JPH0210933A - Burst signal transmission system - Google Patents

Abstract

PURPOSE:To ensure the reception of the succeeding burst from the head devising the system such that demodulation is applied continuously when a 3rd pattern different from a 1st pattern is detected after a 2nd pattern at the reception side and the initial mode of demodulation is transited when the 3rd pattern is not detected. CONSTITUTION:A new voice signal is inputted while a transmission station sends an end of burst(EOB) and a voice detector outputs a detection signal. The transmission station starts sending the next burst corresponding to the new voice signal from a frame next to the frame in which the transmission the EOB of the preceding burst is finished. In this case, each bit of a framing bit F is replaced by a inversion of F being the inverted pattern. On the other hand, the reception station detects the EOB to continue the fixing of the synchronization of a demodulator to await the bit inversion F at the head of the initial frame after the detection of EOB. When the inversion F is detected, the fixing of the synchronization of the detector is continued further to receive the succeeding burst. When no inverted F is detected, the synchronization fixing of the demodulator is opened and the mode is transited to the initial mode awaiting the succeeding burst.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a burst signal transmission system, and particularly to a burst signal transmission system in a digital communication system.

[Conventional technology]

While the audio signal is continuously input, it is digitized and sent out in bursts. Alternatively, when transmitting a series of data information to be transmitted in a burst, the data signal to be transmitted is framed, and in order to achieve frame synchronization on the receiving side, a framing bit (fr) is placed at the beginning of each frame.
A specific pattern for frame synchronization called ``aming bit'' is placed.

A demodulator of a receiving station fixes synchronization to a burst while receiving one burst transmitted from a certain transmitting station,
When reception is complete, the locking of synchronization is released and the mode shifts to an initial mode in which it waits for the next burst from this transmitting station or another transmitting station. In order to quickly and reliably transition this mode of operation, the end-of-burst (end-of-verse)
A pattern called (end of burst, EOB) is arranged so that the receiving side can detect the completion of burst reception.

Conventional burst signal transmission systems use a pattern in which framing bits are repeated over the length of one or two frames as EOB. Assuming that the number of repetitions is M, taking into account transmission errors, the receiving side determines that burst reception is complete when the framing bit is detected N (N5M) times out of M consecutive times.

[Problem to be solved by the invention]

In the conventional burst signal transmission method described above, EO is
Since E is detected by majority decision, a new signal to be transmitted is input to this transmitting station while the transmitting station is transmitting EOB, and EOB is detected.
If you start transmitting the next burst from the next frame after the transmission of The receiving station's demodulator is in the initial mode in the frame, and it takes a certain amount of time to achieve synchronization. Accordingly, reception cannot be performed until the demodulator is synchronized, and for example, if the signal to be transmitted is an audio signal, there is a drawback that the topic will be lost.

An object of the present invention is to provide a burst signal transmission system that allows the receiving side to reliably receive the next burst from the beginning even if the transmitting station starts transmitting the next burst from the next frame after completing transmitting the EOB. be.

[Means to solve the problem]

In the burst signal transmission method of the present invention, a finite-length digital signal to be transmitted is framed on the transmitting side, a predetermined first pattern is placed at the beginning of each frame, and the first pattern is placed after the last bit of the digital signal. In a burst signal transmission method in which a second pattern, which is a predetermined repetition of a pattern of In response to this new signal, a burst is sent in which the first pattern in the first frame is replaced with a predetermined third pattern different from this first pattern, and the receiving side replaces the first pattern with a predetermined third pattern. If the third pattern is detected at the beginning of the first frame after the first frame is detected, demodulation is continued; if the third pattern is not detected, the mode shifts to the initial mode of demodulation.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a time chart showing a burst frame structure in an embodiment of the present invention.

The following explanation assumes that the signal to be transmitted is an audio signal.

When a voice signal is input to a certain transmitting station, a voice detector detects this voice signal and outputs a detection signal. While this detection signal continues, the audio signal is digitized and framed by the encoder. A framing bit F is placed at the beginning of each frame, as indicated by F in FIG. The framing bits F are a specific pattern consisting of, for example, 16 bits.

Information bits of the digitized audio signal are arranged in periods other than the framing bit F of each frame. Also, when the input of the audio signal is finished and the detection signal of the voice detector disappears, an EOB, which is a repetition of the framing bit F M times, is placed after the last information bit, and the bit string created in this way becomes the first It is sent out in bursts as shown in the figure. The number of repetitions M is set so that the length of the EOB is, for example, one frame length.

The receiving station that receives this burst synchronizes the frame with the burst to be received by detecting the framing bit F in the received signal, and thereafter fixes the synchronization of the demodulator to this burst and continues receiving until it detects EOB. continue. E
As described above, the detection of OH is performed by a majority decision in which the framing bit F is detected N times out of M consecutive times.

Even if EOB is detected, as will be explained later, the synchronization of the demodulator continues to be fixed at least until the timing at which the framing bit of the next frame is located.

Now, when a new voice signal is input to the transmitting station while the transmitting station is transmitting an EOB and the voice detector outputs a detection signal again, the transmitting station will transmit the next burst corresponding to this new voice signal to the EOB of the previous burst. Transmission starts from the frame following the frame that has been transmitted. However, in this case, the framing bits of the first frame of the next burst are replaced with framing bits D, which is a pattern in which each bit of framing bit F is inverted. FIG. 1 illustrates this case.

On the other hand, the receiving station continues to fix the synchronization of the demodulator even after detecting EOB, and at the timing of the beginning of the first frame after detecting EOB, the receiving station will frame the next burst following the previous burst from the same transmitting station. It is determined that the next burst has been transmitted, the demodulator continues to be synchronized, and the next burst is received. Also, if framing pitch) F is not detected,
The locking of the demodulator's synchronization is released and the mode moves to an initial mode in which it waits for the next burst from the same transmitting station or another transmitting station.

When transmitting the next burst following the previous burst from the same transmitting station, the pattern of the framing bits placed at the beginning of the next burst can be easily called the framing bit F by inverting the normal framing bit F. Since the EO of the previous burst can be identified
Even if the framing bit F in B and the framing bit F at the beginning of the next burst are close to each other, the beginning of the next burst can be reliably detected. The pattern of framing bits placed at the beginning of the next burst is the same as the EO of the previous burst.
The pattern may be any pattern that is easily distinguishable from the framing bit F in B and is suitable for frame synchronization, and does not necessarily have to be an inversion pattern of the framing bit F.

〔Effect of the invention〕

As explained above, in the present invention, the transmitting side uses EO, which is a plurality of repetitions of the first pattern which is the framing bit
When the next burst starts to be transmitted from the next frame after the transmission of B is completed, the pattern of framing bits placed at the beginning of the burst is set to a third pattern different from the first pattern.
pattern, and the receiving side confirms that the third pattern is not detected at the beginning of the first frame after detecting EOB before moving to the initial mode.
Even if the transmitting station transmits the next burst following the previous burst, the beginning of the next burst can be reliably detected, and the effect is that it is possible to prevent the beginning frame of the next burst from becoming unreceivable.

F, F...Framing bit.

Claims (1)

[Claims] On the transmitting side, a finite-length digital signal to be transmitted is framed, a predetermined first pattern is placed at the beginning of each frame, and a predetermined plurality of predetermined times of the first pattern are placed after the last bit of the digital signal. In a burst signal transmission method in which a repeating second pattern is arranged and transmitted in a burst, when a new signal to be transmitted is input to the transmitting side while the second pattern is being transmitted, a signal is transmitted corresponding to the new signal. A burst is sent in which the first pattern in the first frame is replaced with a predetermined third pattern different from the first pattern, and the receiving side detects the second pattern and then replaces the first pattern with a predetermined third pattern different from the first pattern. A burst signal transmission system characterized in that when the third pattern is detected at the beginning, demodulation is continued, and when the third pattern is not detected, the mode shifts to an initial mode of demodulation.