JP7623064B2 - Continuous transmission filter device, radar device, and continuous transmission filter method - Google Patents

Description

The present invention relates to a continuous transmission filter device, a radar device, and a continuous transmission filter method.

In order to comply with recent strict radio wave laws, it is necessary to reliably remove unnecessary radio waves.
Several techniques are known in relation to the process of filtering out unwanted radio waves from a radar transmitter.

For example, Patent Literature 1 discloses a technique for switching between a plurality of transmitters that transmit radio waves (signals) of different frequencies provided in a radar device by physically switching a waveguide. By switching the transmitter according to the frequency to be transmitted and performing filtering according to the frequency, unnecessary radio waves can be removed.
Furthermore, Patent Document 2 discloses a technique for switching between a plurality of transmitters in a radar device having the plurality of transmitters, with a configuration in which at least one transmitter is always in operation.

JP 2019-140425 A Patent No. 2818490

However, the above-mentioned related techniques have the following problems.
That is, the related technology described in Patent Document 1 may not be able to prevent the radar device from stopping transmission when physically switching between multiple transmitters. Also, the related technologies described in Patent Documents 1 and 2, which simply switch transmitters, may not be able to reliably remove unnecessary radio waves with a filter when radio waves transmitted from one transmitter contain multiple frequencies.

In view of the above-mentioned problems, the object of the present invention is to provide a continuous transmission filter device, a radar device, and a continuous transmission filter method that solve the problem of filtering out unnecessary radio waves without causing a radar device to stop transmitting.

To solve the above problem, the first configuration of the present invention relates to a continuous transmission filter device, and is characterized in that it includes a splitter that splits a radar transmission signal into at least two or more split signals of different frequencies, at least two or more bandpass filters that filter each of the at least two or more split signals into a predetermined frequency band, an amplitude adjustment circuit that adjusts the amplitude of the at least two or more filtered split signals, and a combiner that combines the at least two or more split signals whose amplitudes have been adjusted.

The second aspect of the present invention relates to a continuous filter method, and is characterized by having a step of splitting a radar transmission signal into at least two or more split signals of different frequencies, a step of filtering each of the at least two or more split signals into a predetermined frequency band, a step of adjusting the amplitude of the at least two or more filtered split signals, and a step of combining the at least two or more split signals whose amplitudes have been adjusted.

In consideration of the above-mentioned problems, the present invention makes it possible to remove unnecessary radio waves using a filter without causing the radar device to stop transmitting.

1 is a configuration diagram showing a configuration of a radar device including a continuous transmission filter device according to a first embodiment. 1 is a configuration diagram showing a configuration of a continuous transmission filter device according to a first embodiment. FIG. 2 is a diagram showing a processing flow of the continuous broadcast filter device according to the first embodiment. 2 is a block diagram illustrating a configuration of an amplitude adjustment circuit included in the continuous transmission filter device according to the first embodiment. FIG. FIG. 4 is a diagram showing a processing flow of an amplitude adjustment circuit according to the first embodiment; 5 is an explanatory diagram illustrating a process of an amplitude adjustment circuit according to the first embodiment; FIG. FIG. 1 is a first explanatory diagram illustrating a comparison between a filter process according to the present invention and a filter process not using the present invention. FIG. 2 is a second explanatory diagram illustrating a comparison between the filter process according to the present invention and the filter process not using the present invention. FIG. 11 is a third explanatory diagram illustrating a comparison between the filter process according to the present invention and the filter process not using the present invention. FIG. 4 is a fourth explanatory diagram illustrating a comparison between the filter process according to the present invention and the filter process not using the present invention. FIG. 5 is a fifth explanatory diagram illustrating a comparison between the filter process according to the present invention and the filter process not using the present invention. 1 is an explanatory diagram illustrating a case where the continuous transmission filter device according to the first embodiment is attached to a radar device. FIG. FIG. 2 is a configuration diagram showing a configuration of a continuous transmission filter device according to a first modified example of the first embodiment. FIG. 11 is a configuration diagram showing an application example of a continuous transmission filter device according to a second modified example of the first embodiment. FIG. 11 is a configuration diagram showing an application example of a continuous transmission filter device according to a third modified example of the first embodiment.

First Embodiment
Hereinafter, a non-stop transmission filter device according to a first embodiment and a radar device including the non-stop transmission filter device will be described with reference to Figures 1 to 3. Note that the same or corresponding components in all the drawings are denoted by the same reference numerals, and common descriptions will be omitted.
FIG. 1 is a diagram showing the configuration of a radar device 1 including a continuous transmission filter device 20 according to a first embodiment.
As shown in FIG. 1, the radar device 1 includes a radar transmitter 10, a continuous transmission filter device 20, a circulator 30, a radar antenna 40, and a radar receiver 50, which are connected to each other.
The radar device 1 can transmit the radar transmission signal 11 output from the radar transmitter 10 as radio waves E from the radar antenna 40 via the continuous transmission filter device 20 and the circulator 30. The radar device 1 can also receive the radio waves E received by the radar antenna 40 as a radar reception signal 51 at the radar receiver 50 via the circulator 30.

The radar transmitter 10 can output a radar transmission signal 11 and input it to the continuous transmission filter device 20. Furthermore, the radar transmitter 10 can output a frequency selection signal 12 that specifies the transmission frequency of the radar transmission signal 11 and input it to the continuous transmission filter device 20. A radio wave E having a transmission frequency specified by the frequency selection signal 12 is transmitted from the radar device 1. In the following, the radar transmitter 10 is described as being capable of selectively transmitting radar transmission signals 11 having five different transmission frequencies. Furthermore, the radar transmitter 10 has one built-in amplifier (not shown), and outputs the radar transmission signal 11 amplified by the amplifier.

The continuous transmission filter device 20 performs filtering to remove unnecessary radio waves from the input radar transmission signal 11, as described below with reference to Figures 2 and 3, and can output the signal as a filtered radar transmission signal 13.

The circulator 30 can output the filtered radar transmission signal 13 input from the continuous transmission filter device 20 to the radar antenna 40, and can also output the radar reception signal 51 input from the radar antenna 40 to the radar receiver 50.

The radar antenna 40 can transmit the filtered radar transmission signal 13 input from the circulator 30 as radio waves E. The radar antenna 40 can also output the received radio waves E and input them to the circulator 30.

FIG. 2 is a diagram showing the configuration of the continuous transmission filter device 20 according to the first embodiment.
2, the continuous transmission filter device 20 includes a splitter 21, at least two or more bandpass filters 22, an amplitude adjustment circuit 23, and a combiner 24, which are connected in sequence. Note that the continuous transmission filter device 20 may include at least two or more bandpass filters 22, but the following description will be given of a case where the continuous transmission filter device 20 includes five bandpass filters 22A to 22E (hereinafter, when the filters are collectively referred to as bandpass filters 22 without distinction) as shown in FIGS. 2 and 4.

The splitter 21 can split the radar transmission signal 11 input from the radar transmitter 10 into at least two or more split signals 110 of different frequencies. Here, the splitter 21 is assumed to be able to withstand the power of the radar transmitter 10. Note that it is sufficient for the splitter 21 to split the radar transmission signal 11 input from the radar transmitter 10 into at least two or more split signals of different frequencies, but below, a case will be described in which the splitter 21 splits the radar transmission signal 11 into five split signals 110A to 110E (hereinafter, when they are collectively referred to without distinction, they will be referred to as split signals 110) as shown in Figures 2 and 4.
2, the splitter 21 splits the radar transmission signal 11 into split signals 110A, 110B, 110C, 110D, and 110E having center frequencies of F, F+X, F+2X, F+3X, and F+4X (Hz), respectively. F and X are constant values and may be values in the range of 0 to ^10-15 , for example.

The bandpass filters 22A to 22E filter each of the demultiplexed signals 110A to 110E input from the demultiplexer 21 into a predetermined frequency band. In the case shown in Fig. 2, the bandpass filters 22A, 22B, 22C, 22D, and 22E filter the input demultiplexed signals into frequency bands with center frequencies of F, F+X, F+2X, F+3X, and F+4X (Hz), respectively. In the case shown in Fig. 2, the bandwidth of the frequency band passed by the bandpass filters 22A to 22E is a predetermined bandwidth equal to or less than X. As described above, F and X are constant values.
The passbands (frequency bands to be passed) and out-of-band attenuation of the bandpass filters 22A to 22E may have characteristics that comply with the Radio Law and are calculated from individual radio wave types, etc. depending on the type of radar device 1, etc.

The amplitude adjustment circuit 23 can adjust the amplitude of at least two or more branched signals 110 filtered by at least two or more bandpass filters 22. In the case shown in FIG. 2, the amplitude adjustment circuit 23 adjusts the amplitude of each of the five branched signals 110A to 110E filtered by the five bandpass filters 22A to 22E. The amplitude adjustment circuit 23 adjusts the amplitude of the branched signals 110A to 110E based on the frequency selection signal 12 input from the radar transmitter 10. That is, the amplitude adjustment circuit 23 grasps the transmission frequency based on the frequency selection signal 12, and when the transmission frequency is switched, detects the switching and can correct the phase and transmission power of the branched signals 110A to 110E according to the transmission frequency. The configuration and processing of the amplitude adjustment circuit 23 will be described later with reference to FIGS. 4 to 6.

The combiner 24 can combine at least two or more branched signals 110 whose amplitudes have been adjusted by the amplitude adjustment circuit 23 into a filtered radar transmission signal 13. In the case shown in FIG. 2, the combiner 24 combines five branched signals 110A-110E whose amplitudes have been adjusted by the amplitude adjustment circuit 23 into a filtered radar transmission signal 13. Here, the filtered radar transmission signal refers to the radar transmission signal 11 for which appropriate filtering according to the selected transmission frequency has been completed.

In addition, when the radar device 1 has a large power and the burden on the splitter 21 and the bandpass filter 22 is large, the burden on the splitter 21 and the bandpass filter 22 may be reduced by connecting a bandpass filter, highpass filter, or lowpass filter that has the function of removing harmonic components and has a bandwidth that passes all transmission frequencies to a position immediately before the splitter 21 on the path from the radar transmitter 10 to the splitter 21.

(Processing flow of non-stop transmission filter device)
FIG. 3 is a diagram showing a process flow of the continuous broadcast filter device 20 according to the first embodiment.
3 starts when the radar transmission signal 11 is input to the continuous transmission filter device 20. Here, a case will be described in which the transmission frequency of the radar transmission signal 11 input from the radar transmitter 10 is F (Hz).

As shown in FIG. 3, the splitter 21 of the continuous transmission filter device 20 splits the radar transmission signal 11 input from the radar transmitter 10 into at least two or more split signals 110 of different frequencies (step S101). Here, it is assumed that the radar transmitter 10 can transmit the radar transmission signal 11 at five different transmission frequencies. Therefore, the splitter 21 of the continuous transmission filter device 20 splits the radar transmission signal 11 input from the radar transmitter 10 into five split signals 110A to 110E of different frequencies. Specifically, the splitter 21 splits the radar transmission signal 11 into split signals 110A, 110B, 110C, 110D, and 110E with center frequencies of F, F+X, F+2X, F+3X, and F+4X (Hz), respectively.

Next, at least two or more bandpass filters 22 of the continuous transmission filter device 20 filter each of the at least two or more demultiplexed signals 110 input from the demultiplexer 21 into a predetermined frequency band (step S102). In the case shown in Fig. 2, five bandpass filters 22A to 22E of the continuous transmission filter device 20 filter each of the five demultiplexed signals 110A to 110E input from the demultiplexer 21 into a predetermined frequency band.
2, the bandpass filters 22A, 22B, 22C, 22D, and 22E filter the input demultiplexed signal into frequency bands with center frequencies of F, F+X, F+2X, F+3X, and F+4X (Hz), respectively. Thus, the demultiplexed signal 110A with a center frequency of F (Hz) is filtered into a frequency band with a center frequency of F (Hz) by passing through the bandpass filter 22A. Similarly, the demultiplexed signals 110B to 110E other than the demultiplexed signal 110A are filtered into the corresponding frequency bands by passing through the corresponding bandpass filters 22B to 22E.

Next, the amplitude adjustment circuit 23 of the continuous transmission filter device 20 adjusts the amplitudes of at least two or more demultiplexed signals 110 filtered by at least two or more bandpass filters 22 (step S103). In the case shown in Fig. 2, the amplitude adjustment circuit 23 of the continuous transmission filter device 20 adjusts the amplitudes of five demultiplexed signals 110A to 110E filtered by five bandpass filters 22A to 22E.
4 to 6, the amplitude adjustment circuit 23 adjusts the amplitude based on the frequency selection signal 12 that specifies the transmission frequency of the radar transmission signal 11 input from the radar transmitter 10 so as to cancel out unnecessary power of the branched signals 110B to 110E other than the transmission frequency F (Hz) of the radar transmission signal 11. The amplitude adjustment circuit 23 also adjusts the transmission power of the branched signal 110A as desired by attenuating the amplitude of the branched signal 110A having the transmission frequency F (Hz) of the radar transmission signal 11 based on the frequency selection signal 12 input from the radar transmitter 10.

Next, the combiner 24 of the continuous transmission filter device 20 combines at least two or more branched signals 110 whose amplitudes have been adjusted by the amplitude adjustment circuit 23 into the filtered radar transmission signal 13 (step S104). In the case shown in FIG. 2, the combiner 24 of the continuous transmission filter device 20 combines five branched signals 110A-110E whose amplitudes have been adjusted by the amplitude adjustment circuit 23 into the filtered radar transmission signal 13. This completes the processing flow shown in FIG. 3.

(Amplitude adjustment circuit)
Next, the amplitude adjustment circuit 23 will be specifically described with reference to FIGS.

(Configuration of Amplitude Adjustment Circuit)
FIG. 4 is a diagram illustrating the configuration of the amplitude adjustment circuit 23 included in the continuous transmission filter device 20 according to the first embodiment.
As shown in FIG. 4, the amplitude adjustment circuit 23 includes distributors 230A to 230E (hereinafter, when referred to collectively without distinction, referred to as distributor 230) connected in sequence to each of the five bandpass filters 22A to 22E, two parallel phase shifters 231A to 231E and 232A to 232E (hereinafter, when referred to collectively without distinction, referred to as two phase shifters 231 and 232), and amplitude adjustment combiners 233A to 233E (hereinafter, when referred to collectively without distinction, referred to as amplitude adjustment combiner 233).
The procedure for adjusting the amplitude using a distributor, a phase shifter, and a combiner is disclosed in, for example, Japanese Patent Application Laid-Open No. 3-198401.
4, the amplitude adjustment circuit 23 further includes a phase-shift controller 234 that transmits a phase-shift control signal 120 for controlling the amount of phase shift to each of the phase shifters 231A to 231E and 232A to 232E. For convenience, the phase-shift control signals 120 are collectively referred to as the phase-shift control signals 120 here, but since the phase-shift control signals 120 are transmitted to each of the phase shifters 231A to 231E and 232A to 232E, there are ten systems of phase-shift control signals 120.

The distributors 230A to 230E can distribute the demultiplexed signals 110A to 110E input from the five bandpass filters 22A to 22E, respectively, into two signals with equal phase and equal amplitude.
Two phase shifters 231A to 231E and 232A to 232E connected in parallel to each of the dividers 230A to 230E can change the phase of each of the two divided demultiplexed signals 110A to 110E input from the dividers 230A to 230E. Here, changing the phase is referred to as phase shifting.
Specifically, when the frequency of the demultiplexed signal 110 is other than the transmission frequency of the radar transmission signal 11, the two phase shifters 231 and 232 make the phases of the two distributed demultiplexed signals 110 opposite to each other. Furthermore, when the frequency of the demultiplexed signal 110 is the transmission frequency of the radar transmission signal 11, the two phase shifters 231 and 232 process the phases of the two distributed demultiplexed signals to a predetermined phase difference within the range of 0° to 180°.

The amplitude adjustment combiners 233A-233E combine the two split signals 110A-110E, which have had their phases changed by the two phase shifters 231A-231E and 232A-232E, into one split signal 110A-110E. Note that the amplitude adjustment combiner 233 is capable of combining signals of equal amplitude but different phases.

The phase shift controller 234 transmits a phase shift control signal 120 to each of the phase shifters 231A-231E and 232A-232E to control the amount of phase shift, and changes the phase of the two-distributed branched signals input to each of them.

(Processing flow of the amplitude adjustment circuit)
Fig. 5 is a diagram showing a processing flow of the amplitude adjustment circuit 23 according to the first embodiment. That is, Fig. 5 shows details of the processing content of step S103 in the processing flow of the continuous transmission filter device 20 according to the first embodiment shown in Fig. 3. Therefore, when step S102 in Fig. 3 is completed, the processing flow in Fig. 5 starts, and when the processing flow in Fig. 5 ends, the processing proceeds to step S104 in Fig. 3.
FIG. 6 is an explanatory diagram illustrating the processing of the amplitude adjustment circuit 23 according to the first embodiment.

As shown in FIG. 5, the distributors 230A-230E of the amplitude adjustment circuit 23 distribute the demultiplexed signals 110A-110E input from each of the five bandpass filters 22A-22E into two with equal phase and equal amplitude (step S103A).

Next, the phase shift controller 234 of the amplitude adjustment circuit 23 determines whether each of the split signals 110A-110E split into two by the splitters 230A-230E is the transmission frequency F (Hz) of the radar transmission signal 11 based on the frequency selection signal 12 that specifies the transmission frequency of the radar transmission signal 11 input from the radar transmitter 10 (step S103B).

Of the two split signals 110A to 110E, the frequencies of the split signals 110B to 110E are not the transmission frequency F (Hz) of the radar transmission signal 11 (NO in step S103B), so for the split signals 110B to 110E, the phase shift controller 234 changes the phases of the two split signals 110B to 110E to be opposite to each other.
That is, the phase-shift controller 234 transmits a phase-shift control signal 120 for controlling the amount of phase shift to each of the phase shifters 231B to 231E and 232B to 232E, and changes the two distributed branched signals 110B to 110E to opposite phases with respect to the branched signals 110B to 110E other than the transmission frequency F (Hz) of the radar transmission signal 11. As a result, when the two distributed branched signals 110B to 110E are combined by the amplitude adjustment combiners 233B to 233E, unnecessary power can be cancelled out.

Figure 6 shows in outline how unnecessary power can be cancelled out by combining signals that are split into two equal phases and equal amplitudes by splitter 230, and then changing their phases to opposite phases. In Figure 6, the split signals are shown as vectors a and b. The right side of Figure 6 shows the state in which the split signals (vectors a and b) shown on the left side of Figure 6 have been changed to opposite phases. As shown in Figure 6, it is clear that by changing the split signals (vectors a and b) to opposite phases, the amplitude of vector a+b, which is the sum of vectors a and b resulting from the combination of vectors a and b, is cancelled out.

Of the two split signals 110A to 110E, the frequency of the split signal 110A is the transmission frequency F (Hz) of the radar transmission signal 11 (YES in step S103B), so for the split signal 110A, the phase shift controller 234 changes the split signal 110A to have equal amplitude and a predetermined phase difference.
That is, the phase-shift controller 234 transmits a phase-shift control signal 120 for controlling the amount of phase shift to each of the phase shifters 231A and 232A, and changes the two-distributed branched signal 110A of the transmission frequency F (Hz) of the radar transmission signal 11 to have equal amplitude and a predetermined phase difference. As a result, when the two-distributed signals are combined by the amplitude adjustment combiner 233A, the transmission power of the branched signal 110A is attenuated, and the transmission power can be adjusted as desired.

Next, the amplitude adjustment combiners 233A to 233E of the amplitude adjustment circuit 23 combine the two distributed demultiplexed signals 110A to 110E after the phases have been changed by the two phase shifters 231A to 231E and 232A to 232E into one demultiplexed signal 110A to 110E (step S103E).
As described above, for the branched signals 110B to 110E other than the transmission frequency F (Hz) of the radar transmission signal 11, the two branched signals 110B to 110E are in opposite phase to each other, so that unnecessary power can be cancelled out by combining them with the amplitude adjustment combiners 233B to 233E. Also, for the branched signal 110A having the transmission frequency F (Hz) of the radar transmission signal 11, the two branched signals 110A have equal amplitudes and a predetermined phase difference, so that the transmission power can be attenuated by combining them with the width adjustment combiner 233A, and the transmission power can be adjusted as desired.

(Comparison of filtering according to the present invention with filtering without the present invention)
Next, the differences between the filtering process using the continuous transmission filter device 20 according to the present invention and the filtering process not using the present invention will be compared with reference to FIGS.
7 to 11 are first to fifth explanatory diagrams respectively illustrating a comparison between the filtering process according to the present invention and a filtering process not using the present invention.

7 and 8, the horizontal axis indicates frequency (Hz) and the vertical axis indicates power (dB).
FIG. 7A shows a case where the radar transmission signal 11 output by the radar transmitter 10 according to the present invention has five types of transmission frequencies with center frequencies of F, F+X, F+2X, F+3X, and F+4X (Hz).
FIG. 8B' shows, by a solid line, a single frequency domain through which a signal passes when a single band-pass filter BPF is used as filtering without using the present invention.
On the other hand, Figure 8 (c') shows five frequency ranges, each of which is shown by a solid line, that pass signals when five band-pass filters 22A to 22E are used for filtering using the non-stop filter device 20 of the present invention.

FIG. 7(b) shows the result of applying a filter process not using the present invention as shown in FIG. 8(b') to the radar transmission signal 11 shown in FIG. 7(a).
FIG. 7(c) shows the result of applying filter processing to the radar transmission signal 11 shown in FIG. 7(a) using the non-stop transmission filter device 20 according to the present invention, as shown in FIG. 8(c').
Comparing Figure 7(b) and Figure 7(c), it can be seen that the filter processing not using the present invention, which has a wide passband as shown in Figure 8(b'), does not remove unnecessary radio waves in the middle frequency channel. For this reason, there is a possibility that the standards of the stricter Radio Law in recent years will not be met.
In contrast, as shown in Figure 8 (c'), the filter processing using the continuous transmission filter device 20 of the present invention reliably removes unnecessary radio waves in the middle frequency channel portion, thereby meeting the standards of recent strict radio wave laws.

Next, as a filtering process not using the present invention, a filtering process using a filter device F shown in Fig. 9 will be compared with a filtering process according to the present invention. In the filter device F shown in Fig. 9, two waveguide switches 80 and 90 are used instead of the splitter 21 and combiner 24 in the present invention.
In the filtering process by the filter device F shown in Fig. 9, two waveguide switches 80 and 90 are configured to switch the waveguide based on a frequency selection signal 12 that specifies the transmission frequency of the radar transmission signal 11 input from the radar transmitter 10. As a result, in the filter device F shown in Fig. 9, the waveguide is switched to a bandpass filter from among the five bandpass filters 22A to 22E that corresponds to the transmission frequency, and this is used as the path of the input radar transmission signal 11.

FIG. 10 illustrates a situation that may arise when using a filter process that does not utilize the present invention as shown in FIG.
In Fig. 10, a radar device R equipped with a filter device F shown in Fig. 9 transmits radio waves E1 to a target T to capture and track the target T. In response to this, a jamming device 500 intercepts the radio waves E1 with a radio detector 510 as shown by the dotted arrow. Furthermore, the jamming device 500 analyzes and identifies the radio waves E1 with an analysis and identification device 520, and transmits jamming radio waves E' that jam the radio waves E1 from a jamming radio wave transmission device 530 in accordance with the results.
In this situation, if one attempts to switch radio waves E1 to radio waves of a different transmission frequency that is not subject to interference, the filter device F shown in Figure 9 requires physically switching the waveguide, which can result in a time lag and an interruption in radio wave transmission during the switching, making it impossible to track the target T.

Figure 11 shows the same situation as that shown in Figure 10, but shows the situation when a radar device 1 equipped with a continuous transmission filter device 20 according to the present invention is used instead of the radar device R equipped with a filter device F not using the present invention shown in Figure 9.
In Fig. 11, a radar device 1 equipped with the non-stop transmission filter device 20 according to the present invention transmits radio waves E1 to a target T to capture and track the target T. In response to this, a jamming device 500 intercepts the radio waves E1 with a radio detector 510 as shown by the dotted arrow. Furthermore, the jamming device 500 analyzes and identifies the radio waves E1 with an analysis and identification device 520, and transmits jamming radio waves E' that jam the radio waves E1 from a jamming radio wave transmission device 530 according to the results.
Here, in the uninterruptible transmission filter device 20 according to the present invention, unlike the filter device F not using the present invention shown in Fig. 9, the radio wave E1 can be switched to another transmission frequency E2 that is not disturbed, with all of the multiple band pass filters 22A to 22E (22) constantly connected to the transmission system. Therefore, in the uninterruptible transmission filter device 20 according to the present invention, there is no time lag or stoppage of radio wave transmission when switching the radio waves, so tracking of the target T can be continued.

(Action, Effect)
As described above, the continuous transmission filter device 20 of the first embodiment includes a distributor 230 that branches the radar transmission signal 11 into at least two or more branched signals of different frequencies, at least two or more bandpass filters 22A to 22E (22) that filter each of the at least two or more branched signals into a predetermined frequency band, an amplitude adjustment circuit 23 that adjusts the amplitude of the at least two or more filtered branched signals, and a combiner 24 that combines the at least two or more amplitude-adjusted branched signals.

According to the above-mentioned configuration, the continuous transmission filter device 20 of the first embodiment is configured to filter the branched signals branched by the distributor 230 into predetermined frequency bands by each of the multiple bandpass filters 22A to 22E (22) and then combine the signals by the combiner 24. This achieves a state in which at least two or more bandpass filters 22A to 22E (22) are constantly connected to the transmission system, and makes it possible to reliably remove unnecessary radio waves by the filters without causing a transmission interruption state of the radar device 1.
Furthermore, even if it becomes necessary to change the transmission frequency of the radio waves E transmitted from the radar device 1 due to jamming radio waves from the jamming device 500 as described above, it is possible to reliably continue tracking of the target T without causing a time lag or stopping of radio wave transmission when switching the radio waves E.

In addition, the continuous transmission filter device 20 according to the first embodiment is configured to include at least two or more bandpass filters 22A to 22E (22) that filter each of at least two or more branched signals into a predetermined frequency band.
In this way, the continuous transmission filter device 20 can reliably remove unnecessary radio waves in the middle frequency channel portion from the radar transmission signal 11 (i.e., the radio waves E transmitted by the radar device 1), thereby satisfying the standards of recent strict radio wave laws.

Furthermore, in the continuous transmission filter device 20 of the first embodiment, the amplitude adjustment circuit 23 includes distributors 230A to 230E (230) connected in sequence to each of at least two or more bandpass filters 22A to 22E (22), two parallel phase shifters 231A to 231E and 232A to 232E (231, 232), and an amplitude adjustment combiner 233A to 233E (233).
Furthermore, the amplitude adjustment circuit 23 divides the filtered branched signals 110B to 110E, which are the branched signals 110A to 110E other than the transmission frequency F (Hz) of the radar transmission signal 11, into two with equal phase and equal amplitude by distributors 230B to 230E, and then shifts them to opposite phases by two phase shifters 231B to 231E, 232B to 232E (231, 232), and then combines them in an amplitude adjustment combiner 233B to 233E (233).
Furthermore, the amplitude adjustment circuit 23 is configured such that, of the at least two or more filtered branched signals 110A to 110E, the branched signal 110A having the transmission frequency F (Hz) of the radar transmission signal 11 is divided into two with equal phase and equal amplitude by a distributor 230A (230), and then processed to a predetermined amplitude by two phase shifters 231A, 232A (231, 232), and then combined by an amplitude adjustment combiner 233A (233).
In this way, the amplitude can be adjusted so as to reliably cancel out the unnecessary power of the branched signals 110B to 110E other than the transmission frequency F (Hz) of the radar transmission signal 11. Furthermore, the unnecessary power due to the occurrence of weak power leakage can also be reliably canceled in the same way. Furthermore, for the branched signal 110A of the transmission frequency F (Hz) of the radar transmission signal 11, the transmission power that differs depending on the transmission frequency F (Hz) can be appropriately adjusted as desired, for example, by adjusting it to the same level.

Furthermore, in the continuous transmission filter device 20 of the first embodiment, the amplitude adjustment circuit 23 is configured to receive a frequency selection signal 12 that specifies the transmission frequency of the radar transmission signal 11 together with the radar transmission signal 11 from the radar transmitter 10 that outputs the radar transmission signal 11.
With this configuration, the amplitude adjustment circuit 23 can appropriately filter the radar transmission signal 11 in accordance with the timing at which the radar transmitter 10 changes the transmission frequency of the radar transmission signal 11. Therefore, even in a situation in which the transmission frequency of the radio waves E transmitted by the radar device 1 is changed, it is possible to reliably remove unwanted radio waves from the radio waves E and satisfy the standards of recent strict radio wave laws.

In addition, in the continuous transmission filter device 20 of the first embodiment, the amplitude adjustment circuit 23 further includes a phase-shift controller 234 that transmits a phase-shift control signal 120 to the phase shifters 231 and 232 to control the phase shift amount of the phase shifters 231 and 232 based on the frequency selection signal 12.
With this configuration, the amplitude adjustment circuit 23 can individually control the phase shifters 231 and 232 to accurately and reliably filter the radar transmission signal 11 in accordance with the transmission frequency. This makes it possible to reliably remove unwanted radio waves from the radio waves E transmitted by the radar device 1 and to satisfy the standards of recent strict radio wave laws.

Furthermore, since the continuous transmission filter device 20 according to the first embodiment has a simple and concise circuit shape, it can be very easily added to an existing radar device 1 as an adapter to meet the strict standards of recent radio wave laws. Therefore, according to the continuous transmission filter device 20 according to the first embodiment, the cost and time required for installation can be reduced compared to the case of installing a new radar device 1.
Hereinafter, an example of a procedure for attaching the continuous transmission filter device 20 according to the first embodiment to the existing radar device 1 will be described with reference to FIG.

FIG. 12 is an explanatory diagram illustrating a case where the continuous transmission filter device 20 according to the first embodiment is attached to the radar device 1.
As shown in Fig. 12, when the continuous transmission filter device 20 is added as an adapter to an existing radar device 1, the continuous transmission filter device 20 is connected between the radar transmitter 10 and the circulator 30. At this time, if an existing bandpass filter is connected, it is removed as shown by the dotted line in Fig. 12. Note that in the case of a radar device 1 with high power, if there is a possibility that the power resistance of the bandpass filter is insufficient, the continuous transmission filter device 20 may be used in combination with the existing bandpass filter.
Furthermore, since it is necessary to detect the transmission frequency and its switching in order to correct the phase and transmission power, the frequency selection signal 12 output from the radar transmitter 10 is input to the continuous transmission filter device 20, as in the case described using Figure 4.

<Modification of the first embodiment>
The above provides a detailed explanation of the uninterrupted transmission filter device 20 according to the first embodiment. However, the specific aspects of the uninterrupted transmission filter device 20 are not limited to those described above, and various design changes, etc. can be made within the scope that does not deviate from the gist of the invention.
(First Modification of the First Embodiment)
For example, in the continuous transmission filter device 20 of the first embodiment, a case has been described in which the number of at least two or more bandpass filters 22A to 22E (22) is five, that is, a case in which the radar transmitter 10 is capable of selectively transmitting the radar transmission signal 11 at five different transmission frequencies.
Here, as a first modified example of the first embodiment, the number N of the band pass filters 22 may be any natural number other than 5. N is 2 or more.

FIG. 13 is a configuration diagram showing the configuration of an uninterrupted transmission filter device 20 according to a first modified example of the first embodiment.
As shown in FIG. 13, when the radar transmitter 10 is capable of transmitting the radar transmission signal 11 at N different transmission frequencies, the same effect as in the first embodiment can be achieved by setting the number of bandpass filters 22A to 22N (22) to N.
13, the continuous transmission filter device 20 may further include a circulator 60 that outputs the input radar transmission signal 11 to the branching filter 21 and outputs a slight reflected wave 610, which is generated due to the matching state of the input side of the bandpass filter 22, to a dummy load 70. The dummy load 70 is configured to absorb the reflected wave 610 and terminate it with the same impedance as the transmission line.
According to the above-described configuration, it is possible to prevent a situation in which a reflected wave returns to the radar transmitter 10 or the like that is the source of the radar transmission signal 11 and exerts an influence thereon.

(Second Modification of the First Embodiment)
Next, a continuous transmission filter device 20 according to a second modified example of the first embodiment will be described with reference to FIG.

For example, the continuous transmission filter device 20 according to the first embodiment has been described with reference to the case where the radar transmitter 10 includes one amplifier.
As a second modification of the first embodiment, the continuous transmission filter device 20 may be applied to a radar transmitter 10 including two or more amplifiers.
FIG. 14 is a configuration diagram showing an application example of an uninterrupted transmission filter device 20 according to a second modified example of the first embodiment.

14 includes two amplifiers 101 and 102 that amplify an excitation signal ES output from an exciter 100. As shown in FIG 14, a continuous transmission filter device 20 according to the second modification of the first embodiment may be provided between the amplifiers 101 and 102.
According to the above-described configuration, although it is not possible to remove unnecessary radio wave components generated by the amplifier 102 provided downstream of the uninterruptible transmission filter device 20, by providing the uninterruptible transmission filter device 20 within the radar transmitter 10C, installation space can be saved compared to the case where the uninterruptible transmission filter device 20 is provided outside, and therefore this is very effective, for example, in cases where there are restrictions on the installation location, etc.

(Third Modification of the First Embodiment)
Next, a continuous transmission filter device 20 according to a third modified example of the first embodiment will be described with reference to FIG.

For example, the continuous transmission filter device 20 according to the first embodiment has been described in relation to the case where the radar transmission signal 11 is output from one radar transmitter 10 .
Here, as a third modified example of the first embodiment, the continuous transmission filter device 20 may also be applied to a case where the radar transmission signal 11 is output from two radar transmitters connected in parallel.
FIG. 15 is a configuration diagram showing an application example of the continuous transmission filter device 20 according to the third modified example of the first embodiment.

A radar transmitter 10D shown in FIG. 15 has a configuration in which two transmitters 105 and 106 are connected in parallel to a combiner 107.
15, radar transmission signals of two different transmission frequencies output from two transmitters 105 and 106 are mixed in a mixer 107, and the mixed radar transmission signal 11 is input to the continuous transmission filter device 20. Furthermore, a frequency selection signal 12 specifying the two different transmission frequencies of the radar transmission signal 11 and a transmission synchronization signal 15 are input from the radar transmitter 10D to the continuous transmission filter device 20. The transmission synchronization signal 15 is a synchronization signal for achieving appropriate synchronization when two different types of transmission frequencies based on each of the two transmitters 105 and 106 are transmitted together.
The frequency selection signal 12 may be input to the continuous transmission filter device 20 as a transmission mode selection signal further including information on the transmission mode that specifies the transmission mode. The transmission modes may be, for example, a transmission mode A in which transmission is performed using both the transmitters 105 and 106, a transmission mode B in which transmission is performed using only the transmitter 105, and a transmission mode C in which transmission is performed using only the transmitter 106.

According to the above-described configuration, by adjusting the excitation timing of the two transmitters 105 and 106, the radar transmission signal 11 having two different transmission frequencies can be processed by the continuous transmission filter device 20 and transmitted from the radar device 1, thereby improving resilience.
In the above example, the radar transmission signal 11 having two different transmission frequencies is transmitted using the two transmitters 105 and 106. However, any number of transmitters, two or more, may be used to transmit the radar transmission signal 11 having any number of different transmission frequencies, two or more.
Furthermore, by using the combiner 107 instead of a switch at the joining point of the outputs of the transmitters 105 and 106, adjustment can be made using the phase shifters 231 and 232 in the continuous transmission filter device 20. Therefore, even if an abnormality occurs in either of the transmitters 105 and 106 and the transmission mode is switched from transmission mode A to transmission mode B or C based on a transmission mode selection signal, the transmitter can be switched without stopping transmission, so that a configuration with excellent redundancy can be achieved.

The present invention described above may be used in radar devices that monitor fast-moving targets, such as aircraft in the military defense field. It is also useful to use the present invention in fixed ground radar devices, which are particularly susceptible to the radio waves they use being detected and analyzed by other parties.

Some or all of the above embodiments may be described as follows, but are not limited to the following:

(Appendix 1) An uninterruptible filter device comprising: a splitter that splits a radar transmission signal into at least two or more split signals of different frequencies; at least two or more bandpass filters that filter each of the at least two or more split signals into a predetermined frequency band; an amplitude adjustment circuit that adjusts the amplitude of the at least two or more filtered split signals; and a combiner that combines the at least two or more split signals whose amplitudes have been adjusted.

(Appendix 2) The amplitude adjustment circuit includes a distributor connected in sequence to each of the at least two or more bandpass filters, two phase shifters in parallel, and an amplitude adjustment combiner, and the amplitude adjustment circuit divides the at least two or more filtered branched signals, which are other than the transmission frequency of the radar transmission signal, into two with equal phase and equal amplitude by the distributor, then converts them into opposite phases by the two phase shifters, and then combines them by the amplitude adjustment combiner, and divides the at least two or more filtered branched signals, which are the transmission frequency of the radar transmission signal, into two with equal phase and equal amplitude by the distributor, then processes them into a predetermined amplitude by the two phase shifters, and then combines them by the amplitude adjustment combiner. The continuous transmission filter device described in Appendix 1.

(Appendix 3) The continuous transmission filter device described in Appendix 2, in which the amplitude adjustment circuit is configured to cancel unnecessary power of the branched signal that is a frequency other than the transmission frequency of the radar transmission signal.

(Appendix 4) The continuous transmission filter device according to appendix 2 or appendix 3, in which the amplitude adjustment circuit is configured to adjust the transmission power of the branched signal, which is the transmission frequency of the radar transmission signal.

(Appendix 5) The amplitude adjustment circuit is an uninterrupted filter device according to any one of appendices 2 to 4, in which a frequency selection signal that specifies the transmission frequency of the radar transmission signal is input together with the radar transmission signal from a radar transmitter that outputs the radar transmission signal.

(Appendix 6) The amplitude adjustment circuit is a continuous transmission filter device according to Appendix 5, further comprising a phase shift controller that transmits a phase shift control signal to the phase shifter to control the amount of phase shift of the phase shifter based on the frequency selection signal.

(Appendix 7) The continuous transmission filter device according to any one of appendices 1 to 6, further comprising a circulator that inputs the radar transmission signal to the splitter, and a dummy load that is connected to the circulator and absorbs the reflected wave of the split signal.

(Appendix 8) An uninterrupted transmission filter device according to any one of appendices 2 to 7, in which the radar transmission signal has at least two or more types of transmission frequencies.

(Appendix 9) A radar device comprising a continuous transmission filter device according to any one of appendices 1 to 8 and a radar transmitter that outputs the radar transmission signal.

(Appendix 10) A non-stop filter method comprising the steps of: splitting a radar transmission signal into at least two or more split signals of different frequencies; filtering each of the at least two or more split signals into a predetermined frequency band; adjusting the amplitude of the at least two or more filtered split signals; and combining the at least two or more split signals whose amplitudes have been adjusted.

(Appendix 11) The non-stop filter method described in appendix 10, in which the step of adjusting the amplitude includes a step of splitting the at least two or more filtered split signals other than the transmission frequency of the radar transmission signal into two with equal phase and equal amplitude, then converting them into opposite phases and combining them, and a step of splitting the at least two or more filtered split signals into two with equal phase and equal amplitude, then processing them into a predetermined amplitude and combining them.

1, R Radar device 10, 10C, 10D Radar transmitter 11 Radar transmission signal 12 Frequency selection signal 13 Filtered radar transmission signal 15 Transmission synchronization signal 20 Continuous transmission filter device 21 Splitter 22, 22A to 22E, 22N Bandpass filter 23 Amplitude adjustment circuit 24 Combiner 30 Circulator 40 Radar antenna 50 Radar receiver 51 Radar reception signal 60 Circulator 70 Dummy load 80, 90 Waveguide switch 100 Exciter 101, 102 Amplifier 105, 106 Transmitter 107 Combiner 110, 110A to 110E Split signal 120 Phase shift control signal 230, 230A to 230E, 230N Distributors 231, 232, 231A to 231E, 232A to 232E, 231N, 232N Phase shifters 233, 233A to 233E, 233N Amplitude adjustment combiner 234 Phase shift controller 500 Jamming device 510 Radio wave detector 520 Analysis and identification device 530 Jamming radio wave transmitter 610 Reflected wave BPF Single band pass filters E, E1, E2 Radio wave E' Jamming radio wave ES Excitation signal F Filter device T Target

Claims (10)

a demultiplexer that demultiplexes a radar transmission signal into at least two or more demultiplexed signals having different frequencies;
at least two or more bandpass filters that filter each of the at least two or more demultiplexed signals into a frequency band having a different frequency as a center frequency for each of the demultiplexed signals ;
an amplitude adjustment circuit for adjusting the amplitude of the at least two or more filtered branched signals;
a combiner that combines the at least two or more branched signals whose amplitudes have been adjusted;
An uninterruptible transmission filter device comprising: the amplitude adjustment circuit includes a distributor connected in sequence to each of the at least two or more band pass filters, two phase shifters arranged in parallel, and an amplitude adjustment combiner;
The amplitude adjustment circuit includes:
Among the at least two or more filtered branched signals, a branched signal having a frequency other than the transmission frequency of the radar transmission signal is divided into two with equal phase and equal amplitude by the distributor, and then the two phase shifters shift the signals to opposite phases, and the two signals are then combined by the amplitude adjustment combiner;
2. The non-stop filter device according to claim 1, wherein, among the at least two or more filtered branched signals, a branched signal having the transmission frequency of the radar transmission signal is branched into two with equal phase and equal amplitude by the distributor, then processed to a predetermined amplitude by the two phase shifters, and then combined by the amplitude adjustment combiner. The continuous transmission filter device according to claim 2, wherein the amplitude adjustment circuit is configured to cancel unnecessary power of the branched signal that is a frequency other than the transmission frequency of the radar transmission signal. The continuous transmission filter device according to claim 2 or 3, wherein the amplitude adjustment circuit is configured to adjust the transmission power of the branched signal, which is the transmission frequency of the radar transmission signal. The continuous wave filter device according to any one of claims 2 to 4, wherein the amplitude adjustment circuit receives a frequency selection signal that specifies the transmission frequency of the radar transmission signal together with the radar transmission signal from a radar transmitter that outputs the radar transmission signal. the amplitude adjustment circuit includes a phase-shift controller that transmits, to the phase shifter, a phase-shift control signal for controlling the amount of phase shift of the phase shifter based on the frequency selection signal;
The continuous transmission filter device according to claim 5 , further comprising: a circulator that inputs the radar transmission signal to the splitter;
a dummy load connected to the circulator and configured to absorb a reflected wave of the demultiplexed signal;
The continuous transmission filter device according to claim 1 , further comprising: 7. The continuous transmission filter device according to claim 2, wherein the radar transmission signal has at least two or more kinds of the transmission frequencies. The continuous transmission filter device according to any one of claims 1 to 8,
a radar transmitter that outputs the radar transmission signal;
A radar device comprising: demultiplexing the radar transmission signal into at least two or more demultiplexed signals having different frequencies;
filtering each of the at least two or more demultiplexed signals into a frequency band having a center frequency that is a different frequency for each of the demultiplexed signals ;
adjusting the amplitudes of the at least two or more filtered split signals;
combining the at least two or more branched signals whose amplitudes have been adjusted;
A non-stop filter method having the steps:

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