JP2001036506A - Digital radio transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily grasp a state of a transmission channel with a simple and inexpensive configuration in a digital radio transmission system where a transmitter side applies error correction coding to a signal to be sent, applies digital modulation to the obtained signal, transmits the modulated signal as a radio wave, a receiver side digitally demodulates the received signal, applies error correction decoding to the demodulated signal to reproduce the original signal. SOLUTION: A transmitter 31 is provided with an error measurement pattern signal generating section 35, an OFDM(orthogonal frequency division multiplex) transmission section 33 transmits an error measurement pattern signal, a receiver 41 is provided with a transmission error measurement section 45 that has an error count section 46 that counts number of times of transmission error of a pattern signal, an error estimate section 47 that estimates an error before correction depending on a state of error correction, and an error display section 48 that receives outputs to display the error state.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a digital radio transmission technology,
OFDM (Orthogonal Frequency Divi)
TECHNICAL FIELD The present invention relates to a technology for grasping an error state of a transmission line when performing wireless television relay broadcasting by a multiplexing method.

[Industrial applications]

[0002]

2. Description of the Related Art A line level in a television relay employing an analog radio system is grasped by setting a reception level meter on a receiving side and observing both the instruction and a screen actually relayed. ing. However, for example, when broadcasting a marathon event on television,
Since a plurality of mobile relay vehicles and receiving bases are provided, and transmission is performed while moving, it is difficult to grasp the state of the transmission line.

[0003] Various techniques for transmitting information using digital wireless transmission techniques have been developed.
Since the DM modulation method has a feature that it is resistant to disturbances such as fading and multipath, which are particularly likely to occur due to movement, it is being adopted as a digital modulation method for digital audio broadcasting for mobile objects and digital terrestrial television broadcasting. There is a mobile radio television relay system as an application of such an OFDM modulation system, and it has been proved to be particularly effective when used for mobile relay such as a marathon.

[0004]

However, the digital modulation system including the OFDM modulation system has a problem that, although it is strong against disturbance, once it breaks down due to a transmission error, its influence is very large. Therefore, when a digital wireless device is used for mobile relaying, it is important to understand the line status.

FIG. 1 shows a transmission system using a conventional OFDM modulation system. In the OFDM modulation scheme, a transmission error is enhanced by using an error code. Sender OFDM
The transmission device 11 includes an error correction encoder 12 that performs error correction encoding on an input signal to be corrected, and an OFDM transmission unit 1 that performs OFDM modulation on the output signal and outputs a transmission signal having a predetermined frequency.
3 and a transmission antenna 14 are provided.

[0006] The OFDM receiving apparatus 21 on the receiving side demodulates a signal transmitted from the transmitting antenna 14 and received by the receiving antenna 22, and performs error correction by receiving the demodulated signal here. An error correction decoder 24 is provided, and an error-corrected signal is output here as an output signal.

In such an OFDM transmission system,
Even if there is an error in the received signal, if the error is within the correction limit, it will be corrected and it will be received correctly.However, whether there was a minor error or a large error near the correction limit is determined by an error rate measurement device. Cannot be accurately determined unless a pattern signal is input.

Further, in mobile radio television relay broadcasting, fading and multipath are severe due to the influence of terrain and features such as buildings, and the state of transmission errors changes from moment to moment. However, it is extremely difficult to accurately grasp the status of the line. In particular, in a marathon radio relay broadcast, various situations occur depending on the course, and in some cases, a situation may occur where a signal cannot be transmitted from a mobile relay vehicle having an OFDM transmission device to a receiving location. In some cases, it is necessary to transmit a signal from a mobile station via another mobile station, which makes it more difficult to grasp the line status.

In order to reduce such a drawback, as shown by a broken line in FIG.
1, a test pattern signal generator 15 and a switch 16 are provided to supply the test pattern signal to the OFDM transmitting apparatus 13 bypassing the error correction encoder 12 and to the OFDM receiving apparatus 21 on the receiving side. In addition to the above, a switch 25 and an error rate measuring device 26 are provided, and a test run is performed along a predetermined marathon course before an actual broadcast is performed. It has been proposed to grasp the status of a line that changes from moment to moment.

However, since it is necessary to provide the test pattern signal generator 15 on the transmitting side and the error rate measuring device 26 on the receiving side, there is a problem that the whole system becomes complicated. In particular, the test pattern signal generator 15 on the transmitting side usually generates many types of test pattern signals, as well as an error adding function, an error measuring function,
Since it has many functions such as a storage device and a printer, there is a problem that it is large, complicated and expensive. For example, a motorcycle may be used to broadcast a marathon mobile television broadcast, but there is no room for mounting a large test pattern signal generator on a motorcycle with two passengers as described above.

An object of the present invention is to eliminate or alleviate the above-mentioned drawbacks of the conventional radio communication system and to provide a digital radio transmission system capable of easily grasping the line status with a simple configuration. .

Another object of the present invention is to provide a simple, small-sized, and inexpensive radio-television relay broadcasting system using a digital code modulation system such as an OFDM modulation system. It is intended to provide a transmitting device.

Still another object of the present invention is to provide a receiving apparatus capable of easily grasping the state of a line in a radio television relay broadcast using a digital modulation scheme such as an OFDM modulation scheme.

[0014]

In a wireless digital transmission system according to the present invention, a transmitting apparatus encodes a signal to be transmitted by error correction, digitally modulates an obtained signal, and wirelessly transmits the signal. In a digital radio transmission system in which a received signal is digitally demodulated and further error-corrected and decoded to reproduce an original signal, the transmitting apparatus includes an error-measurement pattern signal for generating an error-rate-measurement pattern signal. And a transmission error measuring section for processing the pattern signal and outputting information on a transmission error.

According to the present invention, on the transmission side, a signal to be transmitted is subjected to error correction coding, the obtained signal is digitally modulated and transmitted by radio, and on the reception side, the received signal is digitally demodulated and further subjected to error correction decoding. In a transmitting apparatus in a digital wireless transmission system in which an original signal is reproduced, an error measuring pattern signal generating section for generating a pattern signal for measuring an error rate, and selecting the pattern signal and an error correction coded signal And a switch for performing digital modulation and wireless transmission.

Further, according to the present invention, on the transmitting side, a signal to be transmitted is subjected to error correction coding, the obtained signal is digitally modulated and transmitted by radio, and the receiving apparatus digitally demodulates the received signal and further performs error correction decoding. Receiving a pattern signal for error rate measurement generated from an error measurement pattern signal generator provided in the transmission device, and receiving the digital signal. A transmission error measuring unit for processing a signal obtained by demodulation and outputting information on a transmission error is provided.

In the above-described digital radio transmission system according to the present invention and the transmission device and the reception device used therefor, it is preferable that the signal to be transmitted is error-correction-coded and OFDM-modulated. Furthermore, in this case,
It is particularly preferable that the transmitting device is provided in a mobile relay vehicle that performs mobile radio television relay broadcasting, and the receiving device is provided in another mobile relay vehicle or a receiving base that receives a signal transmitted from the mobile station. It is.

In one embodiment of the receiving apparatus according to the present invention, the transmission error measuring section displays an error count section for counting the number of transmission errors of the pattern signal, and an error status is displayed by the output of the error counting section. An error indicator may be provided.

In another embodiment of the receiving apparatus according to the present invention, the transmission error measuring section includes an error counting section for counting the number of transmission errors of the pattern signal, and an error correction section for correcting an error of the pattern signal. And an error estimator for estimating an error before correction based on the state of error correction in the error corrector, and an output of at least one of the error counter and the error estimator is displayed as information indicating the state of the transmission error. And an error display unit that performs the operation.

In the above-described present invention, the transmitting apparatus is provided with an error measuring pattern signal generating section for generating a pattern signal for measuring an error rate, and the receiving apparatus processes the pattern signal and relates to a transmission error. Since a transmission error measuring unit for outputting information is provided, it is not necessary to separately arrange a test pattern generator on the transmitting side, and it is not necessary to separately provide an error rate measuring device on the receiving side.
The configuration of the entire system can be simplified, the size and weight can be reduced, and the cost can be reduced. Therefore, the digital wireless transmission system according to the present invention is particularly suitable for application to mobile television relay broadcasting, and can easily and accurately grasp an error state of a transmission line. Also, not only during a test drive, but also during an actual relay broadcast, the status of the transmission line can be quickly grasped. Can deal with.

[0021]

FIG. 2 is a block diagram showing the entire configuration of an embodiment of a digital transmission system according to the present invention. As in the conventional transmitting apparatus shown in FIG. 1, the transmitting apparatus 31 includes an error correction encoder 32 for performing error correction encoding of an input signal to be transmitted, and OFDM-modulating the output signal to obtain a signal having a predetermined frequency. An OFDM transmission unit 33 that outputs a transmission signal,
A transmission antenna 34 is provided. In the present invention, the transmitting apparatus 31 further includes a pattern signal generating section 35 for generating a pattern signal for error measurement, and either the output signal of the error correction coding section 32 or the output signal of the pattern signal generating section described above. Select the above-mentioned OFDM transmission unit 33
And a switch 36 for supplying to the power supply.

The receiving-side OFDM receiving apparatus 41 has a receiving antenna 42 for receiving a signal transmitted from the transmitting antenna 34 and a signal demodulated by the receiving antenna.
An OFDM receiver 43 and an error correction decoder 44 for performing error correction by receiving a signal demodulated here are provided, and a pattern signal output from an error measurement pattern signal generator 35 provided in the transmitter is transmitted. A transmission error measuring unit 45 is provided for processing and outputting information on transmission errors.

In this embodiment, the transmission error measuring section 45 provided in the above-mentioned receiving apparatus 41 includes an error counting section 46 for counting the number of transmission errors of the received pattern signal, and an error correction decoding section for the pattern signal. An error estimating unit 47 for estimating an error before correction according to the error correction situation in 44
And an error display unit 48 for displaying at least one of the outputs of the error counting unit 46 and the error estimating unit 47 as information indicating the status of the transmission error, and the output of the error counting unit 46 and the error estimating unit 47 described above. And an error information output section 49 for outputting error information. A display device 50 including a storage device for storing the error information output from the error information output unit 49 is connected to the receiving side.

Next, the operation of the above-described digital radio transmission system according to the present invention will be described by taking as an example the case of performing a marathon radio television relay broadcast. In the case of a marathon relay, a device that digitally compresses an output video signal of a camera that captures an image of a subject and a transmission device 31 that transmits a digital signal output from the camera are mounted on a mobile broadcast van or the like. A receiving device 41 for receiving a transmitted signal is provided at a receiving base or another mobile relay van. When performing television relay broadcasting while moving, there is a possibility that large fading or multiple paths may occur. Therefore, it is necessary to test the marathon course in advance to grasp the condition of the transmission line.

When performing the test run, while switching the switch 36 of the transmitting device 31 mounted on the mobile relay van, the video signal obtained by actually capturing an image is transmitted as usual, or a test signal is transmitted. The coded predetermined pattern signal generated from the pattern signal generating section 35 is supplied to the OFDM transmitting section 33 via the switch 36, and the OFDM-modulated pattern signal is transmitted from the transmitting antenna 34 to check the state of the transmission line. To check. When the switch 36 is used as a test side to transmit an encoded predetermined pattern signal generated from the pattern signal generation unit 35, the reception side transmits the OFDM tone pattern signal received by the reception antenna 42 to the OFDM reception unit 43. And demodulates the output pattern signal from the OFDM receiving section into an error counting section 46 of a transmission error measuring section 45.
To count errors.

The pattern signal demodulated by the OFDM receiver 43 is also supplied to an error correction decoder 44, where error correction is performed. On the transmission side, when a normal video signal is transmitted, the signal output from the error correction decoding unit 44 is digitally expanded as usual, and then displayed on a monitor or recorded on a VTR. Or sent to another station. Further, the above-described error estimating unit 47 estimates an error before correction based on the error correction status in the error correction decoding unit 44. The error correction of the pattern signal may be performed separately from the error correction decoding unit 44 that corrects the error of the original signal. Further, the output signals of the error counting section 46 and the error estimating section 47 are supplied to an error display section 48. The error display section 48 outputs and displays at least one of these two output signals.

The output signals of the error counting section 46 and the error estimating section 47 are also supplied to a display device 50 with a storage device via an error information output section 49. That is, the error information output unit 49 includes the transmission error measurement unit 45 and the display device 5.
0 is an interface for outputting error information when requested by the display device.

Note that, in the embodiment shown in FIG.
The output signal of the receiving unit 43 is also output to the output terminal 51. By connecting the existing error rate measuring device 26 shown in FIG. 1 to this output terminal 51, the error rate can be measured as in the conventional case. However, in the present invention, it is not always necessary to measure the error rate by such an error rate measuring device.

As described above, the error information collected by the error measuring section 45 on the receiving side while transmitting the encoded predetermined pattern signal generated from the pattern signal generating section 35 during the test running is transmitted to the display device 50. Is stored in the storage device. Such a display device 50 can be configured with, for example, a personal computer. In that case, the error counting section 46
The output signal of the error estimating unit 47 can be stored as electronic data in a RAM or a hard disk. The stored electronic data can be read out and displayed in real time or off-line, and can be used to analyze the line status. In this case, simply storing the error information in a time-series manner makes it easier to grasp the line status by comparing with the moving route. In addition, it can be used as a material for grasping the state of the transmission line at the time of mobile transmission performed on the same route. That is, it is common to use the same marathon course, and if data on past error information is stored, the analysis of the line condition in the next mobile transmission becomes accurate and easy.

When an actual digital marathon relay broadcast is performed, an optimum relay can be performed in accordance with the line conditions grasped in the test run described above. In addition, since the error estimating unit 47 is provided, it is possible to grasp the status of the line that changes every moment during actual relaying, and to compare or refer to the error information collected during the test drive. The line status can be accurately grasped, and optimal television relay broadcasting can be performed without being affected by the line status.

The test pattern signal generated by the pattern signal generator 35 provided in the transmission device 31 described above is:
It is standardized as CCITT Recommendation 0.151, and the pattern signal generation unit 35 that generates a pattern signal based on this can be easily realized in a small size, and can be incorporated in the transmission device 31. 2 ²³ -1 patterns (8388) excluding the pattern of all “0” specified in the above-mentioned CCITT Recommendation 0.151
FIG. 3 shows an example of the configuration of the pattern signal generator 35 that generates (607 patterns) test patterns.

The test pattern of this embodiment is of a pseudo random sequence, and can be realized by using a shift register and a simple logic circuit. In FIG. 3, 23 D flip-flops 101 to 123 are cascaded, and an output signal of a first-stage D flip-flop 101 is supplied as an input signal to a next-stage D flip-flop 102. Is supplied as an input signal to the next D flip-flop 103, and so on.
An exclusive OR of the output signal of the eighth D flip-flop 108 and the output signal of the last D flip-flop 123 is obtained by the logic circuit 124, and the output signal of this logic circuit is input to the first D flip-flop 101. Supply as The shift register thus configured is a general M-sequence random signal generator. The output signal of the last D flip-flop 123 is inverted by the inverter 125 to be a test pattern signal.

In the present invention, by providing the test pattern signal generator 35 compatible with the international standard in the transmitter 31 as described above, the signal for error rate measurement as shown by the broken line in FIG. There is no need to provide the generator 15 separately from the transmitter. Moreover, since the pattern signal generated from the pattern signal generator 35 conforms to international standards, a general error rate measuring device can be used on the receiving side.

FIG. 4 shows an example of the configuration of the error counting section 46 provided in the receiving device 41. Input terminal 201
Receives the pattern signal output from the OFDM receiving unit 43 shown in FIG. 2 and supplies it to one input terminal of the exclusive OR circuit 202. This pattern signal is further supplied to an error measurement pattern signal generating circuit 203, and from this, an input pattern signal, for example, as disclosed in Japanese Patent Laid-Open No. 57-46553.
Code synchronization is performed by the method disclosed in Japanese Patent Application Laid-Open Publication No. H11-157, and a code-synchronized error measurement pattern signal is generated and supplied to the other input terminal of the exclusive OR circuit 202.

FIG. 5 shows a pattern signal S1 supplied to the input terminal 201, an error measurement pattern signal generation circuit 203,
5 shows an error measurement pattern signal S2 output from the XOR and an output signal S3 of the exclusive OR circuit 202.
As is apparent from FIG. 5, the exclusive OR circuit 203 outputs a signal of a logic H level only when the pattern signals supplied to its two input terminals do not match, and otherwise outputs a logic L. The number of error bits can be measured by counting the output signal of the exclusive OR circuit 202 with the counter 204. The timer 205 shown in FIG. 4 sets the counting period of the counter 204, and can operate the counter 205 at a cycle corresponding to, for example, 2,000,000 bits.

FIG. 3 shows a detailed configuration of the error estimator 47 shown in FIG. In this example, the data bits before correction and the data bits after correction generated by the error correction unit 44 are supplied to the input terminals 301 and 302, respectively.
The exclusive OR of these data bits is taken by an exclusive OR circuit 303. When the two bits match, the output of the exclusive OR circuit 303 goes to a logic L level, but when there is a mismatch, it goes to a logic H. This is similar to the output of the exclusive OR circuit 202 in the error counting section 46 described above. Therefore, the error estimator 47 also outputs the output signal of the exclusive OR circuit 303. The error estimation value can be output by counting by the counter 304 whose counting time is set by the timer 305. In this example, the configurations of the error counting unit 46 and the error estimating unit 47 are similar, and the same circuit can be used, which is economical.

FIG. 7 shows a display mode of the error display section 48 shown in FIG. 2 on the display panel. In this example, the error display unit 48 displays the degree of the error in five levels.
It has five LEDs 401-405. First LE
D401 is lit when the error rate is 1E-2 or more, second LED 402 is lit when 1E-3 to less than 1E-2, and third LED 403 is when 1E-4 to less than 1E3. And the fourth LED 404 indicates 1E-5 to 1E-5.
The LED is turned on when the error rate is less than E-4, and the fifth LED 405 is turned on when the error rate is less than 1E-5 (pseudo error free). As described above, the error rate that changes every moment can be clearly displayed by the five-stage LED display that is easy to determine in real time.

As described above, the timer 205 provided in the error counting section 46 and the timer 30 provided in the error estimating section 47
5 is operated in a cycle corresponding to, for example, 2,000,000 bits, and if there is an error of 0 to 19 bits in this cycle, the fifth row indicated as UNDER is displayed.
LED 405 is turned on. If there is an error in 20 to 199 bits, the fourth LED 404 is turned on. Similarly, the LEDs 403 and 402 are turned on,
If there is an error of 20,000 bits or more in the cycle of the dimers 205 and 305, the first displayed as 1E-2
LED 401 is turned on. Now, assuming that the bit rate of the OFDM receiving unit 41 shown in FIG. 2 is 16 Mbps, the error display unit 48 updates the content of the display every 0.125 seconds. Can be.

The present invention is not limited to the above-described embodiment, but can be variously modified and modified. For example, in the above-described embodiment, in a marathon television relay broadcast, the transmitting device is mounted on a mobile relay van and the receiving device is arranged in another mobile relay van or a receiving base. The same can be applied to. Further, the present invention can be applied not only to television relay broadcasting but also to many other digital wireless transmissions. Further, in the above-described embodiment, the OFDM modulation method is adopted as the digital modulation method, but another digital modulation method may be adopted.

In the above-described embodiment, the transmission error measuring section 45 of the receiving apparatus is provided with the error estimating section 47 in addition to the error counting section 46 and the error displaying section 48. Can be omitted. Further, in this embodiment, the error estimating unit 47 outputs the data bits before correction from the error correction decoding unit 44 that processes the original signal,
Although the error is estimated by using the corrected data bits, an error correction decoding circuit may be provided in the error estimating unit. In the embodiment, the LED display of five stages has been described as a display example of the error display unit.
Of course, the present invention is not limited to this, and it is also possible to display errors by peak-holding them in a bar graph like a sound level meter.

[0041]

According to the digital radio transmission system of the present invention described above, the transmitting apparatus is provided with the pattern signal generating section for generating the test pattern signal. An error measuring unit that measures a transmission error by processing a pattern signal from a pattern signal generating unit provided in the transmitting device while eliminating the need to arrange a complicated and expensive test pattern signal generating device. Is provided, there is no need to provide a conventional error rate measuring device separately from the receiving device on the receiving side.
In this way, the status of the digital wireless transmission line can be easily and accurately grasped.

Further, according to the present invention, the transmission error rate can be measured and displayed in real time without using a large-scale device, for example, both when the error rate is measured in a test drive and during normal operation. Therefore, the error information obtained in the test run is stored, and when transmitting an actual signal, the error information obtained in the test run is read out and displayed, and the information is constantly changed while referring to the error information. This makes it possible to easily and accurately grasp the status of the line to be connected in real time, and is extremely useful especially in radio television relay broadcasting including mobile relay vehicles.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a conventional digital wireless transmission system using an OFDM modulation scheme.

FIG. 2 is a block diagram showing a configuration of an embodiment of a digital wireless transmission system using an OFDM modulation method according to the present invention.

FIG. 3 is a block diagram showing a configuration of an example of a pattern signal generator shown in FIG. 2;

FIG. 4 is a block diagram illustrating a configuration of an example of an error counting unit illustrated in FIG. 2;

FIG. 5 is a signal waveform diagram for explaining the operation.

FIG. 6 is a block diagram illustrating a configuration of an example of an error estimating unit illustrated in FIG. 2;

FIG. 7 is a diagrammatic plan view showing a configuration of an example of a display portion of an error display section shown in FIG. 2;

[Explanation of symbols]

31 transmission device, 32 error correction coding unit, 33
OFDM transmitting section, 34 transmitting antenna, 35 pattern signal generating section, 41 receiving apparatus, 42 receiving antenna, 43 OFDM receiving section, 44 error correction decoding section,
45 transmission error measuring unit, 46 error counting unit, 47
Error estimation unit, 48 error display unit, 49 error information output unit, 50 display device with storage device

Continued on the front page (72) Inventor Satoshi Oishi 5-6-16 Ikegami, Ota-ku, Tokyo Inside Ikegami Shinshinki Co., Ltd. (72) Inventor Sumio Nakagawa 5-6-16 Ikegami, Ota-ku, Tokyo Nobushin Ikegami (72) Inventor Ryoichi Yajima 2-2-1 Jinnan, Shibuya-ku, Tokyo Japan Broadcasting Corporation Japan Broadcasting Center (72) Inventor Seiichi Koshi 2-2-1 Jinnan, Shibuya-ku, Tokyo Japan Broadcasting Corporation F term in the broadcasting center (reference) 5C059 KK45 RA04 RD03 RF01 RF04 SS02 UA02 UA05 UA38 5K014 AA01 BA05 EA01 FA09 GA02 GA03 5K022 DD00 DD13 DD19 DD31

Claims (13)

[Claims] 1. A transmitting apparatus performs error correction coding on a signal to be transmitted, digitally modulates the obtained signal and wirelessly transmits the signal, and a receiving apparatus digitally demodulates a received signal and further performs error correction decoding. In a digital wireless transmission system that reproduces the original signal by
The transmission device includes an error measurement pattern signal generation unit that generates an error rate measurement pattern signal, and the reception device includes a transmission error measurement unit that processes the pattern signal and outputs information about a transmission error. A digital wireless transmission system comprising: 2. The digital signal processing apparatus according to claim 1, wherein the transmitting apparatus performs OFDM modulation on a signal obtained by performing error correction coding on a signal to be transmitted, and the receiving apparatus performs OFDM demodulation on the received signal. Wireless transmission system. 3. The transmitting device is provided in a mobile relay vehicle that relays mobile radio television, and the receiving device is connected to another mobile relay vehicle or a receiving base that receives a signal transmitted from the mobile relay vehicle. 3. The device according to claim 2, wherein
2. The digital wireless transmission system according to 1. 4. A transmission error measuring section provided in the receiving apparatus, comprising: an error counting section for counting the number of transmission errors of the pattern signal; and an error display section for displaying an error status based on an output of the error counting section. The digital wireless transmission system according to claim 3, wherein the digital wireless transmission system is provided. 5. A transmission error measuring section provided in the receiving apparatus, wherein: an error counting section for counting the number of transmission errors of the pattern signal; an error correcting section for correcting an error of the pattern signal; An error estimator for estimating an error before correction according to the error correction status of the error estimator, and an error indicator for displaying at least one output of the error counter and the error estimator as information indicating the status of the transmission error. The digital wireless transmission system according to claim 2, wherein: 6. The information processing apparatus according to claim 1, wherein information relating to a transmission error due to a pattern signal output from said transmission error measuring unit is stored in a display device having a storage device, and the stored information is displayed. The digital wireless transmission system according to any one of the above. 7. A transmitting side performs error correction coding on a signal to be transmitted, digitally modulates the obtained code and wirelessly transmits the obtained code, and a receiving side digitally demodulates the received signal and further performs error correction decoding to obtain an original signal. In a transmission device in a digital wireless transmission system configured to reproduce the signal of
An error measurement pattern signal generator for generating an error rate measurement pattern signal, and a switch for selectively digitally modulating the pattern signal and the error-correction-coded signal and wirelessly transmitting the same are provided. Transmission device for digital wireless transmission. 8. The transmission apparatus for digital radio transmission according to claim 7, wherein the signal to be transmitted is error-correction-coded and OFDM-modulated. 9. A transmitting side performs error correction coding on a signal to be transmitted, digitally modulates the obtained code and wirelessly transmits the code, and a receiving device digitally demodulates the received signal.
Further, in a digital wireless transmission system in which the original signal is reproduced by error correction decoding, receiving a pattern signal for error rate measurement generated from an error measurement pattern signal generator provided in the transmission device, A receiving device for digital wireless transmission, comprising a transmission error measuring unit for processing a signal obtained by digital demodulation and outputting information on a transmission error. 10. An OFDM receiver for OFDM demodulating a digitally modulated signal transmitted from the transmitting side,
10. The digital wireless transmission receiver according to claim 9, wherein the test pattern signal output from the OFDM receiver is supplied to the transmission error measuring unit. 11. The transmission error measuring section includes an error counting section for counting the number of transmission errors of the pattern signal, and an error display section for displaying an error status based on an output of the error counting section. The receiving device for digital wireless transmission according to claim 9 or 10, wherein 12. A transmission error measuring section provided in the receiving apparatus, wherein: an error counting section for counting the number of transmission errors of the pattern signal; an error correction section for correcting an error of the pattern signal; An error estimator for estimating an error before correction according to the error correction status of the error estimator, and an error display unit for displaying at least one output of the error counter and the error estimator as information indicating the status of the transmission error. The receiving device for digital wireless transmission according to claim 9 or 10, wherein: 13. The display device according to claim 9, further comprising a display device with a storage device for storing and displaying information relating to a transmission error due to a pattern signal output from the transmission error measurement unit. Receiver for digital wireless transmission.