JPH08331570A - Rgb encoder - Google Patents

Abstract

PURPOSE: To provide the RGB encoder from which an analog RGB signal as well as an analog television signal is outputted. CONSTITUTION: The encoder is made up of input terminals 2 to 4 receiving R, G, B digital signals, a circuit 6 generating other television signal than R, G, B digital signals from the R, G, B digital signals, changeover switches 11 to 13 receiving the television signal, lines 14 to 16 leading the R, G, B digital signals from the input terminals to the changeover switches 11 to 13, a switch changeover circuit 10 controlling the changeover switches 11 to 13 to select the television signal or the R, G, B digital signals in response to the mode setting signal, and a D/A converter circuit 18 converting outputs of the changeover switches into an analog signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an RGB encoder used in so-called video CDs, digital video discs (DVDs) and the like.

[0002]

BACKGROUND ART RGB encoder R, G, B digital signal an analog luminance signal (Y _A) and chroma signal (C _A), and outputs the converted composite signal or the like. In the conventional example shown in FIG. 3, reference numeral 30 denotes an MPEG core chip that compresses and outputs image data, and R, G, and B digital signals output from the MPEG core chip are RGB encoders 31.
Is converted into a luminance signal, a composite signal and a chroma signal.

The RGB encoder 31 further converts the luminance signal, the composite signal and the chroma signal into analog quantities and outputs them. Then, this RGB encoder 31
Is a television receiver 33 with a video input terminal
Is supplied to and played on that screen. Television receiver 33, and a case to be processed by entering the case, the composite signal for processing by the input luminance signal (Y _A) a chroma signal (C _A). The choice is the television receiver 3
It can be understood by the function of 3. RGB encoder 31 formed of an IC (integrated circuit), the luminance signal so that it can correspond to either the (Y _A), and is configured to composite signal may also output together with the chroma signal (C _A).

Meanwhile, there is with RGB input terminals as the television receiver 34, a nonexistent television of the luminance signal (Y _A) and chroma signal input terminal for the (C _A) or composite signal In case of machine, R
Even if the output of the GB encoder 31 is received, the output cannot be input and processed. Therefore, in such a case, a 3-channel D / A conversion circuit 32 is separately prepared, and the D / A conversion circuit 32 converts the R, G, B digital signals from the MPEG core chip 30 into analog signals (R). _A , G _A , B _A ) and the television receiver 34
Was to give to.

[0005]

As described above, the conventional RG is used.
In the B encoder 31, the types of output signals are limited, so in the case of an electronic device such as a DVD, an MD is used.
In addition to the EG core chip 30 and the RGB encoder 31, D /
It is necessary to mount the A converter 32, the number of IC chips is increased, and the number of connections of them is also required.
As a result, there is a drawback that the circuit becomes bulky. Further, the IC maker has to prepare the D / A conversion circuit 32 in addition to the RGB encoder 31, which is difficult in terms of manufacturing and product management.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an RGB encoder capable of outputting an analog RGB signal.

[0007]

In order to achieve the above object, in the first aspect of the present invention, an encoder includes an input terminal to which R, G, B digital signals are input, and the R, G, B.
A circuit for forming a television signal other than R, G, B from a digital signal, a changeover switch to which the television signal is given, and a line for guiding the R, G, B digital signals from the input terminals to the changeover switch. And the television signal and R, G, B according to the mode setting signal.
It comprises a switch changeover circuit for controlling the changeover switch so as to select one of the digital signals, and a D / A conversion circuit for converting the output of the changeover switch into an analog signal.

According to a second aspect of the present invention, the encoder is an encoder for converting a digital RGB signal into an analog television signal, and an RGB input terminal,
A first circuit that forms a luminance signal, a chroma signal, and a composite signal from the R, G, and B digital signals input through the RGB input terminals, and 3 formed by the first circuit.
First, second, and third changeover switches to which two signals are respectively applied to the first input terminal, and R, G, and B digital signals input through the RGB input terminals are changed to the first, second, and third changeover switches, respectively. The line leading to the second input terminal of the switch and the first, second, so that one of the signals of the first and second input terminals is selected according to the mode setting signal.
A switch switching circuit for interlockingly switching the third switch,
It comprises a D / A conversion circuit for converting the output of each of the first, second and third changeover switches into an analog signal.

According to a third aspect of the present invention, the above first and second aspects are provided.
The encoder of this aspect is formed of a one-chip integrated circuit, and a mode setting signal can be externally applied via the mode setting input terminal.

Further, the electronic equipment of the present invention comprises an RGB digital signal generating circuit and an encoder for converting the R, G, B digital signals generated from this RGB digital signal generating circuit into an analog television signal. The encoder has an input terminal to which R, G, B digital signals are input, a circuit for forming a television signal other than R, G, B from the R, G, B digital signals, and the television signal. A given changeover switch, a line for guiding the R, G, B digital signals from the input terminals to the changeover switch, and one of the television signal and the R, G, B digital signals is selected according to a mode setting signal. And a switch changeover circuit for controlling the changeover switch to convert the output of the changeover switch into an analog signal. / Consist A conversion circuit.

[0011]

According to the first aspect of the encoder of the present invention, when the switch changeover circuit is set to the first mode, for example,
The input digital signal is converted into an analog RGB signal and output. When the switch switching circuit is set to, for example, the second mode, the input digital signal is converted into an analog television signal (analog television signal other than RGB) and output.

According to the second aspect of the encoder of the present invention, when the switch switching circuit is set to, for example, the first mode, the input digital signal is converted into an analog RGB signal and is output. When the switch switching circuit is set to, for example, the second mode, the input digital signal is converted into an analog luminance signal, an analog chroma signal, and an analog composite signal for output.

According to the third aspect of the encoder of the present invention, the mode setting signal is externally applied to the switch changeover circuit in the integrated circuit.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 is an RGB encoder formed by a one-chip IC. 2, 3, 4 are R, G,
B is an input terminal for inputting a digital signal, and is connected to, for example, the MPEG core chip 30 shown in FIG. Reference numeral 5 is a latch circuit, which latches the input R, G, B digital signals R _D , G _D , B _D and outputs it.

Reference numeral 6 is a circuit for processing the input R, G, B digital signals R _D , G _D , B _D and outputting a television signal other than R, G, B. The circuit 6 outputs a digital luminance signal (Y _D ) on the line 7, a digital composite signal (S _D ) on the line 8 and a digital chroma signal (C _D ) on the line 9. The luminance signal is supplied to the terminal a of the first changeover switch 11, the composite signal (S _D ) is supplied to the terminal a of the second changeover switch 12, and the chroma signal (C _D ) is supplied to the terminal a of the third changeover switch 13. Is supplied to.

Reference numerals 14, 15 and 16 denote outputs R of the latch circuit 5.
These lines lead _D , G _D , and B _D to the terminals b of the first, second, and third changeover switches 11, 12, and 13, respectively. The changeover switches 11, 12, and 13 are switch changeover circuits 10.
Controlled by the output of. The switch switching circuit 1
0 sets switching of switches 11, 12, and 13 in accordance with a mode setting signal externally given through terminal 17. The mode setting signal is, for example, a high level signal and a low level signal.

Reference numeral 18 is a D / A conversion circuit for converting the outputs of the switches 11, 12 and 13 into analog signals. 19 is a terminal for outputting the analog luminance signal (Y _A), 20
Is a terminal for outputting an analog composite signal (S _A ), and 21 is a terminal for outputting an analog chroma signal (C _A ). As shown in FIG. 1, the feature of the present embodiment is that the digital R, G, B signals are passed through to the switches 11, 12, and 1.
3 is added, and a configuration capable of selecting and outputting is added.

Next, FIG. 2 is a block diagram showing the configuration of FIG. 1 in detail. In the figure, the latch circuit 5 includes R, G,
Corresponding to B, three latch circuits 5a, 5b, 5c are provided. Reference numeral 23 is a timing generation circuit that generates the timing signal T ₁ and horizontal and vertical synchronization signals H and V based on the clock CLK input through the terminal 22. The operation timing of the latch circuit 5 is set by the timing signal T ₁ .

24 is a digital R, G, B signal (R _D ,
It is a luminance signal forming circuit that forms a digital luminance signal (Y _D ) based on G _D , B _D ) and its output is transmitted to the terminal a of the first changeover switch 11. 26 digital R, G, B signals _{(R D, G D, B} D) is a color-difference signal forming circuit for forming a digital B-Y signal and R-Y signals on the basis of the color and its output is the modulation circuit 30 The carrier given from the carrier generation circuit 29 is modulated into a modulated signal, and the color carrier is inserted as a color burst signal at the color burst position by the next adder 31.

The combined signal is given to the terminal a of the third changeover switch 13. 25 is an adder which outputs a composite signal (S _D) by adding the luminance signal (Y _D) and chroma signal (C _D), whose output is the second changeover switch 12
Is supplied to the terminal a.

Now, when a high level is applied through the terminal 17, the switch switching circuit 10 sets all of the first, second and third switches to the terminal b side. Input and latch circuits 5a, 5b, 5c
Then, the digital R, G, B signals transmitted through the lines 14, 15, 16 are applied to the D / A conversion circuit 18 through the switches 11, 12, 13.

The D / A converter circuit 18 is provided with three D / A converters 18a, 18b and 18c, and the respective inputs are connected to these D / A converters 18a, 18b and 18c.
Is converted into an analog signal by. In this case, analog R signal to the output terminal 19 (R _A), an analog G signal to the output terminal 20 (G _A), an analog of the B signal (B _A) is output to the output terminal 21.

Next, when a low level is applied through the terminal 17, the switch changeover circuit 10 makes the first, second, and third switches.
Both switches are set to the terminal a side. for that reason,
The luminance signal (Y _D ) from the circuit 24 is input to the D / A converter 18a through the switch 11 and converted into an analog signal here. Further, the chroma signal (C _D ) output from the adder 31 passes through the switch 13 and the D / A converter 18
It is input to c and converted into an analog signal here.

On the other hand, the composite signal (S _D ) output from the adder 25 is input to the D / A converter 18b through the switch 12 and converted into an analog signal here.
As a result, the analog luminance signal to the output terminal 19 (Y _A), an analog composite signal to an output terminal 20 (S _A), analog chroma signal (C _A) is output to the output terminal 21.

[0025]

As described above, according to the encoder of the present invention, not only analog television signals (analog luminance signal, analog chroma signal, analog composite signal) but also analog RGB signals can be output. As described above, it is not necessary to provide two encoder IC chips and D / A conversion IC chips, which is economical.

In addition, the electronic equipment using this encoder has the advantage that the number of IC chips to be mounted is small and the number of connections is small, and the circuit is small in size accordingly. Further, the IC maker does not have to prepare an IC chip for the D / A conversion circuit other than the IC chip of the RGB encoder, which is advantageous in terms of manufacturing and product management.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of an RGB encoder embodying the present invention.

FIG. 2 is a detailed circuit block diagram thereof.

FIG. 3 is a block diagram of a conventional example.

[Explanation of symbols]

 1 Encoder 10 Switch Switching Circuit 11, 12, 13 Switch 14, 15, 16 Line 18 D / A Converter Circuit

Claims (4)

[Claims] 1. An input terminal for inputting R, G, B digital signals, and R, G, B from the R, G, B digital signals.
A circuit for forming a television signal other than B, a changeover switch to which the television signal is given, a line for guiding the R, G, B digital signals from the input terminals to the changeover switch, and a mode setting signal And a D / A conversion circuit for converting the output of the changeover switch into an analog signal, and a switch changeover circuit for controlling the changeover switch so as to select one of the television signal and one of the R, G, B digital signals. Encoder. 2. An encoder for converting a digital RGB signal into an analog television signal, wherein an RGB input terminal and R, which is input through the RGB input terminal,
A first circuit for forming a luminance signal, a chroma signal, and a composite signal from G and B digital signals, and three signals formed by the first circuit are applied to first input terminals, respectively, second, third The changeover switch and the lines for guiding the R, G, B digital signals input through the RGB input terminals to the second input terminals of the first, second, and third changeover switches, respectively, and the line according to the mode setting signal. A switch switching circuit for interlockingly switching the first, second, and third switches so that one of the signals of the first and second input terminals is selected, and the outputs of the first, second, and third switching switches. An encoder including a D / A conversion circuit for converting each to an analog signal. 3. The encoder according to claim 1 or 2, wherein the encoder is formed of a one-chip integrated circuit, and a mode setting signal can be externally applied through a mode setting input terminal of the encoder. Encoder described. 4. An RGB digital signal generating circuit and R
An electronic device comprising an encoder for converting an R, G, B digital signal generated from a GB digital signal generating circuit into an analog television signal, wherein the encoder is an input to which the R, G, B digital signal is input. A terminal, a circuit for forming a television signal other than R, G, B from the R, G, B digital signals, a changeover switch to which the television signal is given, and an R, G, B digital signal from the input terminal A line for guiding a signal to the changeover switch, and a switch changeover circuit for controlling the changeover switch so as to select one of the television signal and one of the R, G and B digital signals according to a mode setting signal,
D for converting the output of the changeover switch into an analog signal
And an A / A conversion circuit.