KR20240045066A - Method and apparatus for detecting weak singals - Google Patents

Abstract

A method and device for detecting extreme signals that are difficult to capture in radio signals or weak signals that appear intermittently with a level below the internal noise of an RF receiver are disclosed. The weak signal detection device includes a cross-correlation spectrum processing unit that generates a cross-correlation spectrum using the correlation between RF reception channels, and an output spectrum with a spectral afterimage function by weighting the current and past waveforms of the cross-correlation spectrum. It includes a waveform combination unit that generates.

Description

Method and device for detecting weak signals {METHOD AND APPARATUS FOR DETECTING WEAK SINGALS}

The present invention relates to weak signal monitoring technology, and more specifically, to a method and device that can detect extreme signals that are difficult to capture in radio frequency signals or weak signals that appear intermittently.

Because radio waves exist anytime and anywhere, various interference problems arise between devices that use radio waves. Devices such as mobile phones that operate in licensed frequency bands must be manufactured so as not to cause interference by leaking radio frequency (RF) levels on adjacent frequencies. However, it is not easy for general communication devices that have various transmission modes and exist simultaneously on multiple networks to satisfy all of these conditions.

Communication devices operating in unlicensed frequency bands must operate normally even in the presence of interference signals, and it is necessary to transmit at low power for only a short period of time to reduce mutual interference with other communication devices.

Digital RF devices, which are a combination of radio frequency (RF) and digital devices, include mobile communication mobile phones, wireless LAN devices, digital multimedia broadcasting (DMB) devices, and RFID (radio frequency identification) devices. there is.

Advances in software defined radio (SDR) and cognitive radio (CR) technologies minimize mutual interference between digital RF devices and support efficient use of radio spectrum, a scarce resource. Recent developments in digital RF device-related technologies such as SDR and CR have enabled digital RF devices to efficiently use the radio spectrum even in complex and diverse radio wave environments.

Meanwhile, measurement equipment that monitors RF services to maintain the usage environment of digital RF devices is used to reliably detect and analyze RF signals with characteristics such as low power and short signal duration to locate and remove interference sources. You can. However, due to complex changes in the radio wave environment, it is difficult to detect radio signals for weak signals that appear intermittently using existing detection technologies.

For example, with the advent of various new radio services, many low-power wireless devices are appearing that transmit signals at low power for a short period of time to reduce mutual interference. Low-power wireless devices include various low-power wireless stations such as LAN (local area network), BAN (body area network), PAN (personal area network), and device-to-device communication. However, for signals from these low-power wireless devices, it is difficult to detect weak signals below the internal noise level of the RF receiver in a digital RF device using the spectrogram or accumulated spectrum of existing technology.

In other words, the existing spectrum analyzer for signal detection was unable to detect weak signals that appeared intermittently and had a low level near the noise floor of the RF receiver. Additionally, existing spectrum analyzers were unable to observe relatively low-level signals within relatively high-level broadband signals.

Meanwhile, in some conventional technologies, intermittent signals can be detected by applying accumulated spectrum to process large amounts of data in real time, but it is difficult to detect weak signals. In addition, the signal-to-noise ratio on the spectrum can be improved by removing random noise components through cross spectrum, but it is still difficult to detect intermittent weak signals.

In this way, there is a need for a new method that can effectively detect weak signals that appear intermittently with a level below the internal noise level of the RF receiver.

The present invention was derived to meet the needs of the prior art described above, and the purpose of the present invention is to overcome the limitation of detecting intermittent weak signals in digital RF devices, spectrum analyzers, etc. due to the relatively low signal-to-noise ratio of the input spectrum. The goal is to provide a weak signal detection device with a new structure that can

Another object of the present invention is to generate a cross-correlation spectrum using the cross-correlation between RF reception channels connected to the antenna, combine the current and past waveforms of the cross-image and spectrum with weights, and accumulate them in the waveform map image memory, The aim is to provide a weak signal detection method and device that can visually or intuitively detect a weak signal that is output intermittently and has a level below the internal noise level of an RF receiver.

A weak signal detection device according to an aspect of the present invention for solving the above technical problem is a device that detects a weak signal that appears intermittently with a level below the internal noise of a radio frequency (RF) receiver. a cross-correlation spectrum processing unit that generates a cross-correlation spectrum using the correlation between reception channels; and a waveform combining unit that generates an output spectrum with a spectral afterimage function by assigning weights to the current and past waveforms of the cross-correlation spectrum.

The waveform combining unit multiplies the cross-correlation spectrum at the n-th time, which is the current waveform, by a first weight (w1), and applies a second weight (w1) to the cross-correlation spectrum at the n-1-th time, which is the immediately past waveform of the current waveform. The output spectrum may be generated by multiplying w2) and adding the cross-correlation spectrum multiplied by the first weight and the cross-correlation spectrum multiplied by the second weight.

The waveform combining unit may include a waveform storage unit that stores the cross-correlation spectrum at the n-1th time.

The weak signal detection device may further include a waveform pixel mapping unit that maps waveforms of the output spectrum to pixels in a pixel memory buffer.

The weak signal detection device may further include a waveform map image memory that includes pixels of a pixel memory buffer and stores the output spectrum waveforms cumulatively for a certain period of time. Digital level data formed by output spectrum waveforms accumulated and stored in the waveform map image memory may be transmitted to the display device at each screen update time of the display device.

The weak signal detection device is, the display device according to the level of the digital level data of each pixel accumulated according to the number of hits or the number of storage of cross-correlation spectrum waveforms stored in each pixel of the waveform map image memory. It may further include a control device that controls the operation of the display device so that different colors are displayed on the screen.

The weak signal detection device may further include at least two RF reception channels connected to at least one antenna and providing complex signals to the cross-correlation spectrum processing unit.

The weak signal detection device may further include a channel selection unit disposed between the three or more RF reception channels and the cross-correlation spectrum processing unit when there are three or more RF reception channels.

The weak signal detection device may include at least two antennas as the at least one antenna. The at least two antennas may be connected to the at least two RF reception channels.

The weak signal detection device may include a single antenna as the at least one antenna, and is disposed between the single antenna and the at least two RF reception channels to branch the received signal of the single antenna to receive the at least two RF reception channels. It may further include a power divider that distributes power to each of the RF reception channels.

Each of the at least two RF reception channels may include an RF down conversion unit. The RF down conversion unit may include a sweep generator connected to its own local oscillator. The sweep generator may operate so that the oscillation frequency of the local oscillator automatically changes with time.

Each of the at least two RF reception channels may further include a digital signal processor. The digital signal processing unit converts the intermediate frequency analog signal coming from the RF down conversion unit into a digital signal, converts the converted digital signal into a baseband signal, and reduces the data sampling rate of the baseband signal to generate complex data. And the generated complex data can be transmitted to the cross-correlation spectrum processing unit.

A weak signal detection method according to another aspect of the present invention for solving the above technical problem is a method of detecting a weak signal that appears intermittently with a level below the internal noise of a radio frequency (RF) receiver, Generating a cross-correlation spectrum using correlation between reception channels; and generating an output spectrum with a spectral afterimage function by combining the current and past waveforms of the cross-correlation spectrum with weights.

The step of generating the output spectrum includes multiplying the cross-correlation spectrum at the n-th time, which is the current waveform, by a first weight, and multiplying the cross-correlation spectrum at the n-1 time, which is the immediately past waveform of the current waveform, by a second weight. The output spectrum may be generated by multiplying the cross-correlation spectrum multiplied by the first weight and the cross-correlation spectrum multiplied by the second weight.

The weak signal detection method may further include storing the cross-correlation spectrum at the n-1th time.

The weak signal detection method may further include mapping waveforms of the output spectrum to pixels of a waveform map image memory.

The weak signal detection method may further include accumulating and storing the output spectrum waveforms in the waveform map image memory for a certain period of time.

The weak signal detection method may further include transmitting digital level data formed by output spectrum waveforms accumulated and stored in the waveform map image memory to the display device at each screen update time of the display device.

The weak signal detection method is based on the level of the digital level data of each pixel accumulated according to the number of hits or the number of storage times of cross-correlation spectrum waveforms stored in each pixel of the waveform map image memory. The method may further include controlling the operation of the display device so that different colors are displayed on the screen.

The weak signal detection method may further include providing a complex signal to a cross-correlation spectrum processor through at least two RF reception channels connected to at least one antenna.

The weak signal detection method may further include, when there are three or more RF reception channels, selecting two channels placed between the three or more reception channels and the cross-correlation spectrum processing unit based on the cross-correlation value. You can.

The weak signal detection method, when a single antenna is provided as the at least one antenna, branches the received signal of the single antenna through a power divider disposed between the single antenna and the at least two RF reception channels. The step of distributing to at least two RF reception channels may be further included.

The weak signal detection method includes, when each of the at least two RF reception channels has an RF down-converter and the RF down-converter has a sweep generator connected to its own local oscillator, the local oscillator is generated by the sweep generator. A step of automatically changing the oscillation frequency over time may be further included.

The weak signal detection method includes converting an intermediate frequency analog signal coming from the RF down conversion unit into a digital signal by the digital signal processing unit when each of the at least two RF receiving channels further includes a digital signal processing unit. The method may further include converting the converted digital signal into a baseband signal, generating complex data by reducing the data sampling rate of the baseband signal, and transmitting the generated complex data to the cross-correlation spectrum processor.

According to the present disclosure, a new structure can overcome the limitation of existing spectrum analyzers that cannot detect weak signals with a relatively low signal-to-noise ratio of the input spectrum, that is, weak signals with a level smaller than the internal noise level during normal operation. And it is possible to provide an intermittent weak signal detection device with a new operating method (hereinafter simply referred to as 'weak signal detection device').

In addition, when using the weak signal detection device of the present disclosure, a weak signal existing at a level below the internal noise of the RF receiver is detected through cross-correlation signal processing between two radio frequency (RF) reception channels received from the antenna. By generating a cross spectrum and plotting the cross spectrum in real time, it is possible to effectively detect weak signals that appear intermittently in wireless signals that were previously unobservable.

In addition, according to the present disclosure, by overcoming the limitations of the display device and configuring the spectrum to be measured and analyzed by storing it in memory in real time, it is possible to detect phenomena that are difficult to capture in radio signals, especially noise levels that appear intermittently ( You can effectively detect low-level signals near the noise floor or observe low-level signals within high-level broadband signals.

In addition, applying the weak signal detection method or weak signal detection device of the present disclosure to a signal detection system can dramatically improve system performance in terms of sensitivity. In other words, by effectively detecting weak signals that appear intermittently, it can be effectively used in fields such as national radio wave management, maritime or aviation safety radio wave monitoring, and national defense electronic warfare.

Figure 1 is a block diagram for explaining the main configuration of a weak signal detection device according to a first embodiment of the present invention.
FIG. 2 is an example diagram of noise levels according to cross-correlation signal processing that can be employed in the weak signal detection device of FIG. 1.
FIG. 3 is a flowchart for explaining the main operations of the weak signal detection device of FIG. 1.
FIG. 4 is a diagram for explaining the operating principle of the waveform combination unit of the weak signal detection device of FIG. 1.
Figure 5 is a schematic block diagram of a weak signal detection device according to a second embodiment of the present invention.
FIG. 6 is a flowchart for explaining digital level data used in the weak signal detection device of FIG. 5.
FIG. 7 is a flowchart for explaining the operating principle of the weak signal detection device of FIG. 5.
Figure 8 is a block diagram of a weak signal detection device according to a third embodiment of the present invention.
Figure 9 is a block diagram of a weak signal detection device according to a fourth embodiment of the present invention.
Figure 10 is a block diagram of a weak signal detection device according to the fifth embodiment of the present invention.
Figure 11 is a block diagram of a weak signal detection device according to a sixth embodiment of the present invention.
Figure 12 is a block diagram of a weak signal detection device according to the seventh embodiment of the present invention.
Figure 13 is a block diagram illustrating a spectrum analyzer of a comparative example.
Figure 14 is an exemplary diagram of a waveform showing frequency vs. level in a spectrum analyzer of a comparative example.
Figure 15 is a diagram illustrating frequency vs. level city waveforms expressed in different colors according to the frequency of appearance in the spectrum analyzer of the comparative example.
Figure 16 is a diagram showing the frequency vs. level waveform expressed in different colors according to the frequency of appearance in the weak signal detection device of this embodiment.
Figure 17 is a schematic block diagram of a configuration applicable to a weak signal detection device according to the eighth embodiment of the present invention.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

Terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, a first component may be named a second component, and similarly, the second component may also be named a first component without departing from the scope of the present invention. The term 'and/or' includes any of a plurality of related stated items or a combination of a plurality of related stated items.

In the embodiments of the present application, 'at least one of A and B' may mean 'at least one of A or B' or 'at least one of combinations of one or more of A and B'. Additionally, in the embodiments of the present application, 'one or more of A and B' may mean 'one or more of A or B' or 'one or more of combinations of one or more of A and B'.

When a component is said to be 'connected' or 'connected' to another component, it is understood that it may be directly connected or connected to the other component, but that other components may exist in between. It should be. On the other hand, when it is mentioned that a component is 'directly connected' or 'directly connected' to another component, it should be understood that there are no other components in between.

The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as 'comprise' or 'have' are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless explicitly defined in the present application, should not be interpreted in an idealized or excessively formal sense. No.

In the description of the embodiments below, a spectrum analyzer measures the amplitude of an input signal versus frequency within the entire frequency range to be analyzed by the equipment. The main use of a spectrum analyzer is to measure the spectral strength of known and unknown signals.

A spectrum analyzer may take the form of a measuring instrument that combines a display device that displays the distribution of frequency spectrum components and a superheterodyne receiver. In addition, the spectrum analyzer may be equipped with a sweep oscillator as a local generator, and the frequency spectrum of the input signal may be received in sequence in response to the change in frequency of the sweep oscillator, and the output may be transmitted by the sweep oscillator on the longitudinal axis of the display device. The sweep repetition signal being swept may have a form applied to the horizontal axis. In addition, a spectrum analyzer is a type of measuring instrument that analyzes RF signals transmitted from a reader or tag, or analyzes RF signals coming through an antenna. It analyzes frequency domain signals into time domain signals through the VSA (vector signal analyzer) function. Functions can be provided.

Electromagnetic waves or spectrum refers to all frequencies including infrared, visible light, ultraviolet rays, X-rays, and gamma rays, including the RF (radio frequency) spectrum. Among these, the RF (radio frequency) spectrum may refer to radio waves in the frequency range of 3 Hz or less. And in this specification, the RF spectrum may be referred to as a frequency spectrum.

A radio frequency (RF) channel refers to a communication line established between a mobile station and a base station in mobile communication. RF channels that enable simultaneous calls or data transmission and reception between mobile terminals or between mobile terminals and fixed terminals have a limited number of channels within the allocated frequency band. RF reception channel may refer to a specific state of an RF channel or a specific communication line that receives signals or data.

Cross correlation can be expressed as R ₁₂ (t) when two random signals X ₁ (t) and X ₂ (t) are defined as follows [Equation 1]. In Equation 1, X ₁ (t) is a random input of a linear stationary system, _and when X ₂ (t) is _the response of You can. In this specification, the cross spectrum can be obtained by cross-correlation signal processing of complex digital data.

Complex data refers to a signal component with a certain periodicity, and can refer to a digital signal converted from an analog signal in a digital processing unit connected to an RF down conversion unit, converted to a baseband complex signal by reducing the sampling rate. Complex data may have a predetermined level in a preset frequency band. Complex data may be referred to as complex signal or complex digital data.

Frequency span refers to the frequency range or frequency width to be measured by an instrument or spectrum analyzer, and may be referred to as a sweep frequency bandwidth or simply as a span. In the frequency band to be analyzed, the center frequency may be the center of the frequency span.

Digital level data is data with a level in a digital form rather than an analog form. In this specification, cross-spectrum waveforms obtained by multiplying and summing the current waveform processed with a cross-correlation signal and the previous waveform processed with a cross-correlation signal by multiplying and summing the weights. It may refer to data that is accumulated and stored in the waveform map image memory by mapping to screen pixels of a preset display device according to frequency and level over the frequency span. These digital level data are accumulated spectrum waveforms and can be displayed on the screen of a non-display device with different colors or brightness preset according to the number of accumulations.

Weak signals refer to low level signals that are near or below the noise floor of the RF receiver. In other words, a weak signal may refer to a signal transmitted at relatively low output for a short period of time to reduce interference between communication equipment such as low-power wireless devices in various new radio service environments. Additionally, a weak signal may refer to a signal with a level below the internal noise of the RF receiver in a digital RF device using a conventional spectrogram or accumulated spectrum. The internal noise level of the RF receiver may range from several tens of decibels [dB] to several decibels.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the attached drawings. The following detailed description is provided for illustrative purposes only and should not be construed as limiting the inventive concept to any particular physical configuration. In order to facilitate overall understanding when describing the present invention, the same reference numerals are used for the same components in the drawings, and duplicate descriptions for the same components are omitted.

Figure 1 is a block diagram for explaining the main configuration of a weak signal detection device according to a first embodiment of the present invention.

Referring to FIG. 1, the weak signal detection device outputs a weak signal, especially a weak signal, intermittently, which is a signal with a level below the internal noise level of the RF receiver of a measuring device such as a digital radio frequency (RF) device or spectrum analyzer. A cross-correlation processing unit 100 and a waveform combination unit 200 are provided to detect intermittent weak signals.

The cross-correlation processor 100 generates a cross-correlation spectrum using the cross-correlation between RF reception channels connected to at least one antenna. The cross-correlation spectrum may be referred to as cross-spectral waveforms or simply as a cross waveform. That is, the cross-correlation processing unit 100 may be configured to cross-correlate signal process complex signals from RF reception channels. A complex signal may correspond to complex data.

Here, the RF receiving channels convert the RF input from the antenna into an intermediate frequency signal, convert the analog signal converted into an intermediate frequency signal into a digital signal, and reduce the sampling rate of the converted digital signal to convert it into a baseband complex signal. It can be configured.

The above-described cross-correlation processing unit 100 may be configured to receive complex signals from two RF reception channels. The cross-correlation processing unit 100 may calculate the cross-correlation value of two or more digital signals to which Fourier transform has been applied.

In this case, the signal detection control unit connected to the cross-correlation processing unit 100 may determine whether there is a correlation between two or more Fourier transformed digital signals. That is, the signal detection unit may be configured to select a low-level signal with correlated frequency components as a weak signal and not select a low-level signal with uncorrelated frequency components as noise. The signal detection control unit may also be briefly referred to as a determination unit or control unit. The determination unit or control unit may correspond to a control device comprised of a microprocessor, processor, etc.

Additionally, the cross-correlation processing unit 100 may be connected to three or more RF reception channels connected to multiple antennas to obtain a diversity effect. In that case, the cross-correlation processor 100 cross-correlates the complex signals of two RF reception channels selected in a predetermined order or randomly among three or more RF reception channels, and processes all RF reception channels or a combination thereof. It may be configured to perform cross-correlation signal processing on a pair of complex data. In this case, the signal detection unit may be configured to select the two RF reception channels with the best noise reduction performance or efficiency based on cross-correlation values for all RF reception channels or a combination pair thereof. The cross-correlation processing unit 100 may be configured to generate a cross-correlation spectrum using the correlation between two RF reception channels selected by the signal detection unit.

The waveform combining unit 200 receives the cross-correlation spectrum from the cross-correlation processing unit 100, multiplies the current waveform and the past waveform of the cross-correlation spectrum over the frequency span, respectively, by a weight, and adds them to generate an output spectrum. It can be configured. The output spectrum is cross-correlated spectral waveforms and may be briefly referred to as a cross waveform.

Here, when the past waveform is the waveform of the first time, the current waveform may be the waveform of the second time later than the first time. The past waveform may be one original waveform or a combination of the first past waveform and the second past waveform with respective weights. Multiplying the current and past waveforms by their respective weights and then adding them can be expressed as a combination of the current waveform and the past waveform. In order to combine the current waveform with the past waveform in the form of accumulation, the current waveform is added based on the level of the past waveform. May include normalization.

The weights given to the current waveform and the past waveform may be the same or different. Each weight may have a value selected from the range of 0 to 1.0.

The above-described cross-correlation processing unit 100 and waveform combining unit 200 may each be formed as independent modules, but are not limited to this and the cross-correlation processing unit 100 and waveform combining unit 200 may be formed as a single module. It may be formed as a correlation waveform generator 300.

According to this embodiment, cross-correlation spectrum waveforms, which are a weighted combination of past waveforms and current waveforms, can be mapped to screen pixels of a display device and stored cumulatively in corresponding pixels of the waveform map image memory. In addition, each pixel in which the waveform is accumulated and stored in the waveform map image memory has an accumulation level according to the cumulative number of waveforms for each pixel or the number of hits of the waveform for each pixel, and a preset color according to the accumulation level. And/or each pixel data configured to represent brightness, that is, digital level data, may be stored. Such digital level data can be transferred from the waveform map image memory to the driving unit of the display device at every screen update time of the display device. According to this configuration, the user can intuitively detect intermittent weak signals on the screen of the display device.

In this embodiment, the weak signal may represent a signal with a low level below the internal noise level of the RF receiver of a signal detection device such as a digital RF device or spectrum analyzer. From the perspective of a signal detection device such as a spectrum analyzer, an intermittent weak signal refers to a low-level signal that appears intermittently in a form where a specific frequency within the frequency band to be detected is used sporadically or occasionally for a certain unit of time and then is not used. can do.

FIG. 2 is an example diagram of noise levels according to cross-correlation signal processing that can be employed in the weak signal detection device of FIG. 1.

Referring to FIG. 2, you can see the results of simulating a WCDMA signal with a center frequency of 2167.2 MHz with a reception bandwidth of 10 MHz, a sampling frequency of 12.8 MHz, a sampling number of 65,400, a cross-correlation number of 128, and a fast Fourier transform number of 1,024. In FIG. 2, 310 indicates the average value of the frequency spectrum, and 330 indicates the cross-correlation processed frequency spectrum.

Looking at the part indicated by two dotted lines in the simulation results, you can see that when complex data corresponding to the frequency spectrum was cross-correlated signal processed, the noise level was reduced by about 10 dB.

Using the cross-correlation value in this way reduces the noise level of the frequency spectrum and increases the signal-to-noise ratio, making it possible to detect weak signals with a level lower than the internal noise level of the original RF receiver. If the cross-correlation number is further increased, the noise level can be further reduced.

FIG. 3 is a flowchart for explaining the main operations of the weak signal detection device of FIG. 1.

Referring to FIG. 3, the weak signal detection device includes performing cross-correlation signal processing between two RF reception channels (S100) and cross-correlation signal processing to detect weak signals that intermittently appear in radio signals. It includes the step of applying an afterimage function to the cross-correlation spectrum by generating a cross waveform that combines the current and past waveforms of the cross-correlation spectrum generated by (S200).

Specifically, in the step of performing cross-correlation signal processing (S100), the cross-correlation processing unit may generate a cross-correlation spectrum by cross-correlating signal processing complex digital data received from two RF reception channels.

In the step of generating a cross waveform (S200), the waveform combining unit may multiply the current waveform and the past waveform of the cross-correlation spectrum from the cross-correlation processing unit by respective weights and add them to generate an output spectrum. The output spectrum may be referred to as a cross waveform, and the cross waveform may include a cross-correlation spectral waveform.

According to the configuration of this embodiment, an output spectrum is generated by combining the current and past waveforms of the cross-correlation spectrum with a reduced noise level with weights, and the generated output spectrum is accumulated and stored in the waveform map image memory through mapping between waveforms and pixels. In addition, an intermittent weak signal can be visually displayed on the screen of the display device using digital level data accumulated and stored in each cell of the waveform map image memory corresponding to the screen pixels of the display device.

FIG. 4 is a diagram for explaining the operating principle of the waveform combination unit of the weak signal detection device of FIG. 1.

Referring to FIG. 4, the waveform combination unit 200 may include a first multiplier, a second multiplier, an adder, and a waveform storage unit (D) to apply an afterimage function to the cross-correlation spectrum.

The waveform combination unit 200 may be configured to multiply the input spectrum (I[n]) at the nth time, which is the current waveform of the cross-correlation spectrum, by the first weight (w1) using the first multiplier. The first weight w1 may be a value selected from the range of 0 or more to 1.0 or less.

Additionally, the output spectrum (O[n]) of the waveform combining unit 200 may be stored in the waveform storage unit (D). Meanwhile, the output spectrum (O[n-1]) previously stored in the waveform storage unit (D) is sent to the second multiplier as a past waveform when the input spectrum (I[n]) is input to the waveform combining unit 200. It can be delivered.

In addition, the waveform combination unit 200 uses a second multiplier to multiply the past waveform, which is the output spectrum (O[n-1]) of the n-1th time coming from the waveform storage unit D, by the second weight (w2). It can be configured to do so. The second weight (w2) may be a value selected from the range of 0 or more to 1.0 or less.

In addition, the waveform combination unit 200 uses an adder to add the current waveform of the cross-correlation spectrum multiplied by the first weight (w1) and the past waveform of the cross-correlation spectrum multiplied by the second weight (w2) to perform a spectral afterimage function. An output spectrum (O[n]) can be generated.

The output spectrum of the current waveform is again stored in the waveform storage unit (D) and can be used when applying the afterimage function to the input spectrum at the n+1 time, which is the next waveform. Here, n may be any natural number.

Figure 5 is a schematic block diagram of a weak signal detection device according to a second embodiment of the present invention.

Referring to FIG. 5, the weak signal detection device includes a cross-correlation waveform generator (300), a waveform pixel mapping unit (400), and a waveform map image memory (WMI). It may be configured to include memory, 500).

The combination of the cross-correlation waveform generator 300, the waveform pixel mapping unit 400, and the waveform map image memory 500 may be referred to as a spectrum processing part (600). The spectrum processing unit 600 may include a component that maps a cross-correlation spectrum with an afterimage function to screen pixels of a display device and stores it cumulatively in the waveform map image memory 500.

Specifically describing the components of the spectrum processing unit 600, the cross-correlation waveform generator 300 may include the cross-correlation processing unit and the waveform combining unit described above with reference to FIG. 1. The cross-correlation waveform generator 300 may generate and output a cross waveform. The cross waveform corresponds to the cross-correlation spectrum waveform as a cross-correlation spectrum with a spectral persistence function and may be referred to as a cross-spectrum waveform.

The waveform pixel mapping unit 400 may map a cross waveform, that is, a cross-correlation spectrum waveform, received from the cross-correlation waveform generator 300 to pixels forming a screen of a preset display device. The cross waveform mapped by the waveform pixel mapping unit 400 may be accumulated and stored in the waveform map image memory 500.

The waveform map image memory 500 can cumulatively store the cross waveforms mapped by the waveform pixel mapping unit 400 in memory cells corresponding to pixels of the display device. A memory cell may be simply referred to as a cell. That is, the cross waveform mapped to pixels with a spectral persistence function can be stored in the corresponding cells so that the level increases by the cumulative number of times. The level of digital data stored in each cell of the waveform map image memory 500 increases according to the number of accumulations or storage times, and can be set to have different colors or brightness on the screen of the display device depending on the level. This digital data may be referred to as cumulative spectrum or digital level data. This waveform map image memory 500 may include a memory buffer, a pixel memory buffer, or an image memory buffer, and the image memory buffer may include a raster image memory buffer.

Additionally, a plurality of cells corresponding to a data frame in the waveform map image memory 500 may be set to correspond to a plurality of pixels on a two-dimensional screen of a display device. In a virtual two-dimensional screen formed by the plurality of pixels described above, the x-axis may correspond to the frequency of the cross waveform, and the y-axis may correspond to the level of the cross waveform. Additionally, the x-axis of the memory buffer may correspond to the horizontal axis of the display window, and the y-axis may correspond to the vertical axis of the display window.

In addition, the waveform map image memory 500 is a memory buffer that assigns different colors to each cell corresponding to a pixel of the display device according to the level of the digital level data currently stored, and the accumulated spectrum assigned to the different colors. may be configured to output as an image signal of the display device.

That is, in the weak signal detection device, digital level data stored in the waveform map image memory 500 may be configured to be transmitted to the display device as frame data or as an image signal every screen update time of the display device.

In this embodiment, digital level data may refer to data whose digital level changes depending on the number of times it is accumulated for each cell of the waveform map image memory 500. For digital level data, each pixel may have a preset initial level (eg, 0, -100, etc.).

According to this embodiment, the complex signal is processed into a cross-correlation signal, each of the current and previous waveforms of the processed cross-correlation spectrum is multiplied and added by weight, and then mapped to the screen pixels of the display device and stored in the waveform map image memory. Accumulatively stored, the digital level data accumulated in each cell is transmitted to the display device at each screen update time of the display device, and each color is displayed to the corresponding pixels on the screen of the display device according to the level of the digital level data corresponding to each cell. and/or expressed in terms of brightness, thereby making it possible to visually/intuitively detect extreme signals or intermittent weak signals.

FIG. 6 is a flowchart for explaining digital level data used in the weak signal detection device of FIG. 5.

Referring to FIG. 6, over time, the first waveform map image memory 510 at a first time, the second waveform map image memory 530 at a second time, and the third waveform map image at a third time. An example of digital level data stored in the memory 550 can be seen.

The first to third waveform map image memories 510, 530, and 550 may be the same image memory buffer except that the digital level data stored varies depending on the passage of time. The third time is later than the second time, and the second time is later than the first time.

Specifically, the digital level data of the first cross waveform at the first time (hereinafter referred to as 'first digital level data') stored in the cells of the first waveform map image memory 510 may be stored in at least some of the first cells. there is. The cross waveform corresponds to the cross-correlation spectrum waveform.

That is, the first waveform map image memory 510 includes only the first cells (see hatched portion) having a first level higher than the initial level due to the cross-correlation spectrum waveform stored in the first cells at the first time. can do.

In other words, each of the first cells is considered to have hit the corresponding cell with respect to the corresponding sample points of the cross waveform, and may be set to have different pre-specified colors and/or brightness according to the accumulated number of hits. .

When the first digital level data stored in the first waveform map image memory is transmitted to the display device, an accumulated spectrum identical to or similar to that of the first waveform map image memory 510 may be displayed on the screen of the display device.

Additionally, digital level data (second digital level data) of the second cross waveform at the second time stored in the cells of the second waveform map image memory 530 may be stored in some of the second cells. At least some of the second cells may overlap with at least some of the first cells. The level of the digital level data of the overlapping second cell may be larger than the level of the digital level data of the overlapping first cell by a preset size, for example, a standard size according to the number of one-time accumulation.

In particular, when an intermittent weak signal appears, for example, digital level data for the intermittent weak signal may be recorded in some of the second cells of the second waveform map image memory 530.

Additionally, digital level data (third digital level data) of the third cross waveform at the third time stored in the cells of the third waveform map image memory 530 may be stored in some of the third cells. At least some of the third cells may overlap with at least some of the second cells. The level of the digital level data of the overlapping third cell may be larger than the level of the digital level data of the overlapping second cell by a preset size, for example, a standard size according to the number of one-time accumulation.

In addition, if the third cross waveform also includes an intermittent weak signal following the second cross waveform, the third digital level data is a level for intermittent weak signals (IWS) with a level that increases according to the cumulative number of signals. May contain information.

Each of the third cells has a level according to the accumulated number of hits for the corresponding sample points of the cross waveform, and the level of each of these third cells is different from each other predetermined according to the size of the corresponding level on the screen of the display device. It can be set to be expressed with color and/or brightness.

In this way, the third digital level data stored in the third waveform map image memory and including the intermittent weak signal (IWS) may be transmitted to the display device at the screen update time of the display device, and accordingly, the third digital level data may be displayed on the screen of the display device. 3 Depending on the level of digital level data previously stored in the waveform map image memory 550, a cumulative spectrum of different colors and/or brightness, including an intermittent weak signal (IWS), may be displayed.

FIG. 7 is a flowchart for explaining the operating principle of the weak signal detection device of FIG. 5.

Referring to FIG. 7, the weak signal detection device generates a cross-correlation spectrum using the cross-correlation between two RF reception channels to detect intermittent weak signals included in radio signals or RF signals, cross-correlation It may include a step (S200) of generating a cross waveform with a spectral afterimage function by combining the current waveform of the spectrum and the past waveform (previous waveform) with a weight. A cross waveform may be referred to as a cross-spectrum waveform, cross-correlation spectrum, or cross-correlation spectrum waveform.

Additionally, the weak signal detection device maps cross-spectrum waveforms to screen pixels of the display device sequentially over time (S400), and stores the cross-spectrum waveforms in an image memory according to the mapping results (S500). Image memory may be referred to as waveform map image memory, image memory buffer, memory buffer, etc.

That is, the waveform pixel mapping unit of the weak signal detection device can map the cross waveform at a specific time with pixels forming the screen of the display device. Additionally, the weak signal detection device may store the mapped cross waveform in cells of a memory buffer corresponding to pixels forming the screen of the display device. Cross waveforms for a certain period of time may be accumulated and stored in cells of a memory buffer.

Additionally, the weak signal detection device may transmit the cross waveforms as image signals to the data driver of the display device at each screen update time of the display device in order to display the cross waveforms stored in the memory buffer on the screen of the display device. That is, the weak signal detection device can transmit the stored cross-spectrum waveforms to the display at a frame update rate (S600).

According to this embodiment, the spectrum is accumulated and mapped for wireless signals including weak signals that appear intermittently in the waveform map image memory, and the frequency vs. level of the mapped spectrum is displayed in different colors in the display window according to the output frequency of the spectrum. It may be configured to be shown as waveforms of the image signal.

Figure 8 is a block diagram of a weak signal detection device according to a third embodiment of the present invention.

Referring to FIG. 8, the weak signal detection device includes a spectrum processing unit 600, a first RF receiving channel unit 700, and a second RF receiving channel unit 800 connected to the input terminal of the spectrum processing unit 600. can do. The first RF reception channel unit 700 and the second RF reception channel unit 800 may be briefly referred to as a first RF reception channel and a second RF reception channel, respectively.

The spectrum processing unit 600 may include the cross-correlation waveform generator 300, the waveform pixel mapping unit 400, and the waveform map image memory 500 described above with reference to FIG. 5.

The first RF reception channel 700 is a first RF down-conversion unit 710 that converts the first RF input from the antenna into an intermediate frequency signal, and a first digital signal connected to the first RF down-conversion unit 710. A processing unit 720 may be provided.

The second RF reception channel 800 is a second RF down converter 810 that converts the second RF input from the antenna into an intermediate frequency signal, and a second digital signal connected to the second RF down converter 810. A processing unit 820 may be provided.

The first RF input and the second RF input may be signals obtained by dividing a radio signal received from a single antenna through a power divider, or may be radio signals received from two independent antennas.

The RF down conversion unit 710 (810) of each RF reception channel may be configured to convert the RF signal received from the antenna into an intermediate frequency signal. The RF down conversion unit may include a preselector, local oscillator, mixer, and filter (see 30 in FIG. 12).

In the case described above, the preselector may pass only signals in a specific frequency range among RF signals received from the antenna and transmit them to the mixer under the control of a processor or control device that controls the operation of the weak signal detection device. The local oscillator may be configured to supply a reference frequency to the mixer under the control of a control device. The mixer can down-convert the frequency to the intermediate frequency band by mixing the reference frequency received from the local oscillator and the RF signal received through the preselector. Additionally, the filter may be configured to band-pass filter and select only a desired channel among several channels included in the intermediate frequency signal under the control of the control device.

The digital signal processing units 720 and 820 of each RF receiving channel may be configured to convert the analog signal converted into an intermediate frequency signal into a digital signal and reduce the sampling rate of the converted digital signal to convert it into a baseband complex signal. Each digital signal processing unit may be equipped with an analog-to-digital converter and a digital down-converter (see 40 in FIG. 12).

In the case described above, the analog-to-digital converter may be configured to convert the intermediate frequency analog signal coming from the RF down-conversion unit into a digital signal. The digital down converter converts the digital signal converted from the analog-to-digital converter into a baseband signal, reduces the data sampling rate, generates complex digital data, and outputs the generated complex digital data to the spectrum processing unit 600. .

The detailed configuration of the spectrum processing unit 600 is replaced with the detailed description of FIG. 5.

Figure 9 is a block diagram of a weak signal detection device according to a fourth embodiment of the present invention.

Referring to FIG. 9, the weak signal detection device includes an antenna 910, a power divider 900, a first RF reception channel 700, a second RF reception channel 800, and a spectrum processing part 600. It may be configured to include. The spectrum processing unit 600 may be connected to a display device.

Looking at each component in more detail, the antenna 910 receives radio frequency (RF) signals in the air (on-air). The antenna 910 may be referred to as an antenna unit, an antenna system, etc.

The power divider 900 branches the RF input from the antenna 910 and supplies the branched RF signals to the two RF reception channels 700 and 800, respectively.

Each of the two RF reception channels 700 and 800 converts the RF signal coming from the antenna 910 into an intermediate frequency signal capable of digital signal processing. The first RF reception channel 700 may include a first RF down conversion part (RF down conversion part) 710 and a first digital signal processing part (digital processing part) 720. Similarly, the second RF reception channel 800 may include a second RF down conversion unit 810 and a second digital signal processing unit 820.

Each of the first RF down-conversion unit 710 and the second RF down-conversion unit 810 may include a preselector, a local oscillator, a mixer, and a filter (see reference numeral 30 in FIG. 12). The first or second RF down conversion unit may further include a sweep generator connected to the local oscillator. The sweep generator may be configured to automatically change the frequency of a specific waveform in the local oscillator over time.

The first digital processing unit 720 and the second digital processing unit 820 each convert the analog signal, which is an intermediate frequency signal generated in each RF down conversion unit, into a digital signal and convert the converted digital signal into a baseband digital signal. and may be configured to generate a baseband complex signal by reducing the data sampling rate of the baseband digital signal. Baseband complex signals may be referred to as complex data.

The spectrum processing unit 600 includes a cross-correlation waveform generator (300), a waveform pixel mapping unit (400), and a waveform map image memory (500). It can be.

The cross-correlation waveform generator 300 may include a cross-correlation spectrum processing unit (cross spectrum unit, 100) and a waveform combination unit (200).

The cross-correlation spectrum processing unit 100 generates a cross-correlation spectrum using the correlation between two RF reception channels. The cross-correlation spectrum processing unit 100 performs fast Fourier transform (FFT) on the I-data and Q-data in the time domain through the correlation between the two channels and then accumulates each frequency component in time. It can be configured as follows. In addition, the cross-correlation spectrum processing unit 100 can improve the signal-to-noise ratio by maintaining the signal component and reducing only the noise component by averaging each frequency bin of the accumulated data of the two receiving channels, thereby improving the spectrum The load of the processing unit 600 can be reduced.

The waveform combining unit 200 may generate an output spectrum by combining the current waveform of the cross-correlation spectrum and the past waveform (for example, the waveform immediately preceding the current waveform) with weights. In other words, when the cross-correlation spectrum, which is an instantaneous waveform, comes in, the waveform combining unit 200 combines the current waveform and the past waveform of the cross-correlation spectrum with respective weights as shown in [Equation 2] below to create a waveform with an afterimage function. An output spectrum can be generated. This is to obtain a spectral afterimage effect and can be implemented by connecting the waveform combining unit 300 to the output terminal of the cross-correlation spectrum processing unit 100.

In [Equation 2] above, O[n] is the output spectrum at time=n, and I[n] is the input spectrum at time=n. , O[n-1] represents the output spectrum at the n-1th time, which is the past time immediately before the nth time, and w1 and w2 represent weighting factors, respectively. w1 and w2 may have real values selected from the range of 0 to 1.

The waveform pixel mapping unit 400 maps the output spectrum waveform to the waveform map image memory 500, which represents a display window. In the pixel memory buffer of the waveform map image memory 500, the x-axis may be mapped to correspond to the frequency of the output spectrum, and the y-axis may be mapped to correspond to the power level of the output spectrum.

The waveform map image memory 500 is colored according to the accumulated number of pixels in the pixel memory buffer for the output spectrum waveform output in a specific frequency band to be analyzed under the control of a processor or control device that controls the operation of the weak signal detection device. Accumulated spectra assigned differently can be stored. The accumulated spectrum is digital level data corresponding to frame data and can be transmitted to the display device 1000 and used to display a weak signal that appears intermittently on the screen of the display device in a specific color.

In this way, the weak signal detection device expresses the digital level data of the accumulated spectrum in a light blue color as the number of accumulations is small, and in a dark red color as the number of accumulations increases, respectively, so that the digital level data is near the noise floor. Intermittent weak signals that are output intermittently as low-level weak signals can be effectively detected. Additionally, the weak signal detection device can effectively detect low-level signals within high-level wideband signals.

In addition, the weak signal detection device uses the overlap mode of decay processing to detect signals that occur intermittently, and continues to overlap the level information in the frame with a new frame until the measurement stops, during the measurement time at the corresponding frequency. It can be configured to display all levels that have appeared.

In other words, the attenuation process has a persistent mode or overwrite mode, similar to the current mode or maxhold mode in the spectral diagram. In this embodiment, in order to observe only the current signal, the afterimage mode of attenuation processing is used to reduce the level information in the frame, while continuously superimposing it on a new frame to display all levels of all frequencies of the RF signal currently appearing at that frequency in the display window. It can be configured to display in different colors, thereby effectively detecting weak signals that appear intermittently.

Figure 10 is a block diagram of a weak signal detection device according to the fifth embodiment of the present invention.

Referring to FIG. 10, the weak signal detection device includes an antenna 910, a distributor 900, a first RF reception channel 701, a second RF reception channel 703, a third RF reception channel 705, and a first RF reception channel 705. It may include 4 RF reception channels 707, a spectrum processing unit 600, and a channel selection unit 950.

The power divider 900 may branch the RF input from the antenna 910 and supply the branched RF signals to the four RF reception channels 701, 703, 705, and 707, respectively.

Each of the four RF reception channels (701, 703, 705, and 707) converts the RF signal coming from the antenna 910 into an intermediate frequency signal capable of digital signal processing, and converts the intermediate frequency signal into a baseband complex signal. It can be converted to .

The first RF reception channel 701 may include a first RF down conversion unit (RF DC #1, 711) and a first digital signal processing unit (DSP #1, 721). The second RF receiving channel 703 may include a second RF down conversion unit (RF DC #2, 713) and a second digital signal processing unit (DSP #2, 723). The third RF receiving channel 705 may include a third RF down conversion unit (RF DC #3, 715) and a third digital signal processing unit (DSP #3, 725). And the fourth RF reception channel 707 may include a fourth RF down conversion unit (RF DC #4, 717) and a fourth digital signal processing unit (DSP #4, 727).

The weak signal detection device of this embodiment is when the received signal of the antenna 910 is distributed by the power divider 910 and enters at least one of the first RF reception channel 701 to the fourth RF reception channel 707, The operation of the channel selection unit 950 may be controlled by a control device that calculates the cross-correlation value to select two reception channels out of four reception channels.

Figure 11 is a block diagram of a weak signal detection device according to a sixth embodiment of the present invention.

Referring to FIG. 11, the weak signal detection device includes a first antenna 910, a second antenna 920, a first RF reception channel 700, a second RF reception channel 800, and a spectrum processor 600. It can be configured to include.

The weak signal detection device of this embodiment is configured such that the received signal from the first antenna 910 enters the first RF receiving channel 700, and the received signal from the second antenna 920 enters the second RF receiving channel 800. Except for, it has substantially the same configuration as the weak signal detection device of the embodiment described above with reference to FIG. 9.

That is, the weak signal detection device of this embodiment is substantially the same as the weak signal detection device described above with reference to FIG. 9, except for the configuration that does not use a power divider, so detailed description thereof will be omitted.

The weak signal detection device of this embodiment may be connected to a computing device to control its operation. A computing device may include a controller or at least one processor. The control device may control the operation of the display device 1000 to display intermittent weak signals in temporally distinct colors.

According to the above-described embodiments, the RF input received by a single antenna or two antennas is converted into complex digital data through two reception channels, and the complex digital data is cross-correlated signal processed to obtain cross-spectrum Generate a cross spectrum, combine the current and past waveforms of the cross-correlation spectrum with weights to generate an output spectrum with a spectral afterimage function, and store the output spectrum waveforms cumulatively in the pixel memory buffer at each update time of the display device. By configuring to create a data frame, the image signal frame can be transmitted to the display device of the digital RF device including the spectrum analyzer at the display update rate, and the power of the digital level data collected by the accumulated raster image memory buffer is thereby possible. It can be configured to provide history based on power level.

According to this configuration, many cross-correlation spectrum waveforms collected over the frequency span of the signal to be analyzed are accumulated in a single raster image buffer at high speed, and the waveforms of the accumulated cross-correlation spectrum (accumulated spectrum) are displayed on a display device. By transmitting at a frame update rate, it is possible to effectively detect weak signals that appear intermittently with a level below the internal noise level of the RF receiver, which could not be observed previously.

Figure 12 is a block diagram of a weak signal detection device according to the seventh embodiment of the present invention.

Referring to FIG. 12, the weak signal detection device includes a first antenna 911, a second antenna 913, a third antenna 915, a fourth antenna 917, a first RF reception channel 701, and a first antenna 911. It may include 2 RF reception channels 703, a third RF reception channel 705, a fourth RF reception channel 707, a spectrum processing unit 600, and a channel selection unit 950.

The first RF reception channel 701 may include a first RF down conversion unit (RF DC #1, 711) and a first digital signal processing unit (DSP #1, 721). The second RF receiving channel 703 may include a second RF down conversion unit (RF DC #2, 713) and a second digital signal processing unit (DSP #2, 723). The third RF receiving channel 705 may include a third RF down conversion unit (RF DC #3, 715) and a third digital signal processing unit (DSP #3, 725). And the fourth RF reception channel 707 may include a fourth RF down conversion unit (RF DC #4, 717) and a fourth digital signal processing unit (DSP #4, 727).

In the weak signal detection device of this embodiment, the received signal of the first antenna 911 enters the first RF receiving channel 701, and the received signal of the second antenna 913 enters the second RF receiving channel 703, The received signal of the third antenna 915 enters the third RF receiving channel 705, the received signal of the fourth antenna 917 enters the fourth RF receiving channel 707, and a control device that calculates the cross-correlation value It can have substantially the same configuration as the weak signal detection device of the embodiment described above with reference to FIG. 11, except for the configuration of the channel selection unit 950 that selects two of the four reception channels under the control of there is.

Additionally, the weak signal detection device may be connected to multiple antennas and four or more RF reception channels connected to multiple antennas to obtain a diversity effect. In that case, the cross-correlation processing unit 100 cross-correlates the complex signal of two RF reception channels selected in a predetermined order or at random among four or more RF reception channels, and performs cross-correlation signal processing on all RF reception channels or a combination thereof. After performing cross-correlation signal processing on the complex data of the pair, the two RF reception channels with the relatively best noise reduction performance or efficiency are based on the cross-correlation values for all RF reception channels or their combination pairs. It can be configured to select .

And, the weak signal detection device generates a cross-correlation spectrum using the correlation between the two RF reception channels selected by the control device by the cross-correlation processing unit 100, and An output spectrum with a spectral afterimage function is generated by combining the current and past waveforms of the correlation spectrum with weights, and the output spectrum mapped by the waveform pixel mapping unit 400 is accumulated and stored in the waveform map image memory 500. , It can be configured to transmit to the display device at the frame update timing so that the intermittent weak signal can be intuitively detected by the user on the screen of the display device.

Figure 13 is a block diagram illustrating a spectrum analyzer of a comparative example.

Referring to FIG. 13, the spectrum analyzer of the comparative example consists of an antenna, an RF conversion unit 30, a digital signal processing unit 40, and a spectrum processing unit 50. A display device 70 is connected to the spectrum processing unit 50.

The RF converter 30 consists of a preselector 31, a mixer 33, a local oscillator 35, a filter 37, and a sweep generator 39. The digital signal processing unit 40 consists of an analog-to-digital converter 41 and a digital down converter 43. And the spectrum processing unit 50 is composed of a detector 51, a complex waveform generator 53, and a waveform map image memory 55.

To explain the operating process of the spectrum analyzer in the comparative example, when an RF signal received by an antenna in the air is input, the RF converter 30 converts the RF signal into an intermediate frequency signal capable of digital signal processing. Next, the digital signal processing unit 40 converts the analog signal into a digital signal using the analog-to-digital converter 41, and converts the digital signal into a baseband signal with a reduced data sampling rate using the digital down converter 43. .

Then, the spectrum processing unit 50 processes the input digital signal and displays it on the screen of the display device in real time. The detector 51 of the spectrum processing unit 50 calculates the power level of complex digital data at the frequency set by the spectrum analyzer.

According to the comparative example, it is possible to detect normal signals that appear intermittently by applying accumulated spectrum to process large amounts of data in real time, but it is impossible to detect weak signals that appear intermittently. In addition, it is possible to improve the signal-to-noise ratio on the spectrum by removing random noise components through cross spectrum, but it is difficult to detect signals that appear intermittently with the configuration of the comparative example.

Figure 14 is an exemplary diagram of a frequency vs. level waveform, that is, a cross spectrum, in a spectrum analyzer of a comparative example. Figure 15 is a diagram illustrating frequency vs. level city waveforms expressed in different colors according to the frequency of appearance in the spectrum analyzer of the comparative example. And FIG. 16 is a diagram showing the frequency vs. level waveform expressed in different colors according to the frequency of appearance in the weak signal detection device (corresponding to the spectrum analyzer) of this embodiment.

As shown in FIG. 14, the waveform of the cross-correlation spectrum obtained from the spectrum analyzer of the comparative example (see FIG. 13) or the general spectrum as shown in FIG. 15 is output to the display window as a cumulative waveform. It can be. However, in the spectrum analyzer of the comparative example, it is impossible to detect weak signals that appear intermittently through the accumulated spectrum.

Meanwhile, as shown in FIG. 16, the weak signal detection device of this embodiment accumulates the cross-correlation spectrum through a spectrum afterimage function, and a waveform shown as frequency versus power level for this accumulated spectrum When output to the display window, a low-level signal that appears intermittently that was not visible in the comparative examples of Figures 14 and 15, that is, a weak signal that is intermittently output with a level below the internal noise level of the RF receiver, is clearly detected. I can show you. That is, according to this embodiment, both high level signals and low level signals including intermittent weak signals can be clearly separated and displayed.

Figure 17 is a schematic block diagram of a configuration applicable to a weak signal detection device according to the eighth embodiment of the present invention.

Referring to FIG. 17, the weak signal detection device 5000 includes a processor 5100 in addition to any one of the weak signal detection devices of the embodiments described above with reference to FIGS. 1, 5, and 9 to 12. It may be configured to further include. Processor 5100 may function as a control device referred to herein.

In addition, the weak signal detection device 5000 optionally further includes a memory 5200, a transmission/reception device 5300, an input interface device 5400, an output interface device 5500, a storage device 5600, or a combination thereof. It can be configured.

Components included in the weak signal detection device 5000 may be connected by a bus 5700 to communicate with each other, or may be connected through individual interfaces or individual buses centered on at least one processor 5100. For example, the processor 5100 may be connected to at least one of the memory 5200, the transmission/reception device 5300, the input interface device 5400, the output interface device 5500, and the storage device 5600 through a dedicated interface. .

The processor 5100 may execute a program command stored in at least one of the memory 5200 and the storage device 5600. The processor 5100 controls the operations of the cross-correlation processor, waveform combination unit, waveform pixel mapping unit, waveform map image memory, and channel selection unit provided to detect intermittent weak signals based on at least one command or program command. It can function to do so. The processor 5100 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor for performing methods according to embodiments of the present invention.

Each of the memory 5200 and the storage device 5600 may be comprised of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 5200 may be comprised of at least one of read only memory (ROM) and random access memory (RAM).

The weak signal detection devices of the above-described embodiments may be implemented with at least some components or functional parts of a digital RF device, a spectrum analyzer, or a weak signal monitoring device.

Meanwhile, the operation of the method according to the embodiment of the present invention can be implemented as a computer-readable program or code on a computer-readable recording medium. Computer-readable recording media include all types of recording devices that store information that can be read by a computer system. Additionally, computer-readable recording media can be distributed across networked computer systems so that computer-readable programs or codes can be stored and executed in a distributed manner.

Additionally, computer-readable recording media may include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, etc. Program instructions may include not only machine language code such as that created by a compiler, but also high-level language code that can be executed by a computer using an interpreter, etc.

Although some aspects of the invention have been described in the context of an apparatus, it may also refer to a corresponding method description, where a block or device corresponds to a method step or feature of a method step. Similarly, aspects described in the context of a method may also be represented by corresponding blocks or items or features of a corresponding device. Some or all of the method steps may be performed by (or using) a hardware device, such as a microprocessor, programmable computer, or electronic circuit, for example. In some embodiments, at least one or more of the most important method steps may be performed by such an apparatus.

In embodiments, a programmable logic device (e.g., a field programmable gate array) may be used to perform some or all of the functionality of the methods described herein. In embodiments, a field-programmable gate array may operate in conjunction with a microprocessor to perform one of the methods described herein. In general, the methods are preferably performed by some hardware device.

Although the present invention has been described with reference to preferred embodiments of the present invention, those skilled in the art may make various modifications and changes to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that it is possible.

Claims (24)

A device that detects weak signals that appear intermittently with a level below the internal noise of a radio frequency (RF) receiver,
A cross-correlation spectrum processing unit that generates a cross-correlation spectrum using the correlation between RF reception channels; and
a waveform combining unit that generates an output spectrum with a spectral afterimage function by assigning weights to the current and past waveforms of the cross-correlation spectrum;
A weak signal detection device comprising: In claim 1,
The waveform combining unit multiplies the cross-correlation spectrum at the n-th time, which is the current waveform, by a first weight (w1), and applies a second weight (w1) to the cross-correlation spectrum at the n-1-th time, which is the immediately past waveform of the current waveform. A weak signal detection device that generates the output spectrum by multiplying w2) and adding the cross-correlation spectrum multiplied by the first weight and the cross-correlation spectrum multiplied by the second weight. In claim 2,
A weak signal detection device, wherein the waveform combination unit includes a waveform storage unit that stores the cross-correlation spectrum at the n-1th time. In claim 1,
Weak signal detection device further comprising a waveform pixel mapping unit that maps the waveforms of the output spectrum to pixels in a pixel memory buffer. In claim 1,
It further includes a waveform map image memory that includes pixels of a pixel memory buffer and stores the output spectrum waveforms cumulatively for a certain period of time,
A weak signal detection device in which digital level data formed by output spectrum waveforms accumulated and stored in the waveform map image memory are transmitted to the display device at each screen update time of the display device. In claim 5,
Different colors are displayed on the screen of the display device according to the level of the digital level data of each pixel accumulated according to the number of storage or hit counts of cross-correlation spectrum waveforms stored in each pixel of the waveform map image memory. A weak signal detection device further comprising a control device that controls the operation of the display device to be displayed. In claim 1,
Weak signal detection device further comprising at least two RF receiving channels connected to at least one antenna and providing complex signals to the cross-correlation spectrum processing unit. In claim 7,
When the RF reception channels are three or more, a weak signal detection device further comprising a channel selection unit disposed between the three or more reception channels and the cross-correlation spectrum processing unit. In claim 7,
The at least one antenna includes at least two antennas,
A weak signal detection device, wherein the at least two antennas are connected to the at least two RF reception channels. In claim 7,
wherein the at least one antenna includes a single antenna,
A weak signal detection device further comprising a power divider disposed between the single antenna and the at least two RF reception channels to branch the received signal of the single antenna and distribute it to the at least two RF reception channels. In claim 7,
Each of the at least two RF reception channels includes an RF down conversion unit,
The RF down conversion unit includes a sweep generator connected to its own local oscillator, where the sweep generator operates so that the oscillation frequency of the local oscillator automatically changes with time. In claim 7,
Each of the at least two RF reception channels further includes a digital signal processor,
The digital signal processing unit converts the intermediate frequency analog signal coming from the RF down conversion unit into a digital signal, converts the converted digital signal into a baseband signal, and reduces the data sampling rate of the baseband signal to determine the cross-correlation spectrum. A weak signal detection device that generates complex data that enters the processing unit. A method of detecting weak signals that appear intermittently with a level below the internal noise of a radio frequency (RF) receiver,
Generating a cross-correlation spectrum using correlation between RF reception channels; and
Generating an output spectrum with a spectral afterimage function by combining the current and past waveforms of the cross-correlation spectrum with weights;
A weak signal detection method comprising: In claim 13,
The step of generating the output spectrum includes multiplying the cross-correlation spectrum at the n-th time, which is the current waveform, by a first weight, and multiplying the cross-correlation spectrum at the n-1 time, which is the immediately past waveform of the current waveform, by a second weight. and generating the output spectrum by adding the cross-correlation spectrum multiplied by the first weight and the cross-correlation spectrum multiplied by the second weight. In claim 14,
Weak signal detection method further comprising the step of storing the cross-correlation spectrum at the n-1th time. In claim 13,
A weak signal detection method further comprising mapping waveforms of the output spectrum to pixels of a waveform map image memory. In claim 16,
Weak signal detection method further comprising the step of accumulating and storing the output spectrum waveforms in the waveform map image memory for a certain period of time. In claim 17,
A weak signal detection method further comprising transmitting digital level data formed by output spectrum waveforms accumulated and stored in the waveform map image memory to the display device at each screen update time of the display device. In claim 18,
Different colors are displayed on the screen of the display device according to the level of the digital level data of each pixel accumulated according to the number of storage or hit counts of cross-correlation spectrum waveforms stored in each pixel of the waveform map image memory. A weak signal detection method further comprising controlling the operation of the display device to be displayed. In claim 13,
A weak signal detection method further comprising providing a complex signal to a cross-correlation spectrum processor through at least two RF receiving channels connected to at least one antenna. In claim 20,
When the RF reception channels are three or more, a weak signal detection method further comprising the step of being disposed between the three or more reception channels and the cross-correlation spectrum processing unit and selecting two channels based on cross-correlation values. In claim 20,
wherein the at least one antenna includes a single antenna,
Weak signal detection further comprising branching the received signal of the single antenna and distributing it to the at least two RF receiving channels, respectively, through a power divider disposed between the single antenna and the at least two RF receiving channels. method. In claim 20,
When each of the at least two RF reception channels is provided with an RF down-conversion unit and the RF down-conversion unit is provided with a sweep generator connected to its own local oscillator, the oscillation frequency of the local oscillator is adjusted over time by the sweep generator. A weak signal detection method further comprising the step of automatically changing. In claim 23,
When each of the at least two RF receiving channels further includes a digital signal processing unit, the digital signal processing unit converts the intermediate frequency analog signal coming from the RF down conversion unit into a digital signal, and converts the converted digital signal into a digital signal. A weak signal detection method further comprising converting to a baseband signal, generating complex data by reducing the data sampling rate of the baseband signal, and transmitting the generated complex data to the cross-correlation spectrum processing unit.

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