JP6720019B2 - Simulated target generation device and method - Google Patents

Description

The present invention relates to a simulated target generation device and method.

An apparatus for generating an RF (radio frequency) signal simulating a reflected wave generated by an incoming radar wave reflected by an object is preferably used for testing a radar apparatus and generating an interfering radio wave. In this specification, such a device will be referred to as a simulated target generator.

The most typical configuration when an RF input signal is used as the simulated target generator is a configuration that uses a DRFM (Digital Radio Frequency Memory). The DRFM is a device configured to perform high-speed A/D conversion on a received radar wave to obtain waveform data representing the waveform of the radar wave and store the waveform data in a memory. Desired digital processing (for example, delay processing or processing that simulates frequency shift (Doppler shift) due to the Doppler effect) is performed on the waveform data stored in the memory, and D is applied to the digital data obtained by the digital processing. If the /A conversion is performed, the target RF signal can be obtained.

One problem with simulated target generators that use DRFM is that the DRFM bandwidth is limited. The bandwidth of DRFM depends on the sampling rate in A/D conversion, and the higher the sampling rate, the wider the bandwidth can be. However, in reality, since the sampling rate has an upper limit, the DRFM bandwidth is limited. Some radar devices in recent years have a frequency agility function that switches the frequency of a radar wave at high speed, and the limitation of the bandwidth of the DRFM is a great constraint in the implementation of the simulated target generator.

As one method for solving the problem of the bandwidth limitation of the DRFM, Japanese Patent No. 4413757 discloses a technique of using two DRFMs having different operating frequency bands. In the technique disclosed in this patent document, an RF input corresponding to a radar wave is distributed to two DRFMs by a distributor to be processed by the two DRFMs, and RF signals output from the two DRFMs are combined. The bandwidth is expanded by combining the signals in phase with each other.

However, according to the study by the inventor, in the technique disclosed in this patent document, since the synthesizer is used, the bandwidth depends on the precision of the synthesizer, and there is a limitation in the width of expansion of the bandwidth. ..

Patent No. 4413757

Therefore, one of the objects of the present invention is to provide a simulated target generator having a wide bandwidth. Other objects and novel features of the present invention will be understood by those skilled in the art from the following disclosure.

The means for solving the problems will be described below with reference to the reference numerals used in the "Description of Embodiments". These reference signs are added to indicate an example of a correspondence relationship between the description of "Claims" and the "Description of Embodiments".

In one aspect of the present invention, a simulated target generator (10) distributes an RF input signal (21) corresponding to a radar wave to generate first to nth RF distribution signals (n is an integer of 2 or more) (22). A distributor (1) for generating _{1 to} 22 ₃ ), first to n-th simulation processing units (2 ₁ to 2 ₃ ) assigned to first to n-th frequency bands different from each other, and a selector (3). It is equipped with. Of the first to n-th simulation processing units (2 ₁ to 2 ₃ ), the i-th simulation processing unit (i is an integer of 1 or more and n or less) (2 _i ) is the first of the _i- th RF distribution signals (22 _i ). The i-th frequency band component is processed to generate the _i- th RF simulated signal (23 _i ). The selector (3) selects one of the first to nth RF simulated signals (2 ₁ to 2 ₃ ) based on the power of the RF input signal (21) in the first to nth frequency bands, and selects the selected signal. Output as an RF output signal (24).

The first to nth frequency bands are preferably set such that a part of the j+1th frequency band (j is an integer of 1 or more and n-1 or less) overlaps with a part of the jth frequency band.

In one embodiment, the i-th simulation processing unit (2 _i ) uses the i-th local oscillation signal for the i-th RF distribution signal (22 _i ) and the local oscillator (14 _i ) that generates the i-th local oscillation signal. A first mixer (11 _i ) for performing down-conversion by performing down conversion, and an _i- DRFM (12 _i ) for performing a process including desired digital processing on the IF input signal obtained by the down-conversion to generate an IF simulated signal, A second mixer (13 _i ) for up-converting the IF simulated signal using the i-th local oscillation signal to generate an _i- th RF simulated signal (23 _i ). The frequencies of the first to n-th local oscillation signals are different from each other.

In one embodiment, the DRFM (12 _{1 to} 12 ₃ ) is an A/D converter (32 _{1 to} 32 ₃ ) that performs A/D conversion on the IF input signal to generate waveform data, and the waveform data. (33 _{1 to} 33 ₃ ), a signal processor (34 _{1 to} 34 ₃ ) that performs digital processing on the waveform data to generate processed data, and D for the processed data. / and a conversion and a D / a converter ₍₃₅ 1 to 35 ₃₎ for generating an IF simulation signal.

In this case, at the first time, the power of the RF input signal (21) in the k-th frequency band (k is any integer of 1 or more and n or less) of the first to n-th frequency bands is detected by the predetermined detection. when the threshold is exceeded, the k simulation processing portion _{(2 k)} signal processor of DRFM (12 _k) of (34 _k) is, memory DRFM (12 _k) of the k-th simulation processing portion _{(2 k)} ( 33 _k ) based on the waveform data after the second time, which is traced back by a predetermined time from the first time, based on the waveform data after the second time, the IF simulated signal after the third time, which is delayed by the predetermined delay time. It is preferable to generate post-processing data corresponding to.

In another aspect of the present invention, the simulated target generation method, first through nRF distributed signals by distributing the RF input signal corresponding to the radar wave (21) (n is an integer of 2 or _{more) (22} 1 to 22 ₃ ) and the first to n-th simulation processing units (2 ₁ to 2 ₃ ) assigned to the first to n-th frequency bands different from each other, the first to n-th RF simulation signals (23 ₁ ) respectively. ~23 ₃ ) and a step of selecting _{one of the first} to n-th RF simulated signals (231 to 23 ₃ ) as the RF output signal (24) and outputting the RF output signal (24). And. The _i- th RF simulation signal (23 _i ) of the _first to n-th RF simulation signals (23 ₁ to 23 ₃ ) is processed by processing the component of the i-th frequency band of the i-th RF distribution signal (22 _i ). Is generated. The RF output signal (24) is selected from the _first to n-th RF simulated signals (23 ₁ to 23 ₃ ) based on the power of the RF input signal (21) in the first to n-th frequency bands.

According to the present invention, it is possible to provide a simulated target generator having a wide bandwidth.

It is a block diagram which shows the structure of the simulation target generator of one Embodiment. It is a conceptual diagram which shows channel allocation (namely, frequency band allocation) in this embodiment. It is a figure explaining the digital process which extends a waveform in a time-axis direction. It is a figure explaining the digital processing which compresses a waveform in the direction of a time axis. It is a block diagram which shows the modification of the simulated target generator of this embodiment. It is a timing chart which shows operation|movement of the simulation target generator of this embodiment. It is a timing chart which shows operation|movement of the simulation target generator when the electric power of the frequency band of channel CH3 exceeds a setting threshold value.

Hereinafter, embodiments will be described with reference to the accompanying drawings. In the following description, the same or corresponding components may be referred to by the same or corresponding reference numerals. Further, when there are a plurality of constituent elements having the same structure, they may be distinguished by adding a subscript to the reference numeral.

FIG. 1 is a block diagram showing the configuration of a simulated target generation device 10 according to an embodiment of the present invention. Simulated target generator 10, a distributor 1 comprises (in this embodiment three) more and simulation processing portion 2 ₁ to 2 _3, a selector 3, a control circuit 4.

The distributor 1 distributes an RF input signal 21 corresponding to a radar wave (for example, a signal obtained by receiving a radar wave by an antenna) to generate a plurality of RF distribution signals 22 _{1 to} 22 ₃ . The RF distribution signals 22 _{1 to} 22 ₃ are supplied to the simulation processing units 2 ₁ to 2 ₃ , respectively.

The simulation processing units 2 _{1 to} 2 ₃ are respectively assigned to different channels. Where a channel is means a frequency band allocated to each of the simulation processing unit 2 ₁ to 2 _3, in this embodiment, three channels of channel CH1~CH3, respectively, simulation processing unit 2 ₁ assigned to to 2 _3.

FIG. 2 is a conceptual diagram showing channel allocation (that is, frequency band allocation) in the present embodiment. In the present embodiment, the channel CH1 assigned to the simulation processing unit 2 ₁ is set to the highest frequency band. Furthermore, the channel CH2 allocated to simulation processing unit 2 ₂ is set to the next higher frequency band, the channel CH3 allocated to simulation processing unit 2 ₃ is set to the lowest frequency band. In FIG. 2, the symbol f _U1 indicates the upper limit frequency of the channel CH1, and the symbol f _L1 indicates the lower limit frequency of the channel CH1. Similarly, the symbol f _U2 indicates the upper limit frequency of the channel CH2, and the symbol f _L2 indicates the lower limit frequency of the channel CH2. Furthermore, the symbol f _U3 indicates the upper limit frequency of the channel CH3, and the symbol f _L3 indicates the lower limit frequency of the channel CH3.

In the present embodiment, the frequency bands of two adjacent channels in the frequency domain partially overlap each other. That is, the upper limit frequency f _U2 of the frequency band of the channel CH2 is higher than the lower limit frequency f _L1 of the frequency band of the channel CH1, and the upper limit frequency f _U3 of the frequency band of the channel CH3 is the upper limit of the frequency band of the channel CH2. _Is higher than the frequency f _L2 .

The widths Δf ₁₂ (=f _U2 −f _L1 ) and Δf ₂₃ (=f _U3 −f _L2 ) of the overlapping portions of the frequency bands of two adjacent channels are determined according to the expected pulse width of the radar wave. Will be decided. In one embodiment, for example, the widths Δf ₁₂ , Δf ₂₃ may be set to the 99% occupied frequency bandwidth of the pulse of the assumed radar wave. As the assumed pulse width is narrower, the widths Δf ₁₂ and Δf ₂₃ are wider.

The simulation processing units 2 _{1 to} 2 ₃ process the components of the frequency bands of the channels to which the RF distribution signals 22 _{1 to} 22 ₃ are assigned, and generate the RF simulation signals 23 ₁ to 23 _3. It is configured. Here, the RF simulation signals 23 ₁ to 23 ₃ are RF signals having a waveform simulating a reflected wave of a radar wave reflected by an object, which will be described in detail later.

The simulation processing unit 2 ₁ includes a mixer 11 ₁ , a DRFM 12 ₁ , a mixer 13 _1, and a local oscillator 14 ₁ . The oscillation frequency of the local oscillator 14 ₁ is f ₁ .

The mixer 11 _{1 down-} converts the RF distribution signal 22 ₁ distributed to the simulation processing unit 2 ₁ using the local oscillation signal of the oscillation frequency f ₁ received from the local oscillator 14 ₁ to obtain the down-conversion. and outputs the IF (intermediate frequency) input signal to DRFM12 _1. The oscillation frequency f ₁ is set so that the component of the frequency band of the channel CH1 of the RF distribution signal 22 ₁ shifts to the frequency band that the DRFM 12 ₁ can process in the IF input signal by down conversion.

The DRFM 12 ₁ is configured to process the IF input signal generated by the down conversion in the mixer 11 ₁ and generate an IF simulation signal having a waveform simulating a reflected wave of a radar wave reflected by an object. DRFM12 _1, in this embodiment, depending on the position of the radar wave is reflected by an object (i.e., depends on the distance between the radar apparatus and the object that generates a radar wave) propagation delay, and the radar wave reflection The IF simulation signal including the information of the waveform simulating the Doppler shift generated according to the speed of the moving object is generated.

In the present embodiment, the DRFM 12 ₁ includes a filter 31 ₁ , an A/D converter 32 ₁ , a memory 33 ₁ , a signal processor 34 _1, and a D/A converter 35 ₁ .

The filter 31 ₁ is configured to receive the IF input signal from the mixer 11 ₁ and remove an alias component included in the IF input signal. The IF signal output from the filter 31 ₁ includes a component derived from the component of the frequency band of the channel CH1 of the RF distribution signal 22 ₁ . As the filter 31 ₁ , for example, a low pass filter can be used.

The A/D converter 32 ₁ performs A/D conversion on the IF signal output from the filter 31 ₁ to generate waveform data. The waveform data output from the A/D converter 32 ₁ indicates the signal waveform of the component of the frequency band of the channel CH1 of the RF distribution signal 22 ₁ .

The memory 33 ₁ and the signal processor 34 ₁ configure a signal processing unit that performs desired digital processing on the waveform data output from the A/D converter 32 ₁ to generate processed data. The memory 33 ₁ is used to store the waveform data output from the A/D converter 32 ₁ and the processed data generated by the signal processor 34 ₁ . The signal processor 34 ₁ digitally processes the waveform data stored in the memory 33 ₁ to generate processed data. After the generated processed data is stored in the memory 33 _1.

The signal processor 34 _1, the digital processing for simulating the waveform of the reflected wave is performed. For example, the Doppler shift with respect to the waveform data stored in the memory 33 _1, which compresses the waveform in the time axis direction, or by performing a digital process of elongation occurs in accordance with the speed of the object by the radar wave is reflected Can be simulated. FIG. 3A illustrates digital processing for expanding a waveform in the time axis direction, and FIG. 3B illustrates digital processing for compressing a waveform in the time axis direction. 3A and 3B, the broken line shows the original waveform (the waveform shown by the waveform data output from the A/D converter 32 ₁ ) and the solid line shows the processed data obtained by digital processing. The waveform is shown. The process of compressing the waveform in the time axis direction is equivalent to the process of shifting the frequency so that the frequency becomes higher, and the process of expanding the waveform in the time axis direction is the process of shifting the frequency so that the frequency becomes lower. Is equivalent to. In addition, by controlling the timing of supplying the processed data obtained by the digital processing to the D/A converter 35 ₁ (providing an appropriate delay in supplying the processed data to the D/A converter 35 ₁₎ . ), the propagation delay in reflection by an object can be simulated.

For example, when the waveform data sampled by the A/D converter 32 _{1 at} time t _i is Q(t _i ) (i=1, 2, 3,... ), the time series data Q(A·(t _i− t _DL )) is delayed by t _{DL in the} time axis direction, and when A>1, the waveform is compressed A times in the time axis direction, and when A<1, the waveform is 1/ The data becomes A times expanded. Waveform data compressing or decompressing the waveform in the time axis direction _{Q ^ (t k) (k} = 1,2,3, ···) is the time-series data _{Q (A · (t i -t} DL)) from the interpolation Can be obtained by In one embodiment, the way time-series data calculated by Q ^ (t _k), may be used as post-processing data.

When simulating only the propagation delay without simulating the Doppler shift, the waveform data output from the A/D converter 32 ₁ may be delayed and supplied to the D/A converter 35 ₁ as processed data. Good.

The D/A converter 35 ₁ performs D/A conversion on the processed data received from the memory 33 ₁ to generate an IF simulated signal. IF simulation signal output from the D / A converter 35 ₁ is supplied to the mixer 13 _1.

The mixer 13 ₁ performs up-conversion on the IF simulation signal received from the D/A converter 35 ₁ using the local oscillation signal received from the local oscillator 14 ₁ to generate the RF simulation signal 23 ₁ .

Channel CH2, simulation processing unit ₂ 2 which frequency band is allocated for CH3, _{2 3} also has the same configuration and operate similarly. In particular, simulation processing unit _{2 2,} a mixer 11 _2, and DRFM12 _2, a mixer 13 _2, and a local oscillator 14 _2, simulation processing unit _{2 3,} a mixer 11 _3, DRFM12 ₃ and , Mixer 13 ₃ and local oscillator 14 ₃ .

Mixer ₁₁ 2, 11 ₃ of the simulation processing unit ₂ 2, _{2 3,} similarly performs downconversion mixers 11 ₁ of simulation processing portion _{2 1,} mixer ₁₃ 2, 13 ₃ of the simulation processing unit ₂ 2, _{2 3} performs up-conversion in the same manner as mixer 13 ₁ of simulation processing portion _{2 1.} The RF simulation signals 23 ₂ and 23 ₃ are output from the mixers 13 ₂ and 13 ₃ .

The DRFM 12 ₂ and DRFM 12 ₃ of the simulation processing units 2 ₂ and 2 ₃ have the same configuration as the DRFM 12 ₁ of the simulation processing unit 2 ₁ , and instead of the RF distribution signal 22 ₁ , the RF distribution signals 22 ₂ and 22 _{3 are included.} And receive the same. DRFM12 ₂ of simulation processing unit _{2 2,} the filter 31 _2, an A / D converter 32 _2, a memory 33 _2, and the signal processor 34 ₂ and a D / A converter 35 _2, simulation processing portion 2 ₃ DRFM12 ₃ includes a filter _313, an a / D converter 32 _3, the memory 33 _3, a signal processor 34 _3, and a D / a converter 35 _3. DRFM12 _2, DRFM12 ₃ of filter ₃₁ 2, 31 _3, except that the receive RF distribution signals ₂₂ 2, 22 ₃ instead of RF distribution signals 22 _1, operates similarly to the filter 31 ₁ of DRFM12 _1. DRFM12 _2, DRFM12 ₃ of A / D converter ₃₂ 2, 32 _3, operates in the same manner as the A / D converter 32 ₁ of DRFM12 _1, DRFM12 _2, DRFM12 ₃ of the memory ₃₃ 2, 33 _3, DRFM12 ₁ memory 33 ₁ and operates in the same manner. _Further, the DRFM12 2, DRFM12 ₃ of signal processor ₃₄ 2, 34 _3, operates in the same manner as the signal processor 34 _first DRFM12 _1, DRFM12 _2, DRFM12 ₃ of the D / A converter ₃₅ 2, 35 _3, DRFM12 ₁ of the D / a converter 35 ₁ and operate similarly.

The local oscillators 14 ₂ and 14 ₃ generate oscillation signals of oscillation frequencies f ₂ and f ₃ , respectively. However, since the frequency band allocated to the simulation processing unit ₂ 2, _{2 3} are different, the oscillation frequency _f 2, _{f 3} of the local oscillator ₁₄ 2, 14 _3, simulation processing portion _{2 1} of the local oscillator 14 _first oscillator It is different from the frequency f ₁ . In the present embodiment, the oscillation frequency f ₂ is lower than the oscillation frequency f ₁ and the oscillation frequency f ₃ is lower than the oscillation frequency f ₂ . The oscillation frequency f ₂ is set by down conversion so that the component of the frequency band of the channel CH2 of the RF distribution signal 22 ₂ shifts to the frequency band that the DRFM 12 ₂ can process, and the oscillation frequency f ₃ is set by down conversion. , The component of the frequency band of the channel CH3 of the RF distribution signal 22 ₃ is set so as to shift to the frequency band that the DRFM 12 ₃ can process.

Selector 3, the output control circuit simulation processing portion ₂ 1 in response to control signals received from the _4, 2 2, ₂ RF simulation signal ₂₃ received from the _{3 1,} 23 2, 23 ₃ of either the RF output signal 24 To do. The output RF output signal 24 may be used, for example, for evaluation of the radar device, or may be amplified and then transmitted toward the direction in which the radar wave is flying by the antenna device.

The control circuit 4 selects any one of the RF simulation signals 23 ₁ , 23 ₂ , and 23 ₃ and generates a control signal for instructing the selector 3 to output the selected RF simulation signal. In the present embodiment, the control circuit 4 selects any one of the RF simulation signals 23 ₁ , 23 ₂ , and 23 ₃ based on the power of the components of the frequency bands of the channels CH1, CH2, and CH3 of the RF input signal 21. At this time, the control circuit 4 receives the RF input from the waveform data received from the A/D converters 32 ₁ , 32 ₂ , 32 ₃ of the DRFMs 12 ₁ , 12 ₂ , 12 ₃ of the simulation processing units 2 ₁ , 2 ₂ , 2 _3. The power of the component of the frequency band of each of the channels CH1, CH2, and CH3 of the signal 21 is specified.

As shown in FIG. 4, instead of receiving the waveform data output from the A/D converters 32 ₁ , 32 ₂ , 32 ₃ , the control circuit 4 stores the waveform data in the memories 33 ₁ , 33 ₂ , 33 ₃ . The stored waveform data may be received, and the powers of the components of the frequency bands of the channels CH1, CH2, and CH3 of the RF input signal 21 may be specified based on the waveform data received from the memories 33 ₁ , 33 ₂ , and 33 _3. .. The selection of the RF simulation signals 23 ₁ , 23 ₂ , 23 ₃ will be described in detail later.

As will be discussed below, the simulated target generation device 10 of the present embodiment allocates different frequency bands to the simulated processing units 2 ₁ , 2 ₂ , and 2 ₃ to make the simulated target generation device 10 have a wide bandwidth as a whole. Has been realized. As a result, the simulated target generation device 10 according to the present embodiment can handle switching of the frequency of the radar wave. Hereinafter, the operation of the simulated target generation device 10 in this embodiment will be described in detail.

FIG. 5 is a timing chart showing an example of the operation of the simulated target generation device 10 in this embodiment. The radar wave is generally generated as a pulse waveform. However, recent radar devices often have a frequency agility function, and as shown in the uppermost stage of FIG. 5, the frequency of radar waves can be switched over a wide range and at high speed. For example, FIG. 5 shows seven pulses #1 to #7, but the pulses #1 to #7 have different frequency bands. The frequency bands of the channels CH1, CH2, CH3 are determined so that each pulse of the assumed radar wave is located in at least one frequency band of the channels CH1, CH2, CH3 in the frequency domain. .. In the example of FIG. 5, the pulses #1 and #2 are located in the frequency band of the channel CH1, and the pulse #3 is located in the frequency band of the channel CH3. Pulse #5 is located in the frequency band of channel CH2, and pulse #6 is located in the frequency band of channel CH3.

Here, as described above, the frequency bands of the channels CH1 and CH2 overlap with each other, and the frequency bands of the channels CH2 and CH3 overlap with each other. Therefore, in the frequency domain, one pulse becomes a frequency band of two channels. Note that there may be situations in place. In the example of FIG. 5, in the frequency domain, the pulse #4 is located in a band where the frequency bands of the channels CH2 and CH3 overlap, and the pulse #7 is a band where the frequency bands of the channels CH1 and CH2 overlap. Is located in.

Hereinafter, the operation of the simulated target generation device 10 of the present embodiment when a radar wave whose frequency changes as shown in the uppermost stage of FIG. 5 is input as the RF input signal 21 will be described.

The RF input signal 21 corresponding to the radar wave is distributed to the RF distribution signals 22 _{1 to} 22 ₃ by the distributor ₁ and supplied to the simulation processing units 2 ₁ to 2 ₃ . The mixers 11 _{1 to} 11 ₃ down-convert the RF distribution signals 22 _{1 to} 22 ₃ , and the IF signals generated by the down conversion are supplied to the DRFMs 12 _{1 to} 12 ₃ , respectively. In the IF signal supplied to the DRFM 12 ₁ , the component of the frequency band of the channel CH1 of the RF distribution signal 22 ₁ is transferred to the frequency band that the DRFM 12 ₁ can process. Similarly, DRFM12 in ₂ IF signal supplied to, IF components of the frequency band of the RF distributed signals 22 _second channel CH2 is, DRFM12 ₂ has been migrated to a frequency band which can be processed, which is supplied to DRFM12 ₃ In the signal, the component of the frequency band of the channel CH3 of the RF distribution signal 22 ₃ has been transferred to the frequency band that the DRFM 12 ₃ can process.

The IF signal supplied to the DRFM 12 ₁ corresponding to the channel CH1 is input to the filter 31 ₁ , and the IF signal passing through the filter 31 ₁ is input to the A/D converter 32 ₁ . The waveform data output from the A/D converter 32 ₁ represents the waveform of the frequency band of the channel CH1 of the RF input signal 21. Waveform data output from the A / D converter 32 ₁ is stored in the memory 33 _1.

Similarly, IF signal supplied to the corresponding DRFM12 ₂ to the channel CH2 is input to the filter 31 _2, IF signal that has passed through the filter 31 ₂ is inputted to the A / D converter 32 _2. Waveform data outputted from the A / D converter 32 ₂ represents the frequency band of the waveform of the channel CH2 of the RF input signal 21. Waveform data output from the A / D converter 32 ₂ is stored in the memory 33 _2.

Furthermore, IF signal supplied to DRFM12 ₃ corresponding to the channel CH3 is input to the filter 31 _3, IF signal that has passed through the filter ₃₁₃ is input to the A / D converter 32 _3. The waveform data output from the A/D converter 32 ₃ represents the waveform of the frequency band of the channel CH3 of the RF input signal 21. Waveform data output from the A / D converter 32 ₃ is stored in the memory 33 _2.

The signal processors 34 ₁ , 34 ₂ , 34 ₃ respectively perform desired digital processing on the waveform data stored in the memories 33 ₁ , 33 ₂ , 33 ₃ to generate processed data. As described above, the digital processing performed by the signal processors 34 ₁ , 34 ₂ , and 34 ₃ includes, for example, processing of compressing or expanding the waveform in the time axis direction. According to such processing, it is possible to simulate the Doppler shift generated according to the speed of the object reflected by the radar wave.

The processed data generated by the signal processors 34 ₁ , 34 ₂ , 34 ₃ are sent to the D/A converters 35 ₁ , 35 ₂ , 35 ₃ , respectively. D/A conversion is performed on the sent processed data by the D/A converters 35 ₁ , 35 ₂ , and 35 ₃ to generate IF signals.

The IF signal output from the D / A converter 35 ₁ is supplied to the mixer 13 _1. The mixer 13 ₁ up-converts the supplied IF signal to generate the RF simulated signal 23 ₁ . Similarly, IF signal output from the D / A converter 35 ₂ is supplied to the mixer 13 _2. The mixer 13 ₂ up-converts the supplied IF signal to generate the RF simulated signal 23 ₂ . Furthermore, IF signal output from the D / A converter 35 ₃ is supplied to the mixer 13 _3. The mixer 13 ₃ up-converts the supplied IF signal to generate an RF simulated signal 23 ₃ .

On the other hand, by the control circuit 4, the waveform data output from the A/D converters 32 ₁ , 32 ₂ , 323 of the channels CH 1, CH 2, CH ₃ (or read from the memories 33 ₁ , 33 ₂ , 33 ₃ ). Waveform data), the power of the frequency band of the channel CH1 of the RF distribution signal 22 ₁ , the power of the frequency band of the channel CH2 of the RF distribution signal 22 ₂ and the frequency band of the channel CH3 of the RF distribution signal 22 ₃ at each time. Each power is calculated. Here, since the RF distribution signals 22 ₁ , 22 ₂ , and 22 ₃ are signals generated by distributing the RF input signal 21, the frequency of the channels CH1, CH2, and CH3 of the RF input signal 21 at each time is calculated by this calculation. The power of each band will be calculated.

The control circuit 4 selects one of the channels CH1, CH2, and CH3 based on the power of each of the frequency bands of the channels CH1, CH2, and CH3 of the RF input signal 21 at each time. Specifically, the control circuit 4 determines at each time point whether the power of each of the frequency bands of the channels CH1, CH2, and CH3 of the RF input signal 21 exceeds a predetermined detection threshold value.

When the power of the frequency band of a certain one channel exceeds the detection threshold value, the control circuit 4 selects the one channel. For example, referring to FIG. 5, when pulse #1 in the frequency band of channel CH1 is input as RF input signal 21, the power in the frequency band of channel CH1 exceeds the detection threshold, so channel CH1 is selected.

Once a channel is selected, it remains selected until another channel is selected. For example, in FIG. 5, after the pulse #1 is input as the RF input signal 21, the state in which the channel CH1 is selected is continued until the pulse #3 in the frequency band of the channel CH3 is input.

When the powers of the frequency bands of the two channels exceed the detection threshold, the control circuit 4 selects the channel with the highest power. For example, for pulse #7, since the frequency bands of the channels CH1 and CH2 are located in the overlapping frequency band, the power of the frequency bands of the channels CH1 and CH2 exceeds the detection threshold. However, since the frequency band of pulse #7 is closer to the center of the frequency band of channel CH1, the power of the frequency band of channel CH1 is higher than that of the frequency band of channel CH2. In such a case, the channel CH1 is selected.

Regarding pulse #4, it is located in a frequency band in which the frequency bands of channels CH2 and CH3 overlap, and the power of the frequency bands of channels CH2 and CH3 is substantially the same. In such a case, either channel CH2 or CH3 may be selected. FIG. 5 illustrates an operation in which the channel CH3 is selected (the state in which the channel CH3 is selected is maintained) according to the pulse #4.

When the power of the frequency band of a certain channel exceeds the detection threshold and the channel is selected by the control circuit 4, the RF simulation output from the simulation processing unit 2 (2 ₁ , 2 ₂ or 2 ₃ ) corresponding to the channel The signal 23 (23 ₁ , 23 ₂ or 23 ₃ ) is selected, and the selected RF simulation signal 23 is output as the RF output signal 24.

It should be noted that when a pulse is input, it takes some time for the power in the frequency band of each channel to rise from the noise level to the detection threshold. When the pulse located in the frequency band of a certain channel is input, when the RF simulation signal 23 is generated based on the waveform data after the time when the power of the frequency band of the channel reaches the detection threshold value, the rising edge of the pulse is simulated. I can't.

In order to deal with such a problem, in the present embodiment, when the power in the frequency band of a certain channel reaches the detection threshold, the time _TL corresponding to the pulse rise time is traced back from the time when the detection threshold is reached. After that time, the waveform data is read from the memory 33, and the RF simulation signal 23 (that is, the RF output signal 24) is generated based on the read waveform data. According to such an operation, the reflected wave of the radar wave pulse can be appropriately simulated.

FIG. 6 illustrates, as an example, the operation of the simulated target generation device 10 when the pulse #3 located in the frequency band of the channel CH3 is input as the RF input signal 21 (the operation of the portion surrounded by the broken line A in FIG. 5). ) Is shown in detail.

Pulse # 3 is input as the RF input signal 21, if the power of the channel frequency band which is at a certain time _{t 1} reaches the detection threshold, the time _t 2 from time _{t 1} going back for a time _{T L} (= _{t 1} - The waveform data after T _L ) is read from the memory 33 _{3 of the} DRFM 12 ₃ corresponding to the channel CH3. In DRFM12 _3, the digital processing performed by post-processing data by the signal processor 34 ₃ relative to the waveform data read out are generated.

Furthermore, processed data generated from the time t ₂ after the waveform data, from the time t ₃ when delayed by a delay time T _D from the time t ₂ begins to be supplied to the D / A converter 35 _3. Here, the delay time T _D is set so as to simulate the delay required for reflection by the object. D / A conversion is performed by the D / A converter 35 ₃ for the processed data IF simulation signal is generated. The post-processing data corresponding to the IF simulated signal after the time t ₃ will be generated from the waveform data after the time t ₂ . The generated IF simulation signal is up-converted to generate the RF simulation signal 23 ₃ .

Further, the channel CH3 is selected by the control circuit 4, and the selector 3 is controlled to output the RF simulation signal 23 ₃ corresponding to the channel CH3 as the RF output signal 24 after the time t ₃ . Time t ₃ after, RF simulation signal 23 ₃ corresponding to the channel CH3 as an RF output signal 24 is output, thereby, a signal having a simulated waveform of the reflected wave pulse # 3, including the rising waveform of the pulse # 3 , RF output signal 24.

As described above, in the present embodiment, the simulation processing units 2 ₁ , 2 ₂ , 2 ₃ that generate the RF simulation signals 23 ₁ , 23 ₂ , 23 ₃ are assigned to different channels (that is, different frequencies). (Allocated to the band), and any _{one of} the RF simulation signals 23 ₁ , 23 ₂ , and 23 ₃ is selected according to the power of each channel of the RF input signal 21. The selected RF simulation signal 23 is output as the RF output signal 24. With such an operation, the simulated target generation device 10 of the present embodiment realizes a wide bandwidth. Such a characteristic is suitable for coping with the switching of the frequency of the radar wave.

Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above embodiments. Those skilled in the art will appreciate that the present invention can be implemented with various modifications.

10: Simulated target generation device 1: Distributor 2 ₁ to 2 ₃ : Simulated processing unit 3: Selector 4: Control circuit 11 _{1 to} 11 ₃ : Mixer 12 _{1 to} 12 ₃ : DRFM (digital radio frequency memory)
13 _{1 to} 13 ₃ : Mixer 14 _{1 to} 14 ₃ : Local oscillator 21: RF input signal 22 _{1 to} 22 ₃ : RF distribution signal 23 ₁ to 23 ₃ : RF simulated signal 24: RF output signal 31 _{1 to} 31 ₃ : Filter 32 _{1 to} 32 ₃ : A/D converter 33 _{1 to} 33 ₃ : memory 34 _{1 to} 34 ₃ : signal processor 35 _{1 to} 35 ₃ : D/A converter

Claims (6)

A distributor that distributes an RF input signal corresponding to a radar wave to generate first to nth RF distribution signals (n is an integer of 2 or more);
First to n-th simulation processing units assigned to first to n-th frequency bands different from each other,
Equipped with a selector,
The i-th simulation processing unit (i is an integer of 1 or more and n or less) of the first to n-th simulation processing units performs processing on the component of the i-th frequency band of the i-th RF distribution signal to perform the i-th RF signal. Configured to generate a simulated signal,
The selector the most power is a signal corresponding to the higher frequency band is the inner shell selected in the first to nRF simulation signal, the signal selected among the first to n frequency bands of the RF input signal A simulated target generator that outputs as an RF output signal. The simulated target generator according to claim 1,
The first to nth frequency bands are set such that a part of the j+1th frequency band (j is an integer of 1 or more and n-1 or less) overlaps with a part of the jth frequency band. .. The simulated target generator according to claim 1 or 2, wherein
The i-th simulation processing unit
A local oscillator that generates an i-th local oscillation signal;
A first mixer for down-converting the i-th RF distribution signal using the i-th local oscillation signal;
A DRFM that performs a process including a desired digital process on the IF input signal obtained by the down conversion to generate an IF simulated signal;
A second mixer that up-converts the IF simulated signal using the i-th local oscillation signal to generate the i-th RF simulated signal;
A simulated target generator in which frequencies of the first to nth local oscillation signals are different from each other. The simulated target generation device according to claim 3,
The DRFM is
An A/D converter that performs A/D conversion on the IF input signal to generate waveform data;
A memory for storing the waveform data,
A signal processor that performs the digital processing on the waveform data to generate processed data,
A simulated target generation device, comprising: a D/A converter that performs D/A conversion on the processed data to generate the IF simulated signal. A distributor that distributes an RF input signal corresponding to a radar wave to generate first to nth RF distribution signals (n is an integer of 2 or more);
First to n-th simulation processing units assigned to first to n-th frequency bands different from each other,
selector
And
The i-th simulation processing unit (i is an integer of 1 or more and n or less) of the first to n-th simulation processing units performs processing on the component of the i-th frequency band of the i-th RF distribution signal to perform the i-th RF processing Configured to generate a simulated signal,
The selector selects one of the first to nth RF simulated signals based on the power of the first to nth frequency bands of the RF input signal, and outputs the selected signal as an RF output signal,
The i-th simulation processing unit
A local oscillator that generates an i-th local oscillation signal;
A first mixer for down-converting the i-th RF distribution signal using the i-th local oscillation signal;
A DRFM that performs a process including a desired digital process on the IF input signal obtained by the down conversion to generate an IF simulated signal;
A second mixer that up-converts the IF simulated signal using the i-th local oscillation signal to generate the i-th RF simulated signal.
And
The frequencies of the first to n-th local oscillation signals are different from each other,
The DRFM is
An A/D converter that performs A/D conversion on the IF input signal to generate waveform data;
A memory for storing the waveform data,
A signal processor that performs the digital processing on the waveform data to generate processed data,
D/A converter for performing D/A conversion on the processed data to generate the IF simulated signal
With and
At the first time, the power of the RF input signal in the k-th frequency band (k is any integer of 1 or more and n or less) of the first to n-th frequency bands exceeds a predetermined detection threshold. In this case, the signal processor of the DRFM of the kth simulation processing section of the first to nth simulation processing sections is stored in the memory of the DRFM of the kth simulation processing section at the first time. The post-processing data corresponding to the IF simulated signal after the third time, which is delayed by a predetermined delay time from the second time, based on the waveform data after the second time, which is traced back by a predetermined time. Generate simulated target generator. Distributing an RF input signal corresponding to a radar wave to generate first to nth RF distribution signals (n is an integer of 2 or more);
Generating first to n-th RF simulation signals by the first to n-th simulation processing units assigned to the first to n-th frequency bands different from each other, respectively.
Selecting any one of the first to nth RF simulated signals as an RF output signal and outputting the RF output signal,
The i-th RF simulation signal of the first to n-th RF simulation signals is generated by performing processing on the i-th frequency band component of the i-th RF distribution signal,
In the RF output signal, a signal corresponding to a frequency band having the highest power in the first to nth frequency bands of the RF input signal is selected from the first to nth RF simulated signals. Method.

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