JP2010118908A - Signal receiving status display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To intuitively recognize to what degree a signal can be stably received with a current received field strength, and further to intuitively recognize a reception-enabled received field strength due to the difference of various modulation systems. <P>SOLUTION: A transmission signal according to a QAM modulation system is demodulated by a QAM demodulator, and a transmission signal by an OFDM modulation system is demodulated by an OFDM demodulator. When a data processor outputs the result of comparing a current received field strength obtained from the demodulation output of the QAM demodulator with a first theoretical characteristic value stored in a memory or outputs the result of comparing a current received field strength obtained from the demodulation output of the OFDM demodulator with a second theoretical characteristic value stored in the memory, in accordance with the output from the data processor, a display controller graphically displays a reception-enabled received field strength depending on the QAM modulation system or the OFDM modulation system on a meter display section 100. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a signal reception status display that displays the received field strength of a transmission signal carrier modulated by a QAM (Quadrature Amplitude Modulation) modulation method, an OFDM (Orthogonal Frequency Division Multiplex) modulation method, or the like. Relates to the device.

  First, referring to FIGS. 6 and 7, a display device for displaying the received electric field strength that has been used conventionally will be described. First, FIG. 6 shows an analog meter 301, which has a scale 301a for displaying the received electric field strength and a pointer 301b for indicating the current received electric field strength.

  In such an analog meter 301, the pointer 301b rotates corresponding to the detected received electric field, and the current received electric field strength is indicated by the scale of the scale 301a pointed to by the pointer 301b.

  On the other hand, FIG. 7 shows a digital meter 401. For example, a scale 401a indicating the received electric field strength on a liquid crystal screen, a bar 401b for indicating the current received electric field strength in an analog manner, and the current received electric field strength. A numerical value 401c is displayed.

  In such a digital meter 401, with respect to the scale 401a indicating the received electric field strength, the bar 401b changes according to the detected received electric field strength, and the current received electric field strength is indicated on the scale 401a indicated by the bar 401b. In addition, the numerical value 401c also indicates the current received electric field strength.

  By the way, in the conventional analog modulation method such as FM modulation, even if the electric field strength is reduced, it is not immediately impossible to receive. For this reason, even if the received electric field strength is displayed on the analog meter 301 in FIG. 6 or the digital meter 401 in FIG. 7 by checking the output video signal on a monitor display or the like, how stable the current received electric field strength is. Thus, the operator who is the user can grasp whether or not the data can be received.

  However, in the digital modulation system such as the QAM modulation system and the OFDM modulation system, when the electric field strength changes, reception suddenly becomes impossible. Therefore, it is determined only by the actual meter display at which electric field strength can be stably received. It ’s difficult.

  In the conventional analog modulation system, the receivable received electric field intensity does not change even when the modulation system (modulation mode) is changed.

  However, in digital modulation schemes such as the QAM modulation scheme and the OFDM modulation scheme, when the modulation schemes (modulation modes) are changed, the receivable received electric field strengths are different. For this reason, in the analog meter 301 in FIG. 6 and the digital meter 401 in FIG. 7 showing only the received electric field strength, the operator can intuitively know how stable the reception is when the modulation method is changed. It is difficult to judge.

  Incidentally, in a digital transmission device including a digital FPU (Field Pick-up Unit) device used for mobile relay broadcasting or the like, for example, when image data is spatially transmitted from a transmission device to a reception device, the effects of rain, The reception electric field on the receiving device side becomes weak due to the influence of the building such as a building, or the BER (Bit Error Rate) characteristic becomes worse than the theoretical value due to multipath due to reflection due to the influence of the building.

  In particular, when using a digital transmission device for radio wave transmission while moving, such as a marathon relay, it is necessary to adjust the direction of receiving strong radio waves by accurately pointing the reception antenna on the receiving side to the transmission antenna of a moving relay vehicle or the like. Become.

  In order to grasp the received electric field strength of such a digital signal, in Patent Document 1, a received input electric field value and a BER (bit error rate) value are detected from received video data, and a received input electric field recorded in a memory is detected. A transmission state display method of a digital transmission apparatus is proposed in which value-BER value characteristic data is compared with a received input electric field value and a BER value and the results are displayed.

Japanese Patent Laying-Open No. 2005-086386

  In the above-mentioned Patent Document 1, since the comparison result between the received input electric field value-BER value characteristic data recorded in the memory and the received input electric field value and the BER value is displayed, the video data is actually spatially transmitted. The received input electric field value and the BER value obtained at that time can be quantitatively confirmed.

  However, in such a transmission state display method of the digital transmission apparatus, since the comparison result between the received input electric field value-BER value characteristic data and the received input electric field value and the BER value is displayed only as a numerical value, There is a problem that it is not possible to intuitively recognize how stable the signal can be received with strength, and it is not possible to intuitively recognize the receivable electric field strength due to the difference in various modulation methods.

  The present invention has been made in view of such a situation. It is possible to intuitively recognize how stable reception is possible with the current reception electric field strength, and due to differences in various modulation methods. An object of the present invention is to provide a signal reception status display device capable of intuitively recognizing receivable received electric field strength.

  The signal reception status display device of the present invention is a signal reception status display device that displays on the meter display section the reception status of the transmission signal at the reception device that receives the digitally modulated transmission signal, and demodulates the transmission signal. Demodulating means, storage means for storing a theoretical characteristic value indicating the limit level of receivable electric field strength, and data processing for outputting the current received electric field strength obtained from the demodulated output of the demodulating means and the theoretical characteristic value And a display control means for graphically displaying the received electric field strength that can be received on the meter display unit in accordance with an output from the data processing means.

  According to the signal reception status display device of the present invention, the meter can be received by the display control means according to the current received electric field strength and the theoretical characteristic value obtained from the demodulated output of the demodulating means from the data processing means. Since the received electric field strength is displayed graphically, it is possible to intuitively recognize how stable the reception can be with the current received electric field strength.

  Details of the embodiment of the present invention will be described below. FIG. 1 is a front view for explaining an outline of a digital reception apparatus to which a signal reception status display apparatus according to an embodiment of the present invention is applied.

  As shown in the figure, the digital receiver 1 includes a meter display unit 100, an information display unit 110, a power switch 111, a changeover switch 112, a level adjustment switch 113, a channel selection switch 114, and the like.

  The meter display unit 100 displays received electric field strength and the like, and details thereof will be described later. The information display unit 110 displays information such as the modulation method, frequency band, and bit rate of the digital signal currently being received.

  The power switch 111 is a main switch that is operated when the digital receiver 1 is turned on. The change-over switch 112 is operated, for example, when receiving either a digital signal based on the QAM modulation system or a digital signal based on the OFDM modulation system. The level adjustment switch 113 is operated when the reception sensitivity is adjusted. The channel selection switch 114 is operated when a reception channel is selected.

  FIG. 2 is a block diagram for explaining the internal configuration of the digital receiver 1.

  As shown in the figure, the digital receiver 1 includes a receiving antenna 10, a down converter 20, a switching unit 30, a QAM demodulating unit 40, a QAM decoding unit 50, an OFDM demodulating unit 60, an OFDM decoding unit 70, a data processing unit 80, A memory 81, a display control unit 90, and a meter display unit 100 are provided.

  The receiving antenna 10 receives a digital signal subjected to OFDM modulation or QAM modulation transmitted from a digital transmission device (not shown). The down converter 20 converts the digital signal received by the receiving antenna 10 into a baseband signal.

  The switching unit 30 performs switching so that the baseband signal converted by the down converter 20 is output to the QAM demodulating unit 40 or the OFDM demodulating unit 60 based on the switching signal according to the operation of the changeover switch 112 described above. When the modulation scheme is changed by the switching unit 30, the modulation scheme corresponding to each modulation scheme is set in the memory 81.

  The QAM demodulator 40 QAM-demodulates the baseband signal. The QAM decoding unit 50 decodes the QAM demodulated signal into the original transmission data. The OFDM demodulator 60 performs OFDM demodulation on the baseband signal. The OFDM decoding unit 70 decodes the OFDM demodulated signal into the original transmission data.

  When the modulation method is the QAM modulation mode, the data processing unit 80 stores the first theoretical characteristic value of the received electric field strength versus the bit error rate for the modulation mode of the QAM modulation method stored in the memory 81, and the QAM demodulation unit. 40, and the current received electric field strength obtained from 40 is output.

  In addition, when the modulation method is the OFDM modulation mode, the data processing unit 80 stores the second theoretical characteristic value of the received electric field strength versus the bit error rate for the modulation mode of the OFDM modulation method stored in the memory 81, and the OFDM The current received field strength obtained from the demodulator 60 is output.

  The memory 81 stores a first theoretical characteristic value of received electric field strength versus bit error rate for the modulation mode of the QAM modulation method and a second theoretical characteristic value of received electric field strength versus bit error rate for the modulation mode of the OFDM modulation method. Has been. Here, the theoretical characteristic value indicates a theoretical characteristic value such as a limit level of receivable electric field strength in a modulation mode of QAM modulation method or a modulation mode of OFDM modulation method, and a margin at which level can be received. Is.

  The display control unit 90 controls the display of the received electric field strength and the like on the meter display unit 100 according to the output from the data processing unit 80. The meter display unit 100 displays received electric field strength and the like.

  Next, a display example of received electric field strength versus bit error rate displayed on the meter display unit 100 will be described with reference to FIG.

  First, as shown in FIG. 3A, the meter display screen 101 of the meter display unit 100 has a numerical value 101a indicating the current received electric field strength, a bit error scale 101b indicating the bit error rate, and a received electric field strength. A received electric field strength scale 101c is displayed. The bit error scale 101b is displayed on the vertical axis, and the received electric field strength scale 101c is displayed on the horizontal axis.

  Further, the meter display screen 101 includes the characteristic image 101d of the first theoretical characteristic value or the second theoretical characteristic value determined by a modulation method such as the QAM modulation method or the OFDM modulation method, and the received electric field intensity actually received. And a characteristic image 101e showing the relationship between the bit error rate and the bit error rate.

  Each of the characteristic image 101d and the characteristic image 101e has a shape as shown in FIG. 3B. These characteristic image 101d and characteristic image 101e, the above-described numerical value 101a, bit error scale 101b, and reception The electric field strength scale 101c is superimposed and displayed on the meter display screen 101 as shown in FIG. At this time, the bit error rate in the characteristic image 101e is displayed in accordance with the bit error rate characteristic of the first theoretical characteristic value or the second theoretical characteristic value within the actually received electric field intensity.

  Incidentally, in FIG. 3A, it can be seen that the current received electric field strength is −47 dBm from the position on the received electric field strength scale 101c indicated by the characteristic image 101e and the value indicated by the numerical value 101a.

  In such a meter display screen 101, a two-dimensional region displayed by combining a bit error scale 101b indicating a bit error rate and a received electric field strength scale 101c indicating a received electric field strength is displayed by a QAM modulation method or an OFDM modulation method. By displaying the theoretically determined characteristic image 101d, the theoretical bit error rate characteristics of the QAM modulation method and the OFDM modulation method are visually displayed.

  As a result, it is possible to intuitively recognize how stably the current reception electric field intensity is received from the characteristic image 101d and the characteristic image 101e partially overlapped with the characteristic image 101d. Thus, it is possible to intuitively recognize how much room there is in the current received electric field strength.

  The characteristic image 101d and the characteristic image 101e can be displayed in different colors. As described above, when the characteristic image 101d and the characteristic image 101e are displayed in different colors, how much stable reception is possible and how much room is present in the current reception electric field strength. Can be recognized more intuitively.

  That is, the characteristic image 101e indicating the characteristics of the current received electric field strength and the error rate has a shape that expresses the theoretical bit error rate characteristic of the QAM modulation method or the OFDM modulation method. A comparison between the bit error scale 101b indicating the rate and the received electric field strength scale 101c indicating the received electric field strength can be visually grasped, and the current received electric field can be determined depending on the area of the characteristic image 101e indicated by color. It is possible to intuitively determine whether the strength is effective.

  In addition, since the current received electric field strength is indicated by the numerical value 101a, the current received electric field strength can be read accurately and easily.

  FIG. 4 is a diagram showing a difference in meter display due to a difference in modulation mode such as 64QAM or QPSK of the QAM modulation method.

  First, FIG. 4A shows an example of a modulation-type meter display screen 101 with a low receivable electric field strength in the QPSK mode, and FIG. 4B shows a receivable electric field strength compared with the QPSK mode in FIG. A meter display screen 102 in a high QAM mode is shown.

  As can be seen from FIGS. 4A and 4B, the first theoretical characteristic value and the second theoretical characteristic value of the received electric field strength versus the bit error rate are reflected on the meter display for each modulation mode such as 64QAM or QPSK of the QAM modulation method. Therefore, for example, the reception state of the meter display screen 102 of FIG. 4B is more current than that of the meter display screen 101 of FIG. It can be intuitively determined that there is no margin in the received electric field intensity.

  FIG. 5 is a diagram showing a meter display example of margin versus received electric field strength with a margin scale 201b instead of the bit error scale 101b displayed on the meter display screen 101.

  First, in FIG. 5A, reference numeral 201 denotes a meter display screen indicating margin versus reception electric field strength, and a numerical value 201a indicating the current reception electric field strength, a margin scale 201b indicating the margin, and reception indicating the reception electric field strength. A field strength scale 201c is displayed.

  Further, the meter display screen 201 has characteristics that are theoretically determined by a QAM modulation method or OFDM modulation method and a CN (Carrier to Noise Ratio) value calculated by the demodulation processing in the QAM demodulation unit 40 or OFDM demodulation unit 60 described above. An image 201d and a characteristic image 101e indicating the relationship between the actually received electric field intensity and the margin are displayed.

  Further, each of the received electric field strength vs. bit error rate image 201d and the characteristic image 201e has a shape as shown in FIG. 5B, and these characteristic image 201d and characteristic image 201e, and the above-described numerical value 201a, The margin scale 201b and the received electric field strength scale 201c are displayed superimposed on the meter display screen 201 as shown in FIG.

  Here, the reception status of the transmission signal of the QAM modulation scheme or the OFDM modulation scheme changes every moment due to fading of the aerial transmission line due to the influence of buildings such as topography and buildings, multipath, noise, and the like. This change is reflected in the CN value calculated by the QAM modulation method or the OFDM modulation method. From this CN value, the lowest receivable electric field strength at which the bit error rate occurring in the current reception situation becomes error-correctable is calculated, and the difference between the lowest receivable electric field strength and the current received electric field strength is calculated as a margin value.

  Then, a characteristic image 201d corresponding to the calculated margin value and the received electric field strength is displayed in a two-dimensional area expressed by combining the scale display of the margin scale 201b and the received electric field strength scale 201c. Displays the margin characteristics.

  Note that the characteristic image 201d and the characteristic image 201e can be displayed in different colors as described above. As described above, when the characteristic image 201d and the characteristic image 201e are displayed in different colors, it is possible to intuitively recognize how much margin there is in the current received electric field intensity. .

  That is, the characteristic image 201e changes in a manner corresponding to the reception situation that changes from moment to moment, and the area of the characteristic image 201e also increases or decreases, so that the operator can receive the margin scale 201b indicating the margin in real time and the received electric field indicating the received electric field strength. The comparison with the intensity scale 201c can be visually grasped, and it is possible to intuitively determine whether or not the current received electric field intensity is effective based on the area of the characteristic image 201e.

  Further, since the current reception field strength is indicated by the numerical value 201a, the current reception field strength can be read accurately and easily.

  As described above, in the present embodiment, the transmission signal according to the QAM modulation method that is the first modulation mode is demodulated by the QAM demodulator 40 that is the first signal demodulator, and the OFDM demodulator 60 that is the second signal demodulator A transmission signal according to the OFDM modulation scheme which is the two modulation mode is demodulated, and the first theoretical characteristic value indicating the limit level of the electric field strength which can be received in each of the QAM modulation scheme and the OFDM modulation scheme is stored in the memory 81 which is the storage means. Whether the theoretical characteristic value is stored, and the current received electric field intensity obtained from the demodulated output of the QAM demodulating unit 40 by the data processing unit 80 as data processing means and the first theoretical characteristic value stored in the memory 81 are output. Or the current received electric field strength obtained from the demodulated output of the OFDM demodulator 60 and the second theoretical characteristic value stored in the memory 81 are output. In response to the output from the data processing unit 80, the display control unit 90, which is a display control unit, graphically displays the receivable received electric field strength depending on the QAM modulation method or the OFDM modulation method on the meter display unit 100. As a result, it is possible to intuitively recognize how stable the current reception field strength is, and intuitively recognize the receivable reception field strength due to the difference in various modulation methods. Can do.

  In addition, since the stability of the current received electric field strength and the receivable received electric field strength due to the difference in various modulation schemes can be intuitively recognized as described above, in particular, the digital FPU (used for mobile relay broadcasting or the like) When applied to a Field Pick-up Unit device, it is possible to easily perform a direction adjustment operation that quickly corresponds to a reception situation that changes every moment.

  In particular, it is possible to easily cope with changing the modulation method so as to perform stable transmission / reception at a low bit rate or changing the modulation method in consideration of a margin. Thereby, the effect that the so-called broadcast accident that communication is interrupted can be prevented is obtained.

  Further, in the present embodiment, as shown in FIG. 5, the margin vs. received electric field strength is also graphically displayed, so that the margin scale 201b indicating the margin and the received electric field strength scale 201c indicating the received electric field strength are compared. It is possible to intuitively determine whether or not the current received electric field strength is effective based on the area of the characteristic image 201e.

  In this embodiment, the QAM modulation method and the OFDM modulation method are exemplified as the digital modulation method. However, the present invention is not limited to this, and other modulation methods such as SS (Spread Spectrum) radio and CDMA (Code Division Multiple Access) are used. Is also applicable.

  Further, in the above embodiment, the characteristic images 101d and 101e or the characteristic images 201d and 201e are displayed so as to overlap each other. In this case, since the characteristic images 101d and 201d reflect the bit error rate and the margin, and the correspondence relationship with the characteristic images 101e and 201e can be easily understood, the characteristic images 101e and 201e have the characteristics reflecting the bit error rate and the margin. It does not have to be an image.

  Even if the modulation method is the same, for example, if a parameter such as modulation by 64QAM or 16QAM is changed, the receivable electric field strength changes. Correspondingly, similarly to the above-described embodiment, it is possible to create meter display screens of received electric field strength versus bit error rate and margin versus received electric field strength, respectively.

  In addition to using the above-described display method in the FPU device, for example, in terrestrial digital broadcasting, it is also applicable to the case of displaying the strengths of radio waves of one-segment broadcasting and full-segment broadcasting with different modulation methods.

  As described above, in the signal reception status display device according to the embodiment of the present invention, the signal reception status in which the reception status of the transmission signal in the reception device that receives the digitally modulated transmission signal is displayed on the meter display unit. A display device, a demodulating means for demodulating the transmission signal, a storage means for storing a theoretical characteristic value indicating a limit level of the receivable electric field strength, and a current received electric field strength obtained from a demodulated output of the demodulating means And a data processing means for outputting the theoretical characteristic value, and a display control means for graphically displaying the received electric field strength that can be received on the meter display unit in accordance with an output from the data processing means. Yes.

  A signal reception status display device according to an embodiment of the present invention is a signal reception status display device that displays a reception status of the transmission signal in a receiving device that receives a digitally modulated transmission signal on a meter display unit. A first signal demodulating means for demodulating the transmission signal in the first modulation mode, a second signal demodulating means for demodulating the transmission signal in the second modulation mode, and each of the first modulation mode and the second modulation mode. Storage means for storing the first theoretical characteristic value and the second theoretical characteristic value indicating the limit level of receivable electric field strength in the signal, the current received electric field strength obtained from the demodulated output of the first signal demodulating means, and the first Data processing means for outputting a theoretical characteristic value or outputting a current received electric field strength obtained from the demodulated output of the second signal demodulating means and the second theoretical characteristic value; and Display control means for graphically displaying the receivable received electric field strength depending on the first modulation mode or the second modulation mode on the meter display unit in accordance with an output from the data processing means. .

  In the signal reception status display device according to the embodiment of the present invention, the receivable received electric field strength to be displayed in graphic is related to a bit error rate or a margin.

It is a front view for demonstrating the outline | summary of the digital receiver with which the signal reception condition display apparatus which concerns on one Embodiment of this invention is applied. It is a block diagram for demonstrating the internal structure of the digital receiver of FIG. It is a figure for demonstrating the example of a display of the received electric field strength versus bit error rate displayed on the meter display part of FIG. It is a figure which shows the difference in the meter display by the difference in a QAM modulation system and an OFDM modulation system displayed on the meter display part of FIG. It is a figure which shows the example of a meter display of margin vs. received electric field strength displayed on the meter display part of FIG. It is a figure for demonstrating the conventional analog meter. It is a figure for demonstrating the conventional digital meter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital receiver 10 Reception antenna 20 Down converter 30 Switching part 40 QAM demodulation part 50 QAM decoding part 60 OFDM demodulation part 70 OFDM decoding part 80 Data processing part 81 Memory 90 Display control part 100 Meter display part 101 Meter display screen 101a Numerical value 101b Bit error scale 101c Received electric field strength scale 101d Characteristic image 101e Characteristic image 102 Meter display screen 110 Information display unit 111 Power switch 112 Changeover switch 113 Level adjustment switch 114 Channel selection switch 201 Meter display screen 201a Numerical value 201b Margin scale 201c Received electric field strength scale 201d characteristic image 201e characteristic image

Claims (1)

A signal reception status display device that displays on a meter display the reception status of the transmission signal in a reception device that receives a digitally modulated transmission signal,
Demodulation means for demodulating the transmission signal;
Storage means for storing a theoretical characteristic value indicating a limit level of receivable electric field strength;
Data processing means for outputting the current received electric field strength obtained from the demodulated output of the demodulating means and the theoretical characteristic value;
A signal reception status display device, comprising: display control means for graphically displaying the received electric field intensity that can be received on the meter display unit in accordance with an output from the data processing means.

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