JP2010041522A - Apparatus, method and program for terrestrial digital broadcast line quality evaluation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To calculate a much more accurate C/N ratio in consideration of the influences of digital interference wave, analog interference wave and apparatus deterioration when evaluating the quality of a terrestrial digital broadcast line on the basis of the C/N ratio of a terrestrial digital broadcast signal. <P>SOLUTION: Each of D/U ratio adding sections 16-2 to 16-N of arithmetic units 10-2 to 10-N adds D/U ratios of analog interference waves at relay stations from the stage of the adding section's own to the pre-stage, and each of equivalent C/N ratio calculating section 12-2 to 12-N calculates an analog interference wave equivalent C/N ratio corresponding to the added D/U ratio of the analog interference waves. Each of the arithmetic units 10-2 to 10-N handles the calculated analog interference equivalent C/N ratio as an analog interference wave equivalent C/N ratio at the relay station of a calculation target. Each of equivalent C/N ratio adding sections 15-2 to 15-N adds a digital interference wave equivalent C/N ratio, apparatus deterioration equivalent C/N ratio, the analog interference wave equivalent C/N ratio and the like and outputs an output signal C/N ratio. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a digital terrestrial broadcast channel quality evaluation apparatus, evaluation method, and evaluation program, and more particularly to a technique for calculating an accurate CN ratio when evaluating the quality of a terrestrial digital broadcast channel using the CN ratio of a terrestrial digital broadcast signal. .

  Conventionally, the influence of digital interference waves, analog interference waves, and device degradation on terrestrial digital broadcast signals has been evaluated by calculating the equivalent CN ratio. This equivalent CN ratio is an equivalent representation of the effects of digital interference waves, analog interference waves, and device deterioration using the CN ratio for Gaussian noise that has the same effect.

  FIG. 7 is a block diagram showing the configuration of a conventional terrestrial digital broadcast channel quality evaluation apparatus. This terrestrial digital broadcast channel quality evaluation apparatus 100 uniformly adds an equivalent CN ratio indicating the influence of a digital interference wave, an equivalent CN ratio indicating an influence of an analog interference wave, and an equivalent CN ratio indicating the influence of apparatus degradation, The quality of the digital terrestrial broadcasting line is evaluated based on the equivalent CN ratio of the addition result.

  The terrestrial digital broadcast channel quality evaluation apparatus 100 includes a plurality of stages of arithmetic units 110-1 to 110-N. Arithmetic units 110-1 to 110-N are processing units corresponding to the respective relay stations, and input a CN ratio (input signal CN ratio) using a terrestrial digital broadcast wave from the transmission station as an input signal, and disturbing stations. The respective equivalent CN ratios indicating the influence of the digital interference wave, the influence of the analog interference wave, and the influence of the apparatus deterioration of the relay station itself are added, and the arithmetic units 110-1 to 110-N corresponding to the respective relay stations are added. An output signal CN ratio is output as an output signal.

  The first stage computing unit 110-1 corresponds to a relay station that retransmits the terrestrial digital broadcast wave transmitted from the transmitting station, and is transmitted from the terrestrial digital broadcast wave input signal CN ratio and the first digital interfering station. The DU ratio of the first digital interference wave, the DU ratio of the first analog interference wave transmitted from the first analog interfering station, and the relay station corresponding to the first stage arithmetic unit 110-1. The first device deterioration amount of the transmitter itself is input. Then, an output signal CN ratio is calculated based on these CN ratio, DU ratio, and deterioration amount, and is output to the second stage arithmetic unit 110-2 (not shown).

  Specifically, the equivalent CN ratio calculation unit 111-1 of the calculation unit 110-1 receives the DU ratio of the first digital interference wave and inputs the first digital interference wave from the DU ratio of the first digital interference wave. The equivalent CN ratio is calculated and output to the equivalent CN ratio adder 114-1. Further, the equivalent CN ratio calculation unit 112-1 receives the DU ratio of the first analog interference wave, calculates the first analog interference wave equivalent CN ratio from the DU ratio of the first analog interference wave, and calculates the equivalent CN It outputs to the ratio addition part 114-1. In addition, the equivalent CN ratio calculation unit 113-1 receives the first device deterioration amount, calculates the first device deterioration equivalent CN ratio from the first device deterioration amount, and supplies the equivalent CN ratio addition unit 114-1 to the equivalent CN ratio addition unit 114-1. Output.

  The equivalent CN ratio addition unit 114-1 includes the input signal CN ratio, the first digital interference wave equivalent CN ratio from the equivalent CN ratio calculation unit 111-1, and the first analog interference from the equivalent CN ratio calculation unit 112-1. The wave equivalent CN ratio and the first device deterioration equivalent CN ratio from the equivalent CN ratio calculation unit 113-1 are input, these equivalent CN ratios are added, and the addition result is output as the output signal CN ratio.

  The second-stage arithmetic unit 110-2 (not shown) corresponds to a relay station that retransmits the terrestrial digital broadcast wave received from the relay station corresponding to the first-stage arithmetic unit 110-1, and the arithmetic unit 110 Output signal CN ratio from -1, the DU ratio of the second digital interference wave transmitted from the second digital jamming station, the DU ratio of the second analog interference wave transmitted from the second analog jamming station, and The second device deterioration amount of the transmitter itself installed in the relay station corresponding to the second stage arithmetic unit 110-2 is input, and the output signal CN ratio is based on these CN ratio, DU ratio, and deterioration amount. Is calculated and output to the third stage computing unit 110-3 (not shown). By repeating such calculation, the output signal CN ratio calculated by the (N-1) -th stage calculation unit 110- (N-1) (not shown) becomes the N-th stage calculation unit 110-N. Is output.

  The Nth stage computing unit 110-N relays the terrestrial digital broadcast wave received from the relay station corresponding to the (N-1) th stage computing unit 110- (N-1) (not shown). The output signal CN ratio from the arithmetic unit 110- (N-1), the DU ratio of the Nth digital interference wave transmitted from the Nth digital jamming station, and the Nth analog jamming station. DU ratio of the Nth analog interference wave and the Nth device deterioration amount of the transmitter itself installed in the relay station corresponding to the Nth stage arithmetic unit 110-N, and the CN ratio, Based on the DU ratio and the deterioration amount, the output signal CN ratio is calculated and output. The configurations of the calculation units 110-2 to 110-N are the same as the configuration of the calculation unit 110-1.

  FIG. 8 is a diagram for explaining the outline of processing by the conventional terrestrial digital broadcast channel quality evaluation apparatus 100 shown in FIG. FIG. 8A is a diagram illustrating an OFDM signal (analog interference signal) affected by an analog interference wave, and FIG. 8B is a diagram illustrating an equivalent CN ratio of the analog interference signal. FIG. 8C is a diagram illustrating an addition process of an equivalent CN ratio. As shown in FIG. 8A, when an OFDM signal, which is a terrestrial digital broadcast wave, is interfered by an analog interference wave, it becomes an analog interference signal.

  FIG. 8B shows that when the analog interference signal is converted into an equivalent CN ratio, the analog interference signal becomes a signal having equivalent Gaussian noise. The equivalent CN ratio of the analog interference signal is equivalently expressed as the CN ratio with respect to Gaussian noise that causes the same deterioration as the analog interference wave. This shows a process in which the equivalent CN ratio calculation units 112-1 to 112-N of the calculation units 110-1 to 110-N shown in FIG. 7 calculate the analog interference wave equivalent CN ratio from the DU ratio of the analog interference wave. ing.

  FIG. 8C shows that the addition result of the equivalent CN ratio is obtained from the CN ratio of a signal obtained by adding power to equivalent noise. That is, the addition result of the equivalent CN ratio is the same as the equivalent CN ratio in the signal after adding the equivalent noise to the power. This shows a process in which the equivalent CN ratio addition units 114-1 to 114-N of the calculation units 110-1 to 110-N shown in FIG. 7 add the equivalent CN ratios.

  Note that the terrestrial digital broadcast signal transmission method shown in FIGS. 7 and 8 is described in Non-Patent Document 1, for example. In addition, techniques for evaluating digital terrestrial broadcast signals using CN ratio and the like are described in, for example, Patent Documents 1 to 3.

Digital terrestrial television broadcasting transmission system, standard ARIB STD-B31, the radio industry JP 2006-246083 A JP 2006-246082 A JP 2006-157333 A

  By the way, even if the subcarrier of the OFDM signal is affected by the digital interference wave and the apparatus deterioration, the difference in the influence between the subcarriers is small, so the influence of the digital interference wave and the apparatus deterioration is approximately equivalent to Gaussian noise. Can be expressed in That is, as shown in FIG. 8C, the addition result of the digital interference wave equivalent CN ratio and the device degradation equivalent CN ratio is the same as the equivalent CN ratio of the actual signal.

  However, when the analog interference wave equivalent CN ratios are added, the addition result is not the same as the equivalent CN ratio of the actual signal. This is because the analog interference wave greatly affects the video signal carrier and the OFDM signal subcarrier around the audio carrier wave of the analog interference wave, and thus differs from the Gaussian noise in terms of frequency characteristics. That is, the analog interference wave has a characteristic different from that of Gaussian noise. Therefore, when an equivalent CN ratio expressed equivalently to Gaussian noise is added, the equivalent CN ratio of the actual signal is not obtained. This is because an accurate result cannot be obtained.

  In the terrestrial digital broadcast channel quality evaluation apparatus 100 shown in FIG. 7, the output signal CN ratio output from the first stage calculation unit 110-1 is calculated by the equivalent CN ratio addition unit 114-1 between the analog interference wave equivalent CN ratios. Is not added, so that the equivalent CN ratio of the actual signal is the same. On the other hand, the arithmetic units 110-2 to 110-N from the second stage to the N-th stage output the analog interference wave equivalent CN ratio output by the previous arithmetic units 110-1 to 110- (N-1). The output signal CN ratio including the analog interference wave equivalent CN ratio output by the equivalent CN ratio calculation units 112-2 to 112-N is added. For this reason, the output signal CN ratio output by the arithmetic units 110-2 to 110-N is different from the equivalent CN ratio of the actual signal.

  That is, in the conventional digital terrestrial broadcasting channel quality evaluation apparatus 100, when adding the equivalent CN ratio, it is necessary to be able to equivalently express the influence of digital interference waves, analog interference waves, and device degradation with Gaussian noise. When the analog interference wave equivalent CN ratios are added, there is a problem that an accurate output signal CN ratio cannot be calculated because the analog interference wave is different from Gaussian noise in terms of frequency characteristics.

  Therefore, in order to solve the above problems, the object of the present invention is to consider the influence of digital interference waves, analog interference waves, and device degradation when evaluating the quality of digital terrestrial broadcasting channels with the CN ratio of terrestrial digital broadcasting signals. Thus, an object of the present invention is to provide a digital terrestrial broadcast channel quality evaluation apparatus, an evaluation method, and an evaluation program that can calculate a more accurate CN ratio.

  In order to solve the above-mentioned problems, the invention of claim 1 is directed to a digital terrestrial broadcast channel quality evaluation apparatus that evaluates the quality of a digital terrestrial broadcast channel by each output signal CN ratio output by a plurality of stages of arithmetic units. A first stage calculation unit that receives a DU ratio of the first digital interference wave transmitted from the first digital jamming station and calculates an equivalent CN ratio; A first device deterioration equivalent CN ratio calculation unit that inputs a first device deterioration amount in a transmitter installed in a relay station corresponding to the first stage arithmetic unit and calculates an equivalent CN ratio, and a transmission from the transmission station An input signal CN ratio using the digital terrestrial broadcast wave as an input signal, an equivalent CN ratio calculated by the first digital interference wave equivalent CN ratio calculation unit, and a first device deterioration equivalent CN ratio calculation unit Calculated equivalence A first equivalent CN ratio adding unit that adds the N ratio and a DU ratio of the first analog interference wave transmitted from the first analog interfering station are input, and a first analog interference that calculates an equivalent CN ratio is input. The addition result of the equivalent CN ratio added by the wave equivalent CN ratio calculation unit, the first equivalent CN ratio addition unit, and the equivalent CN ratio calculated by the first analog interference wave equivalent CN ratio calculation unit A first total equivalent CN ratio adding unit that adds and outputs a first output signal CN ratio, wherein N is an integer equal to or greater than 2, and the Nth stage arithmetic unit is connected to the Nth digital jamming station. Installed in the relay station corresponding to the Nth digital interference wave equivalent CN ratio calculation unit that inputs the DU ratio of the transmitted Nth digital interference wave and calculates the equivalent CN ratio, and the Nth stage arithmetic unit The Nth device deterioration amount in the transmitter is input and the equivalent CN ratio is calculated. N device degradation equivalent CN ratio calculation unit, addition result of equivalent CN ratio added by the equivalent CN ratio addition unit of the previous stage, and equivalent CN ratio calculated by the Nth digital interference wave equivalent CN ratio calculation unit , An Nth equivalent CN ratio adding unit for adding the equivalent CN ratio calculated by the Nth device deterioration equivalent CN ratio calculating unit, and an Nth analog interference wave transmitted from the Nth analog interfering station When the DU ratio is input and the first stage is the first stage, the DU ratio of the first analog interference wave input to the first analog interference wave equivalent CN ratio calculation unit, or the first stage is the second stage or later Inputs the DU ratio addition result of the analog interference wave up to the previous stage, adds the DU ratio of the Nth analog interference wave and the DU ratio or the DU ratio addition result of the first analog interference wave, The Nth analog output that outputs the ratio addition result An interference wave DU ratio addition unit; an Nth analog interference wave equivalent CN ratio calculation unit that inputs an addition result of the DU ratios output from the Nth analog interference wave DU ratio addition unit and calculates an equivalent CN ratio; The addition result of the equivalent CN ratio added by the Nth equivalent CN ratio addition unit and the equivalent CN ratio calculated by the Nth analog interference wave equivalent CN ratio calculation unit are added, and the Nth output And an N-th total equivalent CN ratio adding unit that outputs a signal CN ratio.

The invention according to claim 2 is the digital terrestrial broadcast channel quality evaluation apparatus according to claim 1, wherein the N-th stage arithmetic unit is configured to transmit the N-th digital interference wave transmitted from the N-th digital jamming station. An Nth device degradation amount in a transmitter installed in a relay station corresponding to the Nth digital interference wave equivalent CN ratio calculation unit that inputs the DU ratio and calculates the equivalent CN ratio, and the Nth stage calculation unit And the Nth device deterioration equivalent CN ratio calculation unit for calculating the equivalent CN ratio, and the DU ratio of the Nth analog interference wave transmitted from the Nth analog interference station, and the equivalent CN ratio is calculated. The N-th analog interference wave equivalent CN ratio calculation unit, the addition result of the equivalent CN ratio added by the preceding equivalent CN ratio addition unit, and the equivalent calculated by the N-th digital interference wave equivalent CN ratio calculation unit CN ratio and the Nth device degradation equivalent CN The Nth equivalent CN ratio addition unit for adding the equivalent CN ratio calculated by the calculation unit and the equivalent CN ratio calculated by the Nth analog interference wave equivalent CN ratio calculation unit are input, and the preceding stage is 1 In the case of the stage, the equivalent CN ratio calculated by the first analog interference wave equivalent CN ratio calculation unit, or in the case where the preceding stage is the second stage or later, the smallest of the equivalent CN ratios of the analog interference wave up to the preceding stage. An N-th analog interference wave equivalent CN ratio comparing unit that inputs an equivalent CN ratio, compares the two input equivalent CN ratios, and outputs the smaller equivalent CN ratio;
The addition result of the equivalent CN ratio added by the Nth equivalent CN ratio addition unit and the equivalent CN ratio output by the Nth analog interference wave equivalent CN ratio comparison unit are added to obtain an Nth output signal. And an N-th total equivalent CN ratio addition unit that outputs a CN ratio.

  Further, the invention of claim 3 is the digital terrestrial broadcasting channel quality evaluation apparatus according to claim 2, wherein the N-th stage or the preceding stage arithmetic unit is installed in a relay station corresponding to the N-th stage arithmetic unit. At least one of the transmitters installed in the relay station corresponding to the transmitter or the arithmetic unit in the preceding stage has a symbol determination function for performing threshold determination on the received signal And

  According to a fourth aspect of the present invention, there is provided a digital terrestrial broadcast line quality evaluation apparatus that evaluates the quality of a digital terrestrial broadcast line by each output signal CN ratio output by a plurality of stages of calculation units. Receives the DU ratio of the first digital interference wave transmitted from the first digital jamming station, calculates the equivalent CN ratio, the first digital interference wave equivalent CN ratio calculation unit, and the first stage calculation A first device deterioration equivalent CN ratio calculation unit that inputs a first device deterioration amount in a transmitter installed in a relay station corresponding to the unit and calculates an equivalent CN ratio, and a terrestrial digital broadcast transmitted from the transmission station An input signal CN ratio using a wave as an input signal, an equivalent CN ratio calculated by the first digital interference wave equivalent CN ratio calculation unit, and an equivalent CN calculated by the first device deterioration equivalent CN ratio calculation unit Add the ratio 1 equivalent CN ratio addition unit, a first analog interference wave equivalent CN ratio calculation unit that receives the DU ratio of the first analog interference wave transmitted from the first analog jamming station and calculates the equivalent CN ratio; The addition result of the equivalent CN ratio added by the first equivalent CN ratio addition unit and the equivalent CN ratio calculated by the first analog interference wave equivalent CN ratio calculation unit are added, and the first output A first full equivalent CN ratio adding unit that outputs a signal CN ratio, wherein M is an integer of 3 or more, and the second to M-th arithmetic units are connected to the N-th stage according to claim 1. An arithmetic unit and an Nth stage arithmetic unit according to claim 2 or 3 are included.

According to a fifth aspect of the present invention, an input signal CN ratio using a terrestrial digital broadcast wave transmitted from a transmission station as an input signal and a digital interfering station by a digital terrestrial broadcast line quality evaluation apparatus having a plurality of stages of arithmetic units. The DU ratio of the digital interference wave transmitted from the analog interference wave, the DU ratio of the analog interference wave transmitted from the analog interfering station, and the device deterioration amount in the transmitter installed in the relay station corresponding to the arithmetic unit, In the method of calculating the output signal CN ratio and evaluating the quality of the terrestrial digital broadcasting line based on the output signal CN ratio, the first digital interference wave is calculated from the DU ratio of the first digital interference wave by the first stage calculation unit. A wave equivalent CN ratio is calculated, a first device deterioration equivalent CN ratio is calculated from the first device deterioration amount, the input signal CN ratio, the first digital interference wave equivalent CN ratio, and the first A first step of adding the device deterioration equivalent CN ratio and outputting an addition result of the equivalent CN ratio; a first step of calculating an equivalent CN ratio from the DU ratio of the first analog interference wave; The addition result of the equivalent CN ratio output in the 1-1 step and the equivalent CN ratio calculated in the 1-2 step are added to output a first output signal CN ratio. The Nth digital interference wave equivalent CN ratio is calculated from the DU ratio of the Nth digital interference wave by the Nth stage arithmetic unit, where N is an integer equal to or greater than 2, and Nth step. The N-th device deterioration equivalent CN ratio is calculated from the device deterioration amount of the above, and the addition result of the equivalent CN ratio output in the previous step, the N-th digital interference wave equivalent CN ratio, and the N-th device deterioration equivalent Add CN ratio and output equivalent CN ratio addition result And the N-1 step that,
The DU ratio of the Nth analog interference wave and the DU ratio of the first analog interference wave in the step 1-2 when the previous stage is the first stage, or up to the previous stage when the previous stage is the second stage or later. The N-2th step of adding the DU ratio addition result of the analog interference wave and outputting the DU ratio addition result, and the equivalent CN ratio from the DU ratio addition result output in the N-2th step The N-3th step of calculating the NCN, the addition result of the equivalent CN ratio output in the N-1th step, and the equivalent CN ratio output in the N-3th step are added, and the Nth And (N-4) th step of outputting an output signal CN ratio.

  The invention according to claim 6 is the digital terrestrial broadcast channel quality evaluation method according to claim 5, wherein the N-th operation unit calculates the N-th digital interference wave equivalent from the DU ratio of the N-th digital interference wave. The CN ratio is calculated, the N-th apparatus deterioration equivalent CN ratio is calculated from the N-th apparatus deterioration amount, the addition result of the equivalent CN ratio output in the previous step, the N-th digital interference wave equivalent CN ratio, , Nth step of adding the Nth device degradation equivalent CN ratio and outputting the addition result of the equivalent CN ratio, and an Nth step of calculating the equivalent CN ratio from the DU ratio of the Nth analog interference wave -2 step and the equivalent CN ratio calculated by the (N-2) th step. If the previous stage is the first stage, the equivalent CN ratio calculated by the (1-2) step, or the previous stage is the second stage. In the following cases, analog interference waves up to the previous stage The N-3th step of comparing the smallest equivalent CN ratio among the equivalent CN ratios and outputting the smaller equivalent CN ratio; and the addition result of the equivalent CN ratio output by the N-1 step; And an N-4th step of adding the equivalent CN ratio output in the N-3th step and outputting an Nth output signal CN ratio.

  The invention of claim 7 is characterized in that, by a plurality of stages of arithmetic units, an input signal CN ratio using a terrestrial digital broadcast wave transmitted from a transmitting station as an input signal and a DU ratio of a digital interference wave transmitted from a digital interfering station. And the DU ratio of the analog interference wave transmitted from the analog interfering station and the device deterioration amount in the transmitter installed in the relay station corresponding to the arithmetic unit, respectively, the output signal CN ratio is calculated, A program for evaluating the quality of a digital terrestrial broadcasting line based on an output signal CN ratio, wherein a first digital interference wave equivalent CN ratio is calculated from a DU ratio of a first digital interference wave in a computer by a first stage calculation unit. A first device deterioration equivalent CN ratio is calculated from the first device deterioration amount, and the input signal CN ratio, the first digital interference wave equivalent CN ratio, and the first device deterioration equivalent CN are calculated. And a first step of outputting an equivalent CN ratio addition result, a first step of calculating an equivalent CN ratio from the DU ratio of the first analog interference wave, A 1-3 step of adding a result of adding the equivalent CN ratio output in step 1 and an equivalent CN ratio calculated in step 1-2 and outputting a first output signal CN ratio; And N is an integer equal to or greater than 2, and the N-th arithmetic unit calculates the N-th digital interference wave equivalent CN ratio from the DU ratio of the N-th digital interference wave. The Nth device deterioration equivalent CN ratio is calculated, and the addition result of the equivalent CN ratio output in the previous step, the Nth digital interference wave equivalent CN ratio, and the Nth device deterioration equivalent CN ratio are added. And outputs the addition result of the equivalent CN ratio. Step, the DU ratio of the Nth analog interference wave, and if the previous stage is the first stage, the DU ratio of the first analog interference wave in the step 1-2, or if the previous stage is the second stage or later Is obtained by adding the DU ratio addition result of the analog interference wave up to the previous stage and outputting the DU ratio addition result and the DU ratio addition result output by the N-2 step. Adding the N-3th step of calculating the equivalent CN ratio, the addition result of the equivalent CN ratio output by the N-1 step, and the equivalent CN ratio output by the N-3 step; And an N-4th step of outputting an Nth output signal CN ratio.

  Further, the invention of claim 8 is the terrestrial digital broadcast channel quality evaluation program according to claim 7, wherein the N-th operation unit causes the computer to calculate the Nth digital interference wave from the DU ratio of the Nth digital interference wave. The digital interference wave equivalent CN ratio is calculated, the Nth device deterioration equivalent CN ratio is calculated from the Nth device deterioration amount, the addition result of the equivalent CN ratio output in the previous step, and the Nth digital interference wave The equivalent CN ratio is added to the Nth device degradation equivalent CN ratio, and the equivalent CN ratio is calculated from the (N-1) th step of outputting the addition result of the equivalent CN ratio and the DU ratio of the Nth analog interference wave. The N-2th step to be calculated, the equivalent CN ratio calculated in the N-2th step, and the equivalent CN ratio calculated in the 1-2th step when the previous stage is the first stage, or the previous stage If is after the second stage The smallest equivalent CN ratio among the equivalent CN ratios of the analog interference wave up to the previous stage is compared, and the N-3th step for outputting the smaller equivalent CN ratio and the equivalent output outputted by the N-1th step. The addition result of the CN ratio and the equivalent CN ratio output in the N-3th step are added, and the N-4th step of outputting the Nth output signal CN ratio is executed. To do.

  As described above, according to the present invention, the equivalent CN ratio of the analog interference wave is not obtained by adding the analog interference wave equivalent CN ratios, but is obtained from the addition result of the DU ratios of the analog interference waves, or The analog interference wave equivalent CN ratios are compared and the smaller one is selected. As a result, due to the fact that analog interference waves have characteristics different from Gaussian noise in terms of frequency characteristics, an accurate output signal CN ratio cannot be calculated by adding analog interference wave equivalent CN ratios. Can be solved. Therefore, when evaluating the quality of digital terrestrial broadcasting channels using the CN ratio of terrestrial digital broadcasting signals, it is possible to calculate a more accurate CN ratio in consideration of the effects of digital interference waves, analog interference waves, and device deterioration. It becomes.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings. The first (Example 1) terrestrial digital broadcast channel quality evaluation apparatus according to the embodiment of the present invention provides a DU ratio of analog interference waves in a relay station to be calculated and a DU of analog interference waves up to the previous relay station. The DU ratio of the addition result is handled as the DU ratio of the analog interference wave in the relay station to be calculated. In this case, when an analog wave interferes with an analog interfered wave, it is assumed that two analog waves interfere with a signal that has not been subjected to the original analog interference. At this time, energy is added to the two analog waves (D / U is used as power). This is because it is considered as one analog interference wave and this procedure can be confirmed as a reasonable process from various measurement results. Then, an equivalent CN ratio corresponding to this DU ratio is obtained and treated as the equivalent CN ratio of the analog interference wave in the relay station to be calculated. The first embodiment is used when synthesizing analog interference waves. That is, it is used when an analog interference wave exists in the relay station to be calculated and an analog interference wave also exists in the preceding relay station.

  Also, the second (Example 2) terrestrial digital broadcast channel quality evaluation apparatus according to the embodiment of the present invention provides an equivalent CN ratio of an analog interference wave at a calculation target relay station and an analog interference wave at a previous relay station. And the smaller equivalent CN ratio is treated as the equivalent CN ratio of the analog interference wave in the relay station to be calculated. In the second embodiment, when a transmitter performs symbol determination processing, that is, when a transmitter installed in a calculation target relay station performs symbol determination processing, a transmitter installed in a preceding relay station performs symbol determination. This is used when the symbol determination is performed by the transmitter installed in the relay station to be calculated and the transmitter installed in the preceding relay station. Details will be described later.

  The third (Example 3) terrestrial digital broadcast line quality evaluation apparatus according to the embodiment of the present invention includes the terrestrial digital broadcast line quality evaluation apparatus of Example 1 and the terrestrial digital broadcast line quality evaluation apparatus of Example 2. In combination, the equivalent CN ratio of the analog interference wave is obtained. Hereinafter, Examples 1, 2, and 3 will be described in detail.

[Example 1]
First, Example 1 will be described in detail. In the first embodiment, as described above, the DU ratio of the analog interference wave is added, the result is treated as the DU ratio of the analog interference wave in the relay station to be calculated, and the equivalent CN ratio corresponding to the DU ratio is obtained. Is.

  FIG. 1 is a block diagram showing a configuration of a first (Example 1) terrestrial digital broadcast channel quality evaluation apparatus according to an embodiment of the present invention. This terrestrial digital broadcast channel quality evaluation apparatus 1 includes a plurality of stages of arithmetic units 10-1 to 10-N.

  The first-stage arithmetic unit 10-1 corresponds to a relay station that retransmits the terrestrial digital broadcast wave transmitted from the transmission station, and is transmitted from the input signal CN ratio of the terrestrial digital broadcast wave and the first digital interfering station. The DU ratio of the first digital interference wave, the DU ratio of the first analog interference wave transmitted from the first analog interfering station, and the relay station corresponding to the first stage arithmetic unit 10-1. The first device deterioration amount of the transmitter itself is input, and the output signal CN ratio is calculated based on the CN ratio, DU ratio, and deterioration amount. In addition, a result of adding the first digital interference wave equivalent CN ratio and the first device deterioration equivalent CN ratio is output to the second-stage arithmetic unit 10-2.

  Specifically, the equivalent CN ratio calculation unit 11-1 of the arithmetic unit 10-1 receives the DU ratio of the first digital interference wave and inputs the first digital interference wave from the DU ratio of the first digital interference wave. The equivalent CN ratio is calculated and output to the equivalent CN ratio addition unit 14-1. In addition, the equivalent CN ratio calculation unit 13-1 receives the first device deterioration amount, calculates the first device deterioration equivalent CN ratio from the first device deterioration amount, and sends it to the equivalent CN ratio addition unit 14-1. Output.

ここで、第１の等価ＣＮ比をＣ／Ｎ_１、第２の等価ＣＮ比をＣ／Ｎ_２、第１の等価ＣＮ比と第２の等価ＣＮ比の加算結果をＣ／Ｎ_ａｄｄとする。 The equivalent CN ratio addition unit 14-1 inputs the first digital interference equivalent CN ratio from the equivalent CN ratio calculation unit 11-1 and the first device deterioration equivalent CN ratio from the equivalent CN ratio calculation unit 13-1. Then, these equivalent CN ratios are added, and the addition result is output to the equivalent CN ratio addition unit 15-1 and the second stage calculation unit 10-2. The addition formula of equivalent CN ratio is shown below.

Here, the first equivalent CN ratio is C / N ₁ , the second equivalent CN ratio is C / N ₂ , and the addition result of the first equivalent CN ratio and the second equivalent CN ratio is C / N _add . .

  The equivalent CN ratio calculation unit 12-1 inputs the DU ratio of the first analog interference wave, calculates the first analog interference wave equivalent CN ratio from the DU ratio of the first analog interference wave, and adds the equivalent CN ratio To the unit 15-1. The equivalent CN ratio addition unit 15-1 inputs the equivalent CN ratio that is the addition result from the equivalent CN ratio addition unit 14-1, and the first analog interference wave equivalent CN ratio from the equivalent CN ratio calculation unit 12-1. Then, these equivalent CN ratios are added, and the addition result is output as the first output signal CN ratio.

  The second-stage arithmetic unit 10-2 corresponds to a relay station that retransmits the terrestrial digital broadcast wave received from the relay station corresponding to the first-stage arithmetic unit 10-1, and is equivalent to the arithmetic unit 10-1. CN ratio (addition result of first digital interference wave equivalent CN ratio and first device deterioration equivalent CN ratio), DU ratio of first analog interference wave transmitted from first analog jamming station, second Corresponds to DU ratio of second digital interference wave transmitted from digital jamming station, DU ratio of second analog interference wave transmitted from second analog jamming station, and second stage arithmetic unit 10-2 The second apparatus deterioration amount of the relay station itself to be input is input, and the second output signal CN ratio is calculated based on these CN ratio, DU ratio, and deterioration amount. Further, the result of adding the equivalent CN ratio from the calculation unit 10-1, the second digital interference wave equivalent CN ratio, and the second device degradation equivalent CN ratio is calculated as a third-stage calculation unit 10-3 ( (Not shown).

  Specifically, the equivalent CN ratio calculation unit 11-2 of the calculation unit 10-2 receives the DU ratio of the second digital interference wave and inputs the second digital interference wave from the DU ratio of the second digital interference wave. The equivalent CN ratio is calculated and output to the equivalent CN ratio addition unit 14-2. In addition, the equivalent CN ratio calculation unit 13-2 receives the second device deterioration amount, calculates a second device deterioration equivalent CN ratio from the second device deterioration amount, and sends it to the equivalent CN ratio addition unit 14-2. Output.

  The equivalent CN ratio addition unit 14-2 is an equivalent CN ratio that is an addition result from the equivalent CN ratio addition unit 14-1 of the calculation unit 10-1, and a second digital interference wave from the equivalent CN ratio calculation unit 11-2. The equivalent CN ratio and the second device deterioration equivalent CN ratio from the equivalent CN ratio calculation unit 13-2 are input, these equivalent CN ratios are added, and the addition result is added to the equivalent CN ratio addition unit 15-2 and the third stage. To the computing unit 10-3 (not shown).

ここで、第１のＤＵ比をＤ／Ｕ_１、第２のＤＵ比をＤ／Ｕ_２、第１のＤＵ比と第２のＤＵ比の加算結果をＤ／Ｕ_ａｄｄとする。 The DU ratio adding unit 16-2 inputs the DU ratio of the second analog interference wave from the second analog jamming station and the DU ratio of the first analog interference wave from the first analog jamming station, and these The DU ratio of the analog interference wave is added, and the addition result is output to the equivalent CN ratio calculation 12-2 and the calculation unit 10-3 (not shown). That is, the normalized analog interference wave power is obtained from the DU ratio of the analog interference wave, and the DU ratio of the analog interference wave is added by adding the obtained power. The formula for adding the DU ratio is shown below.

Here, the first DU ratio is D / U ₁ , the second DU ratio is D / U ₂ , and the addition result of the first DU ratio and the second DU ratio is D / U _add .

  The equivalent CN ratio calculation unit 12-2 receives the DU ratio of the analog interference wave as the addition result from the DU ratio addition unit 16-2, calculates the analog interference wave equivalent CN ratio from the DU ratio of the analog interference wave, It outputs to the equivalent CN ratio addition part 15-2.

  The equivalent CN ratio adding unit 15-2 inputs the equivalent CN ratio as an addition result from the equivalent CN ratio adding unit 14-2 and the analog interference wave equivalent CN ratio from the equivalent CN ratio calculating unit 12-2, and these Are added together, and the addition result is output as the first output signal CN ratio.

  By repeating such calculation, the addition result of the equivalent CN ratio calculated by the (N-1) -th stage calculation unit 10- (N-1) (not shown) (input signal CN ratio from the transmission station) , Digital interference wave equivalent CN ratio from the first to (N-1) th digital jamming stations, and arithmetic units 10-1 to 10- (N-1) from the 1st stage to the (N-1) th stage. (Equipment degradation equivalent CN ratio calculated from the device degradation amount at) is output to the equivalent CN ratio addition unit 14-N of the Nth stage computation unit 10-N. In addition, the addition result of the DU ratio (first to (N-1) th analog jamming stations) calculated by the (N-1) th stage arithmetic unit 10- (N-1) (not shown). The result obtained by adding the DU ratios of the analog interference waves is output to the DU ratio adding unit 16-N of the Nth arithmetic unit 10-N.

  The N-th stage computing unit 10-N corresponds to a relay station that retransmits the terrestrial digital broadcast wave received from the relay station corresponding to the (N-1) -th stage computing unit 10- (N-1). Addition result of the equivalent CN ratio from the arithmetic unit 10- (N-1) and the DU ratio of the analog interference wave transmitted from the first to (N-1) th analog interference stations (first to (N-1th) ) Of analog interference wave DU ratio up to)), DU ratio of Nth digital interference wave transmitted from Nth digital jamming station, and Nth analog interference wave transmitted from Nth analog jamming station Based on the DU ratio and the N-th device deterioration amount of the transmitter itself installed in the relay station corresponding to the Nth stage arithmetic unit 10-N, based on these CN ratio, DU ratio, and deterioration amount An Nth output signal CN ratio is calculated.

  Specifically, the equivalent CN ratio calculation unit 11-N of the arithmetic unit 10-N inputs the DU ratio of the Nth digital interference wave and calculates the Nth digital interference wave from the DU ratio of the Nth digital interference wave. The equivalent CN ratio is calculated and output to the equivalent CN ratio addition unit 14-N. Further, the equivalent CN ratio calculation unit 13-N inputs the Nth device deterioration amount, calculates the Nth device deterioration equivalent CN ratio from the Nth device deterioration amount, and sends it to the equivalent CN ratio addition unit 14-N. Output.

  The equivalent CN ratio addition unit 14-N includes an equivalent CN ratio that is an addition result from the equivalent CN ratio addition unit 14- (N−1) in the (N−1) -th operation unit 10- (N−1). The Nth digital interference wave equivalent CN ratio from the equivalent CN ratio calculation unit 11-N and the Nth device deterioration equivalent CN ratio from the equivalent CN ratio calculation unit 13-N are input, and these equivalent CN ratios are added. The addition result is output to the equivalent CN ratio addition unit 15-N.

  The DU ratio adding unit 16-N inputs the DU ratio of the Nth analog interference wave from the Nth analog interfering station, and in the (N-1) th stage arithmetic unit 10-1 (N-1). The addition result of the DU ratios of the first to N-1th analog interference waves is input from the DU ratio addition unit 16- (N-1), the DU ratios of these analog interference waves are added, and the addition result is obtained. Output to equivalent CN ratio calculation 12-N.

  The equivalent CN ratio calculation unit 12-N receives the DU ratio of the analog interference wave as the addition result from the DU ratio addition unit 16-N, calculates the analog interference wave equivalent CN ratio from the DU ratio of the analog interference wave, It outputs to the equivalent CN ratio addition part 15-N.

  The equivalent CN ratio adding unit 15-N inputs the equivalent CN ratio as an addition result from the equivalent CN ratio adding unit 14-N and the analog interference wave equivalent CN ratio from the equivalent CN ratio calculating unit 12-N, and these The equivalent CN ratio is added, and the addition result is output as the Nth output signal CN ratio.

  FIG. 4A is a diagram for explaining the outline of the processing of the first embodiment shown in FIG. As shown in FIG. 4A, in the first embodiment, an analog interference signal in which an OFDM signal, which is a terrestrial digital broadcast wave, is interfered by an analog interference wave and an analog interference wave in the next relay station are obtained. When combining, the DU ratio of the analog interference wave is added. That is, the normalized analog interference wave power is obtained from the DU ratio of the analog interference wave, and the DU ratio of the analog interference wave is added by adding the obtained power.

  As described above, according to the terrestrial digital broadcast channel quality evaluation apparatus 1 of the first embodiment, the arithmetic units 10-2 to 10-N determine the DU ratios of analog interference waves in their relay stations and the previous relay stations. The DU ratio of the addition result is treated as the DU ratio of the analog interference wave at the calculation target relay station, and the equivalent CN ratio calculation units 12-2 to 12-N calculate the equivalent CN ratio corresponding to the DU ratio. In addition, the analog interference wave equivalent CN ratio in the relay station to be calculated is handled. Conventionally, the equivalent CN ratio is calculated from the DU ratio of the analog interference wave at each relay station, the equivalent CN ratio is treated as the analog interference wave equivalent CN ratio at the relay station to be calculated, and the analog interference wave equivalent CN ratio is calculated. Since the equivalent CN ratio was added, an accurate output signal CN ratio could not be calculated. This is because the analog interference wave is different from Gaussian noise in terms of frequency characteristics when the analog interference wave equivalent CN ratio is added. In the first embodiment, the equivalent CN ratio is calculated by adding the DU ratio instead of adding the analog interference wave equivalent CN ratios. Thereby, it is possible to solve the problem that an accurate output signal CN ratio cannot be calculated due to the fact that the analog interference wave has a characteristic different from that of Gaussian noise. Therefore, when evaluating the quality of the digital terrestrial broadcast channel by the CN ratio of the terrestrial digital broadcast signal, it is possible to calculate a more accurate CN ratio in consideration of the influence of the digital interference wave, the analog interference wave, and the apparatus deterioration. .

  The DU ratio of the first digital interference wave transmitted from the first digital jamming station includes the sum of the DU ratios of the respective digital interference waves transmitted from the plurality of digital jamming stations. Similarly, the DU ratio of the first analog interference wave transmitted from the first analog jamming station includes the sum of the DU ratios of the analog interference waves transmitted from the plurality of analog jamming stations. The same applies to the second to Nth digital jamming stations and analog jamming stations. The same applies to Examples 2 and 3 described below.

[Example 2]
Next, Example 2 will be described in detail. In the second embodiment, the analog interference wave equivalent CN ratio is compared as described above, and the smaller equivalent CN ratio is handled as the analog interference wave equivalent CN ratio in the relay station to be calculated.

  FIG. 2 is a block diagram showing the configuration of the second (Example 2) terrestrial digital broadcast channel quality evaluation apparatus according to the embodiment of the present invention. The terrestrial digital broadcast channel quality evaluation apparatus 2 includes a plurality of stages of arithmetic units 20-1 to 20-N.

  Comparing the terrestrial digital broadcast line quality evaluation apparatus 1 of the first embodiment shown in FIG. 1 with the terrestrial digital broadcast line quality evaluation apparatus 2 of the second embodiment shown in FIG. 2 differs from the first embodiment in that equivalent CN ratio comparison units 27-2 to 27-N are provided instead of the DU ratio addition units 16-2 to 16-N of the first embodiment. Equivalent CN ratio calculation units 21-1 to 21-N, equivalent CN ratio calculation units 23-1 to 23-N, equivalent CN ratio addition units 24-1 to 24-N, and equivalent CN ratio addition unit 25- of the second embodiment. 1 to 25-N are equivalent CN ratio calculation units 11-1 to 11-N, equivalent CN ratio calculation units 13-1 to 13-N, equivalent CN ratio addition units 14-1 to 14-N, and It corresponds to the equivalent CN ratio adding units 15-1 to 15-N, respectively. Since these components have already been described in the first embodiment, description thereof is omitted here.

  The second stage arithmetic unit 20-2 corresponds to a relay station that retransmits the terrestrial digital broadcast wave received from the relay station corresponding to the first stage arithmetic unit 20-1, and is equivalent to the equivalent CN of the arithmetic unit 20-1. The addition result from the ratio adding unit 24-1, the analog interference wave equivalent CN ratio from the equivalent CN ratio calculating unit 22-1 in the arithmetic unit 20-1, and the second digital interference wave transmitted from the second digital jamming station. DU ratio of the second analog interference wave transmitted from the second analog interfering station, and the second of the transmitter itself installed in the relay station corresponding to the second stage arithmetic unit 20-1. And the second output signal CN ratio is calculated based on these CN ratio, DU ratio, and deterioration amount. The addition result from the equivalent CN ratio addition unit 24-1 of the arithmetic unit 20-1, the result of adding the second digital interference wave equivalent CN ratio, and the second device deterioration equivalent CN ratio, and the first As a comparison result between the analog interference wave equivalent CN ratio and the second analog interference wave equivalent CN ratio, the smaller analog interference wave equivalent CN ratio is output to the third stage computing unit 20-3 (not shown).

  Specifically, the equivalent CN ratio calculation unit 22-2 of the calculation unit 20-2 calculates the second analog interference wave equivalent CN ratio from the DU ratio of the second analog interference wave, and the equivalent CN ratio comparison unit 27 Output to -2. The equivalent CN ratio comparison unit 27-2 inputs the second analog interference wave equivalent CN ratio from the equivalent CN ratio calculation unit 22-2, and at the same time, the equivalent CN ratio calculation unit 22- of the first stage calculation unit 20-1. The first analog interference wave equivalent CN ratio is inputted from 1 and the two equivalent CN ratios inputted are compared, and the smaller equivalent CN ratio is compared with the equivalent CN ratio adder 25-2 and the arithmetic unit 20-3 (not shown). Output).

  The equivalent CN ratio addition unit 25-2 inputs the comparison result from the equivalent CN ratio comparison unit 27-2 and the addition result from the equivalent CN ratio addition unit 24-2, adds these equivalent CN ratios, and adds The result is output as the second output signal CN ratio.

  By repeating such calculation, the addition result of the equivalent CN ratio (input signal CN ratio from the transmitting station) calculated by the (N-1) -th stage calculation unit 20- (N-1) (not shown). , Digital interference wave equivalent CN ratios from the first to (N-1) th digital jamming stations, and arithmetic units 20-1 to 20- (N-1) from the 1st stage to the (N-1) th stage. (Equivalent CN ratio addition result calculated from the device deterioration amount) is output to the equivalent CN ratio addition unit 24-N of the N-th operation unit 20-N. Further, the comparison result of the analog interference wave equivalent CN ratio calculated by the (N-1) -th stage calculation unit 20- (N-1) (not shown) (the first to (N-1) th analogs). The smallest equivalent CN ratio among the interference wave equivalent CN ratios) is output to the equivalent CN ratio comparison unit 27-N of the Nth stage calculation unit 20-N.

  The N-th stage computing unit 20-N corresponds to a relay station that retransmits the terrestrial digital broadcast wave received from the relay station corresponding to the (N-1) -th stage computing unit 20- (N-1). Results of addition from the equivalent CN ratio adding unit 24- (N-1) of the arithmetic unit 20- (N-1) (input signal CN ratio and digital from the first to (N-1) th digital jamming stations. The result of addition of the interference wave equivalent CN ratio and the device deterioration equivalent CN ratio in the arithmetic units 20-1 to 20- (N-1) from the first stage to the (N-1) th stage) and from the first to the ( N-1) The smallest equivalent CN ratio among analog interference wave equivalent CN ratios, the DU ratio of the Nth digital interference wave transmitted from the Nth digital jamming station, and the Nth analog jamming station. Installed in the relay station corresponding to the DU ratio of the Nth analog interference wave and the Nth stage arithmetic unit 20-N Enter the device deterioration amount of the N transmitter itself, to calculate the output signal CN ratio of the CN ratio, a based on the DU ratio and deterioration amount N.

  Specifically, the equivalent CN ratio calculation unit 22-N of the calculation unit 20-N calculates the Nth analog interference wave equivalent CN ratio from the DU ratio of the Nth analog interference wave, and the equivalent CN ratio comparison unit 27 Output to -N. The equivalent CN ratio comparison unit 27-N inputs the Nth analog interference wave equivalent CN ratio from the equivalent CN ratio calculation unit 22-N, and calculates the (N-1) -th stage calculation unit 20- (N-1). Equivalent CN ratio comparison section 27- (N-1) in FIG. 1 inputs analog interference wave equivalent CN ratios from the first to the (N-1) th, compares the two equivalent CN input ratios, and calculates the smaller equivalent The CN ratio is output to the equivalent CN ratio adding unit 25-N.

  The equivalent CN ratio addition unit 25-N inputs the comparison result from the equivalent CN ratio comparison unit 27-N and the addition result from the equivalent CN ratio addition unit 24-N, adds these equivalent CN ratios, and adds The result is output as the Nth output signal CN ratio.

  FIG. 4B is a diagram for explaining the outline of the processing of the second embodiment shown in FIG. As shown in FIG. 4B, the second embodiment selects a signal having a small equivalent CN ratio from two signals having equivalent noise. That is, the second embodiment compares two analog interference wave equivalent CN ratios, and selects the analog interference wave equivalent CN ratio having a smaller value.

  As described above, according to the terrestrial digital broadcast channel quality evaluation device 2 of the second embodiment, the calculation units 20-2 to 20-N have the analog interference wave equivalent CN ratio in their own relay station and the previous relay station. The smallest equivalent CN ratio among them is handled as the analog interference wave equivalent CN ratio in the relay station to be calculated. Conventionally, the equivalent CN ratio is calculated from the DU ratio of the analog interference wave in each relay station, the equivalent CN ratio is treated as the analog interference wave equivalent CN ratio in the relay station to be calculated, and the analog interference wave equivalent CN ratio is calculated. Because of the addition, an accurate output signal CN ratio could not be calculated. This is because analog interference waves differ from Gaussian noise in terms of frequency characteristics when adding analog interference wave equivalent CN ratios. In the second embodiment, instead of adding the analog interference wave equivalent CN ratios, the smallest equivalent CN ratio among the analog interference wave equivalent CN ratios is treated as the analog interference wave equivalent CN ratio in the relay station to be calculated. I made it. Thereby, it is possible to solve the problem that an accurate output signal CN ratio cannot be calculated due to the fact that the analog interference wave has characteristics different from Gaussian noise. Therefore, when evaluating the quality of the digital terrestrial broadcast channel by the CN ratio of the terrestrial digital broadcast signal, it is possible to calculate a more accurate CN ratio in consideration of the influence of the digital interference wave, the analog interference wave, and the apparatus deterioration. .

  The terrestrial digital broadcast channel quality evaluation apparatus 2 according to the second embodiment is particularly effective when a transmitter installed in a relay station performs symbol determination processing. 5 and 6 are diagrams for explaining the effects of the terrestrial digital broadcast channel quality evaluation apparatus according to the second embodiment. FIG. 5A is a schematic diagram illustrating a basic configuration of a normal transmitter. This transmitter includes a receiving antenna that receives terrestrial digital broadcast waves, analog interference waves, etc., a frequency converting unit that converts the frequency of the received signal, a power amplifying unit that amplifies the power of the frequency converted signal, and power amplification A transmission antenna for transmitting signals is provided.

  FIG. 5B is a schematic diagram illustrating a basic configuration of a transmitter having a symbol determination function. This transmitter is the same as the ordinary transmitter shown in FIG. 5A, but is different from the ordinary transmitter in that the frequency conversion unit performs symbol determination processing. . Symbol determination processing refers to processing for determining a threshold value of a signal after equalization processing in a frequency conversion unit, and is for eliminating noise included in a received signal and preventing signal deterioration. Thereby, the CN ratio of the received signal can be improved.

  FIG. 5C is a diagram for explaining a normal effect by the symbol determination process. As shown in FIG. 5C, by performing symbol determination processing on a signal having equivalent noise, noise is eliminated and the CN ratio is improved. However, when symbol determination processing is performed on an analog interfered signal (a signal in which an OFDM signal, which is a digital terrestrial broadcast wave interferes with the influence of the analog interference wave), noise is eliminated and the CN ratio is improved. It is not always done.

  FIG. 5D is a diagram for explaining the effect of the symbol determination process in the case of the analog interference signal. As shown in FIG. 5D, when the symbol determination process is performed on the analog interference signal, the symbol determination process is a threshold determination process, and thus is sufficiently affected by the analog interference wave. The subcarrier CN ratio becomes 0 dB. As a result, the analog interference signal after symbol determination becomes a signal containing an error that cannot be repaired. Hereinafter, such a signal is referred to as a signal after a symbol determination error.

  FIG. 6A is a diagram for explaining a case where symbol determination is not performed after combining by combining a signal after a symbol determination error and an analog interference wave. FIG. 6A shows a digital terrestrial broadcast channel quality evaluation apparatus 2 according to the second embodiment shown in FIG. 2, for example, where a transmitter installed in a relay station corresponding to the first stage arithmetic unit 20-1 is a symbol. It shows a case where a transmitter having a determination function and installed in a relay station corresponding to the second stage arithmetic unit 20-2 does not have a symbol determination function. That is, the signal after the symbol determination error is a signal from the transmitter in the first stage arithmetic unit 20-1, and the analog interference wave is a signal received by the second stage arithmetic unit 20-2. The upper part of FIG. 6A shows a signal after a symbol determination error, an analog interference wave, and an analog interference signal (with determination error) obtained by synthesizing these signals. The analog interference signal (with determination error) includes a subcarrier that has caused a symbol determination error.

  In general, even if a signal after a symbol determination error including a subcarrier that has once caused a symbol determination error is affected again by an analog interference wave, its quality does not change much. That is, the equivalent CN ratio of the combined analog interference signal (with determination error) does not change much compared to the equivalent CN ratio of the signal after the original symbol determination error. However, when the analog interference equivalent CN ratio indicating the influence of the analog interference wave to be combined is lower than the equivalent CN ratio of the signal after the symbol determination error, the quality of the analog interference signal is higher than the signal after the symbol determination error. Since it is bad, the equivalent CN ratio of the combined analog interference signal (with determination error) changes compared to the equivalent CN ratio of the signal after symbol determination error. Therefore, in the above-described example, the second stage calculation unit 20-2 performs the equivalent CN ratio of the signal after the symbol determination error output from the equivalent CN ratio calculation unit 22-1 in the first stage calculation unit 20-1. Is compared with the analog interference wave equivalent CN ratio output from the equivalent CN ratio calculation unit 22-2 in the second stage arithmetic unit 20-2, and the smaller equivalent CN ratio is treated as the analog interference wave equivalent CN ratio. The second output signal CN ratio is calculated.

  FIG. 6B is a diagram for describing a case where symbol determination processing is performed after combining by combining a signal after a symbol determination error and an analog interference wave. FIG. 6B shows a digital terrestrial broadcasting channel quality evaluation apparatus 2 according to the second embodiment shown in FIG. 2, for example, where a transmitter installed in a relay station corresponding to the first stage arithmetic unit 20-1 is a symbol. It shows a case where a transmitter having a determination function and installed in a relay station corresponding to the second stage arithmetic unit 20-2 also has a symbol determination function. That is, the signal after the symbol determination error shown on the left side of the upper stage of FIG. 6B is a signal from the transmitter in the first stage arithmetic unit 20-1, and the analog interference wave shown in the center is the second stage. This is a signal received by the arithmetic unit 20-2, and the signal shown on the right is a signal after a symbol determination error obtained by combining these and performing symbol determination processing after the combination.

  Similar to FIG. 6A, even if a signal after a symbol determination error including a subcarrier that has once caused a symbol determination error is affected by an analog interference wave again, its quality does not change much. That is, the equivalent CN ratio of the signal after the symbol determination error after combining does not change much compared to the equivalent CN ratio of the signal after the original symbol determination error. Therefore, in the above-described example, the second stage calculation unit 20-2 performs the equivalent CN ratio of the signal after the symbol determination error output from the equivalent CN ratio calculation unit 22-1 in the first stage calculation unit 20-1. Is compared with the equivalent CN ratio of the signal after the symbol determination error output from the equivalent CN ratio calculation unit 22-2 in the second stage arithmetic unit 20-2, and the smaller equivalent CN ratio is equivalent to the analog interference wave equivalent. Treated as a CN ratio, the second output signal CN ratio is calculated.

Example 3
Next, Example 3 will be described in detail. In the third embodiment, as described above, the analog interference wave equivalent CN ratio is obtained by combining the first and second embodiments.

  FIG. 3 is a block diagram showing the configuration of the third (Example 3) terrestrial digital broadcast channel quality evaluation apparatus according to the embodiment of the present invention. This terrestrial digital broadcast channel quality evaluation apparatus 3 includes a plurality of stages of arithmetic units 30-1 to 30-N.

  The terrestrial digital broadcast line quality evaluation apparatus 1 of the first embodiment shown in FIG. 1, the terrestrial digital broadcast line quality evaluation apparatus 2 shown in FIG. 2, and the terrestrial digital broadcast line quality evaluation apparatus 3 of the third embodiment shown in FIG. In the terrestrial digital broadcast channel quality evaluation apparatus 3 of the third embodiment, the calculation units 30-2 to 30-N combine the calculation units 10-2 to 10-N and the calculation units 20-2 to 20-N. It differs in that it is structured. Equivalent CN ratio calculation units 31-1 to 31-N, equivalent CN ratio calculation units 33-1 to 33-N, equivalent CN ratio addition units 34-1 to 34-N, and equivalent CN ratio addition unit 35- of the third embodiment. 1-35 are equivalent CN ratio calculation units 11-1 to 11-N, equivalent CN ratio calculation units 13-1 to 13-N, equivalent CN ratio addition units 14-1 to 14-N, and The equivalent CN ratio adding units 15-1 to 15-N correspond to the equivalent CN ratio calculating units 21-1 to 21-N, the equivalent CN ratio calculating units 23-1 to 23-N, and the equivalent CN of the second embodiment. This corresponds to the ratio adding units 24-1 to 24-N and equivalent CN ratio adding units 25-1 to 25-N, respectively. Since these components have already been described in the first embodiment, description thereof is omitted here.

  The second-stage arithmetic unit 30-2 has the same configuration as the arithmetic units 10-2 to 10-N of the first embodiment illustrated in FIG. Similarly, the third stage arithmetic unit 30-3 (not shown) has the same configuration as the arithmetic units 20-2 to 20-N of the second embodiment shown in FIG. Similarly, the Nth stage computing unit 30-N has the same configuration as the computing units 20-2 to 20-N of the second embodiment shown in FIG.

  As described above, according to the terrestrial digital broadcast channel quality evaluation apparatus 3 of the third embodiment, the calculation units 30-2 to 30-N are replaced with the calculation units 10-2 to 10-N of the first embodiment and the second embodiment. It was configured by combining arithmetic units 20-2 to 20-N. That is, the arithmetic units 30-2 to 30-N add the DU ratios of analog interference waves in their own relay station and the previous relay station to obtain an equivalent CN ratio corresponding to this DU ratio, or The smallest equivalent CN ratio among the analog interference wave equivalent CN ratios at the relay station and the previous relay station is obtained and treated as the analog interference wave equivalent CN ratio at the calculation target relay station. As a result, similarly to the first and second embodiments, the conventional problem that the accurate output signal CN ratio cannot be calculated due to the analog interference wave having different characteristics from the Gaussian noise is solved. be able to. Therefore, when evaluating the quality of the digital terrestrial broadcast channel by the CN ratio of the terrestrial digital broadcast signal, it is possible to calculate a more accurate CN ratio in consideration of the influence of the digital interference wave, the analog interference wave, and the apparatus deterioration. .

  The terrestrial digital broadcast line quality evaluation devices 1, 2, and 3 are configured by a computer having a volatile storage medium such as a CPU and a RAM, a non-volatile storage medium such as a ROM, and an interface. Arithmetic units 10-1 to 10-N included in the terrestrial digital broadcast line quality evaluation apparatus 1, arithmetic units 20-1 to 20-N included in the terrestrial digital broadcast line quality evaluation apparatus 2, and terrestrial digital broadcast line quality evaluation apparatus 3 The functions of the arithmetic units 30-1 to 30-N included in the above are realized by causing the CPU to execute a program describing these functions. These programs can also be stored and distributed in a storage medium such as a magnetic disk (floppy (registered trademark) disk, hard disk, etc.), optical disk (CD-ROM, DVD, etc.), semiconductor memory, or the like.

  The present invention has been described with reference to the embodiment. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the technical idea thereof. For example, analog interference waves input by the arithmetic units 10-1 to 10-N, 20-1 to 20-N, 30-1 to 30-N corresponding to the relay stations are only analog broadcast waves received by the analog television. In addition, a signal having a biased frequency characteristic is also included.

It is a block diagram which shows the structure of the 1st (Example 1) terrestrial digital broadcast line quality evaluation apparatus by embodiment of this invention. It is a block diagram which shows the structure of the 2nd (Example 2) terrestrial digital broadcast line quality evaluation apparatus by embodiment of this invention. It is a block diagram which shows the structure of the 3rd (Example 3) terrestrial digital broadcast line quality evaluation apparatus by embodiment of this invention. It is a figure explaining the outline | summary of the process by the terrestrial digital broadcast channel quality evaluation apparatus of Example 1 and Example 2. FIG. It is a figure explaining the effect by the terrestrial digital broadcast channel quality evaluation apparatus of Example 2. It is a figure following FIG. 5 explaining the effect by the terrestrial digital broadcast line quality evaluation apparatus of Example 2. FIG. It is a block diagram which shows the structure of the conventional digital terrestrial broadcasting line quality evaluation apparatus. It is a figure explaining the outline | summary of the process by the conventional digital terrestrial broadcasting line quality apparatus.

Explanation of symbols

1, 2, 3, 100 Terrestrial digital broadcast channel quality evaluation device 10, 20, 30, 110 Arithmetic unit 11, 12, 13, 21, 22, 23, 31, 32, 33, 111, 112, 113 Equivalent CN ratio calculation Units 14, 15, 24, 25, 34, 35, 114 Equivalent CN ratio adding unit 16, 36 DU ratio adding unit 27, 37 Equivalent CN ratio comparing unit

Claims (8)

In a terrestrial digital broadcast line quality evaluation apparatus that evaluates the quality of a digital terrestrial broadcast line by each output signal CN ratio output by a plurality of stages of arithmetic units,
The first stage computing unit is
A first digital interference wave equivalent CN ratio calculation unit for inputting a DU ratio of the first digital interference wave transmitted from the first digital jamming station and calculating an equivalent CN ratio;
A first device deterioration equivalent CN ratio calculation unit that inputs a first device deterioration amount in a transmitter installed in a relay station corresponding to the first stage calculation unit and calculates an equivalent CN ratio;
An input signal CN ratio using a terrestrial digital broadcast wave transmitted from a transmission station as an input signal, an equivalent CN ratio calculated by the first digital interference wave equivalent CN ratio calculation unit, and the first device deterioration equivalent CN A first equivalent CN ratio addition unit that adds the equivalent CN ratio calculated by the ratio calculation unit;
A first analog interference wave equivalent CN ratio calculation unit that inputs a DU ratio of the first analog interference wave transmitted from the first analog jamming station and calculates an equivalent CN ratio;
The addition result of the equivalent CN ratio added by the first equivalent CN ratio addition unit and the equivalent CN ratio calculated by the first analog interference wave equivalent CN ratio calculation unit are added to obtain a first output signal. A first full equivalent CN ratio addition unit that outputs a CN ratio,
N is an integer of 2 or more,
The Nth stage arithmetic unit is
An Nth digital interference wave equivalent CN ratio calculation unit that inputs a DU ratio of the Nth digital interference wave transmitted from the Nth digital jamming station and calculates an equivalent CN ratio;
An N-th device deterioration equivalent CN ratio calculation unit that inputs an N-th device deterioration amount in a transmitter installed in a relay station corresponding to the N-th operation unit, and calculates an equivalent CN ratio;
The addition result of the equivalent CN ratio added by the equivalent CN ratio addition unit in the previous stage, the equivalent CN ratio calculated by the Nth digital interference wave equivalent CN ratio calculation unit, and the Nth device deterioration equivalent CN ratio calculation An Nth equivalent CN ratio addition unit for adding the equivalent CN ratio calculated by the unit;
The DU ratio of the Nth analog interference wave transmitted from the Nth analog interference station is input, and if the previous stage is the first stage, the first analog input to the first analog interference wave equivalent CN ratio calculation unit is input. Input the DU ratio of the analog interference wave, or, if the previous stage is the second or later stage, the addition result of the DU ratio of the analog interference wave up to the previous stage, and the DU ratio of the Nth analog interference wave and the first analog An Nth analog interference wave DU ratio adding unit that adds the DU ratio of the interference wave or the addition result of the DU ratio and outputs the addition result of the DU ratio;
An Nth analog interference wave equivalent CN ratio calculation unit that inputs an addition result of the DU ratio output by the Nth analog interference wave DU ratio addition unit and calculates an equivalent CN ratio;
The addition result of the equivalent CN ratio added by the Nth equivalent CN ratio addition unit and the equivalent CN ratio calculated by the Nth analog interference wave equivalent CN ratio calculation unit are added, and the Nth output signal A terrestrial digital broadcast channel quality evaluation apparatus comprising: an Nth total equivalent CN ratio addition unit that outputs a CN ratio. In the terrestrial digital broadcast channel quality evaluation apparatus according to claim 1,
The Nth stage arithmetic unit is:
An Nth digital interference wave equivalent CN ratio calculation unit that inputs a DU ratio of the Nth digital interference wave transmitted from the Nth digital jamming station and calculates an equivalent CN ratio;
An N-th device deterioration equivalent CN ratio calculation unit that inputs an N-th device deterioration amount in a transmitter installed in a relay station corresponding to the N-th operation unit, and calculates an equivalent CN ratio;
An Nth analog interference wave equivalent CN ratio calculation unit for inputting a DU ratio of the Nth analog interference wave transmitted from the Nth analog jamming station and calculating an equivalent CN ratio;
The addition result of the equivalent CN ratio added by the equivalent CN ratio addition unit in the previous stage, the equivalent CN ratio calculated by the Nth digital interference wave equivalent CN ratio calculation unit, and the Nth device deterioration equivalent CN ratio calculation An Nth equivalent CN ratio addition unit for adding the equivalent CN ratio calculated by the unit;
The equivalent CN ratio calculated by the Nth analog interference wave equivalent CN ratio calculation unit is input. If the previous stage is the first stage, the equivalent CN calculated by the first analog interference wave equivalent CN ratio calculation unit is input. Ratio, or when the preceding stage is the second or later stage, the smallest equivalent CN ratio among the equivalent CN ratios of the analog interference wave up to the preceding stage is input, the two equivalent CN ratios inputted are compared, and the smaller equivalent CN An Nth analog interference wave equivalent CN ratio comparison unit that outputs the ratio;
The addition result of the equivalent CN ratio added by the Nth equivalent CN ratio addition unit and the equivalent CN ratio output by the Nth analog interference wave equivalent CN ratio comparison unit are added to obtain an Nth output signal. A terrestrial digital broadcast channel quality evaluation apparatus comprising: an Nth total equivalent CN ratio addition unit that outputs a CN ratio. In the terrestrial digital broadcast line quality evaluation apparatus according to claim 2,
The N-th stage or the preceding stage computing unit is a transmitter installed in a relay station corresponding to the N-th stage computing unit or a transmitter installed in a relay station corresponding to the preceding stage computing unit. A digital terrestrial broadcast channel quality evaluation apparatus, wherein at least one transmitter has a symbol determination function for performing threshold determination on a received signal. In a terrestrial digital broadcast line quality evaluation apparatus that evaluates the quality of a digital terrestrial broadcast line by each output signal CN ratio output by a plurality of stages of arithmetic units,
The first stage computing unit is
A first digital interference wave equivalent CN ratio calculation unit for inputting a DU ratio of the first digital interference wave transmitted from the first digital jamming station and calculating an equivalent CN ratio;
A first device deterioration equivalent CN ratio calculation unit that inputs a first device deterioration amount in a transmitter installed in a relay station corresponding to the first stage calculation unit and calculates an equivalent CN ratio;
An input signal CN ratio using a terrestrial digital broadcast wave transmitted from a transmission station as an input signal, an equivalent CN ratio calculated by the first digital interference wave equivalent CN ratio calculation unit, and the first device deterioration equivalent CN A first equivalent CN ratio addition unit that adds the equivalent CN ratio calculated by the ratio calculation unit;
A first analog interference wave equivalent CN ratio calculation unit that inputs a DU ratio of the first analog interference wave transmitted from the first analog jamming station and calculates an equivalent CN ratio;
The addition result of the equivalent CN ratio added by the first equivalent CN ratio addition unit and the equivalent CN ratio calculated by the first analog interference wave equivalent CN ratio calculation unit are added to obtain a first output signal. A first full equivalent CN ratio addition unit that outputs a CN ratio,
M is an integer greater than or equal to 3,
The terrestrial digital, wherein the second to Mth arithmetic units include the Nth arithmetic unit according to claim 1 and the Nth arithmetic unit according to claim 2 or 3. Broadcast line quality evaluation equipment. A digital terrestrial broadcast channel quality evaluation apparatus having a plurality of stages of calculation units, and an input signal CN ratio using a terrestrial digital broadcast wave transmitted from a transmission station as an input signal and a DU of a digital interference wave transmitted from a digital jamming station Input the ratio, the DU ratio of the analog interference wave transmitted from the analog interfering station, and the device deterioration amount in the transmitter installed in the relay station corresponding to the arithmetic unit, respectively, to calculate the output signal CN ratio, In the method of evaluating the quality of a digital terrestrial broadcasting line based on the output signal CN ratio,
By the first stage calculation unit,
The first digital interference wave equivalent CN ratio is calculated from the DU ratio of the first digital interference wave, the first device deterioration equivalent CN ratio is calculated from the first device deterioration amount, and the input signal CN ratio, A 1-1 step of adding a first digital interference wave equivalent CN ratio and the first device deterioration equivalent CN ratio and outputting an addition result of the equivalent CN ratio;
A 1-2 step of calculating an equivalent CN ratio from a DU ratio of the first analog interference wave;
The addition result of the equivalent CN ratio output in the 1-1 step and the equivalent CN ratio calculated in the 1-2 step are added to output the first output signal CN ratio 1-3 And having steps of
N is an integer of 2 or more, and the Nth stage arithmetic unit
The Nth digital interference wave equivalent CN ratio is calculated from the DU ratio of the Nth digital interference wave, the Nth device deterioration equivalent CN ratio is calculated from the Nth device deterioration amount, and the equivalent CN output in the previous step An N-1th step of adding a ratio addition result, the Nth digital interference wave equivalent CN ratio, and the Nth device deterioration equivalent CN ratio, and outputting the addition result of the equivalent CN ratio;
The DU ratio of the Nth analog interference wave and the DU ratio of the first analog interference wave in the step 1-2 when the previous stage is the first stage, or up to the previous stage when the previous stage is the second stage or later. N-2th step of adding the DU ratio addition result of the analog interference wave and outputting the DU ratio addition result;
An N-3th step of calculating an equivalent CN ratio from the addition result of the DU ratios output in the N-2th step;
The addition result of the equivalent CN ratio output in the (N-1) th step and the equivalent CN ratio output in the (N-3) th step are added to output the Nth output signal CN ratio. And a digital terrestrial broadcast channel quality evaluation method comprising the steps of: The terrestrial digital broadcast channel quality evaluation method according to claim 5,
By the Nth stage arithmetic unit,
The Nth digital interference wave equivalent CN ratio is calculated from the DU ratio of the Nth digital interference wave, the Nth device deterioration equivalent CN ratio is calculated from the Nth device deterioration amount, and the equivalent CN output in the previous step An N-1th step of adding a ratio addition result, the Nth digital interference wave equivalent CN ratio, and the Nth device deterioration equivalent CN ratio, and outputting the addition result of the equivalent CN ratio;
An N-2th step of calculating an equivalent CN ratio from a DU ratio of the Nth analog interference wave;
The equivalent CN ratio calculated in the N-2 step and the equivalent CN ratio calculated in the 1-2 step when the previous stage is the first stage, or up to the previous stage when the previous stage is the second stage or later. N-3th step of comparing the smallest equivalent CN ratio among the equivalent CN ratios of the analog interference wave and outputting the smaller equivalent CN ratio;
The addition result of the equivalent CN ratio output in the (N-1) th step and the equivalent CN ratio output in the (N-3) th step are added to output the Nth output signal CN ratio. And a digital terrestrial broadcast channel quality evaluation method comprising the steps of: The input signal CN ratio using the terrestrial digital broadcast wave transmitted from the transmitting station as the input signal, the DU ratio of the digital interference wave transmitted from the digital interfering station, and the analog interfering station transmitted by the multistage arithmetic unit The DU ratio of the analog interference wave and the device deterioration amount in the transmitter installed in the relay station corresponding to the calculation unit are input, the output signal CN ratio is calculated respectively, and the terrestrial digital broadcast line is calculated based on the output signal CN ratio. A program that evaluates the quality of
By the first stage calculation unit,
The first digital interference wave equivalent CN ratio is calculated from the DU ratio of the first digital interference wave, the first device deterioration equivalent CN ratio is calculated from the first device deterioration amount, and the input signal CN ratio, A 1-1 step of adding a first digital interference wave equivalent CN ratio and the first device deterioration equivalent CN ratio and outputting an addition result of the equivalent CN ratio;
A 1-2 step of calculating an equivalent CN ratio from a DU ratio of the first analog interference wave;
The addition result of the equivalent CN ratio output in the 1-1 step and the equivalent CN ratio calculated in the 1-2 step are added to output the first output signal CN ratio 1-3 And execute the steps of
N is an integer of 2 or more, and the Nth stage arithmetic unit
The Nth digital interference wave equivalent CN ratio is calculated from the DU ratio of the Nth digital interference wave, the Nth device deterioration equivalent CN ratio is calculated from the Nth device deterioration amount, and the equivalent CN output in the previous step An N-1th step of adding a ratio addition result, the Nth digital interference wave equivalent CN ratio, and the Nth device deterioration equivalent CN ratio, and outputting the addition result of the equivalent CN ratio;
The DU ratio of the Nth analog interference wave and the DU ratio of the first analog interference wave in the step 1-2 when the previous stage is the first stage, or up to the previous stage when the previous stage is the second stage or later. N-2th step of adding the DU ratio addition result of the analog interference wave and outputting the DU ratio addition result;
An N-3th step of calculating an equivalent CN ratio from the addition result of the DU ratios output in the N-2th step;
The addition result of the equivalent CN ratio output in the (N-1) th step and the equivalent CN ratio output in the (N-3) th step are added to output the Nth output signal CN ratio. And a digital terrestrial broadcast channel quality evaluation program characterized in that The terrestrial digital broadcast channel quality evaluation program according to claim 7, wherein the computer includes:
By the Nth stage arithmetic unit,
The Nth digital interference wave equivalent CN ratio is calculated from the DU ratio of the Nth digital interference wave, the Nth device deterioration equivalent CN ratio is calculated from the Nth device deterioration amount, and the equivalent CN output in the previous step An N-1th step of adding a ratio addition result, the Nth digital interference wave equivalent CN ratio, and the Nth device deterioration equivalent CN ratio, and outputting the addition result of the equivalent CN ratio;
An N-2th step of calculating an equivalent CN ratio from a DU ratio of the Nth analog interference wave;
The equivalent CN ratio calculated in the N-2 step and the equivalent CN ratio calculated in the 1-2 step when the previous stage is the first stage, or up to the previous stage when the previous stage is the second stage or later. N-3th step of comparing the smallest equivalent CN ratio among the equivalent CN ratios of the analog interference wave and outputting the smaller equivalent CN ratio;
The addition result of the equivalent CN ratio output in the (N-1) th step and the equivalent CN ratio output in the (N-3) th step are added to output the Nth output signal CN ratio. And a digital terrestrial broadcast channel quality evaluation program characterized in that

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