JP2013062593A - Communication device, reception signal detection device and reception signal detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably and accurately detect the moment of rising of a reception signal with a simple structure without depending on a change in environment.SOLUTION: A communication device 1000 is comprised of a pseudo noise addition unit 40, an FM detection processing unit 50, an HPF unit 60, and a rising detection unit 90. The pseudo noise addition unit 40 adds pseudo noise to a complex envelope signal of a reception signal and outputs a complex envelope signal with pseudo noise. The FM detection processing unit 50 converts the complex envelope signal with pseudo noise output by the pseudo noise addition unit 40 into an FM signal and outputs the FM signal. The HPF unit 60 filters a high-frequency component of the FM signal output by the FM detection processing unit 50 and outputs a high-frequency signal. The reception signal detection processing unit 90 compares the amplitude of the high-frequency signal output by the HPF unit 60 with a preset prescribed threshold, and based on a result of this comparison, detects rising of the reception signal.

Description

  The present invention relates to a communication device, a reception signal detection device, and a reception signal detection method, and, for example, relates to a technique for detecting a rising edge of a reception signal.

  In recent years, as a technique for detecting a rising edge of a received signal in a communication apparatus, a technique using a difference value between a low frequency component and a high frequency component of an FM signal after FM detection processing is known (for example, Patent Documents). 1). That is, in the technique described in Patent Document 1, first, the FM detection circuit converts the digital complex envelope signal of the received signal into an FM signal by FM detection processing. Next, a high pass filter (HPF) filters the high frequency component of the FM signal to obtain a high frequency signal. A low pass filter (LPF) filters the low frequency component of the FM signal to obtain a low frequency signal. Then, the rising edge detection processing circuit compares the difference value between the high frequency component and the low frequency component of the FM signal with a predetermined threshold value to detect the rising edge of the received signal.

  At this time, the FM detector circuit detects white noise of a relatively high signal level with a flat frequency characteristic when there is no signal, and a rising waveform and a speech waveform of a relatively low signal level when a signal arrives. In particular, in the rising waveform when a signal arrives, energy is concentrated on the low frequency side. In the technique described in Patent Document 1, the rising edge of the received signal is detected by utilizing the fact that the energy ratio of the low frequency component and the high frequency component of the FM signal differs between when there is no signal and when the signal arrives. doing.

  Patent Document 2 discloses a technique for detecting noise using only a high frequency component of an FM signal after FM detection processing. That is, in the technique described in Patent Document 2, first, the HPF filters high frequency components from the FM signal output from the FM detection circuit. Next, a technique is disclosed in which a pulse detector detects and outputs a high frequency component of an FM signal that is equal to or higher than a predetermined threshold value compared with a predetermined threshold value.

  Further, as a reference technique, Patent Document 3 discloses a technique relating to a press talk type radio receiver.

JP 2006-211241 A JP-A-1-109932 JP-A-6-29880

  However, the technique described in Patent Document 1 requires processing for filtering high-frequency components by HPF after FM detection processing, and processing for filtering low-frequency components of FM signals by LPF, and the scale of the hardware. There was a problem that would become larger.

  In order to reduce the scale of hardware, it is also conceivable to apply the technique described in Patent Document 2 and perform rise detection using only the high frequency components of the FM signal. However, in this case, if the noise level at the time of no signal is small, the level difference between the power of the high frequency component of the FM signal becomes small between the time of no signal and the arrival of the signal, and the rising of the received signal is detected. There was a problem that processing became unstable.

  The present invention has been made in view of such circumstances, and provides a technique capable of stably and accurately detecting the rising edge of a received signal with a simple configuration without depending on environmental changes. There is to do.

  The communication apparatus of the present invention includes a pseudo noise adding unit that adds a pseudo noise to a complex envelope signal of a received signal and outputs a complex envelope signal with a pseudo noise, and a complex envelope signal with a pseudo noise output by the pseudo noise adding unit. An FM detection processing unit for converting the FM signal into an FM signal, a high pass filter unit for filtering the high frequency component of the FM signal output by the FM detection processing unit and outputting a high frequency signal, and a high pass filter unit A reception signal detection processing unit that compares the magnitude of the output high frequency signal with a predetermined threshold value that is set in advance and detects the rising edge of the reception signal based on the comparison result is provided.

  According to the present invention, it is possible to detect a rising edge of a received signal stably and accurately with a simple configuration without depending on environmental changes.

It is a figure which shows the structure of the communication apparatus in the 1st Embodiment of this invention. It is a figure which shows the signal characteristic at the time of the non-signal of the FM signal by which FM detection processing is carried out by the FM detection process part, and a signal arrival. It is a figure for demonstrating the effect by a pseudo noise addition part. It is a figure for demonstrating the effect by a pseudo noise addition part. It is a figure for demonstrating the effect by a pseudo noise addition part. It is a figure for demonstrating the effect by a pseudo noise addition part. It is a figure which shows the operation | movement flow of the communication apparatus in the 1st Embodiment of this invention. It is a figure for demonstrating the effect of the communication apparatus in the 1st Embodiment of this invention. It is a figure which shows the structure of the communication apparatus in the 2nd Embodiment of this invention. It is a figure which shows the operation | movement flow of the communication apparatus in the 2nd Embodiment of this invention.

<First Embodiment>
Communication apparatus 1000 according to the first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows the configuration of the communication apparatus 1000. The communication device 1000 is a device that transmits and receives intermittent signals, such as a Presstalk type communication device, and can detect the rising of a signal transmitted from a communication device on the other side of communication. .

  As shown in FIG. 1, the communication apparatus 1000 includes an antenna unit 10, a receiving unit 20, an A / D (Analog Digital) analog unit 30, a pseudo noise adding unit 40, and an FM detection processing unit. 50, a high-pass filter (hereinafter referred to as HPF) unit 60, a high-frequency signal level calculating unit 70, a smoothing unit 80, and a received signal detection processing unit 90. In addition, the pseudo noise adding unit 40, the FM detection processing unit 50, the HPF unit 60, the high frequency signal level calculation unit 70, the smoothing unit 80, and the reception signal detection processing unit 90 include the reception signal of the present invention. The detection device 100 is configured.

  The antenna unit 10 is connected to the receiving unit 20 and corresponds to a predetermined radio signal (for example, specified by a frequency or the like).

  The receiving unit 20 receives a radio signal via the antenna unit 10 and performs predetermined reception processing (frequency conversion or the like) on the radio signal to generate a received signal (also referred to as an intermediate frequency signal). Then, the reception unit 20 outputs the reception signal to the A / D conversion unit 30.

  The A / D converter 30 performs analog-to-digital conversion on the received signal, generates a complex envelope signal of the received signal from the digital complex envelope signal of the received signal, and outputs this to the received signal detection apparatus 100. The digital complex envelope signal corresponds to the complex envelope signal of the present invention.

  The pseudo noise adding unit 40 includes a pseudo noise generator 41 and an adder 42. The pseudo noise adding unit 40 adds pseudo noise to the digital complex envelope signal input from the A / D conversion unit 30 and outputs a digital complex envelope signal with pseudo noise. Note that the digital complex envelope signal with pseudo noise corresponds to the complex envelope signal with pseudo noise of the present invention.

  The pseudo noise generator 41 generates pseudo noise and outputs it to the adder 42. The adder 42 adds pseudo noise to the digital complex envelope signal input from the A / D conversion unit 30.

  A method for generating the pseudo noise is, for example, as follows. That is, after generating a uniformly distributed random number using a random number generation function of a computer program, Gaussian noise is acquired using a box Mueller method. Thereby, Gaussian noise can be generated as pseudo-noise of the present invention. Alternatively, a pseudo noise signal of a certain time may be generated in advance and stored in a memory (not shown) or the like, and the pseudo noise signal stored in the memory may be repeatedly used. This method is practical because it can eliminate the load that occurs during processing that generates noise.

  The FM detection processing unit 50 converts the digital complex envelope signal with pseudo noise output from the pseudo noise adding unit 40 into an FM signal and outputs the FM signal.

  The HPF unit 60 filters a high frequency component (for example, 30 to 40 kHz) of the FM signal output from the FM detection processing unit 50 and outputs a high frequency signal. In addition, 30-40 kHz is an example of the high frequency component of FM signal, Comprising: It is not limited to this. At this time, it is necessary to select a high frequency component so that a power difference is generated between no signal and signal arrival.

  The high frequency signal level calculation unit 70 includes a multiplier 71. The high frequency signal level calculation unit 70 calculates the signal level of the high frequency signal output from the HPF unit 60 (for example, the power signal level) as the high frequency signal level, and smoothes the high frequency signal level. To the unit 80. The high frequency signal level is a value related to the magnitude of the high frequency signal. Here, a value obtained by squaring the power of the high frequency signal is set as the high frequency signal level. However, the high frequency signal level may be a value related to the magnitude of the high frequency signal, and is not limited to a value obtained by squaring the power of the high frequency signal. For example, a value obtained by squaring the power of the high frequency signal and then performing a square root process on the square value may be used as the high frequency signal level. In this case, the output of the high frequency signal level calculation unit 70 is not the level of the power signal but the level of the envelope signal.

  The smoothing unit 80 smoothes the high frequency signal level calculated by the high frequency signal level calculating unit 70 and outputs the smoothed high frequency signal level to the received signal detection processing unit 90.

  The reception signal detection processing unit 90 compares the high frequency signal level output from the smoothing unit 80 with a predetermined threshold set in advance. The reception signal detection processing unit 90 detects the rising edge of the reception signal based on the comparison result.

  Next, signal characteristics at the time of no signal and signal arrival of an FM signal subjected to FM detection processing by the FM detection processing unit 50 will be described with reference to the drawings. FIG. 2 shows signal characteristics at the time of no signal and signal arrival of the FM signal subjected to FM detection processing by the FM detection processing unit 50.

  As shown in FIG. 2, the vertical axis represents the high frequency signal level (dB) and the horizontal axis represents the frequency (Hz). FIG. 2 illustrates the result of performing FM detection processing by the FM detection processing unit 50 on the digital complex envelope signal with a sampling frequency of 80 Hz, and measuring the power spectrum in the high frequency range (30 to 40 kHz) of the FM signal. ing. In FIG. 2, a value obtained by squaring the power of the high frequency signal is shown as the high frequency signal level.

  Referring to FIG. 2, it can be seen that the high frequency signal level is high when there is no signal and low when the signal arrives. Therefore, using such signal characteristics, the moment when the high-frequency signal level falls below a predetermined threshold can be detected as the rising edge of the signal. In the example shown in FIG. 2, the measurement result in the high frequency range (30 to 40 kHz) is used, but the present invention is not limited to this. That is, a high frequency component may be selected so that a power difference occurs between no signal and signal arrival.

  Here, the digital complex envelope signal generated by the A / D conversion unit 30 is expressed as “S (n) + N (n)” where S (n) is a signal component and N (n) is a noise component. The n represents a sample point of each component.

Further, when the pseudo noise generated by the pseudo noise generator 41 is N ′ (n), the digital complex envelope signal S ′ (n) with pseudo noise is expressed as the following (Equation 1).

  At this time, the pseudo noise N ′ (n) is set higher than the minimum input level of the A / D conversion unit 30. The minimum input level of the A / D conversion unit 30 is a minimum value of a signal level at which the A / D conversion unit 30 can perform analog-digital conversion on a received signal (analog signal). The minimum input level of the A / D converter 30 is a value for an analog signal before analog-digital conversion. Thus, the pseudo noise N ′ (n) is not set to S ′ (n) = 0 by setting it higher than the minimum input level of the A / D converter 30.

  Next, the effect of the pseudo noise adding unit 40 will be described with reference to the drawings. 3-6 is a figure for demonstrating the effect by the pseudo noise addition part 40. FIG. 3 and 4 show a case where the pseudo noise adding unit 40 is not provided. 5 and 6 show a case where the pseudo noise adding unit 40 is provided.

  First, a case where the pseudo noise adding unit 40 is not provided will be described with reference to FIGS. 3 and 4.

  3A shows a state in which the signal level N of noise input to the A / D conversion unit 30 is higher than the minimum input level L of the A / D conversion unit 30. FIG. FIG. 3B shows the high frequency of the FM signal output from the high frequency signal level calculation unit 70 via the FM detection processing unit 50 and the HPF unit 60 when the relationship shown in FIG. Indicates the frequency signal level.

  As shown in FIG. 3A and FIG. 3B, when the signal level N of noise input to the A / D converter 30 is higher than the minimum input level L of the A / D converter 30, it is high. The local frequency signal level is higher when there is no signal than when the signal arrives. For this reason, if a threshold is set between the signal level at the time of no signal and the arrival of the signal, the rising edge of the received signal can be detected.

  4A shows a state in which the signal level N of noise input to the A / D conversion unit 30 is lower than the minimum input level L of the A / D conversion unit 30. FIG. FIG. 4B shows the high level of the FM signal output from the high frequency signal level calculation unit 70 via the FM detection processing unit 50 and the HPF unit 60 when the relationship shown in FIG. Indicates the frequency signal level.

  As shown in FIGS. 4A and 4B, when the noise level N input to the A / D converter 30 is lower than the minimum input level L of the A / D converter 30, A / D The D conversion unit 30 cannot extract noise. For this reason, the signal level of the digital complex envelope signal output from the A / D conversion unit 30 is 0, and the high frequency signal level of FM at the time of no signal becomes unstable. In this case, as will be described later, the high-frequency signal level when there is no signal is generally 0, but when 0 is converted to a dB scale, it is −∞ (dB) and cannot be expressed in the figure. Therefore, in FIG. 4B, the signal level is shown as 0 (dB).

  Here, the fact that the high frequency signal level at the time of no signal becomes indefinite when the signal level of the digital complex envelope signal output from the A / D conversion unit 30 becomes 0 will be described in detail using equations. .

The digital complex envelope signal S (n) is expressed as (Equation 2), assuming that the in-phase component is I (n) and the complex component Q (n).

Further, since the instantaneous phase shift φ (n) of S (n) is an arctangent of a value obtained by dividing Q (n) by I (n), it is expressed as (Equation 3).

Further, the change amount e _FM (n) of the instantaneous phase shift φ (n) is a one-time differential value of φ (n) and is expressed as (Equation 4). Note that e _FM (n) is also called an FM detection signal.

In (Formula 2), when S (n) = 0, I (n) = Q (n) = 0. Therefore, the instantaneous phase shift φ (n) when S (n) = 0 is an arctangent of 0/0 and is indefinite. In this case, e _FM (n) is also undefined.

Thus, when the signal level of the digital complex envelope signal output from the A / D conversion unit 30 becomes S (n) = 0, the high frequency signal level at the time of no signal becomes unstable. When S (n) = 0, φ (n) = 0 is often obtained, and e _FM (n) = 0. Accordingly, in the following description, it is assumed that e _FM (n) = 0 is output when S (n) = 0. Although the case where φ (n) is indefinite is not described in detail, it is clear that the received signal detection device 100 of the present invention does not operate normally.

  As described above, when the FM signal output by the FM detection processing unit 50 is 0, the high frequency signal level of the FM signal is also 0, which is −∞ (dB) when converted to the dB scale. Here, as shown in FIG. 4B, the high frequency signal level is assumed to be 0 (dB). In FIG. 4B, the high-frequency signal level is lower when there is no signal than when the signal arrives, unlike in FIG. 3B.

  Therefore, when the pseudo noise adding unit 40 is not provided, when the FM signal output from the FM detection processing unit 50 becomes 0, the high frequency signal level of the FM signal is also 0 (dB) as described above. ), The received signal detection processing unit 90 erroneously recognizes the absence of a signal as the arrival of a signal, and the instant of rising of the received signal cannot be detected correctly.

  Next, the case where the pseudo noise addition part 40 is provided is demonstrated based on FIG. 5 and FIG.

  5A shows a state in which the level N of noise input to the A / D conversion unit 30 is higher than the minimum input level L of the A / D conversion unit 30. FIG. FIG. 5B shows the high frequency of the FM signal output from the high frequency signal level calculation unit 70 via the FM detection processing unit 50 and the HPF unit 60 when the relationship shown in FIG. Indicates the frequency signal level.

  As shown in FIG. 5A and FIG. 5B, when the signal level N of noise input to the A / D converter 30 is higher than the minimum input level L of the A / D converter 30, The local frequency signal level is higher when there is no signal than when the signal arrives. That is, even when a signal obtained by adding a noise signal and a pseudo noise signal is used, the same characteristics as in the case where only the noise signal is used (see FIGS. 3A and 3B) are exhibited. For this reason, if a threshold value is set between the signal level when there is no signal and when the signal arrives, the rising edge of the received signal can be detected correctly.

  6A shows a state where the level N of noise input to the A / D conversion unit 30 is smaller than the minimum input level L of the A / D conversion unit 30. FIG. FIG. 6B shows the high frequency of the FM signal output from the high frequency signal level calculation unit 70 via the FM detection processing unit 50 and the HPF unit 60 when the relationship shown in FIG. Indicates the frequency signal level.

  As shown in FIGS. 6A and 6B, when the signal level N of noise input to the A / D converter 30 is smaller than the minimum input level L of the A / D converter 30, A The / D conversion unit 30 cannot extract noise. However, since pseudo noise greater than at least the minimum input level L of the A / D conversion unit 30 is added, the signal level input to the FM detection processing unit 50 uses FIGS. 4 (a) and 4 (b). Unlike the case described above, it is not 0 (dB). Therefore, in this case, the FM detection processing unit 50 can perform FM detection processing on at least the pseudo noise signal N ′. As a result, as shown in FIG. 6B, the high frequency signal level of the FM signal is higher when there is no signal than when the signal arrives. This is the same characteristic as in the state where the level N of noise input to the A / D conversion unit 30 is higher than the minimum input level L of the A / D conversion unit 30 (see FIG. 5B).

  As described above, even when the level N of the noise input to the A / D conversion unit 30 is smaller than the minimum input level L of the A / D conversion unit 30, the pseudo noise addition unit 40 is provided, By adding pseudo noise to the digital complex envelope signal generated by the D conversion unit 30, the high frequency signal level of the FM signal becomes higher than the level when no signal arrives. Therefore, the rising of the received signal can be detected by setting a threshold value between the signal level at the time of no signal and when the signal arrives.

  4 and 6 exemplify a case where the signal level of noise in the receiving unit 20 is always lower than the minimum input level of the A / D conversion unit 30 so that the technical contents of the present invention can be easily understood. Thus, the rising edge detection process of the received signal has been described. Actually, as the noise signal level decreases and approaches the minimum input level of the A / D converter 30, an abnormality is likely to occur in the rising detection process of the received signal. That is, as the noise signal level decreases, the proportion of time that falls below the minimum input level of the A / D conversion unit 30 increases. With this increase, the rate at which the high frequency signal level of the FM signal output from the high frequency signal calculation unit 70 via the FM detection processing unit 50 becomes 0 (dB) increases. For this reason, the signal level smoothed by the smoothing unit 80 (that is, the input of the received signal detection processing unit 90) becomes a small value, and the signal level approaches when the signal arrives.

  Next, the operation of the communication apparatus 1000 according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 7 shows an operation flow of the communication apparatus 1000.

  The signal received by the receiving unit 20 via the antenna unit 10 is converted into an intermediate frequency signal. Then, as shown in FIG. 7, the A / D converter 20 converts the intermediate frequency signal input by the receiver 20 into a digital complex envelope signal (a complex envelope signal of the received signal), and a pseudo noise adder 40 (S701).

  In the pseudo noise addition unit 40, the adder 42 adds the pseudo noise generated by the pseudo noise generator 41 and the digital complex envelope signal input by the A / D conversion unit 20 (S702). As a result, the pseudo noise adding unit 40 generates a complex envelope signal with pseudo noise and outputs it to the FM detection processing unit 50.

  The FM detection processing unit 50 performs FM detection processing on the complex envelope signal with pseudo noise, and generates an FM signal (S703). Then, the FM detection processing unit 50 outputs the FM signal to the HPF unit 60.

  The HPF unit 60 filters only the high frequency component of the FM signal output from the FM detection processing unit 50 (FM detection processing), and uses this as a high frequency signal to obtain a high frequency signal level calculation unit 70. (S704).

  In the high frequency signal level calculation unit 70, the multiplier 71 squares the high frequency signal (S705). Thereby, the high frequency signal level calculation part 70 calculates the high frequency signal level which shows the magnitude | size of a high frequency signal. Then, the high frequency signal level calculation unit 70 outputs the high frequency signal level to the smoothing unit 80. The high frequency signal level may be a value related to the magnitude of the high frequency signal, and is not limited to the square value of the high frequency signal, as described above.

  The smoothing unit 80 smoothes (smoothing processing) the high frequency signal level input by the high frequency signal level calculator 70 (S706). Then, the smoothing unit 80 outputs the smoothed high frequency signal level to the received signal detection processing unit 90.

  The reception signal detection processing unit 90 detects the rising edge of the reception signal in S707 and S708 as described below.

  First, the received signal detection processing unit 90 compares the smoothed high-frequency signal level with a predetermined threshold value for the previous sample (S707). When the high frequency signal level after smoothing is equal to or higher than a predetermined threshold for the previous sample (S707, Yes), the received signal detection processing unit 90 performs smoothing for the sample received at the present time. The local frequency signal level is compared with a predetermined threshold (S708). On the other hand, if the high frequency signal level after smoothing is not equal to or higher than the predetermined threshold value for the previous sample (S707, No), the processing after S701 is performed again.

  When the high frequency signal level after smoothing is equal to or lower than a predetermined threshold for the sample received at the present time (S708, Yes), the received signal detection processing unit 90 externally detects that the rising edge of the received signal has been detected. A circuit (not shown) is notified (S709). At the same time, the received signal detection apparatus 100 records the smoothed high frequency signal level in a memory (not shown) for the sample received at the present time. Note that the memory used at this time may be an external circuit of the received signal detection apparatus 100. On the other hand, if the smoothed high-frequency signal level is not equal to or lower than the predetermined threshold value (S708, No), the processing from S701 onward is performed again.

  In this way, the received signal detection processing unit 90, with respect to the sample received at the present time, when the smoothed high frequency signal level is equal to or higher than the predetermined threshold (Yes in S707). When the high frequency signal level after smoothing is equal to or lower than the predetermined threshold (S708, Yes), the moment is detected as the rising edge of the received signal.

  And the communication apparatus 1000 repeatedly performs the process of above S701-S709 for every sample of a digital complex envelope signal.

  As described above, the communication apparatus 1000 according to the first embodiment of the present invention includes the pseudo noise adding unit 40, the FM detection processing unit 50, the HPF unit 60, and the rising detection unit 90. . The pseudo noise adding unit 40 adds pseudo noise to the complex envelope signal of the received signal and outputs a complex envelope signal with pseudo noise. The FM detection processing unit 50 converts the complex envelope signal with pseudo noise output from the pseudo noise addition unit 40 into an FM signal and outputs the FM signal. The HPF unit 60 filters the high frequency component of the FM signal output from the FM detection processing unit 50 and outputs a high frequency signal. The reception signal detection processing unit 90 compares the magnitude of the high frequency signal output from the HPF 60 unit with a predetermined threshold value, and detects the rising edge of the reception signal based on the comparison result.

  Thus, in communication apparatus 1000 according to the first embodiment of the present invention, by providing pseudo-noise adding unit 40, a complex envelope signal with pseudo-noise obtained by adding pseudo-noise to the complex envelope signal of the received signal. Is input to the FM detection processing unit 50. In the FM detection processing unit 50, for example, if the signal level of the input signal becomes small due to the influence of fading or the like, the input signal cannot be detected, and the signal level of the FM signal that is the output signal becomes indefinite or becomes 0 in some cases. Or Such a phenomenon becomes remarkable particularly when there is no signal. On the other hand, the FM detection processing unit 50 of the present invention receives a complex envelope signal with pseudo noise obtained by adding pseudo noise to the complex envelope signal of the received signal, and performs FM detection processing on the complex envelope signal with pseudo noise. Is going. For this reason, the signal level of the FM signal output from the FM detection processing unit 50 does not become indefinite or zero. Then, the HPF unit 60 filters the high frequency component of the FM signal generated by the FM detection processing unit 50, and outputs this as a high frequency signal. For this reason, the magnitude of the high frequency signal input to the rising edge detection unit 90 does not become indefinite or 0 (dB) even when the reception signal becomes no signal. Therefore, the rising edge detection unit 90 can detect the rising edge of the received signal by using a high frequency signal having a certain magnitude or more and comparing it with a predetermined threshold value.

  As a result, as a first effect, according to the communication apparatus 1000 in the first embodiment of the present invention, the rising edge of the received signal can be stabilized with a simple configuration without depending on environmental changes such as fading. And can be detected accurately. In the present invention, since the FM detection processing is performed without using the envelope information in the FM detection processing unit 50, it is not easily affected by fading. In addition, an SN (Signal Noise) ratio improvement effect also acts as a characteristic property by FM detection processing.

  As a second effect, according to the communication apparatus 1000 in the first embodiment of the present invention, unlike the technique described in Patent Document 1, it is not necessary to provide both HPF and LPF, and the hardware scale Can be easy. That is, the first effect can be obtained with a simpler configuration as compared with the technique described in Patent Document 1. In particular, since a member that performs processing such as filtering on the low frequency region of the received signal is not required, the hardware scale can be reduced. Further, for example, even when processing such as filtering is performed by software on a computer, it is not necessary to perform processing on the low frequency region of the received signal, so the amount of calculation is reduced. Thereby, compared with the case where the technique described in Patent Document 1 is used, the rising detection process of the received signal can be realized using an inexpensive computer having a simpler configuration. In the present invention, compared to the technique described in Patent Document 1, a pseudo-noise adding unit 40 is added. However, the processing load of the pseudo noise adding unit 40 is significantly lower than the processing load of the LPF described in Patent Document 1. This is because the process of adding pseudo-noise only performs one addition process for one sample input signal, while the filter process using LPF or the like performs multiple processes for one sample input signal. This is because it is necessary to perform multiplication and addition.

  As described above, when the first effect and the second effect are summarized, according to the communication apparatus 1000 in the first embodiment of the present invention, for example, rising of a received signal without depending on environmental changes such as fading. Can be detected stably and accurately with a simple configuration.

  In addition, the communication device 1000 according to the first embodiment of the present invention may further include an A / D conversion unit 30. That is, the A / D conversion unit 30 performs analog-digital conversion on the received signal and outputs a complex envelope signal of the received signal. In this case, the pseudo noise adding unit 40 adds pseudo noise to the complex envelope signal of the reception signal output from the A / D conversion unit 30 and outputs a complex envelope signal with pseudo noise. At this time, the pseudo noise is larger than the minimum input level of the A / D conversion unit 30. Note that the minimum input level of the A / D conversion unit 30 is the minimum value of the signal level at which the A / D conversion unit 30 can perform analog-digital conversion on the received signal (analog signal) as described above. The minimum input level of the A / D conversion unit 30 is a value at the time of an analog signal before analog-digital conversion.

  As described above, when the A / D conversion unit 30 is further provided, the pseudo noise addition unit 40 adds the pseudo noise to the complex envelope signal of the reception signal output by the A / D conversion unit 30 and adds the pseudo noise. Outputs a complex envelope signal. At this time, the pseudo noise is set to a value larger than at least the minimum input level of the A / D converter 30. If such pseudo noise is added to the complex envelope signal of the received signal by the pseudo noise adding unit 40, the level of the signal input to the FM detection processing unit 50 does not become 0, and the FM signal becomes indefinite or 0. There is no. Indefinite or 0 (dB). Therefore, even if the noise is smaller than the minimum input level of the A / D conversion unit 30, the FM detection processing unit 50 can perform the FM detection processing on at least the pseudo noise. Thereby, the signal level in the high frequency region of the FM signal becomes higher when there is no signal than when the signal arrives.

  Therefore, even if the level of noise input to the A / D conversion unit 30 is smaller than the minimum input level L of the A / D conversion unit 30, the pseudo noise addition unit 40 is provided, and the A / D conversion unit By adding pseudo-noise to the digital complex envelope signal generated by 30, the signal level in the high frequency region of the FM signal becomes higher than the level when no signal arrives. Thereby, if a threshold value is set between the signal level at the time of no signal and the arrival of the signal, the rising edge of the received signal can be detected. As a result, the rising edge of the received signal can be detected more stably and more accurately with a simple configuration without depending on environmental changes.

  As a further effect, according to the communication apparatus 1000 in the first embodiment of the present invention, the cost for adjusting the signal level of the reception signal between the reception unit 20 and the A / D conversion unit 30 can be reduced. . In the present invention, since the pseudo noise adding unit 40 adds pseudo noise to the signal input to the FM detection processing unit 50, the minimum input level of the A / D conversion unit 30 is set in the received signal of the receiving unit 20. This is because it is not necessary to adjust to the signal level of the noise. In particular, since the signal level of noise output by the receiving unit 20 is easily affected by aging and temperature changes, the minimum input level of the A / D conversion unit 30 is set to the noise level in the received signal of the receiving unit 20. It is very difficult to adjust appropriately according to the signal level. In the present invention, as described above, the pseudo noise adding unit 40 adds the pseudo noise to the signal input to the FM detection processing unit 50, so that such a problem can be solved.

  Moreover, according to the communication apparatus 1000 in the 1st Embodiment of this invention, an effective dynamic range can be expanded. FIG. 8 is a diagram for explaining the effect of the communication apparatus 1000. FIG. 8A is a diagram illustrating a dynamic range when the pseudo noise adding unit 40 is not provided. On the other hand, FIG. 8B is a diagram showing a dynamic range when the pseudo noise adding unit 40 is provided.

  As shown in FIGS. 8A and 8B, the A / D converter 30 is set with a minimum input level L and a maximum input level H. Note that the minimum input level L of the A / D conversion unit 30 is the minimum value of the signal level at which the A / D conversion unit 30 can perform analog-digital conversion on the received signal (analog signal) as described above. The maximum input level H of the A / D conversion unit 30 is the maximum value of the signal level at which the A / D conversion unit 30 can perform analog-digital conversion on the received signal (analog signal). N represents the noise component of the digital complex envelope signal generated by the A / D conversion unit 30 as described above.

  As shown in FIG. 8A, when the pseudo noise adding unit 40 is not provided, in order to prevent a signal of 0 from being input to the FM detection processing unit 50, it is adjusted to the minimum value of the signal level of noise N. Therefore, it is necessary to set the minimum input level L of the A / D converter 30. For this reason, as shown in FIG. 8A, the effective dynamic range DL1 is limited and narrowed.

  On the other hand, when the pseudo noise adding unit 40 is provided, even if a 0 signal is output from the A / D conversion unit 30, the signal to which the pseudo noise is added by the pseudo noise adding unit 40 is subjected to FM detection processing. Input to the unit 50. Therefore, as shown in FIG. 8B, the minimum input level L of the A / D converter 30 can be set to a level smaller than the minimum value of the signal level of the noise N. Thereby, as shown in FIG. 8B, the effective dynamic range DL2 can be widened (DL2> DL1).

  As described above, according to the communication apparatus 1000 in the first embodiment of the present invention, the provision of the pseudo noise adding unit 40 can expand the effective dynamic range.

  The communication device 1000 according to the first embodiment of the present invention further includes a high frequency signal level calculation unit 70. The high frequency signal level calculator 70 calculates a high frequency signal level that is a value related to the magnitude of the high frequency signal output from the HPF unit 60. Then, the rise detection unit 90 compares the high frequency signal level calculated by the high frequency signal level calculation unit 70 with a predetermined threshold value set in advance, and based on this comparison result, the rise of the received signal Perform detection.

  Thereby, the high frequency signal level calculation part 70 outputs the high frequency signal level which is a natural number as a value regarding the magnitude | size of a high frequency signal. Therefore, the rising edge detection unit 90 can easily set a predetermined threshold value using a natural number. In addition, since the configuration of the high frequency signal level calculation unit 70 can be set in accordance with a predetermined threshold value set in advance, the degree of design freedom can be increased.

  The communication apparatus 1000 according to the first embodiment of the present invention further includes a smoothing unit 80. The smoothing unit 80 smoothes the high frequency signal level calculated by the high frequency signal level calculating unit 70. The rising edge detection unit compares the high frequency signal level smoothed by the smoothing unit 80 with a predetermined threshold value, and detects the rising edge of the received signal based on the comparison result. As a result, the rising edge of the received signal can be detected after eliminating the extraneous signal level.

<Second Embodiment>
A communication apparatus 1000A according to the second embodiment of the present invention will be described with reference to the drawings.

  FIG. 9 shows the configuration of the communication apparatus 1000A. As illustrated in FIG. 9, the communication device 1000 </ b> A includes a pseudo noise adding unit 40, an FM detection processing unit 50, an HPF unit 60, and a received signal detection processing unit 90. Further, the pseudo noise adding unit 40, the FM detection processing unit 50, the HPF unit 60, and the reception signal detection processing unit 90 constitute a reception signal detection device 100A of the present invention. In FIG. 9, components equivalent to the components shown in FIG. 1 are denoted by the same symbols as those shown in FIG. 1.

  Here, FIG. 1 and FIG. 9 are compared. In FIG. 1, the antenna unit 10, the reception unit 20, the A / D conversion unit 30, the high frequency signal level calculation unit 70, and the smoothing unit 80, whereas in FIG. 9, It differs in that it does not have these configurations.

  The pseudo noise adding unit 40 receives a digital complex envelope signal (a complex envelope signal of a received signal). The pseudo noise adding unit 40 adds pseudo noise to the digital complex envelope signal and outputs a digital complex envelope signal with pseudo noise.

  The FM detection processing unit 50 converts the digital complex envelope signal with pseudo noise output from the pseudo noise adding unit 40 into an FM signal and outputs the FM signal.

  The HPF unit 60 filters the high frequency component of the FM signal output from the FM detection processing unit 50 and outputs a high frequency signal.

  The received signal detection processing unit 90 compares the magnitude of the high frequency signal output from the HPF 60 unit with a predetermined threshold value set in advance. The reception signal detection processing unit 90 detects the rising edge of the reception signal based on the comparison result.

  Next, the operation of the communication apparatus 1000A according to the second embodiment of the present invention will be described with reference to the drawings. FIG. 10 shows an operation flow of the communication apparatus 1000A. In FIG. 10, S902 to S904 and S907 to S909 correspond to S702 to S704 and S707 to S709 in FIG.

  First, the pseudo noise adding unit 40 adds pseudo noise to the input digital complex envelope signal, and outputs a digital complex envelope signal with pseudo noise (S902). As a result, the pseudo noise adding unit 40 generates a complex envelope signal with pseudo noise and outputs it to the FM detection processing unit 50.

  The FM detection processing unit 50 performs FM detection processing on the complex envelope signal with pseudo noise, and generates an FM signal (S903). Then, the FM detection processing unit 50 outputs the FM signal to the HPF unit 60.

  The HPF unit 60 filters only the high frequency component of the FM signal output by the FM detection processing unit 50 (FM detection processing), and outputs this as a high frequency signal to the received signal detection processing unit 90 (S909).

  The reception signal detection processing unit 90 detects the rising edge of the reception signal in S907 and S908 as described below.

  First, the received signal detection processing unit 90 compares the magnitude of the high frequency signal with a predetermined threshold value for the previous sample (S907). When the magnitude of the high frequency signal is greater than or equal to a predetermined threshold for the previous sample (S907, Yes), the received signal detection processing unit 90 determines the magnitude of the high frequency signal for the currently received sample. The predetermined threshold is compared (S908). On the other hand, if the magnitude of the high frequency signal is not equal to or greater than the predetermined threshold value for the previous sample (S907, No), the communication apparatus 1000 performs the processing subsequent to S902 again.

  If the magnitude of the high frequency signal is equal to or smaller than a predetermined threshold value for the sample received at this time (S908, Yes), the received signal detection processing unit 90 detects that the rising edge of the received signal has been detected. (S909). At the same time, the received signal detection apparatus 100 records the magnitude of the high frequency signal in a memory (not shown) for the sample received at the current time. Note that the memory used at this time may be an external circuit of the received signal detection apparatus 100. On the other hand, when the magnitude of the high frequency signal is not equal to or less than the predetermined threshold value (No in S908) for the sample received at the current time, the communication apparatus 1000 performs the processing from S702 onward.

  In this way, the received signal detection processing unit 90 determines the high frequency signal for the previous sample when the magnitude of the high frequency signal is equal to or greater than the predetermined threshold (Yes in S907). When the magnitude of the local frequency signal is equal to or smaller than the predetermined threshold (S908, Yes), the moment is detected as the rising edge of the received signal.

  Then, the communication apparatus 1000A repeatedly executes the above processes of S902 to S909 for each sample of the digital complex envelope signal.

  As described above, the communication apparatus 1000A according to the second embodiment of the present invention includes the pseudo noise adding unit 40, the FM detection processing unit 50, the HPF unit 60, and the reception signal detection processing unit 90. ing. The pseudo noise adding unit 40 adds pseudo noise to the complex envelope signal of the received signal and outputs a complex envelope signal with pseudo noise. The FM detection processing unit 50 converts the complex envelope signal with pseudo noise output from the pseudo noise addition unit 40 into an FM signal and outputs the FM signal. The HPF unit 60 filters the high frequency component of the FM signal output from the FM detection processing unit 50 and outputs a high frequency signal. The reception signal detection processing unit 90 compares the magnitude of the high frequency signal output from the HPF 60 unit with a predetermined threshold value, and detects the rising edge of the reception signal based on the comparison result.

  Thereby, there exists an effect similar to the communication apparatus 1000 in the 1st Embodiment of this invention mentioned above.

  The present invention has been described above based on the embodiment. The embodiment is an exemplification, and various modifications, increases / decreases, and combinations may be added to the above-described embodiments without departing from the gist of the present invention. It will be understood by those skilled in the art that modifications to which these changes, increases / decreases, and combinations are also within the scope of the present invention.

  In the description of the above-described embodiment (particularly, description of FIGS. 7 and 10), it has been described that each process is repeatedly executed for each sample of the digital complex envelope signal. However, each process may be repeatedly executed for each of a plurality of samples of the digital complex envelope signal.

  In the description of the above-described embodiment (particularly, FIG. 7 and FIG. 10), the received signal detection processing unit 90 has the magnitude of the high frequency signal (high frequency signal level) for the previous sample. The rising edge of the received signal is detected when the magnitude of the high frequency signal (high frequency signal level) is equal to or lower than the predetermined threshold for the sample received at the present time as well as when it is equal to or higher than the predetermined threshold. However, on the contrary, for the previous sample, the magnitude of the high-frequency signal (high-frequency signal level) is equal to or lower than a predetermined threshold, and the high-frequency signal is received for the sample received at the present time. The received signal detection processing unit 90 may be provided with a detection function of detecting that the received signal is instantaneous when the magnitude (high frequency signal level) is equal to or greater than a predetermined threshold.

DESCRIPTION OF SYMBOLS 10 Antenna part 20 Reception part 30 A / D conversion part 40 Pseudo noise addition part 41 Pseudo noise generator 42 Adder 50 FM detection process part 60 HPF part 70 High frequency signal level calculation part 71 Multiplier 80 Smoothing part 90 Reception signal Detection processing unit 100, 100A received signal detection device 1000, 1000A communication device

Claims (7)

A pseudo noise adding unit that adds pseudo noise to the complex envelope signal of the received signal and outputs a complex envelope signal with pseudo noise;
An FM detection processing unit that converts the complex envelope signal with pseudo noise output from the pseudo noise addition unit into an FM signal and outputs the FM signal;
A high-pass filter unit that filters a high-frequency component of the FM signal output by the FM detection processing unit and outputs a high-frequency signal;
A reception signal detection processing unit that compares the magnitude of the high-frequency signal output by the high-pass filter unit with a predetermined threshold value that is set in advance and detects the rising edge of the reception signal based on the comparison result; A communication device comprising: An A / D converter that performs analog-digital conversion on the received signal and outputs a complex envelope signal of the received signal,
The pseudo noise adding unit adds pseudo noise to the complex envelope signal of the reception signal output by the A / D conversion unit, and outputs a complex envelope signal with pseudo noise,
The communication apparatus according to claim 1, wherein the pseudo noise is larger than a minimum input level of the A / D conversion unit. A high-frequency signal level calculating unit that calculates a high-frequency signal level that is a value related to the magnitude of the high-frequency signal output by the high-pass filter;
The reception signal detection processing unit compares the high frequency signal level calculated by the high frequency signal level calculation unit with a predetermined threshold value set in advance, and based on the comparison result, The communication apparatus according to claim 1, wherein the rising edge is detected. A smoothing unit for smoothing the high frequency signal level calculated by the high frequency signal level calculator;
The received signal detection processing unit compares the high frequency signal level smoothed by the smoothing unit with a predetermined threshold value, and detects a rising edge of the received signal based on the comparison result. The communication apparatus according to claim 3.   The received signal detection processing unit compares the magnitude of the high-frequency signal output from the high-pass filter unit with a predetermined threshold value, and based on the comparison result, eliminates the received signal. The communication device according to claim 1 to detect. A pseudo noise adding unit that adds pseudo noise to the complex envelope signal of the received signal and outputs a complex envelope signal with pseudo noise;
An FM detection processing unit that converts the complex envelope signal with pseudo noise output from the pseudo noise addition unit into an FM signal and outputs the FM signal;
A high-pass filter unit that filters a high-frequency component of the FM signal output by the FM detection processing unit and outputs a high-frequency signal;
A reception signal detection processing unit that compares the magnitude of the high-frequency signal output by the high-pass filter unit with a predetermined threshold value that is set in advance and detects the rising edge of the reception signal based on the comparison result; A received signal detecting device. A pseudo noise adding step of adding pseudo noise to the complex envelope signal of the received signal and outputting a complex envelope signal with pseudo noise;
An FM signal converting step of converting the complex envelope signal with pseudo noise output from the pseudo noise adding unit into an FM signal and outputting the FM signal;
A signal filtering step of filtering a high frequency component of the FM signal output by the FM detection processing unit and outputting a high frequency signal;
A reception step of comparing the magnitude of the high-frequency signal output from the high-pass filter unit with a predetermined threshold set in advance and detecting the rising edge of the received signal based on the comparison result Signal detection method.

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