JPH066234A - Decoder - Google Patents

Abstract

PURPOSE:To make it unnecessary to manually perform the mode switching operation of a decoding method at a reception side at the time of a data transmission between remote places. CONSTITUTION:A decoding device which receives plural different coded signals, and operates a decoding corresponding to the signals, is equipped with a decoding circuit 5, control circuit 6 which controls the decoding circuit 5, and oscillator 7. The control circuit 6 controls the decoding of the decoding circuit 5 by applying a composite control flag CF to the decoding circuit 5 in response to an error flag EF outputted from the decoding circuit 5 when the decoding which doesn't correspond to the coding is operated. and a clock signal CL from the oscillator 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decoding device.

[0002]

2. Description of the Related Art When data is transmitted between remote places, there are cases in which a plurality of types of data encoding methods are set on the transmitting side.

[0003]

For example, even if data is transmitted to the receiving side by a certain type of encoding method, the receiving side may not be able to decode the data as it is. In that case, it is necessary for the operator to manually select another decoding method on the receiving side by mode switching operation and to decode the data by making the decoding method of the data correspond to the coding method of the transmitting side. .

As described above, there is a problem that it is very complicated for the operator on the receiving side to manually perform the mode switching operation according to the type of encoding method of the data sent from the transmitting side.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a decoding device capable of easily and automatically transmitting data without requiring an operator to perform a mode switching operation of the decoding method on the receiving side.

[0006]

According to the present invention, there is provided a decoding device capable of receiving a plurality of differently encoded signals and performing decoding corresponding to the signals. The decoding device includes a decoding circuit, a control circuit that controls the decoding circuit, and an oscillator, and the control circuit outputs an error flag output from the decoding circuit when decoding that does not correspond to encoding is performed. And a clock signal from the oscillator to provide a decoding control flag to the decoding circuit to control the decoding of the decoding circuit.

The control circuit may be configured to have a counter which is reset by the previous error flag and counts the previous clock signal, and a latch circuit which latches the output of this counter.

Preferably, the oscillation frequency of the clock signal of the oscillator can be controlled.

The latch circuit may be provided with at least two.

[0010]

The decoding control flag is decoded when a decoding process which is not compatible with the encoding is performed in order to receive a plurality of differently encoded signals or data and perform the decoding corresponding to the signal. It is given to the circuit to automatically control the signal of the decoding circuit.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the examples described below are suitable specific examples of the present invention, and therefore, various technically preferable limitations are given, but the scope of the present invention particularly limits the present invention in the following description. Unless otherwise stated, the present invention is not limited to these modes.

FIG. 1 shows a data transmission system having a preferred embodiment of the decoding device of the present invention. A signal or data transmission path 3 is formed between the transmission side device and the reception side device 2 of the data transmission system. As the transmission line 3, for example, an optical fiber or a wireless transmission line can be adopted. The encoder 4 of the transmission side apparatus 1 encodes the data in a plurality of different ways, and the decoder 5 of the reception side apparatus 2 passes through the transmission path 3 to combine the data according to the encoding method.

The selection among a plurality of different types of coding methods in the transmission side device 1 is made according to the state of the transmission path 3, etc.
Encoding processing is performed by the encoding method in which the data is selected by the encoder 4. The decoder 5 performs the encoding process selected by the encoder 4, that is, the decoding process corresponding to the predetermined encoding method, that is, the predetermined decoding method, on the reception signal or the reception data.

FIG. 2 is a block diagram showing a preferred configuration of the receiving side device 2. The reception side device 2 has a decoder 5 as a decoding circuit, a decoder control circuit 6, and an oscillator 7. The oscillator 7 is connected to the decoder control circuit 6. Also,
The decoder 5 is connected to the decoder control circuit 6. The input data ID passed through the transmission path 3 can be input to the decoder 5. This input data ID can be output as output data OD from the decoder 5 after decoding processing. Then, the error flag EF is sent from the decoder 5 to the decoder control circuit 6.
Can be sent. From the decoder control circuit 6 to the decoder 5, a decoder control flag CF (flag CF1,
Flag CF2) can be sent.

The decoder 5 decodes the input data ID by the decoding method (decoding method) selected by the instruction of the decoder control flag CF, and outputs the output data OD. At this time, when the encoding method in the encoder 4 of the transmission side apparatus 1 of FIG. 1 is changed depending on the state of the transmission path 3 or when the correct decoding method of the decoder 5 which is suitable for the encoding method is not selected, As indicated by the timing A, the error flag EF is set.

The decoder control circuit 6 uses the error flag EF.
While is on, the decoder control flag CF is changed according to the pulse of the clock signal CL of the oscillator 7. The oscillation frequency of the clock signal CL can be controlled. The decoder control circuit 6 is also called a decoder control unit, and its circuit side is shown in FIG. The decoder control circuit 6 includes a counter 10 and a D-
It has flip-flops 11 and 12. The counter 10 is reset when the error flag EF enters the CLR terminal. The counter 10 starts counting in response to the pulse of the clock signal CL of the oscillator 7 when the error flag EF rises or enters. When the error flag EF goes down or is no longer input, the output of the counter 10 is fixed at 0. The D-flip-flops 11 and 12 change the output while the error flag EF is increasing and the counter 10 is counting up, and when the error flag EF is decreasing, the output is fixed to the previous value.

The decoder 5 of FIG. 2 changes the decoding method among a plurality of different decoding methods depending on the change of the decoding control flag CF (CF1, CF2) (see timings B and C and waveforms CF1 and CF2 of FIG. 4). ). After a certain time after selecting the correct decoding method (period E in FIG. 4,
F), the error flag EF goes down and the system stabilizes.

A period E of FIG. 4 shows a delay time from when the decoder 5 of FIG. 2 selects a correct decoding method to when it outputs correct output data OD. The period F in FIG.
Indicates the delay time for lowering the error flag EF. Also, the period E is from timing C to timing D, and the period F starts from timing D. The oscillation frequency f0 of the oscillator 7 is equal to the delay time of the period E of FIG.
Then, if the delay time under the period F in FIG.

[0019]

[Equation 1]

When the error rate of the transmission line 3 in FIG. 1 is high, the oscillation frequency of the oscillator 7 is lowered. Alternatively, FIG.
The output of the counter 10 is shifted to the upper bits. That is, by shifting, the interval between timings A and B in FIG. 4 becomes longer, and malfunction can be prevented.

The present invention is not limited to the above embodiment. Further, not only the D-flip-flops 11 and 12 of FIG. 3 but also the number of D-flip-flops set can be increased to cope with an increase in the types of decoding methods. That is, the number of D-flip-flops is 3 or more if the decoding method is 3 or more.

[0022]

According to the present invention, according to the type of data encoding method (encoding method) used on the transmitting side,
The receiving side can automatically decrypt the data. In other words, a manual mode conversion operation by an operator, which is conventionally required, is unnecessary, and operation and setup in a digital SNG system can be simplified. When the encoding system is changed on the transmitting side, the receiving side automatically follows and decodes, so that mode switching is possible during digital SNG operation.

[Brief description of drawings]

FIG. 1 is a diagram showing a data transmission system having a preferred embodiment of a decoding device of the present invention.

FIG. 2 is a block diagram showing an example of the configuration of a decoding device according to the present invention.

FIG. 3 is a diagram showing an example of a configuration of a decoder control circuit of the decoding device of the present invention.

FIG. 4 is a timing chart showing an operation example of the decoding device according to the present invention.

[Explanation of symbols]

 1 Transmitting Side Device 2 Receiving Side Device 3 Transmission Line 4 Encoder 5 Decoder (Decoding Circuit) 6 Decoder Control Circuit (Control Circuit) 7 Oscillator 10 Counters 11 and 12 D-Flip-Flop (Latch Circuit)

Claims (4)

[Claims] 1. A decoding device capable of receiving a plurality of differently encoded signals and performing decoding corresponding to the signals, the decoding device including a decoding circuit and a control for controlling the decoding circuit. The control circuit has a circuit and an oscillator, and the control circuit sets a decoding control flag in response to an error flag output from the decoding circuit and a clock signal from the oscillator when decoding not corresponding to encoding is performed. A decoding device, characterized in that the decoding device is provided to control the decoding of the decoding circuit. 2. The control circuit according to claim 1, wherein the control circuit includes a counter that is reset by the previous error flag and counts the previous clock signal, and a latch circuit that latches the output of the counter. Decoding device. 3. The decoding device according to claim 2, wherein the oscillation frequency of the clock signal of the oscillator is controllable. 4. The decoding device according to claim 2, further comprising at least two latch circuits.