Transceiver circuit and associated interference mitigation method

Abstract

In an example, a system (e.g., 400) includes an analog-to-digital converter (ADC) (e.g., 416); a receiver path (e.g., 452) including a transimpedance amplifier (e.g., 424) having an output coupled to the ADC; and a controller (e.g., 420) coupled to the receiver path and configured to increase transconductance of the transimpedance amplifier from a first transconductance value to a second transconductance value upon detection of an interference event of the receiver path.

Description

Technical Field

[0001] The present description relates generally to electronic systems and methods, and in particular examples, to a transceiver circuit and associated interference mitigation method. Background Art

[0002] FIG1 shows a schematic diagram of an exemplary millimeter wave radar system 100. During normal operation, a frequency modulated continuous wave (FMCW) synthesizer 114 generates a transmitter signal S TX , the transmitter signal includes a chirp to be transmitted by a power amplifier (PA) 108 via a transmit antenna 104. The chirp transmitted by the transmit antenna 104 is reflected by an object (e.g., 101) in the field of view of the radar system 100 and is received by the receive antenna 102. The reflected chirp received by the receive antenna is amplified by a low noise amplifier (LNA) 106 to produce a receiver signal S RX . Transmitter signal S TX and the receiver signal S RX The mixer 110 mixes the intermediate frequency signal S IF . Intermediate frequency signal S IF The output voltage V out Output voltage V out The data is digitized using an analog-to-digital converter (ADC) 116 to generate raw radar digital data D raw Data D raw The radar is then processed by the radar processing system 118, such as detecting and tracking targets, classifying targets, etc.

[0003] In general, the time between chirps (also called pulse repetition time or PRT) indicates the system's ability to unambiguously detect the maximum velocity of a target (shorter pulse repetition times produce higher maximum velocities of the target for unambiguous detection, following the relationship: Where c is the speed of light, f0 is the carrier frequency of the system, and T c is the pulse repetition time). Therefore, for a given carrier frequency, a shorter T c It is generally highly desirable to meet the practical needs of sensors used in various automotive fields as part of advanced driver assistance systems (ADAS) (the predecessor of self-driving cars), and example applications include, for example, automatic emergency braking (AEB), cruise control, cross traffic alert (CTA), backside detection (BSD) to avoid collisions, etc. Summary of the Invention

[0004] In an example, a system includes an analog-to-digital converter (ADC); a receiver path including a transimpedance amplifier having an output coupled to the ADC; and a controller coupled to the receiver path and configured to increase a transconductance of the transimpedance amplifier from a first transconductance value to a second transconductance value when a jammer event is detected for the receiver path.

[0005] In an example, a system includes an analog-to-digital converter (ADC); a transmitter path; a receiver path including a transimpedance amplifier having an output coupled to the ADC; and a controller coupled to the transmitter path and the receiver path, wherein the controller is configured to increase a transconductance of the transimpedance amplifier from a first transconductance value to a second transconductance value, enable the transmitter path simultaneously with or after increasing the transconductance of the transimpedance amplifier, and decrease the transconductance of the transimpedance amplifier from the second transconductance value to the first transconductance value after a first signal begins to be transmitted in the enabled transmitter path and while the first signal is being transmitted in the enabled transmitter path. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] For a more complete understanding of the present specification and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

[0007] FIG1 shows a schematic diagram of an exemplary millimeter wave radar system;

[0008] Figure 2 A plurality of cars are shown on a road in an example of the present specification;

[0009] Figure 3 shows exemplary behavior of the radar of FIG1 during a jamming event;

[0010] Figure 4 A schematic diagram showing a millimeter wave radar system in an example of this specification;

[0011] Figure 5 The examples shown in this specification are Figure 4 waveforms associated with radar systems;

[0012] Figure 6 The examples shown in this manual Figure 4 Schematic diagram of a transimpedance amplifier;

[0013] Figure 7 A schematic diagram showing a variable current source in an example of this specification;

[0014] Figure 8 A schematic diagram showing an amplifier in an example of this specification;

[0015] Figure 9 The examples shown in this specification are Figure 4 waveforms associated with radar systems;

[0016] Figure 10 A schematic diagram showing a circuit for generating a transconductance control signal in an example of this specification;

[0017] Figure 11 A schematic diagram showing a millimeter wave radar system in an example of this specification;

[0018] Figure 12 A motor vehicle is shown in the examples of this specification;

[0019] Figure 13 A flowchart illustrating an example method for interference mitigation in a millimeter wave radar system in an example of the present specification;

[0020] Figure 14 and 15 A flowchart illustrating an example method for cross-coupling interference mitigation in a millimeter-wave radar system in an example of this specification; and

[0021] Figure 16 A flow chart illustrating an example method for interference mitigation in a millimeter-wave radar system in the examples of this specification.

[0022] Corresponding reference numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated.The drawings are drawn to clearly illustrate the relevant aspects of the preferred embodiments and are not necessarily drawn to scale. DETAILED DESCRIPTION

[0023] The following describes in detail how to make and use the described embodiments. However, this description provides many applicable inventive concepts that can be implemented in a wide variety of specific situations. The specific embodiments described are merely illustrative of specific ways to make and use the described embodiments and do not limit the scope of the description.

[0024] The following description shows various specific details to provide an in-depth understanding of several examples in the description. Examples can be obtained without one or more specific details or with other methods, components, materials, etc. In other cases, known structures, materials or operations are not shown or described in detail to avoid confusing different aspects of the examples. References to "examples" in this specification indicate that a specific configuration, structure or feature described relative to the example is included in at least one example. Therefore, phrases such as "in an example" that may appear in different places in this specification do not necessarily refer to the same example. In addition, specific forms, structures or features can be combined in any appropriate manner in one or more examples.

[0025] Examples of this specification will be described in the context of a specific application, such as an intermediate frequency (IF) or baseband (e.g., transimpedance) amplifier in the receiver path of a millimeter-wave radar, such as one used in automotive applications. Examples of this specification can also be used in other types of applications, such as industrial and consumer applications. Some examples can be used in systems other than radar, such as wireless communication systems (e.g., Bluetooth, WiFi, 5G, etc.).

[0026] In an example of the present specification, when interference is detected (which may occur over multiple frames), the 1 dB compression point (also referred to as P1dB) of an amplifier in the receiver path of a millimeter-wave radar system is temporarily increased in a controlled manner and without any instability. Increasing the P1dB of the amplifier in the presence of interference can advantageously improve the millimeter-wave radar system's ability to detect objects in the presence of interference.

[0027] In some instances, by increasing the transconductance g of the amplifier m To increase the amplifier's P1dB, for example by increasing the amplifier's bias current.

[0028] In some examples, the amplifier's P1dB is temporarily increased in a controlled manner and without any instability during the start of each chirp (instead of or in addition to increasing the amplifier's P1dB in the presence of interference) to reduce the effects of self-coupling when the transmitter path of the millimeter-wave radar system is enabled. By temporarily increasing P1dB during the start of each chirp, some examples advantageously reduce the settling time of the IF amplifier, which can advantageously increase the usable operating bandwidth of the millimeter-wave radar system and can advantageously allow for a reduction in pulse repetition time without significantly affecting power consumption.

[0029] Motor vehicles increasingly include one or more millimeter wave radars. As the number of radars on the road increases, the chances of a radar interfering with other radars increase. For example, Figure 2 In the example of this specification, a plurality of cars (210, 220, 230) are shown on a road. Each car (210, 220, 230) includes a plurality of millimeter wave radars 100. As shown, cars 210 and 220 are shown moving in one direction, and car 230 is shown moving in the opposite direction.

[0030] like Figure 2 As shown, the radar 100 at the back of the car 220 b The generated radar signal 222 may temporarily cause interference (eg, cause saturation of the corresponding ADC 116) with the radar 100 at the front of the car 210. f (For example, when the radar signal 222 received by the corresponding amplifier 112 via the antenna 102 exceeds the P1dB of the amplifier 112). Similarly, the radar 100 at the front of the car 230 fThe generated radar signal 232 may cause interference with the radar 100 at the front of the car 210. f and the radar 100 at the left side of the car 210 l .

[0031] Figure 3 Radar 100 is shown f Demonstrate exemplary behavior during a disturbance event. Figure 3 As shown, a jamming event, such as that caused by another radar, may last for multiple chirps. During a jamming event, when ADC 116 is enabled (when S ADC_EN =1), the raw data D generated by ADC116 raw Saturation (constantly high in this example). In some cases, saturation of ADC 116 may be manifested in other ways. For example, in some cases, saturation of ADC 116 may occur only at certain frequencies (tones). In some cases, an interference event may cause the voltage V out Saturation (eg, high or low). In some cases, an interference event may cause the total energy of the system (across all frequency bands) to increase beyond a predetermined threshold.

[0032] While a jamming event may be caused by another radar, it may also be caused in other ways. For example, it may be caused by an increase in self-coupling, such as due to deformation of the housing containing the radar, or by additional coupling due to ice formation in the radar module.

[0033] In examples of the present specification, ADC saturation during a jamming event is mitigated by temporarily increasing the P1dB of an amplifier having an output coupled to the ADC. By preventing or otherwise removing ADC saturation during a jamming event, some examples advantageously enable target detection and other radar signal processing tasks (e.g., target tracking, classification, etc.) to be performed during a jamming event.

[0034] Figure 4A schematic diagram of a millimeter wave radar system 400 in an example of this specification is shown. Millimeter wave radar system 400 includes a controller 420, a transmitter path 450, a receiver path 452, an ADC 416, and a radar processing system 418. Transmitter path 450 includes an FMCW synthesizer 414 and a power amplifier 408. Receiver path 452 includes an LNA 406, a mixer 410, and an amplifier 412. Additional example details of amplifiers in radar systems can be found in commonly assigned U.S. patent application Ser. No. 17 / 566,047, filed Dec. 30, 2021, entitled “Intermediate Frequency Amplifier with a Configurable High-Pass Filter,” which is incorporated by reference in its entirety.

[0035] Figure 5 5. The waveforms associated with radar system 400 in the examples of this specification are shown. Curve 502 shows signal S TX The frequency of the signal S is plotted over time. TX_EN 、S ACD_EN 、S DFE_START 、S jam and S gm_EN Digital status over time. Figure 4 and 5 Can be described together.

[0036] During normal operation, the FMCW synthesizer 414 generates the transmitter signal S TX , which includes a (eg, upper) chirp, as shown by curve 502. The transmitter signal S TX The chirp is transmitted by a power amplifier (PA) 408 via a transmit antenna 404 toward an object in the field of view of the radar system 400. The chirp transmitted by the transmit antenna 404 is reflected by an object (e.g., 101) in the field of view of the radar system 400 and is received by the receive antenna 402. The reflected chirp received by the receive antenna is amplified by a low noise amplifier (LNA) 406 to produce a receiver signal S RX . Transmitter signal S TX and the receiver signal S RX The mixer 410 mixes the intermediate frequency signal S IF . Intermediate frequency signal S IF The output voltage V out Output voltage V out The data is digitized using an analog-to-digital converter (ADC) 416 to generate raw radar digital data D raw Data Draw The radar processing system 418 then processes the radar signal, such as detecting, tracking, identifying, and / or classifying the target.

[0037] like Figure 4 As shown, in some examples, amplifier 412 can be implemented with a forward path 422 and a feedback path 430. Forward path 422 includes a gain transimpedance amplifier 424 (which can be implemented as a transimpedance amplifier). Feedback path 430 includes high-pass filters 431 and 433 (which form a second-order high-pass filter in some examples). Figure 4 As shown, in some examples, the output V out After being fed back, high-pass filtered by high-pass filters 431 and 433, and from node N 410 Subtracting, the node can be from the signal S IF Remove high frequency content from the signal V out Remove this high frequency content. For example, Figure 4 As shown, the output signal from the high-pass filter 431 is inverted by the inverting unity gain buffer 464 and injected into the node N 410 and is also inverted by the high-pass filter 433 and injected into the node N 410 Thus, the output from the inverting buffer 464 and the amplifier 434 is output from the node N 410 minus.

[0038] like Figure 5 As shown, in some examples, transmitter path 350 (eg, circuit 408 or a portion thereof) may be enabled (eg, by asserting signal S TX_EN , e.g., high) for chirp transmission and is disabled between chirps (e.g., by deasserting signal S TX_EN , e.g. low), which can advantageously reduce power consumption.

[0039] In some instances, upon re-enabling the transmitter path 450 (when the signal S TX_EN When the ADC 416 is asserted and chirps are transmitted, cross coupling may occur between the transmitter path 450 and the receiver path 452, which may temporarily saturate the ADC 416. In some examples, the time that the ADC 416 remains saturated depends on the corner frequency of the high-pass filters 431 and 433. In some examples, once the ADC 416 is no longer saturated, the signal S DFE_START Pulsed to mark data D raw The start of useful (e.g., non-saturated) ADC samples.

[0040] like Figure 5 As shown, when an interference event is detected, the signal S jam is asserted (eg, high). In some instances, the interference detection and signal S jamThe assertion is performed by the controller 420. In some examples, a signal S is received from an external circuit. jam .

[0041] In some examples, interference with the millimeter wave radar system 400 is detected by monitoring the output of the ADC 416. For example, when an interference event is detected, such as when the output D raw When saturation is not expected (e.g., time t 13 With t 14 When the signal S jam For example, in some instances where ADC 416 is implemented other than with a sigma-delta ADC (e.g., SAR, pipeline, etc.), a jammer may be detected by detecting more than one consecutive ADC sample outside of the normal operating window (e.g., stuck at the maximum code or stuck at the minimum code for 2 or more samples).

[0042] In some instances, interference may be detected in other ways. For example, in some instances (independent of the topology of ADC 416), the interference may be detected by monitoring the voltage V out (For example, using a comparator, such as a window comparator, Figure 4 not shown) and determine when the voltage V out Interference is detected by an interference event that occurs when the signal S is above a predetermined maximum threshold or below a predetermined minimum threshold. jam can be generated from the output of this window comparator.

[0043] As another example, in some instances, when the total energy of the system (e.g., across all frequency bands, such as based on D raw An interference event is detected when the FFT of

[0044] After the interference event is detected, the signal S jam is deasserted (e.g., low). In some instances, when the total energy of the system (e.g., across all frequency bands, such as based on D raw When the FFT of the detected interference event is lower than a predetermined threshold, the radar processing system 418 may perform the detection end.

[0045] like Figure 5 As shown, the signal S can be asserted for multiple chirps jam For example, Figure 5 Show the assertion signal S for n+1 chirps jam , where n is a positive integer greater than or equal to 0.

[0046] like Figure 5 As shown, the signal S jamThe assertion of the signal S gm_EN Assertions of (for example, at the same time or shortly thereafter). Figure 4 As shown, the signal S gm_EN Provided to the transimpedance amplifier 424. When the signal S is asserted gm_EN After that, the transconductance g of the transimpedance amplifier m This increases the P1dB of the transimpedance amplifier 424, thereby advantageously increasing the transimpedance amplifier 424's ability to process the signal S during a jammer event. IF without saturating the transimpedance amplifier 424. In some examples, the radar processing system 418 compensates for any varying gain that may be caused by changes in the transconductance gm of the amplifier 424.

[0047] The FMCW synthesizer 414 is configured to generate a transmitter signal S TX And this transmitter signal S TX is provided to the power amplifier 408. In some examples, the transmitter signal S TX In some instances, the transmitter signal S TX In some examples, FMCW synthesizer 414 can be implemented in any manner known in the art.

[0048] In some examples, the chirp generated by the FMCW synthesizer 414 may have a starting and ending frequency of 76 GHz and 81 GHz, respectively. Other frequencies may also be used. For example, in some examples, the chirp generated by the FMCW synthesizer 414 may have a starting and ending frequency of 57 GHz and 64 GHz, respectively.

[0049] In some examples, power amplifier 408 is configured to transmit a radar signal via transmit antenna 404 (based on, for example, by amplifying signal S TX In some examples, power amplifier 408 can be implemented in any manner known in the art.

[0050] In some examples, LNA 406 is configured to receive the reflected radar signal via receive antenna 402 and convert the amplified (and, for example, filtered) reflected signal S RX is provided to mixer 410. In some examples, LNA 406 can be implemented in any manner known in the art.

[0051] In some examples, the mixer 410 is configured to TX and S RX Mixing is performed to generate an intermediate frequency signal S IF In some examples, the signal S IF is a current signal. In some examples, the signal S IFIn some examples, mixer 410 can be implemented in any manner known in the art.

[0052] In some examples, ADC 416 is configured to receive a voltage V from amplifier 412. out , and based on the voltage V out In some examples, ADC 416 can be used to generate one or more digital codes based on the signal S. ADC_EN is asserted (e.g., high), and is enabled when signal S ADC_EN In some examples, ADC 416 can be implemented in any manner known in the art.

[0053] In some examples, radar processing system 418 is configured to process digital data D raw , such as detecting, identifying, tracking, and / or classifying a target. In some examples, the radar processing system 418 may be based on the signal S DFE START And process data D raw For example, in some instances, for each chirp, the signal S DFE_START The data D received after being asserted (e.g., pulsed) raw can be processed, and the signal S DFE_START Data received before being asserted may be corrupted (e.g., saturated) and may be ignored. For example, in some instances, before signal S DFE_START Data D generated by ADC 416 and / or received by radar processing system 418 before being asserted raw was discarded.

[0054] In some examples, radar processing system 418 may include a general or custom controller or processor coupled to a memory and configured to execute instructions stored in this memory.Other implementations are also possible.

[0055] In some examples, controller 420 is configured to control circuits of millimeter wave radar system 400 or provide one or more inputs to the circuits, such as circuits 408, 414, 412, 416, and 418. For example, controller 420 may be configured to assert and deassert signal S gm_EN 、S ADC_EN and / or S DFE_START Controller 420 may deliver these signals to circuits 412, 416, and 418, as Figure 4As shown. By controlling one or more of these signals, controller 420 can be configured to enable and / or disable circuits 412, 416, and / or 418. In some examples, controller 420 can include a general-purpose or custom controller or processor coupled to a memory and configured to execute instructions stored in this memory. In some examples, controller 420 can include a finite state machine. Other implementations are also possible.

[0056] This described functionality is attributed to radar system 400 and controller 420. Radar system 400 and controller 420 may include processing circuitry, such as one or more processors. Radar system 400 and controller 420 may include any combination of integrated circuitry, discrete logic circuitry, and analog circuitry, such as one or more microprocessors, microcontrollers, digital signal processors, application specific integrated circuits, central processing units, graphics processing units, field programmable gate arrays, and / or any other processing resources. In some examples, radar system 400 and controller 420 may include multiple components, such as any combination of the processing resources listed above, as well as other discrete or integrated logic circuitry and / or analog circuitry.

[0057] The techniques described in this description may also be embodied or encoded in an article of manufacture that includes a non-transitory computer-readable storage medium. Example non-transitory computer-readable storage media may include random access memory (RAM), read-only memory (ROM), programmable ROM, erasable programmable ROM, electronically erasable programmable ROM, flash memory, a solid-state drive, a hard drive, magnetic media, optical media, or any other computer-readable storage device or tangible computer-readable medium. The term "non-transitory" may indicate that the storage medium is not embodied in a carrier wave or propagating signal. In some examples, a non-transitory storage medium may store data that may change over time (e.g., in RAM or cache).

[0058] In some examples, the IF amplifier 412 is configured to amplify and filter the signal S IF To generate an output voltage V out As shown, in some examples, IF amplifier 412 includes a forward path 422 and a feedback path 430 .

[0059] In some examples, forward path 422 includes amplifier 424, resistor 426, and capacitor 428. In some examples, amplifier 424, resistor 426, and capacitor 428 form a low-pass filter (with a corner frequency higher than the corner frequencies of high-pass filters 431 and 433). In some examples, amplifier 426 has a gain greater than 1.

[0060] In some examples, feedback path 430 includes high-pass filters 431 and 433. High-pass filter 431 includes amplifier 432, capacitor 442, and resistor 440. High-pass filter 433 includes amplifier 434, capacitor 460, and resistor 448.

[0061] like Figure 4 As shown, in some examples, amplifiers 424, 432, and 434 can be implemented as single-ended amplifiers. In some examples, amplifiers 424, 432, and 434 can be implemented as differential amplifiers.

[0062] In some examples, buffer 464 is configured to invert and buffer the signal from the output of amplifier 432 at unity gain into resistor 466. In some examples, the gain of buffer 464 can be different than 1. In some examples, buffer 464 can be implemented in any manner known in the art.

[0063] In signal S IF In some examples where the current is a current, the amplifier 424 can be implemented as a transimpedance amplifier (TIA). IF is the current (e.g., marked as I IF ), the amplifier 424 is implemented as a transimpedance amplifier that generates a current I IF Proportional output voltage V out (eg, where the gain has a magnitude higher than 1).

[0064] Signal S jam Indicates that an interference event is detected on the millimeter wave radar 400. In some examples, the signal S jam is generated by the controller 420 or external to the radar 400. In some examples, the signal S jam Generated based on the output of ADC 416 (eg, after saturation is detected at a time when saturation is not expected).

[0065] Signal S gm_EN is configured to increase the transconductance of the transimpedance amplifier 424 when asserted (eg, high). In some examples, the signal S gm_EN In response to the signal S jam Asserted by the assertion of the signal S jam In some instances, the signal S gm_EN With signal S jam Same (for example, signal S jam can be provided directly to amplifier 424).

[0066] Figure 6 A schematic diagram of a transimpedance amplifier 600 in an example of this specification is shown.IF In some examples, amplifier 424 can be implemented as a transimpedance amplifier 600 .

[0067] During normal operation, transistor 606 is biased with a voltage V B bias, and the voltage V out With current I IF is proportional to the transconductance g of the transimpedance amplifier 600. m Based on the currents I generated by current sources 602 and 604, respectively 602 and I 604 For example, a higher current I 602 and I 604 This results in a higher transconductance gm of the transimpedance amplifier 600 .

[0068] like Figure 6 As shown, the variable current sources 602 and 604 can be used with the signal S gm_EN In some examples, the signal S gm_EN The assertion causes the current I 602 Increase from the first current to the second current, and make the current I 604 In some examples, the signal S gm_EN The deassertion of the current I 602 The current I 604 The fourth current is reduced to the third current.

[0069] In some examples, variable current sources 602 and 604 can be implemented in any manner known in the art.

[0070] like Figure 6 As shown, in some examples, the transimpedance amplifier 600 can be single-ended. In some examples, the transimpedance amplifier 600 can be implemented as a differential amplifier (eg, by replacing single-ended inputs with differential inputs and single-ended outputs with differential outputs in a known manner).

[0071] Figure 7 Schematic diagram of a variable current source in examples of this specification is shown. In some examples, variable current sources 602 and / or 604 can be implemented as variable current source 700.

[0072] During normal operation, when the signal S gm_EN When de-asserted (eg, low), switch 706 is open (eg, deactivated), and the current I 704 is zero, and the current I generated by the current source 700 700 = equal to the current I generated by current source 702 702 When the signal S gm_ENWhen asserted (eg, high), switch 706 is closed (eg, activated), and the current I 700 Equal to I 702 +I 704 .

[0073] like Figure 4 As shown, in some examples, high frequency filters (e.g., 431, 433) are implemented as part of the feedback path 430. In some examples, one or more high pass filters may be implemented in the forward path rather than the feedback path. For example, Figure 8 A schematic diagram of amplifier 800 is shown in examples of the present specification. In some examples, amplifier 412 can be implemented as amplifier 800.

[0074] In some examples, amplifier 800 operates in a similar manner to amplifier 412, and Figure 5 The waveforms shown in FIG may be associated with amplifier 800. However, amplifier 800 includes a high pass filter 807 as part of the forward path 801 and a high pass filter 805 as part of the feedback path 803.

[0075] like Figure 8 As shown, amplifiers 802, 812, and 832 are differential amplifiers. Figure 8 As shown, the differential amplifier 802 receives the signal S gm_EN And in signal S gm_EN is asserted (e.g., by increasing the bias current, e.g., with Figure 6 and 7 In a similar manner as shown in FIG. 1 , the gm of amplifier 802 is increased.

[0076] In some examples, amplifiers 802 , 812 , and 832 can be implemented as single-ended amplifiers.

[0077] Advantages of some examples include the ability to successfully perform target detection and other radar signal processing tasks (eg, target tracking, classification, etc.) during jamming events.

[0078] As described above, some examples may be implemented in a millimeter wave radar system (e.g., 400). Some examples may be implemented in other types of systems, such as wireless communication systems, such as Bluetooth and WiFi systems. For example, in some examples, a receiver of a wireless communication device may be interfered with by the presence of a strong signal in the same frequency band (e.g., emitted by another nearby device). During this interference event, the signal S gm_EN Increasing the P1dB of the gain transconductance amplifier (eg, 424, 802) in the receiver path of the communication device may be asserted to eliminate saturation of the ADC and allow the received signal to be processed during the jammer event.

[0079] like Figure 4 and 5 As shown, the control signal S TX_EN The power amplifier 408 may be periodically shut down (e.g., after each chirp) to save power and, for example, to avoid thermal reliability issues due to self-heating. Each time the power amplifier 408 is enabled (e.g., at the beginning of each chirp), the cross-coupling between the transmitter path 450 (which includes the transmission path from the output of the FMCW synthesizer 414 to the antenna 404) and the receiver path 452 (which includes the transmission path from the antenna 402 to the input of the mixer 410) may cause the signal S to be IF exhibits strong (high amplitude) values at the low end of the spectrum, which can saturate the ADC 416 for a period of time t settle Therefore, the data D generated by ADC 416 raw In time period t settle Periods may not apply. Data D raw The useful samples (e.g., the time t of each chirp) 13 With t 14 between) can be further processed by the radar processing system 418.

[0080] In examples of the present specification, the saturation time of the ADC during the start of each chirp caused by cross-coupling when the transmitter path is enabled is reduced by temporarily increasing the P1dB of the amplifier (e.g., 424, 802) having its output coupled to the ADC. By reducing the saturation time of the ADC, some examples can advantageously reduce the pulse repetition time (e.g., Figure 5 t in 10 With t 14 time between chirps), and advantageously increases the number of samples available per chirp (and, therefore, the effective bandwidth of the millimeter-wave radar system).

[0081] Figure 9 5. The waveforms associated with radar system 400 in the examples of this specification are shown. Curve 502 shows signal S TX The frequency over time. Curves 504, 506, 910, 908 and 914 respectively show the signal S TX_EN 、S ACD_EN 、S DFE_START 、S FASTSET_EN and S gm_EN Digital status over time. Figure 4 and 9 Can be described together.

[0082] like Figure 9 As shown, in some examples, the signal S gm_EN Based on the signal S FASTSET_EN Rather than based on signal S jamAnd produced.

[0083] like Figure 9 As shown, in some examples, transmitter path 450 (eg, circuit 408 or a portion thereof) may be enabled (eg, by asserting signal S TX_EN , e.g., high) for chirp transmission and is disabled between chirps (e.g., by deasserting signal S TX_EN , for example, low), which can advantageously reduce power consumption. TX_EN When OUTPUT_P is asserted and chirps are transmitted, cross coupling may occur between transmitter path 450 and receiver path 452, which may temporarily saturate ADC 416. In some examples, the time that ADC 416 remains saturated depends on the P1dB of amplifier 424 and can be reduced by temporarily increasing the P1dB of amplifier 424.

[0084] In some examples, the P1dB of amplifier 424 is increased at or before the start of each chirp (by asserting signal S FASTSET_EN ) to reduce the time that ADC 416 remains saturated when transmitter path 450 is re-enabled. Once ADC 416 is no longer saturated, the P1dB of amplifier 424 is reduced to its original value (by 23 Deassert signal S FASTSET_EN ) to remind chirp.

[0085] In some instances, some instances advantageously exhibit a larger bandwidth B by reducing settling time. 400 , this is because time t 13 With t 14 The time between the two is longer when compared with the longer settling time. Larger bandwidth B 400 A better range resolution can advantageously be produced, for example, by adhering to the following relationship:

[0086] where d res represents the range resolution, c represents the speed of light, and B represents the chirp bandwidth.

[0087] By increasing the P1dB of amplifier 424 only during the beginning of the chirp, some examples advantageously achieve faster settling times without significantly impacting power consumption (because the amount of time that the P1dB of amplifier 424 is increased is relatively small).

[0088] In some examples, the signal S FASTSET_EN When asserted, causes the P1dB of the amplifier 424 to increase from a first value to a second value; and when de-asserted, causes the P1dB of the amplifier 424 to decrease from the second value to the first value.

[0089] In some instances, S FASTSET_ENThe duration of the pulse (e.g., S FASTSET_EN The duration that the pulse is asserted (e.g., high) and the start time of the SFASTSET_EN pulse are programmable.

[0090] In some instances, the signal S TX_EN The controller 420 generates a signal S simultaneously with or before the assertion of FASTSET_EN .

[0091] In some examples, the signal S gm_EN is configured to increase the transconductance of the transimpedance amplifier 424 when asserted (eg, high). In some examples, the signal S gm_EN In response to the signal S FASTSET_EN Asserted by the assertion of the signal S FASTSET_EN In some instances, the signal S gm_EN With signal S FASTSET_EN Same (for example, signal S FASTSET_EN can be provided directly to amplifier 424).

[0092] Although reducing the settling time by increasing the P1dB of amplifier 424 has been described with respect to radar 400, a similar approach may be implemented in radar 800 (e.g., by increasing the P1dB of amplifier 424 based on signal S FASTSET_EN The signal S gm_EN ).

[0093] like Figure 9 As shown, the signal S gm_EN Based on the signal S FASTSET_EN Instead of signal S jam In some examples, except for the signal S jam In addition, signal S gm_EN It can also be based on the signal S FASTSET_EN For example, in some instances, in the absence of an interference event (when S jam is low), signal S gm_EN It can be asserted periodically at the beginning of each chirp (e.g. Figure 9 to reduce the stabilization time t settle ; and in the presence of interference events (when S jam is high), signal S gm_EN The assertion may be maintained (e.g., for multiple chirps, e.g., Figure 5 In some such instances, the Figure 10 The OR gate (eg, 1002) shown generates a signal S gm_EN .

[0094] As described in co-pending U.S. patent application Ser. No. 18 / 157,511 (associated with attorney docket T101996US01), the settling time t settle Also in response to the signal S FASTSET_EN The assertion of is reduced by increasing the high pass corner frequency of high pass filters 433 and 431 in radar 400 and high pass filters 805 and 807 in radar 800. In some examples, signal S FASTSET_EN The assertion of simultaneously causes the high-pass corner frequency of the high-pass filters (433 and 431 of radar 400; and 805 and 807 of radar 800) to be increased, for example in the manner described in co-pending U.S. patent application Ser. No. 18 / 157,511 (associated with attorney docket No. T101996US01), and the P1dB of the transimpedance amplifiers (424 of radar 400; 802 of radar 800), which can advantageously further reduce the settling time t settle This is achieved without substantially increasing silicon area and power consumption, while maintaining the ability to detect close objects.

[0095] Figure 11 A schematic diagram of a millimeter wave radar system 1100 in an example of the present specification is shown. The millimeter wave radar system 1100 operates in a similar manner to the millimeter wave radar system 400. However, the millimeter wave radar system 1100 includes an OR gate 1002 for activating an OR gate at the beginning of each chirp (e.g., Figure 9 ) and during interference events (as shown in Figure 5 The millimeter wave radar system 1100 further includes high pass filters 1133 and 1131, which can respond to the signal S FASTSET_EN The assertion of increases its associated high-pass corner frequency by closing (e.g., activating) switches 1146 and 1138, respectively.

[0096] In some examples, the OR function implemented by OR gate 1002 can be implemented by controller 1120. Additionally, controller 1120 can be configured to assert and de-assert signal S TX 、S FASTSET_EN 、S ADC_EN and / or S DFE_START Controller 1120 may deliver these signals to circuits 408, 1112, 416, and 418, as Figure 11 As an example, the controller 1120 may be configured to control the signal S FASTSET_EN to activate or deactivate switches 1138 and 1146.

[0097] With about Figure 11In a similar manner as described above, the millimeter wave radar 800 can be modified so that the high-pass corner frequencies of the high-pass filters 805 and 807 are increased in response to the signal SFASTSET_EN, while the signal S provided to the amplifier 802 is gm_EN By signal S jam With S FASTSET_EN An OR function is performed between (eg, using OR gate 1002) to generate.

[0098] Figure 12 A motor vehicle is shown in the examples of this specification. The vehicle includes one or more millimeter wave radar systems 1200 (which can be implemented, for example, using radar systems 400, 800, or 1100). In some examples, radar system 1200 can be used to detect and track pedestrians, other vehicles, and / or other objects associated with travel on a road (e.g., sidewalks, streetlights, etc.).

[0099] Figure 13 A flowchart of an example method 1300 for interference mitigation in a millimeter wave radar system in an example of this specification is shown. The method 1300 can be performed, for example, by the millimeter wave radar systems 400, 1100, and 1202.

[0100] During step 1302, the controller (eg, 420, 1120) determines whether an interference event is detected. In some instances, when an interference signal (eg, S jam ) is asserted, the controller determines when a jamming event occurs. In some examples, the controller determines when the output voltage V out In some examples, the controller determines that when the output of the ADC (eg, 416) (eg, D raw ) is saturated. In some examples, the controller determines that when the total energy of the system (e.g., across all frequency bands, such as based on D performed by the radar processing system (e.g., 418) raw An interference event occurs when the FFT of

[0101] When a jammer event is detected ("yes" output during step 1302), the P1dB of the transconductance amplifier is increased from the first value to the second value during step 1304. In some examples, the P1dB of the transconductance amplifier is increased by increasing a bias current of the transconductance amplifier.

[0102] During step 1306, the controller determines whether the jamming event has ended. In some examples, the controller determines when the jamming event has ended when the jamming signal is deasserted. In some examples, the controller determines when the jamming event has ended when the total energy of the system (e.g., across all frequency bands, such as based on D raw The interference event ends when the FFT of

[0103] When the interference event ends ("yes" output during step 1306), the P1dB of the transconductance amplifier decreases from the second value to the first value, for example during step 1308. In some examples, the P1dB of the transconductance amplifier is decreased by decreasing the bias current of the transconductance amplifier.

[0104] Figure 14 A flow chart of an example method 1400 for mitigating cross-coupling interference in a millimeter-wave radar system according to an example of the present specification is shown. The method 1400 may be performed, for example, by the millimeter-wave radar systems 400, 1100, and 1202.

[0105] During step 1304 , a P1dB of (eg, 424 , 802 ) in a receiver path (eg, 452 , 1152 ) of a transceiver of a millimeter wave radar system (eg, 400 , 1100 , 1202 ) is increased from a first value to a second value.

[0106] During step 1404, while or after executing step 1304, the transmitter path (eg, 450) of the millimeter wave radar system is enabled (eg, by asserting signal S TX_EN ). In some examples, enabling the transmitter path includes enabling a power amplifier of the transmitter path (eg, 408).

[0107] During step 1406, and after enabling the transmitter path, a first signal (e.g., a chirp) is transmitted in the transmitter path, eg, using a power amplifier and via an antenna (e.g., 404).

[0108] During step 1408 , and during transmission of the first signal in the transmitter path, the corner frequency of the high pass filter is decreased (eg, from the second value to the first value).

[0109] Figure 15 A flow chart of an example method 1500 for mitigating cross-coupling interference in a millimeter-wave radar system according to an example of the present specification is shown. The method 1500 may be implemented, for example, by the millimeter-wave radar systems 400, 1100, and 1202.

[0110] During step 1502, the angular frequency of a high-pass filter (e.g., 431, 433, 805, 807, 1131, 1133) of a first amplifier (e.g., 412, 800, 1112) in a receiver path (e.g., 452, 1152) of a transceiver of a millimeter-wave radar system (e.g., 400, 1100, 1202) is increased from a first value to a second value.

[0111] During step 1504, while executing step 1502 or after, the transmitter path (eg, 450) of the millimeter wave radar system is enabled (eg, by asserting signal S TX_EN ). In some examples, enabling the transmitter path includes enabling a power amplifier of the transmitter path (eg, 408).

[0112] During step 1506, and after enabling the transmitter path, a first signal (e.g., a chirp) is transmitted in the transmitter path, eg, using a power amplifier and via an antenna (e.g., 404).

[0113] During step 1508, and during transmission of the first signal in the transmitter path, the corner frequency of the high pass filter is decreased (eg, from the second value to the first value).

[0114] In some examples, methods 1300, 1400, and 1500 may be combined. For example, Figure 16 A flow chart of an example method 1600 for interference mitigation in a millimeter wave radar system in an example of the present specification is shown. The method 1600 or portions thereof may be performed, for example, by the millimeter wave radar systems 400, 1100, and 1202.

[0115] like Figure 16 As shown, method 1600 can be performed in a similar manner to method 1300. However, in method 1600, when no interference event is detected ("No" output during step 1302), methods 1400 and / or 1500 can be performed. In some examples of performing both methods 1400 and 1500, steps 1304 and 1502 are performed simultaneously, steps 1404 and 1504 are performed simultaneously, steps 1406 and 1506 are the same step, and steps 1408 and 1508 are performed simultaneously.

[0116] Also like Figure 16 As shown, in method 1600, during an interference event ("No" output during step 1306), method 1500 may be performed periodically (eg, for each chirp transmission).

[0117] Example 1. A system includes: an analog-to-digital converter (ADC); a receiver path comprising a transimpedance amplifier having an output coupled to the ADC; and a controller coupled to the receiver path and configured to increase a transconductance of the transimpedance amplifier from a first transconductance value to a second transconductance value when an interference event is detected in the receiver path.

[0118] Example 2. The system of example 1, wherein the controller is further configured to reduce the transconductance of the transimpedance amplifier from the second transconductance value to the first transconductance value upon detecting an end of the jammer event of the receiver path.

[0119] Example 3. The system of any of examples 1 or 2, wherein the controller is configured to detect a jammer event based on an output of the ADC.

[0120] Example 4. The system of any of examples 1-3, wherein the transimpedance amplifier comprises a variable current source, and wherein the controller is configured to increase the transconductance of the transimpedance amplifier by increasing a current generated by the variable current source.

[0121] Example 5. The system of any one of examples 1 to 4, wherein the transimpedance amplifier is a single-ended transimpedance amplifier.

[0122] Example 6. The system of any one of examples 1 to 5, wherein the transimpedance amplifier is a differential transimpedance amplifier.

[0123] Example 7. The system of any of Examples 1-6, further comprising a transmitter path, wherein the controller is further coupled to the transmitter path, and wherein the controller is configured to: enable the transmitter path; and after enabling the transmitter path, cause the first signal to be transmitted via the transmitter path; and after transmitting the first signal via the transmitter path, disable the transmitter path.

[0124] Example 8. The system of any of Examples 1 to 7, wherein the controller is configured to: increase a transconductance of the transimpedance amplifier before transmitting a first signal; after disabling the transmitter path after the first signal is transmitted via the transmitter path, enable the transmitter path and cause a second signal to be transmitted via the transmitter path; and maintain the transconductance of the transimpedance amplifier at a second transconductance value during transmission of the first signal and the second signal.

[0125] Example 9. The system of any of Examples 1 to 8, wherein the controller is further configured to, after the jammer event has ended: increase the transconductance of the transimpedance amplifier from a first transconductance value to a second transconductance value; enable the transmitter path simultaneously with or after increasing the transconductance of the transimpedance amplifier; and decrease the transconductance of the transimpedance amplifier from the second transconductance value to the first transconductance value after the second signal begins to be transmitted in the enabled transmitter path and while the second signal is being transmitted in the enabled transmitter path.

[0126] Example 10. The system of any of Examples 1-9, further comprising a first high-pass filter coupled to the transimpedance amplifier, wherein the controller is further configured to: increase a corner frequency of the first high-pass filter from a first corner frequency value to a second corner frequency value; enable the transmitter path simultaneously with or after increasing the corner frequency of the first high-pass filter; and decrease the corner frequency of the first high-pass filter from the second corner frequency value to the first corner frequency value after the first signal begins to be transmitted in the enabled transmitter path and while the first signal is being transmitted in the enabled transmitter path.

[0127] Example 11. The system of any of examples 1-10, wherein the transmitter path comprises a power amplifier, wherein enabling the transmitter path comprises enabling the power amplifier, and wherein disabling the transmitter path comprises disabling the power amplifier.

[0128] Example 12. The system of any of Examples 1-11, wherein the transmitter path further comprises a frequency modulated continuous wave (FMCW) synthesizer configured to generate the first signal.

[0129] Example 13. The system of examples 1-12, wherein the system is a millimeter wave radar system, wherein the first signal is a chirp, and wherein the output of the FMCW synthesizer is coupled to the input of the transimpedance amplifier via a mixer.

[0130] Example 14. The system of any one of examples 1 to 13, wherein the system is a motor vehicle.

[0131] Example 15. The system of any of Examples 1-14, wherein the vehicle includes a plurality of millimeter-wave radar systems, and wherein the receiver path is part of a millimeter-wave radar system of the plurality of millimeter-wave radar systems.

[0132] Example 16. The system of any one of examples 1 to 15, wherein the system is a wireless communication system.

[0133] Example 17. A system comprising: an analog-to-digital converter (ADC); a transmitter path; a receiver path comprising a transimpedance amplifier having an output coupled to the ADC; and a controller coupled to the transmitter path and the receiver path, wherein the controller is configured to: increase a transconductance of the transimpedance amplifier from a first transconductance value to a second transconductance value, enable the transmitter path simultaneously with or after increasing the transconductance of the transimpedance amplifier, and decrease the transconductance of the transimpedance amplifier from the second transconductance value to the first transconductance value after a first signal begins to be transmitted in the enabled transmitter path and while the first signal is being transmitted in the enabled transmitter path.

[0134] Example 18. The system of Example 17, further comprising a high-pass filter coupled to the transimpedance amplifier, wherein the controller is further configured to: increase the corner frequency of the high-pass filter from the first corner frequency value to the second corner frequency value when the transconductance of the transimpedance amplifier increases from the first transconductance value to the second transconductance value; and decrease the corner frequency of the high-pass filter from the second corner frequency value to the first corner frequency value when the transconductance of the transimpedance amplifier decreases from the second transconductance value to the first transconductance value.

[0135] Example 19. The system of any of Examples 17 or 18, wherein the controller is further configured to increase the transconductance of the transimpedance amplifier from a first transconductance value to a second transconductance value upon detecting a jammer event of the receiver path.

[0136] Example 20. The system of any of examples 17 to 19, wherein the controller is configured to detect a jammer event based on an output of the ADC.

[0137] Modifications to the described examples may be made, and other examples are possible, within the scope of the claims.

Claims

1. A system comprising: Analog-to-digital converter (ADC); a receiver path comprising a transimpedance amplifier having an output coupled to the ADC; and A controller is coupled to the receiver path and configured to increase a transconductance of the transimpedance amplifier from a first transconductance value to a second transconductance value upon detecting a jammer event of the receiver path. 2 . The system of claim 1 , wherein the controller is further configured to reduce the transconductance of the transimpedance amplifier from the second transconductance value to the first transconductance value upon detecting an end of the jammer event of the receiver path. 3 . The system of claim 1 , wherein the controller is configured to detect the jammer event based on an output of the ADC. 4 . The system of claim 1 , wherein the transimpedance amplifier comprises a variable current source, and wherein the controller is configured to increase the transconductance of the transimpedance amplifier by increasing a current generated by the variable current source. The system of claim 1 , wherein the transimpedance amplifier is a single-ended transimpedance amplifier. The system of claim 1 , wherein the transimpedance amplifier is a differential transimpedance amplifier.

7. The system of claim 1 , further comprising a transmitter path, wherein the controller is further coupled to the transmitter path, and wherein the controller is configured to: enabling the transmitter path; and After enabling the transmitter path, causing a first signal to be transmitted via the transmitter path; and After the first signal is transmitted via the transmitter path, the transmitter path is deactivated.

8. The system of claim 7, wherein the controller is configured to: increasing the transconductance of the transimpedance amplifier before transmitting the first signal; After disabling the transmitter path after the first signal is transmitted via the transmitter path, enabling the transmitter path and causing a second signal to be transmitted via the transmitter path; and During transmission of the first signal and the second signal, the transconductance of the transimpedance amplifier is maintained at the second transconductance value.

9. The system of claim 8, wherein the controller is further configured to, after the interference event has ended: increasing the transconductance of the transimpedance amplifier from the first transconductance value to the second transconductance value; Simultaneously with or after increasing the transconductance of the transimpedance amplifier, enabling the transmitter path; and After a second signal begins transmitting in the enabled transmitter path, and while the second signal is being transmitted in the enabled transmitter path, the transconductance of the transimpedance amplifier is reduced from the second transconductance value to the first transconductance value.

10. The system of claim 7, further comprising a first high pass filter coupled to the transimpedance amplifier, wherein the controller is further configured to: increasing the angular frequency of the first high-pass filter from a first angular frequency value to a second angular frequency value; Simultaneously with or after increasing the corner frequency of the first high-pass filter, enabling the transmitter path; and After the first signal begins transmitting in the enabled transmitter path, and while the first signal is being transmitted in the enabled transmitter path, the corner frequency of the first high pass filter is reduced from the second corner frequency value to the first corner frequency value.

11. The system of claim 7, wherein the transmitter path comprises a power amplifier, wherein enabling the transmitter path comprises enabling the power amplifier, and wherein disabling the transmitter path comprises disabling the power amplifier.

12. The system of claim 11, wherein the transmitter path further comprises a frequency modulated continuous wave (FMCW) synthesizer configured to generate the first signal.

13. The system of claim 12, wherein the system is a millimeter wave radar system, wherein the first signal is a chirp, and wherein the output of the FMCW synthesizer is coupled to the input of the transimpedance amplifier via a mixer.

14. The system of claim 1, wherein the system is a motor vehicle. 15 . The system of claim 14 , wherein the vehicle includes a plurality of millimeter-wave radar systems, and wherein the receiver path is part of a millimeter-wave radar system of the plurality of millimeter-wave radar systems.

16. The system of claim 1, wherein the system is a wireless communication system.

17. A system comprising: Analog-to-digital converter (ADC); transmitter path; a receiver path comprising a transimpedance amplifier having an output coupled to the ADC; and a controller coupled to the transmitter path and the receiver path, wherein the controller is configured to: increasing a transconductance of the transimpedance amplifier from a first transconductance value to a second transconductance value; enabling the transmitter path simultaneously with or after increasing the transconductance of the transimpedance amplifier, and After a first signal begins transmitting in an enabled transmitter path, and while the first signal is being transmitted in the enabled transmitter path, the transconductance of the transimpedance amplifier is reduced from the second transconductance value to the first transconductance value.

18. The system of claim 17, further comprising a high pass filter coupled to the transimpedance amplifier, wherein the controller is further configured to: When the transconductance of the transimpedance amplifier increases from the first transconductance value to the second transconductance value, increasing the corner frequency of the high-pass filter from a first corner frequency value to a second corner frequency value; and When the transconductance of the transimpedance amplifier decreases from the second transconductance value to the first transconductance value, the corner frequency of the high-pass filter decreases from the second corner frequency value to the first corner frequency value.

19. The system of claim 17, wherein the controller is further configured to increase the transconductance of the transimpedance amplifier from the first transconductance value to the second transconductance value upon detecting a jammer event of the receiver path.

20. The system of claim 19, wherein the controller is configured to detect the jammer event based on an output of the ADC.

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