Pulse Detector

Abstract

To obtain a pulse detector with which it is possible to detect multiple types of pulses existing in a versatile range in time and frequency.SOLUTION: The pulse detector comprises: a frequency division unit for dividing an input signal into a plurality of frequency bands for each processing unit time and outputting them as divided signals; a signal band detection unit for outputting, for each processing unit time, signal band information from the spectrum calculated from each divided signal; a pulse waveform detection unit for outputting, for each processing unit time, pulse time information from each divided signal that includes the time in which a pulse exists; a signal band allocation unit for allocating, for each processing unit time, signal band information outputted from the signal band detection unit, to the pulse time information of the detection signal detected by the pulse waveform detection unit and generating pulse information; and a pulse integration unit for integrating pieces of pulse information together that have close signal bands and are adjacent in a time base to generate new pulse information for each processing unit time.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a pulse detection device that detects a plurality of pulses contained in an input signal. [Background technology]

[0002] In a radio detection device that separates and detects multiple pulses contained in a signal of a wide frequency band and identifies the parameters of the signal, a pulse detection device is used that detects multiple pulses contained in an input signal. The pulse detection device is required to have the ability to detect various types of pulses, whose time and frequency are unknown and known, in real time, including pulses that overlap in terms of time or frequency. However, as the bandwidth of radio detection devices increases, it becomes difficult to achieve these simultaneously. In a conventional pulse detection device, for example, there is a device that receives time-varying signals with multiple blind source separation modules and identifies parameters of the separated signals using a filter processing subsystem of each blind source separation module (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-77213 A (Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0004] The pulse detection device described in Patent Document 1 detects pulses using multiple blind source separation modules, so the time and frequency ranges in which detectable pulse signals exist and the number of types of detectable pulses depend on the number and settings of the blind source separation modules. For this reason, as radio detection devices become broader in bandwidth, the time and frequency ranges of pulses to be detected become more diverse and the types of pulses increase, making it difficult to detect those pulses. [Means for solving the problem]

[0005] A pulse detection device according to the present disclosure is a pulse detection device that detects a plurality of pulses included in an input signal, The above A frequency division unit that divides an input signal into a plurality of frequency bands and outputs the divided signals for each processing unit time; The a signal band detection unit that detects a signal band from the spectrum and outputs signal band information; and detecting the pulse or a part of the pulse from each of the divided signals as a detection signal for each processing unit time, The a pulse waveform detection unit that outputs pulse time information including a time when a detection signal exists; and a pulse waveform detection unit that calculates frequency information from a portion of the divided signal corresponding to the detection signal for each of the plurality of detection signals detected by the pulse waveform detection unit in each of the frequency bands for each of the processing unit times. The The frequency information is output from the signal band detection unit. The above A signal band allocation unit that allocates signal band information to generate pulse information, and a unit that integrates the pulse information that is close to each other in the signal band and is also close on the time axis to generate new pulse information. Napa and a pulse integration section for generating pulse information for each processing unit time. Effect of the Invention

[0006] As described above, according to the present disclosure, a pulse detection device can be obtained that is capable of detecting a wide variety of pulses that exist in a diverse range of time and frequency. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating the configuration of a pulse detection device according to a first embodiment and a radio detection device including the pulse detection device. [Diagram 2] 4 is a flowchart illustrating the operation of the pulse detection device according to the first embodiment. [Diagram 3]6 is a diagram illustrating the operation principle of a signal band allocation unit of a modified example of the pulse detection device according to the first embodiment. FIG. [Figure 4] 13 is a diagram illustrating the configuration of a pulse detection device according to a second embodiment and a radio detection device including the pulse detection device. [Diagram 5] 10 is a flowchart illustrating the operation of the pulse detection device according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Embodiment 1 A first embodiment will be described below with reference to Figs. 1 and 2. Fig. 1 is a configuration diagram of a radio detection device including a pulse detection device 9 according to the first embodiment. The radio detection device receives radio waves and detects multiple pulses contained in the received radio waves. The radio detection device converts the received radio waves into a digital signal and inputs it to the pulse detection device 9 as an input signal for the pulse detection device 9. The pulse detection device 9 is part of the radio detection device, and detects multiple pulses contained in the input signal that the radio detection device has converted into a digital signal.

[0009] As shown in Fig. 1, the radio detection device includes a pulse detection device 9 configured with a signal processing circuit, and a receiving section that receives radio waves and generates an input signal to the pulse detection device. The receiving section includes an antenna 1, a filter 2, a mixer 3, a high-frequency signal generating circuit 4, a filter 5, an amplifier 6, an A / D converter 7, and a control device 8. The pulse detection device 9 includes a frequency division section 10, a pulse waveform detection section 11, a signal band detection section 12, a signal band allocation section 13, a low time resolution pulse processing section 14, a pulse integration section 15, and a detection result output section 16. In addition, the signal band allocation section 13 includes a divided signal intra-band allocation section 17 and a continuous pulse band allocation section 18.

[0010] Antenna 1 receives radio waves containing pulses and outputs a received signal. Filter 2 extracts the desired receiving band from the received signal output by the antenna. Control device 8 outputs a predetermined frequency according to the receiving band so that the desired receiving band can be extracted in the receiving section, and controls high frequency signal generating circuit 4. High frequency signal generating circuit 4 outputs a sine wave signal of the frequency output by control device 8. Mixer 3 uses the sine wave signal output by high frequency signal circuit 4 to convert the frequency of the received signal output by filter 2. Filter 5 blocks unnecessary frequency bands of the received signal frequency-converted by mixer 3. Amplifier 6 amplifies the received signal output by filter 5. A / D converter 7 digitizes the received signal amplified by amplifier 6 and outputs an input signal to pulse detection device 9.

[0011] The pulse detection device 9 includes a frequency division unit 10 that divides an input signal into a plurality of frequency bands and outputs the divided signals for each processing unit time, a pulse waveform detection unit 11 that detects a pulse or a portion of a pulse from each divided signal as a detection signal for each processing unit time and outputs pulse time information including the time when the detection signal exists, and a signal band detection unit 12 that calculates a spectrum from each divided signal for each processing unit time, detects a signal band from the calculated spectrum, and outputs signal band information.

[0012] The pulse detection device 9 also includes a signal band allocation unit 13 which, for each processing unit time, calculates frequency information from a portion of the divided signal corresponding to the detection signal for each pulse time information of a plurality of detection signals detected by the pulse waveform detection unit 11 in each frequency band, and generates pulse information by allocating signal band information output from the signal band detection unit 12 whose frequency is close to the calculated frequency information. The signal band allocation unit 13 includes an intra-divided signal band allocation unit 17 which calculates frequency information from a portion of the divided signal corresponding to the detection signal for each processing unit time, for each pulse time information of a plurality of detection signals detected by the pulse waveform detection unit 11 in each frequency band, and generates pulse information by allocating signal band information output from the signal band detection unit 12 whose frequency is close to the calculated frequency information, and a continuous pulse band allocation unit 18 which, for each processing time unit, integrates pulse information generated by the intra-divided signal band allocation unit 17 for a detection signal that began to be detected from one or more processing unit times before, and pulse information generated in the processing unit time before that whose frequency is close to the signal band information, to generate new pulse information.

[0013] Furthermore, pulse detection device 9 includes a pulse combining unit 15 that combines pulse information that has a similar signal band and is adjacent on the time axis to generate new pulse information for each processing unit time, and a detection result output unit 16 that outputs, for each processing unit time, pulse information that has not been consecutively combined within a number of processing unit times determined by the pulse combining unit 15 as detected pulses.

[0014] Next, the pulse detection device 9 and each component of the pulse detection device will be described in detail. The pulse detection device 9 detects multiple pulses from an input signal by digital signal processing. The digital signal processing may be realized by hardware such as a gate array, or may be realized by a program running on a processor. It may also be realized by a combination of hardware and software.

[0015] The frequency division unit 10 is composed of a filter bank. The filter bank receives an input signal and divides the input signal into a plurality of frequency bands, for example, by an FIR filter, which is a digital filter that is a known technology. Here, for each pulse included in the input signal, the entire pulse may be included in one divided signal, or the pulse may be included across multiple divided signals. When a pulse is included across multiple divided signals, each divided signal includes a portion of the pulse. Hereinafter, for simplicity, the pulse or a portion of the pulse included in each divided signal will be referred to as a detection signal.

[0016] The pulse waveform detection unit 11 detects a detection signal included in each divided signal divided into multiple frequency bands by the frequency division unit 10 for each processing unit time, and outputs pulse time information including the time when the detection signal exists. The pulse waveform detection unit 11 calculates the envelope of the divided signal for each processing unit time, detects the portion where the envelope exceeds a predetermined threshold as a detection signal, and calculates the rise time, fall time, pulse width, amplitude, etc. of the detection signal as pulse time information.

[0017] In the pulse waveform detection unit 11, a low-pass filter may be applied to calculate the envelope in order to reduce false detections when detecting the detection signal. Also, when the pulse waveform detection unit 11 detects the detection signal, different thresholds may be used for the rising and falling parts of the envelope. Also, the pulse waveform detection unit 11 may be configured not to detect pulses of a predetermined length or less that are unnecessary for the operation of the radio detection device as noise. The detected detection signal includes not only pulses that rise and fall during the processing unit time, but also a part of a pulse that continues from one or more previous processing unit times and a part of a pulse that continues to the next processing unit time at the end time of the processing unit time.

[0018] The signal band detection unit 12 calculates a spectrum from each divided signal for each processing unit time divided into a plurality of frequency bands by the frequency division unit 10, detects a signal band from the calculated spectrum, and outputs signal band information. The signal band detection unit 12 calculates a spectrum from the divided signal for the processing unit time by Fourier transform, and if the frequency component at the detection point is greater than a value calculated by a predetermined method from the frequency components around the detection point multiplied by a predetermined coefficient, it determines that a signal component exists at the detection point. This processing performed by the signal band detection unit 12 is similar to CFAR (Constant False Alarm Rate) processing in radar signal processing. Next, the signal band detection unit 12 groups together the points where it is determined that a signal exists continuously as a signal band, and calculates the minimum frequency, maximum frequency, peak power, peak frequency, etc. of the signal band as signal band information. The minimum frequency and maximum frequency may be frequencies at which the power is reduced by a predetermined ratio from the peak power.

[0019] The signal band allocation unit 13 allocates the signal band information generated by the signal band detection unit 12 to each pulse time information of the multiple detection signals detected by the pulse waveform detection unit 11, and generates pulse information. The divided signal intra-band allocation unit 17 of the signal band allocation unit 13 calculates frequency information for the pulse time information of the multiple detection signals detected by the pulse waveform detection unit 11 from a Fourier transform of the part of the divided signal corresponding to the detection signal. The frequency information is a range in which the frequency of the detection signal exists. The frequency information may be calculated by determining the maximum value of the frequency components, and using the range of frequency components larger than the value obtained by multiplying the maximum value by a predetermined coefficient (1 or less) as the frequency information, or may use the frequency range having frequency components larger than a predetermined threshold as the frequency information.

[0020] Next, the divided signal intra-band allocation unit 17 allocates signal band information whose frequency is close to that of the calculated frequency information to the pulse. The divided signal intra-band allocation unit 17 calculates the difference in frequency ranges in which signals exist between the frequency information and the signal band information as follows, and determines that the one with the smallest difference is the one with the closest frequency. The difference in frequency ranges between frequency information a and signal band b is calculated by dividing the minimum frequency of each by f(a) min , f (b) min , the maximum frequency is f (a) max , f (b) max Then, for example, it can be calculated as shown in formula (1).

[0021]

number

[0022] Furthermore, the difference in frequency range between the frequency information a and the signal band b may be expressed as in equation (2).

[0023]

number

[0024] Generally, when calculating the spectrum of a signal, the longer the signal is, the more accurately the spectrum is produced. Therefore, by generating pulse information by allocating the signal band information detected by the signal band detection unit 12 to the pulse time information of the detection signal detected by the pulse waveform detection unit 11, it is possible to obtain pulse information for each detection signal that accurately indicates the time at which the detection signal is detected and the range in which the frequency exists.

[0025] If the detected detection signal is a pulse that began to be detected from one or more processing unit times before, continuous pulse band allocation unit 18 of signal band allocation unit 13 connects the pulse information generated by intra-divided signal band allocation unit 17 with pulse information generated in the previous processing unit time that has a frequency close to that of the signal band information. In the case of a pulse that began to be detected from one or more processing unit times before, signal band information has already been assigned by signal band allocation unit 13 in the processing unit time before. Therefore, frequency information obtained by integrating the signal band information output from signal band detection unit 12 in the current processing unit time and the signal band information already assigned in the processing unit time before, becomes the most accurate frequency information of the pulse.

[0026] If the pulse time information indicating the time when the detection signal exists in the divided signal includes the time when the processing unit time begins, the continuous pulse band allocation unit 18 determines that the detection signal is that of a pulse that began to be detected from one or more processing unit times earlier.

[0027] The continuous pulse band allocation unit 18 divides the frequencies of the signal band a of the pulse information generated by the divided signal intra-band allocation unit 17 and the signal band b of the pulse information generated in the previous processing unit time into the minimum frequencies f (a) min , f (b) min , the maximum frequency is f (a) max , f (b) max Then, the calculation is performed as shown in formula (1) or formula (2). The continuous pulse band allocation unit 18 determines that the signal band information having the smallest difference in frequency range thus calculated among the ones smaller or equal to or less than the determined frequency difference threshold value is close in frequency.

[0028] The continuous pulse band allocating unit 18 combines the two pieces of pulse information. Specifically, the method of combining is as follows.

[0029] The minimum frequency of each of the signal band information of two pulse information a and b is f (a) min , f (b) min Then, the minimum frequency f (c) min is expressed as equation (3).

[0030]

number

[0031] The maximum frequency of each of the signal band information of two pulse information a and b is f (a) max , f(b) max Then, the maximum frequency f of the concatenated signal band information c is (c) max is expressed as equation (4).

[0032]

number

[0033] The peak power of each of the two pulse information a and b is P (a) peak , P (b) peak Then, the peak power P (c) peak is expressed as equation (5).

[0034]

number

[0035] The peak frequency of each of the two pulse information a and b is f (a) peak , f (b) peak Then, the peak frequency f of the concatenated signal band information c is (c) peak is expressed as equation (6).

[0036]

number

[0037] The rise time of each of the two pulses a and b is t (a) s , t (b) s Then, the rise time t of the concatenated signal band information c (c) s is expressed as equation (7).

[0038]

number

[0039] The fall time of each of the two pulse information a and b is t (a) f , t (b) f Then, the rise time t of the concatenated signal band information c (c) f is expressed as equation (8).

[0040]

number

[0041] In addition, the pulse width of the concatenated signal band information c is T (c) PD Then, T (c) PD is expressed as equation (9).

[0042]

number

[0043] Furthermore, the amplitude of each of the two pulse information a and b is A (a) , A (b) Then, the amplitude A of the concatenated pulse information c (c) is expressed as equation (10).

[0044]

number

[0045] The low time resolution pulse processing unit 14 regards the signal band information not assigned by the signal band assignment unit as a pulse present in the processing unit time currently being processed, and generates pulse information as a low time resolution pulse signal, which is a type of detection signal in which a part of a pulse is detected. The pulse information of the low time resolution pulse signal is hereinafter referred to as low time resolution pulse information. In the pulse information with low time resolution, the time when the processing unit time of the divided signal in which the low time resolution pulse signal is detected starts is set as the rising time, and the time when the processing unit time ends is set as the falling time.

[0046] A low time resolution pulse signal is generally a part of a pulse following the previous and next processing unit times or a part of a continuous signal. Therefore, the low time resolution pulse processing unit 14 connects it to low time resolution pulse information created in the previous processing unit time if their frequencies are close. The low time resolution pulse processing unit 14 calculates the difference in frequency range between signal band information using equation (1) or equation (2), and determines that the signal band information with the smallest distance calculated in this way is shorter or less than a predetermined frequency difference threshold value is close in frequency. The low time resolution pulse processing unit 14 also connects two low time resolution pulse information to each other using equations (3) to (8).

[0047] The low time resolution pulse processing unit 14 outputs, among the pulse information with low time resolution created in the previous processing unit time, information that is not connected in the currently processed processing unit time, assuming that the pulse ended in the previous processing unit time. Also, since there is a possibility that the low time resolution pulse information integrated in the currently processed processing unit time will be further connected in the next processing unit time, it is not output and continues to be held for a determined time inside the low time resolution pulse processing unit 14.

[0048] The pulse integration unit 15 integrates pulse information that has a close signal band and is also close on the time axis, targeting pulse information to which signal band information is assigned by the signal band allocation unit 13 in a plurality of frequency bands, pulse information output from the low time resolution pulse processing unit, and pulse information integrated by the pulse integration means itself and held for a predetermined period. The pulse integration unit 15 integrates two pieces of pulse information as shown in equations (3) to (8). The pulse integration unit 15 calculates the difference in frequency range between the signal band information of each piece of pulse information by equation (1) or equation (2), and determines that the signal band information with the smallest calculated difference among those that are shorter or shorter than a predetermined frequency difference threshold are close in frequency. The pulse integration unit 15 also calculates the distance between two pieces of pulse information on the time axis by equation (11), and determines that the signal band information with the smallest calculated distance among those that are shorter or shorter than a predetermined time threshold are close on the time axis.

[0049]

number

[0050] Next, the operation will be described with reference to Fig. 2, which is a flowchart showing the operation of the pulse detection device according to the first embodiment.

[0051] Every time a processing time unit elapses (ST10), the pulse detection device 9 receives the input signal output by the A / D converter 7 at the frequency division unit 10. Here, the frequency division unit 10 checks whether there is a new input signal (ST20), and if there is no new input signal (NO in ST20), it returns to ST10 and waits for a new input signal to be input until the next processing time unit. If there is a new input signal (TES in ST20), the frequency division unit 10 divides the input signal into a plurality of frequency bands and outputs them as divided signals (ST30). The divided signals output by the frequency division unit 10 for each processing unit time are input to the pulse waveform detection unit 11 and the signal band detection unit 12 for each processing unit time.

[0052] Next, the signal band detection unit 12 calculates a spectrum from the divided signal input from the frequency division unit 10, detects the signal band from the calculated spectrum, and generates signal band information (ST40). In parallel with the signal band detection unit 12, the pulse waveform detection unit 11 detects a detection signal from the divided signal input from the frequency division unit 10, and generates pulse time information (ST50).

[0053] The signal band allocation unit 13 calculates frequency information from the detection signal detected by the pulse waveform detection unit 11, and allocates, to the detection signal, signal band information output from the signal band detection unit 12, whose frequency is close to that of the calculated frequency information (ST60). The signal band allocation unit 13 generates pulse information based on the pulse time information of the detection signal and the allocated signal band information (ST70). Furthermore, the signal band allocation unit 13 connects, for pulses that have been detected in the detection signal from one or more previous processing unit times, to pulse information that has been detected from the previous processing unit time (ST80).

[0054] On the other hand, for signal band information that was not assigned to the detection signal by the signal band assignment unit 13, the low time resolution pulse processing unit 14 generates pulse information using the signal for which the signal band information was generated as a low time resolution pulse signal (ST90). In addition, the low time resolution pulse processing unit 14 links the generated pulse information with the low time resolution pulse signal generated in the previous processing unit time, and outputs the unlinked pulse information (ST100).

[0055] Pulse integration section 15 compares the pulse information generated in this processing time unit with the pulse information generated in this processing time unit with the pulse information generated in the previous processing time unit, and pulse time information and signal band information, and integrates pulse information that has a similar signal band and is adjacent on the time axis (ST110). When pulse integration section 15 integrates the pulse information, detection result output section 16 outputs the detected pulses for which integration of the pulse information has been completed (ST120).

[0056] When pulse combining section 15 outputs the detected pulse, pulse detection device 9 returns to ST10 and repeats the processes from ST10 to ST120 for each processing time unit.

[0057] As described above, in the pulse detection device according to the first embodiment, the input signal is divided into a plurality of frequency bands, and the detection signals detected from the divided signals for each processing time unit are integrated in the pulse combining unit, so that pulses whose time and frequency ranges are distributed beyond the frequency bands and processing time units of one divided signal can be efficiently detected. Furthermore, prior to the processing in the pulse combining unit, pulses detected from one or more previous processing time units are concatenated in the signal band allocation unit, so that pulses whose time ranges are distributed beyond the processing time units can be efficiently detected and accurate pulse information can be obtained.

[0058] In addition, even for pulses whose time and frequency are distributed within the frequency band or processing time unit of a single divided signal, by combining a pulse waveform detection unit with high time resolution with a signal band detection unit with high frequency resolution, it is possible to efficiently detect each of the signals in which pulses exist within a variety of time and frequency ranges within the divided signal, and obtain accurate pulse information.

[0059] A modified example of the pulse detection device according to the first embodiment will now be described. Fig. 3 is a diagram showing the operating principle of a signal band allocation section of a modified example of the pulse detection device according to the first embodiment. In the above description, divided signal intra-band allocation section 17 of signal band allocation section 13 calculates frequency information from a Fourier transform of a portion of the divided signal corresponding to the detection signal of the divided signal, for pulse information of a plurality of detection signals detected by pulse waveform detection section 11. However, divided signal intra-band allocation section 17 of signal band allocation section 13 may further divide the divided signal into a plurality of short-time units, calculate frequency information for each of the short-time units, and integrate the frequency information of the short-time units included in the corresponding portion of the pulse detected from the divided signal to calculate the frequency information of the corresponding portion.

[0060] In Fig. 3, (a) shows an example of a pulse detected from a divided signal. In this example, the divided signal is further divided into eight, from short-time unit 1 to short-time unit 8. Here, an example will be described in which the frequency of the pulse changes between short-time unit 2 to short-time unit 5, as in Fig. 3(a). In Fig. 3, (b) shows an example of the results of Fourier transforming the divided signal in each unit time, and the frequency information for each short-time unit and the frequency information of the entire pulse obtained from the results.

[0061] The divided signal band allocation unit 17 performs a Fourier transform for each short time unit, and obtains frequency information that is the band (upper and lower frequency limits) of the frequency signal for each unit time. The frequency information may be a range of frequency components greater than a value obtained by multiplying the maximum value of the frequency components by a predetermined coefficient (1 or less) for each short time unit, or a frequency range having frequency components greater than a predetermined threshold. The short time units are represented as short time unit 1, short time unit 2, ..., short time unit K, and the short time units in which a pulse exists are represented as short time unit (1), short time unit (2), ..., short time unit (N). In the case of FIG. 3, {time unit (1), time unit (2), ..., time unit (N)} is {time unit 2, time unit 3, ..., time unit 5}.

[0062] The minimum frequency of the pulse in each short time unit (i) is f (i) min Then, the minimum frequency of the entire pulse is f (m) min is expressed as in equation (12).

[0063]

number

[0064] Also, the maximum frequency of the pulse in each short time unit (i) is f (i) max Then, the maximum frequency of the entire pulse is f (m) maxis expressed as in equation (13).

[0065]

number

[0066] In addition, the peak power and peak frequency of the pulse in each short time unit (i) are P (i) peak , f (i) peak Then, the peak power of the entire pulse P (m) peak , peak frequency f (m) peak are expressed as equations (14) and (15), respectively.

[0067]

number

[0068]

number

[0069] By determining the frequency range of the detection signal in this manner, the divided signal intra-band allocation unit 17 can determine the frequency band of the signal through standard processing even if the time during which a pulse signal exists within the divided signal changes.

[0070] Embodiment 2 The second embodiment will be described with reference to Figs. 4 and 5. In pulse detection device 9 of the first embodiment, pulse combining unit 15 combines pulse information that has a similar signal band and is adjacent on the time axis, targeting pulse information to which signal band information has been assigned by signal band allocation unit 13, pulse information combined by pulse combining unit 15 itself, and pulse information output from low time resolution pulse processing unit 14. In contrast, pulse detection device 9A of the second embodiment includes an unnecessary pulse deletion unit that compares each piece of pulse information before pulse combining unit 15 combines the pulse information, determines whether one piece of pulse information is unnecessary pulse information due to spectral leakage from the frequency band of the other pulse information, and deletes the unnecessary pulse information.

[0071] Fig. 4 is a diagram showing the configuration of pulse detection device 9A according to embodiment 2 and a radio detection device including pulse detection device 9A. In Fig. 4, pulse detection device 9A includes unnecessary pulse removal unit 19. Unnecessary pulse removal unit 19 compares pulse information to which signal band information has been assigned by signal band allocation unit 13, pulse information integrated by pulse integration unit 15, and pulse information output from low time resolution pulse processing unit 14, determines whether one piece of pulse information is unnecessary pulse information due to spectral leakage from the frequency band of the other pulse information, and removes the unnecessary pulse information.

[0072] Pulse combining unit 15 combines pulse information that has similar signal bands and is adjacent on the time axis, targeting pulse information to which signal band information has been assigned by signal band allocation unit 13 after unnecessary pulse deletion unit 19 has deleted unnecessary pulse information, pulse information integrated by pulse combining unit 15 itself, and pulse information output from low time resolution pulse processing unit 14. Pulse combining unit 15 also outputs the combined pulse information to unnecessary pulse deletion unit 19. Other than the above, pulse detection device 9A has the same configuration as pulse detection device 9, so a description thereof will be omitted.

[0073] Next, the unnecessary pulse removing unit 19 will be described in detail. The unnecessary pulse removing unit 19 calculates pairs of pulse information of different frequency bands for pulse information assigned with signal band information by the signal band assigning unit 13 in a plurality of frequency bands and pulse information output by the low time resolution pulse processing unit 14, and removes pulses a and b of each pair if either one is an unnecessary pulse due to spectral leakage. To reduce the calculation load, the pulse information for which pulse pairs are calculated may be limited to pulse information generated from the same divided signal and pulse information generated from divided signals having adjacent frequency bands.

[0074] A method for determining whether an unwanted pulse is present will now be described. In the description, it will be assumed, without loss of generality, that the amplitude of pulse a is greater than that of pulse b. Unwanted pulses due to spectral leakage are generated because the amplitude of the pulse causing the spectral leakage changes in a short period of time, causing the spectrum to spread at the rising and falling edges of the pulse. For this reason, the amplitude of the unwanted pulse due to spectral leakage is smaller than that of the pulse causing the spectral leakage. Therefore, if the amplitude of pulse b is smaller than the amplitude of pulse a by a predetermined ratio or more, it is determined whether pulse b is an unwanted pulse.

[0075] First, we will explain the case where the pulse causing the spectral leakage is a short pulse. In that case, the arrangement of the two pulses on the time axis will be close, so if the overlap rate of the two pulses on the time axis is equal to or greater than a predetermined ratio and the center of one pulse is included in the time range of the other pulse, the pulse will be determined to be an unwanted pulse. Here, the overlap length of the two pulses on the time axis is expressed as in Equation (13).

[0076]

number

[0077] In this case, if both equations (17) and (18) are satisfied, pulse b is determined to be an unnecessary pulse. OL is a predetermined threshold value.

[0078]

number

[0079]

number

[0080] Next, we will explain the case where the pulse causing the spectral leakage is a long pulse. In that case, since the unwanted pulse occurs at the rising or falling edge of the pulse causing the spectral leakage, for example, pulse b is determined to be an unwanted pulse when the rising time of pulse a is included in the time range of pulse b, or when the falling time of pulse a is included in the time range of pulse b. Specifically, pulse b is determined to be an unwanted pulse when formula (19) or formula (20) is satisfied.

[0081]

number

[0082]

number

[0083] Next, the operation will be described. Fig. 5 is a flow chart showing the operation of pulse detection device 9A according to the first embodiment. As shown in Fig. 5, in pulse detection device 9A, signal band allocation section 13 generates pulse information in ST70 and ST80, low time resolution pulse processing section 14 generates pulse information in ST90 and ST100, and then pulse deletion section 19 deletes unnecessary pulse information (ST105). After pulse deletion section 19 deletes unnecessary pulses, pulse integration section 15 integrates pulse information output from signal band allocation section 13 and low time resolution pulse processing section 14 up to the current processing unit time and pulse information integrated by pulse integration section 15 up to the previous processing unit time (ST110). Operations other than those described above are similar to those of pulse detection device 9, and therefore will not be described.

[0084] As described above, the pulse detection device according to the second embodiment includes an unnecessary pulse deletion unit that compares the pulse information with each other before the pulse integration unit integrates the pulse information, determines whether one pulse information is unnecessary pulse information due to spectral leakage from the frequency band of the other pulse information, and deletes the unnecessary pulse information. As a result, unnecessary pulses generated by spectral leakage are deleted, and erroneous integration of pulse information is reduced, making it possible to obtain a pulse detection device that can detect pulses more accurately. Furthermore, because unnecessary pulse information is deleted before integrating the pulse information with each other, it is possible to obtain a pulse detection device that can efficiently integrate the pulse information with each other. [Explanation of symbols]

[0085] 1 Antenna, 2 Filter, 3 Mixer, 4 High frequency signal generating circuit, 5 filter, 6 amplifier, 7 A / D converter, 8 control device, 9, 9A pulse detection device, 10 frequency division unit, 11 pulse waveform detection unit, 12 signal band detection unit, 13 signal band allocation unit, 14 low time resolution pulse processing unit, 15 pulse integration unit, 16 detection result output unit, 17 division signal band allocation unit, 18 continuous pulse band allocation section, 19 unnecessary pulse deletion section.

Claims

1. A pulse detection device for detecting a plurality of pulses included in an input signal, a frequency division unit that divides the input signal into a plurality of frequency bands and outputs the divided signals for each processing unit time; a signal band detection unit that calculates a spectrum from each of the divided signals for each processing unit time, detects a signal band from the calculated spectrum, and outputs signal band information; a pulse waveform detection unit that detects the pulse or a part of the pulse from each of the divided signals as a detection signal for each processing unit time and outputs pulse time information including a time when the detection signal exists; a signal band allocation unit that calculates frequency information from a portion of the divided signal corresponding to the detection signal for each of the plurality of detection signals detected by the pulse waveform detection unit in each of the frequency bands for each of the processing unit time, and generates pulse information by allocating the signal band information output from the signal band detection unit, the frequency of which is close to the calculated frequency information; a pulse integration unit that integrates the pulse information that is close to each other in the signal band and is also close on the time axis to generate new pulse information for each processing unit time. Pulse detection device.

2. A pulse detection device for detecting a plurality of pulses included in an input signal, a frequency division unit that divides the input signal into a plurality of frequency bands and outputs the divided signals for each processing unit time; a signal band detection unit that calculates a spectrum from each of the divided signals for each processing unit time, detects a signal band from the calculated spectrum, and outputs signal band information; a pulse waveform detection unit that detects the pulse or a part of the pulse from each of the divided signals as a detection signal for each processing unit time and outputs pulse time information including a time when the detection signal exists; a divided signal intra-band allocation unit that calculates frequency information from a portion of the divided signal corresponding to the detection signal for each of the plurality of detection signals detected by the pulse waveform detection unit in each of the frequency bands for each of the processing unit times, and generates pulse information by allocating the signal band information output from the signal band detection unit, the frequency of which is close to the calculated frequency information; a continuous pulse band allocation unit that generates new pulse information by integrating, for each processing time unit, the pulse information generated by the divided signal intra-band allocation unit for the detection signal that has started to be detected since one or more previous processing unit times, and the pulse information generated in the previous processing unit time, the pulse information having a frequency close to that of the signal band information; and a pulse integration unit that integrates the new pulse information generated by the continuous pulse band allocation unit, the new pulse information being close to each other in the signal band and adjacent on the time axis, to generate further new pulse information for each processing unit time. Pulse detection device.

3. The continuous pulse band allocation unit When the time when the detection signal exists in the pulse time information of the pulse information generated by the divided signal intra-band allocation unit includes the start time of the processing unit time, it is determined that the detection signal for which the pulse information was generated has been detected since one or more processing unit times before.

3. The pulse detection device according to claim 2.

4. a detection result output unit configured to output, for each processing unit time, the pulse information that has not been continuously integrated during a number of processing unit times determined by the pulse integration unit as detected pulse information.

4. A pulse detection device according to claim 1.

5. The pulse detection device includes: A low time resolution pulse processing unit is further provided, which creates the pulse information with low time resolution from the signal band information not assigned by the signal band assignment unit in each of the frequency bands, and connects the pulse information with the low time resolution created in the previous processing unit time if the frequency is close to the pulse information with low time resolution created in the previous processing unit time, and outputs the pulse information with low time resolution not connected among the pulse information with low time resolution created in the previous processing unit time, The pulse integrating unit includes: Integrating the pulse information to which the signal band information is assigned by the signal band allocation unit in all of the plurality of frequency bands, the pulse information integrated by the pulse integration unit, and the pulse information with low time resolution output from the low time resolution pulse processing unit.

2. The pulse detection device according to claim 1.

6. The signal band allocation unit, When calculating the frequency information from the portion of the pulse detected from the divided signal that corresponds to the detection signal, the divided signal is divided into a plurality of short-time units, a frequency is calculated for each of the short-time units, and the frequency information of the corresponding portion is calculated by integrating the frequencies of the short-time units that include the detection signal.

6. A pulse detection device according to claim 1 or 5.

7. The pulse information to which the signal band information is assigned by the signal band allocation unit, the pulse information integrated by the pulse integration unit, and the pulse information output from the low time resolution pulse processing unit are targeted, and before processing to integrate the pulse information having a close signal band and adjacent on the time axis, the pulse information is compared with each other to determine whether one of the pulse information is unnecessary pulse information due to spectrum leakage from the frequency band of the other of the pulse information, and the unnecessary pulse information is deleted.

6. The pulse detection device according to claim 5.

Images