUBRAMANIAN - Web page: https://patentgrep.com/patent/US20170285140A1 ## CPC - G01S 7/352: {Receivers} - G01S 7/4021: {of receivers} - G01S 13/343: {using sawtooth modulation} - H03D 1/2245: {using two quadrature channels (H03D1/2209 takes precedence)} - H03D 3/009: {Compensating quadrature phase or amplitude imbalances} - H03D 7/165: {at least two frequency changers being located in different paths, e.g. in two paths with carriers in quadrature (combined with amplitude demodulation H03D1/2245, combined with angle demodulation H03D3/007; N-path filters H03H19/002)} - G01S 7/358: {using I/Q processing} - G01S 13/931: of land vehicles - G01S 2013/9314: {Parking operations} - G01S 2013/9315: {Monitoring blind spots} - 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 - H03D: DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER (masers, lasers H01S; circuits capable of acting both as modulator and demodulator H03C; details applicable to both modulators and frequency-changers H03C; demodulating pulses H03K9/00; transforming types of pulse modulation H03K11/00; coding, decoding or code conversion, in general H03M; repeater stations H04B7/14; demodulators adapted for AC systems of digital information transmission H04L27/00; synchronous demodulators adapted for colour television H04N9/66) ## Abstract A FMCW radar receiver includes a LO providing a chirped LO signal, an in-phase (I) channel for outputting I-data and a quadrature (Q) channel for outputting Q-data. A dynamic correction parameter generator generates IQ phase correction values (P[n]s) and IQ gain correction values (G[n]s) based on a frequency slope rate of the chirped LO signal for generating during intervals of chirps including a first sequence of P[n]s and G[n]s during a first chirp and a second sequence of P[n]s and G[n]s during a second chirp. An IQ mismatch (IQMM) correction circuit has a first IQMM input coupled to receive the I-data and a second IQMM input receiving the Q-data, and the P[n]s and G[n]s. During the first chirp the IQMM correction circuit provides first Q′-data and first I′-data and during the second chirp the IQMM correction circuit provides at least second Q′-data and second I′-data. ## Claims ### Claim 1 A method of IQ mismatch correction for Frequency Modulation Continuous Wave (FMCW) radar, comprising: providing an IQ FMCW receiver including an in-phase (I) channel comprising a first mixer coupled to receive and mix a chirped local oscillator signal (chirped LO signal) and a received scattered chirped radar signal (chirped radar signal) and a first analog-to-digital (A/D) converter for outputting in-phase (I)-data, and a quadrature (Q) channel including a phase shifter for phase shifting said chirped LO signal to provide a phase shifted chirped LO signal, a second mixer coupled to receive and mix said chirped radar signal and said phase shifted chirped LO signal and a second A/D converter for outputting Q phase (Q)-data; dynamically generating IQ phase correction parameter values (P[n]s) and IQ gain correction parameter values (G[n]s) based on a slope rate of a frequency of said chirped LO signal including generating different values during a plurality of intervals for each chirp of said chirped LO signal; coupling said P[n]s and said G[n]s to an IQ mismatch (IQMM) correction circuit having a first IQMM input coupled to receive said I-data from said I channel and a second IQMM input for receiving said Q-data from said Q-channel, wherein said IQMM correction circuit provides corrected Q (Q′) data and corrected I (I′) data. ### Claim 2 (depends on 1) The method of claim 1, wherein said dynamically generating further comprises generating a first sequence of said P[n]s and a first sequence of said G[n]s during a first chirp and a second sequence of said P[n]s and a second sequence of said G[n]s different from said first sequence of said P[n]s and G[n]s during a second chirp, and wherein during a duration of said first chirp said IQMM correction circuit provides first Q′ data and first I′-data and during a duration of said second chirp said IQMM correction circuit provides second Q′ data and second I′-data. ### Claim 3 (depends on 1) The method of claim 1, wherein said dynamically generating comprises utilizing delta (Δ) G IQ correction values (ΔG[n]s) and ΔP IQ correction values (ΔP[n]s) stored in a look-up table (LUT), and wherein based on said slope rate and a starting frequency of said chirped LO signal during each said chirp a LUT index generator causes said LUT to output a selected one of said ΔG[n]s to a gain correction parameter accumulator to generate each one of said G[n]s and one of said ΔP[n]s to a phase correction parameter accumulator to generate each one of said P[n]s. ### Claim 4 (depends on 3) The method of claim 3, wherein said LUT index generator provides selection of a new frequency threshold from a frequency threshold look-up table (LUT) based on a current LUT index provided by said LUT index generator. ### Claim 5 (depends on 1) The method of claim 1, wherein said dynamically generating comprises gated accumulating comprising populating a look-up table (LUT) with an incremental change in a value of said G[n]s and said P[n]s for an absolute jump in frequency (ΔF) of said chirped LO signal for each of said plurality of intervals across a frequency band for said chirped LO signal, wherein an accumulation gating signal generator receives said slope rate for monitoring a change in said frequency of said chirped LO signal based on an accumulation of said slope rate and is coupled to trigger gated accumulations in said gain correction parameter accumulator to output each one of said G[n]s and said phase correction parameter accumulator to output each one of said P[n]s by performing gated accumulations every said ΔF, and wherein said slope rate is further coupled to a LUT index generator that is coupled to provide a slope-rate-based LUT index selection signal to said LUT. ### Claim 6 (depends on 5) The method of claim 5, wherein said LUT index generator includes selection of a new frequency threshold from a frequency threshold look-up table (LUT) based on a current LUT index provided by said LUT index generator. ### Claim 7 (depends on 1) The method of claim 1, wherein said IQ FMCW receiver comprises a CMOS receiver on a silicon substrate, and said method further comprises processing at least said I′-data and said Q′-data using a signal processing algorithm to determine at least one radar parameter. ### Claim 8 A synchronous Frequency Modulation Continuous Wave (FMCW) radar receiver, comprising: a substrate that said receiver is formed on; a local oscillator (LO) controlled for providing a chirped LO signal; an in-phase (I) channel comprising a first mixer coupled to receive and mix said chirped LO signal and a received scattered chirped radar signal (chirped radar signal) and a first analog-to-digital (A/D) converter for outputting in-phase (I)-data, and a quadrature (Q) channel including a phase shifter for phase shifting said chirped LO signal to provide a phase shifted chirped LO signal, a second mixer coupled to receive and mix said chirped radar signal and said phase shifted chirped LO signal and a second A/D converter for outputting Q phase (Q)-data; a dynamic correction parameter generator for dynamically generating IQ phase correction parameter values (P[n]s) and IQ gain correction parameter values (G[n]s) based on a slope rate of a frequency of said chirped LO signal provided by a timing engine 180 including generating different values during a plurality of intervals for each chirp of said chirped LO signal, and an IQ mismatch (IQMM) correction circuit including at least a third mixer having a first IQMM input coupled to receive said I-data from said I channel including and a second IQMM input for receiving said Q-data from said Q-channel, said IQMM correction circuit coupled to receive said P[n]s and said G[n]s; wherein said IQMM correction circuit provides corrected Q (Q′)-data and corrected I (I′)-data. ### Claim 9 (depends on 8) The FMCW radar receiver of claim 8, wherein said dynamically generating further comprises generating a first sequence of said P[n]s and a first sequence of said G[n]s during a first chirp and a second sequence of said P[n]s and a second sequence of said G[n]s different from said first sequence of said P[n]s and G[n]s during a second chirp, wherein during a duration of said first chirp said IQMM correction circuit provides first Q′ data and first I′ data and during a duration of said second chirp said IQMM correction circuit provides second Q′-data and second I′-data. ### Claim 10 (depends on 8) The FMCW radar receiver of claim 8, wherein said dynamically generating comprises utilizing delta (Δ) G IQ correction values (ΔG[n]s) and ΔP IQ correction values (ΔP[n]s) stored in a look-up table (LUT), and wherein based on said slope rate and a starting frequency of said chirped LO signal during each said chirp a LUT index generator causes said LUT to output a selected one of said ΔG[n]s to a gain correction parameter accumulator to generate each one of said G[n]s and one of said ΔP[n]s to a phase correction parameter accumulator to generate each one of said P[n]s. ### Claim 11 (depends on 10) The FMCW radar receiver of claim 10, wherein said LUT index generator includes selection of a new frequency threshold from a frequency threshold look-up table (LUT) based on a current LUT index provided by said LUT index generator. ### Claim 12 (depends on 8) The FMCW radar receiver of claim 8, wherein said dynamically generating comprises gated accumulating comprising populating a look-up table (LUT) with an incremental change in a value of said G[n]s and said P[n]s for an absolute jump in frequency (ΔF) of said chirped LO signal for each of said plurality of intervals across a frequency band for said chirped LO signal, and wherein an accumulation gating signal generator receives said slope rate for monitoring a change in said frequency of said chirped LO signal based on an accumulation of said slope rate and is coupled to trigger gated accumulations in said gain correction parameter accumulator to output each one of said G[n]s and said phase correction parameter accumulator to output each one of said P[n]s by performing gated accumulations every said ΔF, and wherein said slope rate is further coupled to a LUT index generator that is coupled to provide a slope-rate-based LUT index selection signal to said LUT. ### Claim 13 (depends on 12) The FMCW radar receiver of claim 12, wherein said LUT index generator provides selection of a new frequency threshold from a frequency threshold look-up table (LUT) based on a current LUT index provided by said LUT index generator. ### Claim 14 (depends on 8) The FMCW radar receiver of claim 8, further comprising a processor formed on said substrate for processing said first I′ and said first Q′ data and processing at least said second I′-data and said second Q data using a signal processing algorithm to determine at least one radar parameter. ### Claim 15 A Frequency Modulation Continuous Wave (FMCW) radar system, comprising: a substrate that a receiver and a transmitter are both formed on; said receiver comprising: a local oscillator (LO) controlled for providing a chirped LO signal; an in-phase (I) channel comprising a first mixer coupled to receive and mix said chirped LO signal and a received scattered chirped radar signal (chirped radar signal) and a first analog-to-digital (A/D) converter for outputting in-phase (I)-data, and a quadrature (Q) channel including a phase shifter for phase shifting said chirped LO signal to provide a phase shifted chirped LO signal, a second mixer coupled to receive and mix said chirped radar signal and said phase shifted chirped LO signal and a second A/D converter for outputting Q phase (Q)-data; a dynamic correction parameter generator for dynamically generating IQ phase correction parameter values (P[n]s) and IQ gain correction parameter values (G[n]s) based on a slope rate of a frequency of said chirped LO signal provided by a timing engine including generating different values during a plurality of intervals for each chirp of said chirped LO signal, and an IQ mismatch (IQMM) correction circuit including at least a third mixer having a first IQMM input coupled to receive said I-data from said I channel including and a second IQMM input for receiving said Q-data from said Q-channel, said IQMM correction circuit coupled to receive said P[n]s and said G[n]s; wherein said IQMM correction circuit provides corrected Q (Q′)-data and corrected I (I′)-data, said transmitter including a power amplifier (PA) coupled to receive said chirped LO signal that drives a Tx antenna. ### Claim 16 (depends on 15) The FMCW radar system of claim 15, wherein said dynamically generating further comprises generating a first sequence of said P[n]s and a first sequence of said G[n]s during a first chirp and a second sequence of said P[n]s and a second sequence of said G[n]s different from said first sequence of said P[n]s and G[n]s during second chirp, wherein during a duration of said first chirp said IQMM correction circuit provides first Q′-data and first I′-data and during a duration of said second chirp said IQMM correction circuit provides second Q′-data and second I′-data. ### Claim 17 (depends on 15) The FMCW radar system of claim 15, wherein said dynamically generating comprises utilizing delta (Δ) G IQ correction values (ΔG[n]s) and ΔP IQ correction values (ΔP[n]s) stored in a look-up table (LUT), and wherein based on said slope rate and a starting frequency of said chirped LO signal during each said chirp a LUT index generator causes said LUT to output a selected one of said ΔG[n]s to a gain correction parameter accumulator to generate each one of said G[n]s and one of said ΔP[n]s to a phase correction parameter accumulator to generate each one of said P[n]s. ### Claim 18 (depends on 17) The FMCW radar system of claim 17, wherein said LUT index generator provides selection of a new frequency threshold from a frequency threshold look-up table (LUT) based on a current LUT index provided by said LUT index generator. ### Claim 19 (depends on 15) The FMCW radar system of claim 15, further comprising a processor formed on said substrate for processing said first I′-data and said first Q′-data and processing at least said second I′-data and said second Q-data using a signal processing algorithm to determine at least one radar parameter.