JP4237422B2 - Digital broadcast wave reception quality monitoring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a digital broadcast wave reception quality monitoring device for monitoring the reception quality of a digital broadcast wave in, for example, a terrestrial digital broadcast system.
[0002]
[Prior art]
In conventional analog broadcasting, the direction and height of a receiving antenna in a general home are adjusted so that a person can observe the image displayed on the receiver and have the least noise and no ghost.
[0003]
On the other hand, in recent years, various developments for digital terrestrial broadcasting have been promoted for practical use. By the way, in this terrestrial digital broadcasting, since the image displayed on the receiver is a digital system, only the result of whether it becomes a video can be known, and how much the reception margin, that is, the quality of the received signal is degraded. There is a problem that it cannot be determined from the state of the image of the receiver.
[0004]
In addition, in the same digital broadcasting, BS (Broadcasting Satellite) digital broadcasting is characterized by the absence of multipath, and the reception C / N (Carrier to noise ratio) is managed by managing the reception level. However, in digital terrestrial broadcasting, there are cases where an image cannot be restored even if the received electric field strength is high due to the occurrence of multipath, and the reception margin cannot be determined only by the received electric field strength.
[0005]
Therefore, in order to adjust the direction and height of the receiving antenna, it is necessary to measure the BER (Bit Error Rate) of the received digital broadcast signal and adjust the BER so that it is minimized. According to the method based on the Reed-Solomon correction flag after MPEG2 (Moving Picture Experts Group 2) decoding, which is known as a simple method, the displayable range is narrow and it is difficult to confirm a sufficient BER reception margin.
[0006]
[Problems to be solved by the invention]
As described above, in terrestrial digital broadcasting, in order to accurately monitor the reception quality, in addition to the received electric field strength, the frequency characteristics and C / N of the received spectrum are confirmed by the spectrum analyzer, and the multipath by the delay profile device is used. It is necessary to confirm the presence / absence and its D / U ratio, observe the constellation after digital demodulation, monitor the convergence of the phase stable point and the state of noise, and measure the BER.
[0007]
Therefore, these measurements require measurement devices such as field strength measurement devices and spectrum analyzers, and demodulation / decoder circuits that support digital terrestrial broadcasting. Is not suitable.
[0008]
An object of the present invention is a terrestrial digital broadcasting system, which is capable of monitoring reception quality of a digital broadcast wave in the same manner as monitoring reception quality in an analog broadcast when adjusting a receiving antenna. It is to provide a reception quality monitoring apparatus.
[0009]
[Means for Solving the Problems]
The first aspect of the present invention is a digital broadcast wave reception quality monitoring device for monitoring the quality of a digital broadcast signal received by a digital broadcast reception device, a signal extraction means for extracting a received signal of an arbitrary channel from the digital broadcast wave, Measurement means for measuring the characteristics of the received signal of an arbitrary channel extracted by the signal extraction means, and quality deterioration amount generation for generating a pseudo quality deterioration amount corresponding to the channel based on the measurement result of the measurement means And an adding means for adding the quality deterioration amount generated by the quality deterioration amount generating means to the received signal.
[0010]
In this invention, the measuring means measures the power value of the received signal of at least an arbitrary channel, and the quality degradation amount generating means generates a pseudo noise amount corresponding to the channel based on the measurement result of the measuring means. The adding means adds the noise amount generated by the quality deterioration amount generating means to the received signal.
[0011]
Therefore, according to the first invention, by adding artificially generated noise in an arbitrary channel, it is possible to eliminate the influence of signals of other channels and to add accurate noise. By monitoring the additional state of the receiver with a general household receiver and capturing the added amount of noise that makes it difficult to receive as a reception margin, the direction and height adjustment of the receiving antenna is the same as the direction and height adjustment procedure in analog broadcasting It can be done in a simple procedure.
[0012]
The second invention is a digital broadcast wave reception quality monitoring device for monitoring the quality of a digital broadcast signal received by a digital broadcast reception device, and is obtained by the reception means for receiving a digital broadcast wave and the reception means. A measuring means for measuring the characteristics of the received signal, a quality deterioration amount generating means for generating a pseudo quality deterioration amount based on a measurement result of the measuring means, and a quality deterioration generated by the quality deterioration amount generating means. Adding means for adding a quantity to the received signal.
[0013]
Therefore, according to the second aspect of the present invention, it is not necessary to perform frequency conversion by adding noise to all bands allocated to terrestrial digital broadcasting without depending on an arbitrary channel, which is compared with the first aspect of the present invention. Since the circuit configuration is simplified, the reception quality of the digital broadcast wave can be easily monitored because it is very rough.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 is a diagram for explaining a method of using a simple reception margin monitor as a digital broadcast wave quality monitoring apparatus according to the present invention.
[0016]
In order to view a television signal by terrestrial digital broadcasting in a general home, at least a receiving antenna 200 for terrestrial digital broadcasting and a receiver 300 for terrestrial digital broadcasting are required. Further, when the receiving antenna 200 is installed, it is necessary to adjust the direction and height of the receiving antenna 200. In this case, a simple reception margin monitor 100 is interposed between the receiving antenna 200 and the receiver 300. Like to do.
[0017]
Here, the following procedure is executed when the receiving antenna 200 is adjusted.
[0018]
(1) The image of the receiver 300 is monitored, and the limit point at which the image cannot be seen is used as a reference.
[0019]
(2) The position of the reception antenna 200 is set by adjusting the direction and height of the reception antenna 200, and the reception margin at that time is measured by the simple reception margin monitor 100.
[0020]
(3) The position of the reception antenna 200 is set so that the reception margin measured by the simple reception margin monitor 100 is maximized.
[0021]
(First embodiment)
FIG. 2 is a block diagram showing a first embodiment of the simplified reception margin monitor 100. As shown in FIG.
[0022]
The simple reception margin monitor 100 includes a reception unit 111, a frequency conversion unit 112, a power distribution unit 113, a local oscillation unit 114, a band filter 115, a power distribution unit 116, an in-channel power measurement unit 117, The variable attenuating unit 118, the in-channel noise generating unit 119, the power combining unit 120, the frequency converting unit 121, the band filter 122, and the output unit 123 are provided.
[0023]
The RF signal of the digital broadcast wave received by the reception unit 111 is supplied to the frequency conversion unit 112. The frequency converter 112 is supplied with a signal obtained by distributing a local oscillation signal corresponding to an arbitrary channel generated from the local oscillator 114 by the power distributor 113. Then, the frequency conversion unit 112 mixes the signal from the power distribution unit 113 with the input RF signal and converts it to an IF signal.
[0024]
The IF signal passes through the band filter 115 to extract a frequency spectrum having an arbitrary channel frequency as a center frequency, and is then distributed by the power distribution unit 116 and supplied to the power combining unit 120.
[0025]
On the other hand, the power value of the output of the power distribution unit 116 is measured by the in-channel power measurement unit 117. This measurement result is supplied to the variable attenuation unit 118. The variable attenuating unit 118 generates white noise corresponding to an arbitrary channel from the noise generated from the in-channel noise generating unit 119 based on the measured power value, and supplies the white noise to the power combining unit 120.
[0026]
The power combiner 120 combines the white noise provided by the variable attenuator 118 with the output of the power distributor 116. This combined output is converted into an RF signal by the local oscillation signal distributed by the power distribution unit 113 by the frequency conversion unit 121 and then output to the receiver 300 by the output unit 123 through the band filter 122.
[0027]
Next, the principle of the processing operation in the above configuration will be described.
[0028]
In the digital broadcasting system, all reception failure results appear in the BER, BER 2 * 10E-4 before Reed-Solomon error correction is the limit BER, and if the BER becomes larger than this, the video becomes invisible.
[0029]
On the other hand, on the receiver 300 side, it is necessary to grasp how much the reception margin is with respect to the limit at which the image cannot be seen. Therefore, in this embodiment, the receive margin, and to replace the white noise amount have a flat characteristic within the band.
[0030]
Then, in order to determine the amount of white noise added to the IF signal of an arbitrary channel, the power value is measured from the signal distributed by the power distribution unit 116 in the in-channel power measurement unit 117.
[0031]
In response to this measurement result, the variable attenuating unit 118 generates white noise in an amount that makes an image of an arbitrary channel invisible from the noise generated from the in-channel noise generating unit 119, and supplies the white noise to the power combining unit 120. Yes. As a result, white noise is added to the video signal of an arbitrary channel by the power combiner 120, and a reception margin is created equivalently.
[0032]
Therefore, the receiver 300 is defined by digital terrestrial broadcasting without measuring BER using a measuring device such as an electric field strength measuring device, a spectrum analyzer, and a demodulation / decoder circuit corresponding to digital terrestrial broadcasting. The reception margin can be evaluated by the difference from the predetermined C / N corresponding to the digital modulation method.
[0033]
As described above, according to the first embodiment, the noise generated from the in-channel noise generation unit 119 by the variable attenuation unit 118 based on the power value measured by the in-channel power measurement unit 117 in an arbitrary channel. By generating pseudo white noise corresponding to an arbitrary channel from this signal and synthesizing this white noise with an IF signal by the power combiner 120, it is possible to eliminate the influence of signals from other channels and to add accurate noise. It is possible to monitor the added state of the noise with a general household receiver 300, and to detect the added amount of noise that is difficult to receive as a reception margin, thereby adjusting the direction and height of the receiving antenna 200 in analog broadcasting. The same procedure as the direction and height adjustment procedure can be performed.
[0034]
(Second Embodiment)
FIG. 3 is a block diagram showing a second embodiment of the simple reception margin monitor 100. In FIG. 3, the same parts as those in FIG.
[0035]
The simple reception margin monitor 100 includes an RF in-band power measuring unit 124 instead of the in-channel power measuring unit 117, and an RF in-band noise generating unit 126 instead of the in-channel noise generating unit 119. I am doing so.
[0036]
In other words, the RF signal received by the receiving unit 111 and passed through the band filter 115 is supplied to the power distribution unit 116.
[0037]
As for the output of the power distribution unit 116, the power value in the RF band is measured by the RF band power measurement unit 124. The measurement result is supplied to the variable attenuation unit 125.
[0038]
The variable attenuator 125 generates white noise from the noise generated from the RF in-band noise generator 126 based on the measured power value, and supplies the white noise to the power combiner 120.
[0039]
The power combiner 120 combines the white noise provided by the variable attenuator 118 with the output of the power distributor 116. This combined output is output to the receiver 300 by the output unit 123.
[0040]
In such a second embodiment, it is not necessary to perform frequency conversion by adding noise to all the bands allocated to terrestrial digital broadcasting without depending on an arbitrary channel, thereby the frequency conversion unit. 112, the power distributing unit 113, the local oscillating unit 114, the frequency converting unit 121, and the band filter 122 are unnecessary, and the circuit configuration is simpler than that of the first embodiment. Wave reception quality can be monitored.
[0041]
(Other embodiments)
The present invention is not limited to the above embodiments. For example, in addition to white noise, a quality degradation amount such as multipath may be artificially generated and added to the received signal. In addition to the power value, received signal characteristics such as frequency components may be measured.
[0042]
In addition, the configuration of the simple reception margin monitor can be implemented with various modifications without departing from the gist of the present invention.
[0043]
【The invention's effect】
As described above in detail, according to the present invention, in the terrestrial digital broadcasting system, when the reception antenna is adjusted, the reception quality of the digital broadcast wave is monitored in the same manner as the reception quality monitoring in the analog broadcasting. Therefore, it is possible to provide a digital broadcast wave reception quality monitoring device capable of performing
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an application example of a simple reception margin monitor as a digital broadcast wave quality monitoring apparatus of the present invention.
2 is a block diagram showing a first embodiment of a simple reception margin monitor shown in FIG. 1; FIG.
FIG. 3 is a block diagram showing a second embodiment of the simple reception margin monitor shown in FIG. 1;
[Explanation of symbols]
100: Simple reception margin monitor,
111 ... receiving part,
112, 121 ... frequency converter,
113, 116 ... power distribution unit,
114: Local oscillator,
115, 122 ... band filter,
117: In-channel power measurement unit,
118, 125 ... variable attenuation section,
119 ... In-channel noise generator,
120, 127 ... power combiner,
123 ... output unit,
124 ... RF in-band power measurement unit,
126: RF in-band noise generator.

Claims (6)

In a digital broadcast wave reception quality monitoring device that monitors the quality of a digital broadcast signal received by a digital broadcast reception device,
Signal extraction means for extracting a received signal of an arbitrary channel from the digital broadcast signal ;
Measuring means for measuring the characteristics of the received signal of an arbitrary channel extracted by the signal extracting means;
Based on the measurement result of the measuring means, and the quality deterioration amount generating means for generating a quality deterioration amount corresponding to the channel in a pseudo manner,
An apparatus for monitoring the reception quality of a digital broadcast wave, comprising: addition means for adding the quality deterioration amount generated by the quality deterioration amount generation means to the received signal.   2. The digital broadcast wave reception quality monitoring apparatus according to claim 1, wherein the measurement unit measures a power value of a reception signal of at least an arbitrary channel. Said quality deterioration amount generating means, based on the measurement result of the measuring means, to generate a miscellaneous volume corresponding to the channel in a pseudo manner,
2. The digital broadcast wave quality monitoring apparatus according to claim 1, wherein the adding unit adds the amount of noise generated by the quality deterioration amount generating unit to the received signal. In a digital broadcast wave reception quality monitoring device that monitors the quality of a digital broadcast signal received by a digital broadcast reception device,
Receiving means for receiving the digital broadcast signal ;
Measuring means for measuring the characteristics of the received signal obtained by the receiving means;
Based on the measurement result of this measuring means, quality deterioration amount generating means for generating a quality deterioration amount in a pseudo manner ,
An apparatus for monitoring the reception quality of a digital broadcast wave, comprising: addition means for adding the quality deterioration amount generated by the quality deterioration amount generation means to the received signal.   5. The digital broadcast wave reception quality monitoring apparatus according to claim 4, wherein the measurement means measures at least the power value of the reception signal. The quality degradation amount generation means generates a noise amount in a pseudo manner based on the measurement result of the measurement means,
5. The digital broadcast wave reception quality monitoring apparatus according to claim 4, wherein the adding means adds the amount of noise generated by the quality degradation amount generating means to the received signal.

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