US-12618939-B2 - Radar transceiver

US12618939B2US 12618939 B2US12618939 B2US 12618939B2US-12618939-B2

Abstract

A device, e.g., a radar transceiver, includes a receiver and a transmitter. One such device includes a phase shifter having a first input to receive an oscillating signal and a second input to receive a control signal. The device also includes a signal generator having a quadrature (Q) channel output to output a quadrature phase version of the oscillating signal; and a Q channel mixer having an input coupled to the Q channel output. A feedback path of the device includes a filter having an output and an input coupled to an output of the Q channel mixer, and an integrator having an input coupled to the output of the filter. The integrator has an output coupled to the second input of the phase shifter, in which the integrator outputs the control signal to the phase shifter.

Inventors

Sreekiran SAMALA
Venkatesh Srinivasan
Vijaya B. Rentala

Assignees

TEXAS INSTRUMENTS INCORPORATED

Dates

Publication Date: 20260505
Application Date: 20240206

Claims (20)

1 . A device comprising: a phase shifter having a first input configured to receive an oscillating signal and a second input configured to receive a control signal, the phase shifter having an output; a signal generator having a quadrature (Q) channel output configured to output a quadrature phase version of the oscillating signal; a Q channel mixer having an input coupled to the Q channel output of the signal generator, the Q channel mixer having an output; and a feedback path including a filter having an output and an input coupled to the output of the Q channel mixer, and an integrator having an input coupled to the output of the filter, the integrator having an output coupled to the second input of the phase shifter, wherein the integrator is configured to output the control signal to the phase shifter.
2 . The device of claim 1 , wherein the filter includes a baseband filter, and the integrator includes an analog integrator.
3 . The device of claim 2 , further comprising: a transmitter modulation control circuit having an output; wherein the feedback path further includes: a summation circuit having a first input coupled to the output of the transmitter modulation control circuit, a second input coupled to the output of the analog integrator, and an output coupled to the second input of the phase shifter.
4 . The device of claim 3 , wherein the phase shifter is a first phase shifter, the device further comprising: a second phase shifter having a first input configured to receive the oscillating signal, and a second input coupled to the output of the transmitter modulation control circuit.
5 . The device of claim 1 , wherein the signal generator has an input coupled to the output of the phase shifter.
6 . The device of claim 1 , further comprising an amplifier having an input, wherein the signal generator has an input configured to receive the oscillating signal, and the output of the phase shifter is coupled to the input of the amplifier.
7 . A radar transceiver comprising: a transmitter; a receiver including: a first amplifier having an output; a phase shifter having a first input configured to receive an oscillating signal and a second input configured to receive a control signal, the phase shifter having an output; quadrature (Q) channel circuitry including: a second amplifier having an input coupled to the output of the first amplifier; a signal generator having an input coupled to the output of the phase shifter, the signal generator having a quadrature (Q) channel output configured to output a quadrature phase version of the oscillating signal; a mixer having a first input coupled to the output of the second amplifier, and a second input coupled to the Q channel output of the signal generator; and a feedback path coupled to the transmitter and including a filter having an output and an input coupled to an output of the mixer, and an integrator having an input coupled to the output of the filter, the integrator having an output coupled to the second input of the phase shifter.
8 . The radar transceiver of claim 7 , wherein the transmitter has an input configured to receive the oscillating signal, the transmitter having an output coupled to the feedback path.
9 . The radar transceiver of claim 8 , wherein the mixer is a first mixer, and the feedback path further includes a second mixer having a first input coupled to the output of the integrator, a second input coupled to the output of the transmitter, and an output coupled to the second input of the phase shifter.
10 . The radar transceiver of claim 8 , wherein: the transmitter includes a transmitter modulation control circuit having first and second outputs; and the receiver includes a summation circuit having a first input coupled to the first output of the transmitter modulation control circuit, a second input coupled to the output of the integrator, and an output coupled to the second input of the phase shifter.
11 . The radar transceiver of claim 10 , wherein the phase shifter is a first phase shifter, and the transmitter further includes a second phase shifter having a first input configured to receive the oscillating signal, a second input coupled to the second output of the transmitter modulation control circuit, and an output.
12 . The radar transceiver of claim 7 , wherein the filter includes a baseband filter, and the integrator includes an analog integrator.
13 . The radar transceiver of claim 7 , further comprising an analog-to-digital converter coupled to an output of the filter.
14 . A radar transceiver comprising: a transmitter; and a receiver configured to: generate an amplified signal in a quadrature (Q) channel of the receiver based on received radar signals; receive an oscillating signal, and apply a phase shift to the oscillating signal to generate a phase-shifted oscillating signal in response to a control signal; generate an output signal that is a quadrature phase version of one of the oscillating signal and the phase-shifted oscillating signal; mix the output signal with the amplified signal to generate a mixed signal; apply a filter operation to the mixed signal to generate a filtered signal; and integrate the filtered signal to generate the control signal.
15 . The radar transceiver of claim 14 , wherein one of the transmitter and the receiver includes a phase shifter.
16 . The radar transceiver of claim 15 , wherein: the phase shifter is included in the receiver; and the output signal is a quadrature phase version of the phase-shifted oscillating signal.
17 . The radar transceiver of claim 14 , wherein the receiver includes a feedback path that includes a baseband filter and an analog integrator, the baseband filter configured to apply the filter operation to the mixed signal to generate the filtered signal, and the analog integrator configured to integrate the filtered signal to generate the control signal.
18 . The radar transceiver of claim 14 , wherein the amplified signal is a first amplified signal, the output signal is a first output signal, the mixed signal is a first mixed signal, the filtered signal is a first filtered signal, and the filter operation is a first filter operation, the receiver further configured to: generate a second amplified signal in an in-phase (I) channel of the receiver based on the received radar signals; generate a second output signal that is an in-phase version of one of the oscillating signal and the phase-shifted oscillating signal; mix the second output signal with the second amplified signal to generate a second mixed signal; and apply a second filter operation to the second mixed signal to generate a second filtered signal; and integrate the second filtered signal.
19 . The radar transceiver of claim 18 , wherein the first filter operation applied to the first mixed signal and the integrate operation applied to the first filtered signal function to reduce DC voltage in the Q channel and increase DC voltage in the I channel.
20 . The radar transceiver of claim 18 , wherein the control signal tracks one or more characteristics of radar signals from a strong reflector to maintain the I channel in an amplitude noise (AN) condition.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority to U.S. Non-Provisional patent application Ser. No. 16/680,647, filed Nov. 11, 2019, which claims priority to U.S. Provisional Patent Application No. 62/760,312, filed Nov. 13, 2018, both of which are hereby incorporated herein by reference in their entireties. BACKGROUND Radar systems are used to detect objects in a variety of applications. In vehicular applications, radar is used to detect objects, such as other vehicles, in the operating environment of the radar enabled vehicle. In a radar system, an antenna radiates radio signals generated by a transmitter. A signal reflected from a target is received and the reflected signal is mixed with a local oscillator signal to down-convert the reflected signal to an intermediate frequency. The down-converted signal is processed to determine a location of the target. SUMMARY Devices including a radar transceiver with improved signal-to-noise ratio in the presence of a strong reflector are disclosed herein. In an example, a device includes a phase shifter having a first input configured to receive an oscillating signal and a second input configured to receive a control signal. The phase shifter has an output. The device also includes a signal generator having a quadrature (Q) channel output configured to output a quadrature phase version of the oscillating signal; and a Q channel mixer having an input coupled to the Q channel output of the signal generator. The Q channel mixer has an output. A feedback path of the device includes a filter having an output and an input coupled to the output of the Q channel mixer, and an integrator having an input coupled to the output of the filter. The integrator has an output coupled to the second input of the phase shifter, in which the integrator is configured to output the control signal to the phase shifter. In another example, a radar transceiver includes a transmitter, and a receiver. The receiver includes a first amplifier having an output; a phase shifter having a first input configured to receive an oscillating signal and a second input configured to receive a control signal, the phase shifter having an output; quadrature (Q) channel circuitry including a second amplifier having an input coupled to the output of the first amplifier; a signal generator having an input coupled to the output of the phase shifter, the signal generator having a quadrature (Q) channel output configured to output a quadrature phase version of the oscillating signal; a mixer having a first input coupled to the output of the second amplifier, and a second input coupled to the Q channel output of the signal generator; and a feedback path coupled to the transmitter and including a filter having an output and an input coupled to the output of the mixer, and an integrator having an input coupled to the output of the filter, the integrator having an output coupled to the second input of the phase shifter. In yet another example, a radar transceiver includes a transmitter, and a receiver. The receiver is configured to generate an amplified signal in a quadrature (Q) channel of the receiver based on received radar signals; receive an oscillating signal, and apply a phase shift to the oscillating signal to generate a phase-shifted oscillating signal in response to a control signal; generate an output signal that is a quadrature phase version of one of the oscillating signal and the phase-shifted oscillating signal; mix the output signal with the amplified signal to generate a mixed signal; apply a filter operation to the mixed signal to generate a filtered signal; and integrate the filtered signal to generate the control signal. BRIEF DESCRIPTION OF THE DRAWINGS For a detailed description of various examples, reference will now be made to the accompanying drawings in which: FIG. 1 shows a block diagram for a radar system that includes a first example radar transceiver having a phase/frequency feedback loop in accordance with this description; FIGS. 2A, 2B, and 2C show example signals provided in a radar receiver that includes a phase/frequency feedback loop in accordance with this description; FIG. 3 shows a block diagram for a radar system including a second example radar transceiver having a phase/frequency feedback loop in accordance with this description; FIG. 4 shows a block diagram for an example radar receiver that includes a phase/frequency feedback loop in accordance with this description; FIG. 5 shows a block diagram for an example radar receiver that includes a phase/frequency feedback loop in accordance with this description; FIG. 6 shows a block diagram for a radar system that includes a third example radar transceiver having a phase/frequency feedback loop in accordance with this description; FIG. 7 shows equations used to set loop bandwidth for cancellation of vibration of a strong reflector in accordance with this description; FIG. 8 shows an example simulati