JPH066388A - Unequal-length encoding transmission system - Google Patents

Abstract

PURPOSE:To improve the transmission efficiency of effective data as to a system which stores and sends out unequal-length encoded data, compressing the unequal-length encoded data according to the storage state, and inserting dummy data and performing transmission. CONSTITUTION:The output of an unequal-length encoder(ENC) 2 is stored in a transmitting buffer(SBF) 4, a monitor circuit(SUP) 7 controls the compressibility of the ENC2 according to the storage contents, and if the contents of SBF4 become deficient, a switch(SW) 3 is controlled to insert the dummy data from a dummy data generating circuit(DDG) 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an unequal length coding transmission system used for transmitting various data.

[0002]

2. Description of the Related Art As shown in the block diagram of FIG. 2, a transmitted data 1 becomes an unequal length code of an indefinite length bit rate D _{n1 in} an unequal length encoder (hereinafter, ENC) 2 and a switch (hereinafter, SW). ) 3 through the send buffer (hereinafter SB
F) The bit rate D _{n2 of the} transmission path 5 after being accumulated in 4
Is transmitted as a code having a constant length.

However, for the purpose of preventing the transmitted data from becoming zero due to the reduction of the data amount of the transmitted data 1 and the empty contents of the SBF 4, the pseudo data which can be easily distinguished from the output of the ENC 2 is simulated. Data generation circuit (hereinafter,
DDG) 6, which is SW at a fixed ratio
It is inserted into the output of ENC2 via 3, and the content of SBF4 including this is monitored by a monitoring circuit (hereinafter referred to as SUP) 7. When the content of SBF4 is large, the compression rate of encoding by ENC2 is increased. , E if the content of SBF4 is small
Feedback control of the compression rate is performed in the direction of decreasing the compression rate of the encoding by NC2.

On the other hand, after the data of the bit rate D _n2 sent to the transmission path 5 is accumulated in the receiving buffer (hereinafter, RBF) 8, the pseudo data removing circuit (hereinafter, DDE) 9 removes the pseudo data. , Unequal length decoding (hereinafter,
Decoded in DEC 10 and transmitted data 1
Is transmitted as the reception data 11 equivalent to

[0005]

However, considering the amount of data, the amount of pseudo data accumulated in the SBF 4 is shown in FIG.
As described above, while the storage amount S sequentially increases with the passage of the time T, the similar storage amount S of the unequal-length coded data sent from the ENC2 tends to be as shown in FIG.
The total amount S of data stored in SBF4 is shown in FIG.
It can be estimated that the result is as shown in (C).

Therefore, the effective data amount to be transmitted is S _a in FIG. 3B at the time point t, and EN corresponding to this
As shown in FIG. 4, the compression rate R of C2 is S _{a when the} data amount S is S _a.
If so, R _a is optimal, but in the conventional case, S a
The data amount S _b of FIG. 3 (C) is used according to the total storage amount in the BF 4, and the bit rate D _n2 sent to the transmission path 5 after the compression of ENC2 is performed by the compression rate R _b of FIG. However, the absolute amount of effective data in the data is reduced, which causes a drawback that the transmission efficiency is deteriorated.

The present invention has been made by paying attention to such a drawback, and rationalizes compression in unequal length coding,
It is an object of the present invention to provide an unequal length coded transmission method that significantly improves the transmission effect of valid data.

[0008]

In order to achieve the above-mentioned object, the present invention compresses unequal length encoded data according to the amount of effective data to be transmitted, and when the data to be transmitted becomes insufficient. It is supposed that the pseudo data is inserted only in.

[0009]

Therefore, the compression rate is determined only by the amount of valid data, and the transmission efficiency of valid data is greatly improved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the block diagram of FIG. In the same figure, the transmitted data 1 is converted into unequal length encoded data by the ENC 2 as in the case of FIG. 2, but an SBF 4 is provided next to the ENC 2, and the unequal length encoded data is stored in the SBF 4. Only the amount is monitored by SUP7, and the compression rate of unequal length coding by ENC2 is feedback-controlled according to the content of SBF4. Only when the transmitted data 1 decreases and the content of SBF4 becomes insufficient. SW3 is switched, pseudo data from the DDG 6 is inserted, and the data is sent to the transmission line 5.

Therefore, the compression ratio of ENC2 is as shown in FIG.
According to the storage amount S _a of (B), R _{a of} FIG. 4 is always applied, and in the configuration of FIG. 1, since the content of SBF 4 is only valid data to be transmitted, it is transmitted at the bit rate D _n2. The effective data transmission efficiency in the transmission line 5 is significantly improved.

Contrary to FIG. 2, the data sent to the transmission line 5 as described above is first stored in the RBF 8 after the pseudo data is removed in the DDE 9 and then stored in the DEC 10.
In this case, the data is decoded and then sent as the received data 11.

[0013]

As is apparent from the above description, according to the present invention, the unequal length encoded data is compressed according to the amount of accumulated effective data to be transmitted, so that the effective data transmission efficiency is improved. Is significantly improved, so that a remarkable effect can be obtained in a method of transmitting various data as unequal length codes.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional example.

FIG. 3 is a diagram showing a data accumulation state.

FIG. 4 is a diagram showing a relationship between a data storage amount and a compression rate.

[Explanation of symbols]

 2 unequal length encoder 3 switch 4 transmission buffer 5 transmission path 6 pseudo data generation circuit 7 monitoring circuit

Claims (1)

[Claims] 1. A method of compressing unequal-length encoded data according to the storage status of the data and transmitting by inserting pseudo data, wherein the unequal-length data is transmitted according to the amount of effective data to be transmitted. An unequal-length coded transmission method in which encoded data is compressed, and the pseudo data is inserted only when the data to be transmitted becomes insufficient.