JPH0823325A - Digital transmission system and its burst error countermeasure method - Google Patents

Abstract

PURPOSE:To avoid much noise from being generated in a reproduced sound signal even when a hit of a radio wave takes place due to occurrence of fading or the like in a radio channel resulting that a burst error is caused in digital data. CONSTITUTION:A reception circuit 4 receives digital data via a radio channel. A frame synchronization pattern of the digital data is detected by a frame synchronization detection circuit 5. When the frame synchronization detection circuit 5 cannot detect a frame synchronization pattern, it is regarded that out of synchronism takes place and a discrimination circuit 6 discriminates the presence of a burst error. When the burst error is detected, a zero interpolation control circuit 7 processes digital data so as to make a sound signal reproduction output zero when the burst error takes place. The noise resulting from the burst error is not produced in a sound signal outputted from a D/A converter 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital transmission system for transmitting a digital signal such as an acoustic signal, and more particularly to a burst error countermeasure method in this type of system.

[0002]

2. Description of the Related Art As a digital data wireless transmission system, a system is known in which an acoustic signal picked up by an acoustic sensor or the like is converted into digital data and wirelessly transmitted. That is, in the device on the transmitting side, first, an acoustic signal is picked up by an acoustic sensor or the like, the acoustic signal is converted into digital data, and then transmitted wirelessly to the device on the receiving side. In the device on the receiving side, the digital data wirelessly received from the device on the transmitting side is converted into an analog signal, and the obtained analog signal is reproduced and output as an acoustic signal. Further, the synchronization between the device on the transmission side and the device on the reception side can be realized by adding a synchronization pattern to a frame used for transmitting digital data.

[0003]

However, in the system having such a configuration, when fading occurs in the wireless transmission line, the receiving device can normally receive the digital data due to the instantaneous interruption of the radio wave. Disappear. When such a situation occurs, a burst-like data error occurs, as indicated by "unreceivable" in FIG. 4, and the reproduced acoustic signal contains much noise.

The present invention has been made for the purpose of solving such a problem, and even in the case where a momentary interruption of radio waves occurs due to fading or the like in a wireless transmission line, a device on the receiving side has The purpose is to prevent noise, which is the influence of burst errors, from appearing in the reproduced signal.

[0005]

In order to achieve such an object, a burst error countermeasure method according to the present invention comprises a step of wirelessly transmitting an acoustic signal and the like as digital data, and receiving the transmitted digital data. A step of detecting a burst error occurring in the transmitted digital data, and a step of replacing the burst error data in the received digital data with a predetermined value when the burst error is detected. Is characterized by.

The digital transmission system according to the present invention further comprises means for wirelessly transmitting acoustic signals and the like as digital data, means for receiving the transmitted digital data, and detection of burst errors occurring in the transmitted digital data. Means for replacing the burst error data in the received digital data with a predetermined value when a burst error is detected.

In the present invention, synchronization information is added to digital data at the time of transmission, the synchronization information is used at the time of reception to synchronize with the transmission side, and a burst error is detected when a loss of synchronization occurs. Is characterized by.

[0008]

In the present invention, first, acoustic signals and the like are transmitted and received as digital data. In addition, during this transmission / reception, a burst error that occurs in digital data due to fading of a wireless transmission path or the like is detected, and when the burst error is detected, the burst error data in the received digital data has a predetermined value, for example, zero. Is replaced by. Therefore, in the present invention, even if the transmitted digital data contains a burst error, the influence of the burst error on the signal such as the acoustic signal obtained from the received digital data, for example, a large amount. There is no noise. Therefore, in the present invention, a suitable burst error countermeasure is realized in digital transmission of audio signals and the like.

Further, in the present invention, burst error detection is performed in response to out-of-sync detection. That is, when synchronizing data is added to the digital data when transmitting and receiving the digital data, and when synchronous transmission is performed between the transmitting and receiving devices, burst errors are detected when the synchronization is lost, so that the above-described respective operations are preferable. Will be realized.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration of a transmitting side device in a system according to an embodiment of the present invention, and FIG. 2 shows a configuration of a receiving side device.

The device on the transmission side shown in FIG. 1 comprises an A / D converter 1, a frame synchronization pattern addition circuit 2 and a transmission circuit 3. The A / D converter 1 converts the acoustic signal picked up by an acoustic sensor or the like into digital data, and the frame synchronization pattern adding circuit 2 adds a frame synchronization pattern to this digital data.
The transmission circuit 3 wirelessly transmits the digital data to which the frame synchronization pattern is added from the antenna.

The receiving side device shown in FIG. 2 comprises a receiving circuit 4, a frame synchronization detecting circuit 5, a judging circuit 6, a zero interpolation control circuit 7 and a D / A converter 8. The receiving circuit 4 receives the digital data transmitted from the transmitting side device through the antenna, demodulates the digital data, and supplies it to the frame synchronization detecting circuit 5. The frame synchronization detection circuit 5 detects the frame synchronization pattern added by the frame synchronization pattern addition circuit 2 to synchronize the transmission side device and the reception side device. When synchronization is acquired by the frame synchronization detection circuit 5, the digital data received and demodulated by the reception circuit 4 is converted into an analog signal by the D / A converter 8,
This analog signal is supplied to a circuit in the subsequent stage (not shown) as a reproduced acoustic signal.

The feature of this embodiment resides in that, when out-of-synchronization is detected in the frame synchronization detection circuit 5, the acoustic signal in the period in which a burst error occurs is interpolated with a zero value. That is, when the frame synchronization detection circuit 5 cannot detect the frame synchronization pattern, the determination circuit 6 detects the burst error in accordance with this, and when the burst error is detected, the zero interpolation control circuit 7 Command zero interpolation to. The zero interpolation control circuit 7
As shown in FIG. 3, a period in which a burst error occurs and normal reception cannot be performed (a period of “unreceivable” in the figure) is interpolated so that the value of the generated acoustic signal becomes zero. .

Therefore, in this embodiment, even if a radio wave instantaneous interruption occurs due to fading or the like in the wireless transmission path of the digital data, the burst error generated in the digital data due to the radio interruption is reproduced. A large amount of noise is not generated in the generated audio signal, and a reproduced audio signal with less noise than in the past can be realized.

[0016]

As described above, according to the present invention,
Since a burst error in digital data is detected and the burst error data is replaced with a predetermined value in response to the detection, it is possible to prevent a large amount of noise from being generated in a signal such as an acoustic signal obtained from the received digital data. You can Therefore, according to the present invention, it is possible to realize a digital transmission system that is resistant to fading in a wireless transmission path. Furthermore, since the burst error can be detected in accordance with the detection of the loss of synchronization, the above-described effect can be realized with a relatively simple circuit configuration.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a system according to an exemplary embodiment of the present invention, particularly a configuration of a transmission side device thereof.

FIG. 2 is a block diagram showing a configuration of a receiving side apparatus in this embodiment.

FIG. 3 is a reproduced sound signal diagram showing the effect of this embodiment.

FIG. 4 is a reproduction acoustic signal diagram showing a conventional problem.

[Explanation of symbols]

 1 A / D converter 2 Frame synchronization pattern addition circuit 3 Transmission circuit 4 Reception circuit 5 Frame synchronization detection circuit 6 Judgment circuit 7 Zero interpolation control circuit 8 D / A converter

Claims (3)

[Claims] 1. A step of wirelessly transmitting an acoustic signal or the like as digital data, a step of receiving the transmitted digital data, a step of detecting a burst error occurring in the transmitted digital data, and a burst error being detected. And a burst error data in the received digital data is replaced with a predetermined value, the burst error countermeasure method. 2. A means for wirelessly transmitting an acoustic signal or the like as digital data, a means for receiving the transmitted digital data, a means for detecting a burst error occurring in the transmitted digital data, and a burst error being detected. And a means for replacing the burst error data in the received digital data with a predetermined value in the case of being processed, the digital transmission system. 3. The method or system according to claim 1 or 2, wherein synchronization information is added to digital data at the time of transmission, synchronization is performed at the transmission side by using the synchronization information at the time of reception, and a synchronization loss occurs. A method or system characterized by performing bursty error detection.