Method and radar MMIC device for determining phase information relating to RF transmission channel

Abstract

The invention relates to a method and a radar MMIC device for determining phase information related to an RF transmit channel. The method comprises generating a frequency modulated RF signal comprising a frequency ramp; coupling a first representation of the frequency modulated RF signal to an RF transmit channel to generate a first frequency modulated RF output signal; and coupling the second representation of the frequency modulated RF signal to the test phase shifter. Generating a set of measurement samples during the frequency ramp; and calculating phase information related to the RF transmit channel based on the set of measurement samples.

Description

Technical Field

[0001] The present disclosure relates to the field of determining phase information associated with an RF transmit channel, and in particular to determining phase information of a transmit channel of a radar MMIC device. Background Art

[0002] Nowadays, radar sensors are used in many cars and other vehicles to assist drivers or provide autonomous driving, wherein the radar sensors use at least one radar monolithic microwave integrated circuit (MMIC) device. Such applications require a high degree of safety, because a failure of the radar MMIC device or operation outside the specified operating range of the radar MMIC device may result in unreliable operation or failure of the auxiliary system. Typically, several safety goals of the radar MMIC device are defined for certain transmission signal parameters. These parameters are usually monitored by the radar MMIC device to achieve the required safety level.

[0003] Typically, the phase and amplitude balance between all transmit (TX) channels involved in radar measurements needs to be within certain ranges to ensure operation defined in the device specification. For the phase of the transmit channels, usually only a few degrees of phase imbalance is allowed.

[0004] In view of the above, a concept is needed to provide an improved determination of phase information for the transmit channel of a radar MMIC. Summary of the invention

[0005] According to one example, a method for determining phase information associated with an RF transmit channel includes generating a frequency modulated RF signal, the frequency modulated RF signal including a frequency ramp; coupling a first representation of the frequency modulated RF signal to the RF transmit channel to generate a first frequency modulated RF output signal; and coupling a second representation of the frequency modulated RF signal to a test phase shifter. A set of measurement samples is generated during the frequency ramp, the set of measurement samples being generated based on: during the frequency ramp, setting a phase offset provided by the test phase shifter to each phase offset value in a predetermined phase offset value set, and phase shifting the second representation of the frequency modulated RF signal according to the corresponding phase offset value to generate a frequency modulated RF test signal; generating a down-converted signal based on mixing the first representation of the first frequency modulated RF output signal with the frequency modulated RF test signal; sampling the down-converted signal to generate a corresponding measurement sample in the set of measurement samples for each phase offset value in the set of phase offset values, the method also including calculating the phase information associated with the RF transmit channel based on the set of measurement samples.

[0006] According to another example, a radar MMIC device includes a local oscillator for generating a frequency modulated RF signal including a frequency ramp, an RF transmit channel, a test phase shifter, and a first coupler, the first coupler being configured to couple a first representation of the frequency modulated RF signal to the RF transmit channel and a second representation of the frequency modulated RF signal to the test phase shifter. The RF transmit channel is configured to generate a first frequency modulated RF output signal based on the frequency modulated RF signal, and the test phase shifter is configured to phase shift the second representation of the frequency modulated RF signal according to a phase offset applied to the test phase shifter and generate a frequency modulated RF test signal. A second coupler is coupled to the RF transmit channel to generate a first representation of the frequency modulated RF output signal. A mixer is coupled to the test phase shifter and the second coupler to receive the first representation of the frequency modulated RF output signal and the frequency modulated RF test signal, wherein the mixer is further configured to generate a down-converted signal based on mixing the first representation of the frequency modulated RF output signal with the frequency modulated RF test signal. A controller is configured to set the phase offset applied to the test phase shifter during the frequency ramp to each phase offset value in a predetermined phase offset value set. A sampler is provided to sample the down-converted signal to generate a corresponding measurement sample in a set of measurement samples for each phase offset value in the set of phase offset values. A processor calculates phase information related to a transmission channel based on the set of measurement samples.

[0007] Those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present disclosure is illustrated by way of example and not limitation in the figures of the accompanying drawings, in which the same reference numerals represent similar or identical elements. The elements in the accompanying drawings are not necessarily drawn to scale relative to each other. Unless mutually exclusive, the features of the various illustrated examples may be combined.

[0009] Figure 1 illustrates a circuit diagram according to an example;

[0010] FIG. 2A to FIG. 2C A process of generating a set of measurement samples according to an example is illustrated;

[0011] Figure 3 illustrates an estimation of phase error according to an example;

[0012] Figure 4 Another example of generating a set of measurement samples is illustrated; and

[0013] Figure 5 A flow chart according to an example is illustrated. DETAILED DESCRIPTION

[0014] The examples described herein provide a new concept for determining phase information for calibration and monitoring routines. The new concept allows reducing the spectral power density generated during the determination of the phase information and, in some examples, also allows determining the phase information based on a frequency modulated continuous wave (FMCW) signal during field operation of a radar MMIC device.

[0015] Existing solutions use a continuous wave signal with a constant frequency from a phase-locked loop (PLL) to determine the phase information of the transmit channel. In contrast, the use of an FMCW signal to determine the phase information achieves a significant reduction in the average power spectral density emitted by the MMIC device during operation, because the frequency of the signal used to determine the phase information is no longer concentrated at one frequency, but is spread over a certain frequency band. This allows staying within the emission requirements of standard bodies such as ETSI (European Telecommunications Standards Institute) without having to reduce the transmit power.

[0016] Furthermore, the same type of signal (i.e., FMCW signal) is used for both the specified field operation (i.e., determining the distance, speed, or direction of arrival) and monitoring or calibration. Monitoring and calibration are thus performed under realistic conditions and the safety level is increased. Furthermore, the measurement is performed only during one frequency ramp, which allows for a quick determination of phase information suitable for field operation.

[0017] The determination of the phase information may be performed periodically during field operation, for example between respective FMCW ramps (chirps) or between FMCW ramp frames.

[0018] In other examples, the same FMCW signal transmitted during the frequency ramp used to detect the distance, velocity, or angle of arrival of an object may be used for monitoring and calibration.

[0019] The determination of the phase information proposed herein allows the integration of the required components in one semiconductor chip (eg one MMIC chip), and thus the concept can be implemented as a chip-internal measurement (all required steps are performed in one semiconductor chip).

[0020] Reference now Figure 1 , the radar device 10 is shown to include a plurality of transmit channels 12-1 to 12-4 for generating transmit signals. The radar device 10 may be an MMIC semiconductor chip, and for the sake of clarity, Figure 1Other functions that can be implemented in the radar device 10, such as receiving channels, are omitted. Each input of the corresponding transmit channel is coupled to a local oscillator (LO) 18 via a first coupler 14 and a second coupler 16. The first coupler 14 and the second coupler 16 are implemented as a splitter formed by passive components. Each transmit channel includes a phase shifter 20 (hereinafter referred to as a transmit phase shifter 20), a power amplifier 22, and a coupler 24. Each transmit channel in the transmit channels 12-1 to 12-4 may include other components not shown for simplicity. The local oscillator 18 is configured to generate a frequency modulated radio frequency signal 25 (frequency modulated RF signal 25) including a frequency ramp. In the example, the frequency modulated RF signal 25 is a frequency modulated continuous wave signal (FMCW signal), which includes a linear frequency ramp with a start frequency and a stop frequency. The frequency ramp can be a rising ramp so that the frequency increases over time, or a falling ramp so that the frequency decreases over time.

[0021] The frequency modulated RF signal 25 is split by the first coupler 14 into a first representation of the frequency modulated RF signal (referred to herein as a transmit path signal 26) and a second representation of the frequency modulated RF signal (referred to herein as a test path signal 28). The transmit path signal 26 and the test path signal 28 are copies of the frequency modulated RF signal with a reduced power level compared to the LO signal. The test path signal 28 is transmitted to a test circuit device 30, which will be described in more detail below. The transmit path signal 26 is coupled to the input of the second coupler 16. The second splitter 16 splits the transmit path signal 26 into four representations, which are transmitted to the transmit channels 12-1 to 12-4 via the outputs of the second splitter 16, respectively. The transmit channels 12-1 to 12-4 can be controlled to be activated for processing or deactivated, for example by enabling the power amplifier 22 or disabling the power amplifier 22. During radar processing operations, for example, all or a set of transmit channels in the transmit channels 12-1 to 12-4 can be activated. During a monitoring or calibration operation to be described below, only one of the plurality of transmission channels may be activated.

[0022] The activated transmit channel processes the received transmit path information 26 by applying a corresponding phase shift via the transmit phase shifter 20 and amplifying the phase-shifted transmit path signal 26 to generate a frequency modulated RF output signal 32. The frequency modulated RF output signal 32 is transmitted to the input of the coupler 24, which couples a first representation 34 of the frequency modulated RF output signal 32 to the input of the combiner 36. A second representation 38 of the frequency modulated RF output signal 32 may be transmitted to the antenna port associated with the corresponding transmit channel. The second representation may be a major portion of the frequency modulated RF output signal 32, i.e., the signal power of the second representation 38 may be higher than the signal power of the first representation 34.

[0023] Combiner 36 may include an input associated with each of transmit channels 12-1 through 12-4 that is coupled to the corresponding transmit channel's coupler 24. Combiner 36 couples first representation 34 of frequency modulated RF output signal 32 to a first input of mixer 38 (also referred to herein as test mixer 38) of test circuitry 30.

[0024] The test circuit device 30 also includes a phase shifter 40 (also referred to herein as a test phase shifter 40). In some examples, the test phase shifter 40 may include a passive phase shifter that improves the accuracy of the phase offset. The input of the test phase shifter 40 is coupled to the output of the coupler 14 to receive the test path signal 28. The test phase shifter 40 applies a phase offset to the test path signal 28 to generate a frequency modulated RF test signal 29, which has a phase offset based on the phase offset value applied to the test phase shifter 40 by the controller 50. The output of the test phase shifter 40 is coupled to a second input of the test mixer 38 to transmit the frequency modulated RF test signal 29 to the test mixer 38. The test mixer 38 mixes the two signals (also referred to herein as down-converting) and provides a down-converted signal 42 at the output, which can be amplified by an optional amplifier 44. The amplified down-converted signal 42 is provided to an analog-to-digital converter 46 to generate a set of measurement samples, as will be described in more detail below.

[0025] The measurement sample set is provided to a processor 48, which is configured to calculate phase information associated with the corresponding transmission channel. The controller 50 is configured to set the phase offset applied to the test phase shifter 40 during the frequency ramp to each phase offset value in the predetermined phase offset value set, as will be described in more detail. The controller 50 also controls the sampling of the measurement samples so that at least one measurement sample is generated for each phase offset value in the phase offset value set. The controller 50 and the processor 48 can be implemented as hardware circuits, software, firmware or any combination thereof. The processor 48 can, for example, include a Goertzel filter or FFT circuit and a programmable arithmetic logic unit or a digital processor capable of performing data processing or executing a programming step. In some examples, the controller 50 can utilize the same components in whole or in part, or can be implemented as one unit. For example, the controller 50 can use the processor 48 to perform control operations.

[0026] Reference now FIG. 2A to FIG. 2C , the setting of the phase offset during the frequency ramp and the sampling of the measurement samples will be described in more detail. Figure 2A The frequency of the frequency modulated RF signal 25 is shown as a function of time during a frequency ramp. Figure 2AThe frequency of the frequency modulated RF signal 25 is shown to increase linearly during the frequency ramp from the start frequency to the stop frequency. In other examples, the frequency may decrease linearly. Although the examples shown herein use a linear frequency ramp, other examples may deviate from a linear ramp characteristic. The start frequency and the stop frequency may, for example, be within a dedicated radar frequency band, for example, between 76 GHz and 81 GHz.

[0027] Figure 2B 1 shows the phase offsets applied by the test phase shifter 40 to generate the frequency modulated RF test signal 29. During a frequency ramp of the frequency modulated RF test signal 28 (which corresponds to the frequency ramp of the frequency modulated RF signal 25), each phase offset value in the phase offset value set 100 is applied to the test phase shifter 40 to provide a corresponding phase offset to the frequency modulated RF test signal 29. In other words, the frequency modulated RF test signal 29 can be viewed as being divided into a sequence of time intervals. During corresponding time intervals in the sequence of time intervals, the frequency modulated RF test signal 29 contains a phase offset that is based on the phase offset of the phase offset value set 100 assigned to that time interval. Figure 2B In the example of , the phase offset value is a sequence of eight phase offset values ​​that increase from 0 to 7π / 4 in equally spaced steps. Figure 2B Eight phase offset values ​​are shown as being applied during the frequency ramp, but it should be noted that in other examples, other numbers of phase offset values ​​may be applied. The number of phase offset values ​​may be N, and the phase offset values ​​may increase from 0 to 2π(N-1) / N. Furthermore, it should be noted that in other examples, the phase offset value set 100 may include a sequence of decreasing phase offset values. Figure 2B The time intervals during which the respective phase offsets are applied are shown to have the same duration. However, in other examples, the durations may not be equal.

[0028] As previously described, the frequency modulated RF test signal 29 is mixed with the first representation 34 of the frequency modulated RF output signal 32 to generate the down-converted signal 42 .

[0029] The frequency modulated RF test signal 29 can be described by the following equation:

[0030]

[0031] Where S PMLO is the frequency modulated RF test signal 29, t is the time in the interval [0, T], T is the duration of the frequency ramp, k is the slope of the frequency ramp, f0 is the starting frequency of the frequency ramp, and A1 is the constant amplitude. is the phase shift in radians applied by the test phase shifter 40 and can be obtained by is defined by , where N is the number of phase offset values ​​in the phase offset value set, and n=0, 1, ..., N-1 is an index defined by an integer sequence.

[0032] The first representation 36 of the frequency modulated RF output signal 34 may be described by the following equation:

[0033]

[0034] where s TX (t) is a first representation 36 of the frequency modulated RF output signal 34, is the configured phase offset imposed by the phase shifter 20 in the corresponding transmit channel, and τ represents the signal s at the test mixer 40 PMLO (t) and s TX The arrival time difference between (t) and (t) (also referred to as RF delay time in this article). Figure 1 As shown, τ is caused by the signal delay caused by the additional circuit components of the transmit channel.

[0035] After mixing, the down-converted signal 42 is obtained as

[0036]

[0037] where mixout(t) is the down-converted signal 42 .

[0038] Consider that in the first summand of mixout(t), the term 4πf0t corresponds to the frequency 2f0, which is in the range of tens or hundreds of GHz, while the other time-dependent terms 2πkτt and 2πkt 2 The frequency is only slightly modified, the first addend can be neglected due to the low pass filtering characteristics of the circuitry following the test mixer 38 (eg, amplifier 44), and the down converted signal 42 at the input of the analog to digital converter 46 can be represented by

[0039]

[0040] Note that the arrival time difference τ introduces oscillations in the down-converted signal 42 at frequency kτ. It should also be noted that for τ = 0 (no arrival time difference), the down-converted signal 42 will be a DC value that matches the DC value obtained when using a continuous wave signal without frequency modulation (k = 0). The phase term of this function is given by Assuming that the samples of the down-converted signal 42 are time-aligned with the phase offset setting every nTs, where Ts is the sampling interval and n is the index variable introduced previously, the sampled down-converted signal s[n] can be regarded as a set of measurement values

[0041]

[0042] Note that when τ is in the picosecond range, the term πkτ 2 In an example, the time alignment may include that the time interval between two consecutive settings of the phase offset corresponds to the time interval between two consecutive samplings of the measurement sample, which allows reducing the workload in processing and implementation.

[0043] Figure 2C The sampling time T s An example of a set 102 of acquired measurement samples. Thus, the set of measurement values ​​s[n] contains N discrete measurement points constituting one sampling period of the cosine wave as a function of the index variable n. Figure 2C The relationship between the sampled values ​​(in volts) of eight measurement samples s1 ... s7 and time is shown, and for ease of explanation, the corresponding cosine function s(t) mentioned above is also illustrated.

[0044] The frequency of the first-order harmonic function is given by Definition. Compared with continuous wave signals, the use of FM signals introduces an additional frequency component 2πkτT s , which can be regarded as the error frequency. The phase term of this first-order harmonic function is It should be noted that all information for determining amplitude and phase parameters can be derived from the first-order harmonic bin values ​​(intervals with frequency index 1 in the frequency index set m=0, 1, ..., M-1, M=N) of the Fourier transform result (first-order harmonic Fourier coefficient) by fast Fourier transform (FFT) or single-point digital Fourier transform (e.g., using a Goertzel filter). The result can be used to calibrate and / or monitor safety-related emission parameters within the radar device 10.

[0045] The first-order harmonic interval value is a complex value and can be written as z1=Re(z1)+Im(z1), where Re is the real part of the complex-valued first-order harmonic interval value and Im is the imaginary part of the complex-valued first-order harmonic interval value.

[0046] In πkτ 2 Under the assumption that It can be derived by determining or estimating the inverse tangent of (Im(z1) / Re(z1)) or arctan2(Im(z1), ReIm(z1)). For example, the inverse tangent or arctan2 can be estimated using a Cordic implementation or using a processor capable of calculating or estimating the inverse tangent function.

[0047] It should be noted that the phase term Contains the phase of the transmit channel to be determined and a factor 2πf0τ caused by the arrival time difference τ, which is the same for all transmit channels. By determining the above phase term between two or more transmit channels, relative phase information between the channels can be determined, which allows the transmit channels to be calibrated and monitored relative to each other.

[0048] Furthermore, it should be noted that due to discrete sampling, a phase error may be introduced considering the use of a frequency modulated RF signal instead of a fixed frequency signal as the test signal. The phase error can be estimated by integrating the above error frequency over the full harmonic swing. Since s[n] represents a digital signal, the integration can be replaced by a summation and the analytical phase error can be estimated by

[0049]

[0050] The introduced error and the post-processing error correction depend on the slope k of the ramp, the sampling interval Ts and the number N of phase offsets in the phase offset sequence. All these parameters can be determined or are known, and the phase error can be calculated and corrected based on these parameters. The RF delay time τ can be estimated from the zero-order harmonic interval (DC mean). Considering the following values ​​k = 1 MHz / μs, T s =3μs, N=8 and τ=250ps (which are typical values ​​for radar applications), the expected error is calculated to be e=0.945°.

[0051] The test circuit device 30 of the radar device 10 estimates the phase value corresponding to the true phase value based on applying a Fourier transform to s[n]. This further leads to the deviation of the phase term , effectively resulting in a sinusoidal fluctuation around e. It can be shown that the actual error can be approximated by

[0052]

[0053] Phase error FT Depends on the phase term and thus effectively depends on the phase to be determined

[0054] Figure 3 is shown as the phase term The above estimation of the phase error as a function of is shown in graph 200. Curve 202 shows the phase error It is calculated as e = 0.945° and is related to the phase term Curve 202 shows the phase error introduced by the digital Fourier transform (DFT), and curve 204 shows the phase error introduced by the DFT The above estimate of the phase error introduced. Note that the mean of curves 202 and 204 is πkτTs (N-1).

[0055] It can be observed that curve 204 is almost identical to curve 202, which indicates that the introduced phase error can be accurately corrected using the above approximation.

[0056] It should also be noted that a delayed start of sampling may introduce further phase errors, which will refer to Figure 4 Give a description.

[0057] Figure 4 shows a delay time T D This results in the frequency f0 being replaced by the effective frequency f0+kT D .Notice, Figure 4 A decreasing ramp with a negative slope K is shown. The set of measured values ​​is obtained by the following formula

[0058]

[0059] From the above equation, we can see that the delay time T D The additional term 2πkτT is introduced D , which can also be calculated and corrected.

[0060] Reference now Figure 5 A basic flow chart example of a method using the proposed concept is described. The method first generates a frequency modulated RF signal, the frequency modulated RF signal comprising a frequency ramp (S10). A first representation of the frequency modulated RF signal is coupled to an RF transmit channel to generate a first frequency modulated RF output signal (S20). A second representation of the frequency modulated RF signal is coupled to a test phase shifter (S30). A set of measurement samples is generated during the frequency ramp, the set of measurement samples being generated based on sub-steps S40-1 to S40-3. Sub-step S40-1, during the frequency ramp, a phase offset provided by the test phase shifter is set to each phase offset value in a predetermined phase offset value set, and a second representation of the frequency modulated RF signal is phase shifted according to the corresponding phase offset value to generate a frequency modulated RF test signal. Sub-step S40-2 includes generating a down-converted signal based on mixing the first representation of the first frequency modulated RF output signal with the frequency modulated RF test signal. Sub-step S40-3 includes sampling the down-converted signal to generate a corresponding measurement sample in the set of measurement samples for each phase offset value in the set of phase offset values. Finally, in step S50, phase information related to the RF transmission channel is calculated based on the set of measurement samples.

[0061] In addition to the above examples, the following examples are also disclosed herein.

[0062] Example 1 is a method for determining phase information associated with an RF transmit channel, the method comprising:

[0063] generating a frequency modulated RF signal, the frequency modulated RF signal comprising a frequency ramp,

[0064] coupling a first representation of the frequency modulated RF signal to the RF transmit channel to generate a first frequency modulated RF output signal,

[0065] coupling a second representation of the frequency modulated RF signal to a test phase shifter,

[0066] A set of measurement samples is generated during the frequency ramp, the set of measurement samples being generated based on:

[0067] during the frequency ramp, setting the phase offset provided by the test phase shifter to each phase offset value in a predetermined set of phase offset values ​​and phase shifting the second representation of the frequency modulated RF signal according to the respective phase offset values ​​to generate a frequency modulated RF test signal,

[0068] generating a down-converted signal based on mixing a first representation of the first frequency modulated RF output signal with the frequency modulated RF test signal,

[0069] sampling the down-converted signal to generate a corresponding measurement sample in a set of measurement samples for each phase offset value in the set of phase offset values, and

[0070] The phase information associated with the RF transmit channel is calculated based on the set of measurement samples.

[0071] Example 2 is the method of Example 1, wherein the sampling of the down-converted signal and the setting of the phase offset are aligned in time.

[0072] Example 3 is a method according to Example 2, wherein a time interval between two consecutive settings of the phase offset corresponds to a time interval between two consecutive samplings of a measurement sample.

[0073] Example 4 is a method according to any one of Examples 1 to 3, wherein calculating the phase information includes generating first-order harmonic information related to a first-order harmonic included in the set of measurement values.

[0074] Example 5 is a method according to Example 4, wherein generating first-order harmonic information comprises a Fourier transform of the set of measurement values, and wherein the first-order harmonic information corresponds to first-order harmonic Fourier transform coefficients.

[0075] Example 6 is a method according to Example 4 or 5, wherein the first-order harmonic information includes an imaginary part and a real part, and determining the phase information is based on using the imaginary part and the real part.

[0076] Example 7 is a method according to Example 6, wherein the method further comprises:

[0077] A phase error correction value is estimated, and the phase information is determined based on the phase error correction value.

[0078] Example 8 is the method of Example 7, wherein the phase error correction value is estimated based on a slope of the frequency ramp.

[0079] Example 9 is a method according to any one of Examples 7 or 8, wherein the phase error correction value is estimated based on a sampling rate used in the sampling of the down-converted signal.

[0080] Example 10 is a method according to any one of Examples 7 to 9, wherein the phase error correction value is estimated based on an RF delay time corresponding to an arrival time difference between the first frequency modulated RF output signal and the frequency modulated RF test signal.

[0081] Example 11 is a method according to any one of Examples 7 to 10, wherein the phase error correction value is estimated based on the number of phase offset values ​​in the set of phase offset values.

[0082] Example 12 is a method according to any one of Examples 7 to 11, wherein the phase error correction value is estimated based on a time difference between a start of the frequency ramp and a start of sampling of the down-converted signal.

[0083] Example 13 is a method according to any one of Examples 1 to 12, wherein the time point at which the phase offset changes from a previously applied phase offset value to a currently applied phase offset value is offset from the time point at which the down-converted signal is sampled to generate the corresponding measurement sample corresponding to the currently applied phase shift value.

[0084] Example 14 is a method according to any one of Examples 1 to 13, further comprising storing the phase information related to the transmit channel in a memory, and setting the phase offset of the phase shifter in the transmit channel based on the stored phase information.

[0085] Example 15 is a method according to any one of Examples 1 to 14, further comprising determining whether the phase information exceeds a predetermined standard, and generating monitoring alarm information if the phase information exceeds the predetermined standard.

[0086] Example 16 is a method according to any one of Examples 1 to 15, further comprising coupling a second representation of the first frequency modulated RF output signal to an antenna for transmission, receiving a reflected signal of the second representation of the first frequency modulated RF signal from an object, and processing the reflected signal to determine at least one of a distance or a speed or a direction of arrival of the object.

[0087] Example 17 is a method according to any one of Examples 1 to 16, wherein the down-converted signal is low-pass filtered prior to the sampling.

[0088] Example 18 is a radar MMIC device comprising:

[0089] A local oscillator for generating a frequency modulated RF signal including a frequency ramp,

[0090] RF transmit channel,

[0091] Testing the phase shifter,

[0092] a first coupler configured to couple a first representation of the frequency modulated RF signal to the RF transmit channel and a second representation of the frequency modulated RF signal to the test phase shifter, wherein the RF transmit channel is configured to generate a first frequency modulated RF output signal based on the frequency modulated RF signal, and wherein the test phase shifter is configured to phase shift the second representation of the frequency modulated RF signal according to a phase shift applied to the test phase shifter and generate a frequency modulated RF test signal,

[0093] a second coupler coupled to the RF transmit channel to generate a first representation of the frequency modulated RF output signal,

[0094] a mixer coupled to the test phase shifter and the second coupler to receive the first representation of the frequency modulated RF output signal and the frequency modulated RF test signal, wherein the mixer is further configured to generate a down-converted signal based on mixing the first representation of the frequency modulated RF output signal with the frequency modulated RF test signal,

[0095] a controller for setting the phase offset applied to the test phase shifter during the frequency ramp to each phase offset value in a predetermined set of phase offset values,

[0096] a sampler for sampling the down-converted signal to generate a corresponding measurement sample in a set of measurement samples for each phase offset value in the set of phase offset values, and

[0097] A processor is configured to calculate phase information related to the transmission channel based on the set of measurement samples.

[0098] Example 19 is the radar MMIC device of Example 18, wherein the controller is configured to temporally align the setting of the phase offset with the sampling of the down-converted signal.

[0099] Example 20 is a radar MMIC device according to Example 18 or 19, wherein the processor is configured to calculate the phase information based on generating first-order harmonic information related to a first-order harmonic included in the set of measurement values.

[0100] Example 21 is a radar MMIC device according to Example 20, wherein the first-order harmonic information includes an imaginary part and a real part, and wherein the processor is configured to calculate the phase information based on the imaginary part and the real part.

[0101] Example 22 is a radar MMIC device according to any one of Examples 18 to 21, wherein the processor is configured to estimate a phase error correction value and calculate the phase information based on the phase error correction value.

[0102] Example 23 is a radar MMIC device according to any one of Examples 18 to 22, wherein the controller is further configured to determine whether the calculated phase information exceeds a predetermined standard, and to generate monitoring alarm information if the phase information exceeds the predetermined standard.

[0103] Although specific examples have been shown and described herein, it will be appreciated by those skilled in the art that various alternatives and / or equivalent implementations may replace the specific examples shown and described without departing from the scope of the present invention. This application is intended to cover any adaptation or variation of the specific examples discussed herein. Therefore, the present invention is limited only by the claims and their equivalents.

[0104] It should be noted that the methods and devices outlined in this document (including preferred embodiments thereof) may be used alone or in combination with other methods and devices disclosed in this document. Furthermore, features outlined in the context of a device also apply to the corresponding method and vice versa. Furthermore, all aspects of the methods and devices outlined in this document may be combined in any manner. In particular, features of the claims may be combined with each other in any manner.

[0105] It should be noted that the description and the accompanying drawings illustrate only the principles of the proposed method and system. Those skilled in the art will be able to implement various arrangements, which, although not explicitly described or illustrated herein, embody the principles of the present invention and are included within the spirit and scope of the present invention. In addition, all examples and embodiments outlined in this document are primarily intended for explanatory purposes only to help the reader understand the principles of the proposed method and system. In addition, all statements of the principles, aspects and embodiments of the present invention, and specific examples thereof, provided herein are intended to encompass their equivalents.

Claims

1. A method for determining phase information associated with an RF transmit channel, the method comprising: generating a frequency modulated RF signal, the frequency modulated RF signal comprising a frequency ramp, coupling a first representation of the frequency modulated RF signal to the RF transmit channel to generate a first frequency modulated RF output signal, coupling a second representation of the frequency modulated RF signal to a test phase shifter, A set of measurement samples is generated during the frequency ramp, the set of measurement samples being generated based on: during the frequency ramp, setting the phase offset provided by the test phase shifter to each phase offset value in a predetermined set of phase offset values ​​and phase shifting the second representation of the frequency modulated RF signal according to the respective phase offset values ​​to generate a frequency modulated RF test signal, generating a down-converted signal based on mixing a first representation of the first frequency modulated RF output signal with the frequency modulated RF test signal, sampling the down-converted signal to generate a corresponding measurement sample in a set of measurement samples for each phase offset value in the set of phase offset values, and The phase information associated with the RF transmit channel is calculated based on the set of measurement samples. 2 . The method of claim 1 , wherein the sampling of the down-converted signal and the setting of the phase offset are aligned in time. 3 . The method according to claim 2 , wherein the time interval between two consecutive settings of the phase offset corresponds to the time interval between two consecutive samplings of the measurement sample. 4 . The method according to claim 1 , wherein calculating the phase information comprises generating first-order harmonic information related to first-order harmonics included in the set of measurement values.

5. The method of claim 4, wherein generating first-order harmonic information comprises a Fourier transform of the set of measurements, and wherein the first-order harmonic information corresponds to first-order harmonic Fourier transform coefficients. 6 . The method according to claim 4 , wherein the first-order harmonic information comprises an imaginary part and a real part, and determining the phase information is based on using the imaginary part and the real part.

7. The method according to claim 6, wherein the method further comprises: A phase error correction value is estimated, and the phase information is determined based on the phase error correction value.

8. The method of claim 7, wherein the phase error correction value is estimated based on the slope of the frequency ramp.

9. The method according to any one of claims 7 or 8, wherein the phase error correction value is estimated depending on a sampling rate used in the sampling of the down-converted signal.

10. The method of any one of claims 7 to 9, wherein the phase error correction value is estimated based on an RF delay time corresponding to a time difference between the first frequency modulated RF output signal and the frequency modulated RF test signal.

11. The method according to any one of claims 7 to 10, wherein the phase error correction value is estimated according to the number of phase offset values ​​in the set of phase offset values.

12. The method according to any one of claims 7 to 11, wherein the phase error correction value is estimated from a time difference between the start of the frequency ramp and the start of sampling of the down-converted signal.

13. A method according to any one of claims 1 to 12, wherein the time point at which the phase offset is changed from a previously applied phase offset value to a currently applied phase offset value is offset from the time point at which the down-converted signal is sampled to generate the corresponding measurement sample corresponding to the currently applied phase shift value.

14. The method according to any one of claims 1 to 13, further comprising storing the phase information associated with the transmit channel in a memory, and setting a phase offset of a phase shifter in the transmit channel based on the stored phase information.

15. The method according to any one of claims 1 to 14, further comprising determining whether the phase information exceeds a predetermined standard, and generating monitoring alarm information if the phase information exceeds the predetermined standard.

16. The method of any one of claims 1 to 15, further comprising coupling a second representation of the first frequency modulated RF output signal to an antenna for transmission, receiving a reflected signal of the second representation of the first frequency modulated RF signal from an object, and processing the reflected signal to determine at least one of a distance or a speed or a direction of arrival of the object.

17. The method according to any one of claims 1 to 16, wherein the down-converted signal is low-pass filtered prior to the sampling.

18. A radar MMIC device, comprising: A local oscillator for generating a frequency modulated RF signal including a frequency ramp, RF transmit channel, Testing the phase shifter, a first coupler configured to couple a first representation of the frequency modulated RF signal to the RF transmit channel and a second representation of the frequency modulated RF signal to the test phase shifter, wherein the RF transmit channel is configured to generate a first frequency modulated RF output signal based on the frequency modulated RF signal, and wherein the test phase shifter is configured to phase shift the second representation of the frequency modulated RF signal according to a phase shift applied to the test phase shifter and generate a frequency modulated RF test signal, a second coupler coupled to the RF transmit channel to generate a first representation of the frequency modulated RF output signal, a mixer coupled to the test phase shifter and the second coupler to receive the first representation of the frequency modulated RF output signal and the frequency modulated RF test signal, wherein the mixer is further configured to generate a down-converted signal based on mixing the first representation of the frequency modulated RF output signal with the frequency modulated RF test signal, a controller for setting the phase offset applied to the test phase shifter during the frequency ramp to each phase offset value in a predetermined set of phase offset values, a sampler for sampling the down-converted signal to generate a corresponding measurement sample in a set of measurement samples for each phase offset value in the set of phase offset values, and A processor is configured to calculate phase information related to the transmission channel based on the set of measurement samples.

19. The radar MMIC device of claim 18, wherein the controller is configured to temporally align the setting of the phase offset with the sampling of the down-converted signal. 20 . The radar MMIC device according to claim 18 , wherein the processor is configured to calculate the phase information based on generating first-order harmonic information related to a first-order harmonic included in the set of measurement values. 21 . The radar MMIC device of claim 20 , wherein the first-order harmonic information includes an imaginary part and a real part, and wherein the processor is configured to calculate the phase information based on the imaginary part and the real part.

22. The radar MMIC device according to any one of claims 18 to 21, wherein the processor is configured to estimate a phase error correction value and calculate the phase information based on the phase error correction value.

23. The radar MMIC device according to any one of claims 18 to 22, wherein the controller is further configured to determine whether the calculated phase information exceeds a predetermined standard, and generate monitoring alarm information if the phase information exceeds the predetermined standard.

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