JPH04215392A - Color bar signal generator - Google Patents

Abstract

PURPOSE:To obtain first and second color difference data and luminance data with circuit configuration of small scale in the digital signal processing circuit of a color bar to be displayed on a television receiver. CONSTITUTION:A position decoder 2 generates signals (a-g) of parallel eight bits in accordance with a color bar uniquely from switching signals (l), (m), and (n) of three bits obtained from a pulse generation circuit 1, and outputs them from NAND gates A-G by switching sequentially. A color difference decoder 4 and a luminance decoder 5 select the signals (a-g) so as to obtain the first and second color difference data and the luminance data, and selected signals are inputted to NAND gates C1-C8 and L1-L6. Therefore, it is possible to obtain the simplification and small scale of a circuit and to reduce power consumption by generating the data from the switching signal at need.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a color bar signal generating device for displaying color bars on the screen of a television receiver for color adjustment, and particularly relates to a color bar signal generating device for displaying color bars on the screen of a television receiver for color adjustment. The present invention provides a device capable of obtaining signals.

0002

2. Description of the Related Art Some conventional color bar signal generating apparatuses constituted by digital signal processing circuits use data selectors to obtain color bar signals. Therefore, a method for displaying a color bar divided vertically into eight colors of white, yellow, cyan, green, magenta, red, blue, and black on a television receiver will be described. FIG. 3 is a block diagram of a color bar signal generation device that sends out first color difference data, second color difference data, and luminance data that are converted into color bar signals through a D/A converter and a color encoder. It consists of a circuit 6 and data selectors 7, 8 and 9. These data selectors 7, 8, and 9 select white, yellow, cyan, green, magenta, red, blue, and black, respectively, in the order of white, yellow, cyan, green, magenta, red, blue, and black according to switching signals l, m, and n output by the pulse generation circuit 6 within one horizontal scanning period. It has a function of sequentially selecting and outputting the first color difference data, the second color difference data, and the luminance data of the color bar. These first color difference data, second
For example, the color difference data and brightness data of (Table 1)
, (Table 2) and (Table 3) There is 8-bit data corresponding to 3-bit switching signals l, m, n corresponding to each of the color bars shown in (Table 2) and (Table 3).

0003

[Table 1]

0004

[Table 2]

[0005]

[Table 3]

The data selector 9 that selects the luminance data (Table 3) from among these data is inputted for each bit from the 0th bit to the 7th bit, as shown in the block diagram of FIG. Output each brightness data from 0 to 7
8 data selectors 9-7 to 9 to select and output
-0. Of these, data selector 9-7
As shown in its more detailed block diagram in FIG.
From the brightness data 11100000 of the 7th bit of the color bar from white to black that is constantly supplied, the switching signal l
, m, and n, one of them is sequentially selected and outputted to the output 7. The configuration of the logic circuit in FIG. 5 is the same for the data selectors 9-6 to 9-0. Furthermore, although not shown, the data selectors 7 and 8 that output the first color difference data and the second color difference data shown in (Table 1) and (Table 2) are also configured to select each of the 0th bit to 7th bit. Each of the data selectors is composed of eight data selectors having a circuit configuration similar to that shown in FIG. 5, which sequentially selects and outputs one of the data that is always supplied for each bit.

[0007]

In the color bar signal generating device configured as described above, a switching signal l is selected from among the data constantly supplied to the data selector.
, m, and n in order to select and output the first and second color difference data and luminance data.
The circuit configuration has become extremely large and complex.

[0008]

[Means for Solving the Problems] In order to solve the above problems, a color bar signal generation device of the present invention is provided for displaying color bars on the screen of a television receiver through a D/A converter and a color encoder. The first color difference data, second color difference data, and luminance data to be converted into color bar signals are driven by a pulse generating means that generates pulse signals corresponding to each color bar, and each time the pulse signal is applied, The data is created and outputted by a decoder means. Further, the decoder means is driven by the pulse generating means and has a function of sequentially switching and outputting parallel signals uniquely corresponding to each color bar within one horizontal scanning period; and a group of decoders each having a function of creating and outputting the first and second color difference data and luminance data from the signals.

[0009]

[Operation] As described above, by configuring to create the first color difference data, second color difference data, and luminance data each time a pulse signal corresponding to the color bar is applied, the conventional It is possible to realize a color bar signal generating device having a much smaller scale and simpler circuit configuration than the conventional color bar signal generating device.

0010

[Embodiment] An embodiment of the present invention will now be described with reference to figures and tables. Figure 1 shows white, yellow, cyan, green, magenta, red, blue colors displayed on the screen of a television receiver.
FIG. 2 is a block diagram of a color bar signal generation device for displaying a color bar divided vertically into eight colors including black. D/
A color bar signal generation device that outputs first color difference data, second color difference data, and luminance data that are converted into color bar signals through an A converter and a color encoder includes a pulse generation circuit 1, a position decoder 3, and a color difference decoder. 4 and a decoder means 2 consisting of a luminance decoder 5. The pulse generating circuit 1 has the same functions as the conventional example. In addition, this color bar signal generator is
It is configured to output the first color difference data, second color difference data, and luminance data shown in Tables 1 to 3, which are the same as in the conventional example.

Now, as shown in the timing chart of FIG. 2, the pulse generating circuit 1 generates a signal 1 having the same frequency as the horizontal synchronizing frequency of the television, a signal m having a frequency twice the horizontal synchronizing frequency, and a horizontal synchronizing frequency. Since a switching signal of a signal n having a frequency four times that of the frequency is output, a 3-bit signal corresponding to each color of the color bar is sequentially switched and inputted to the position decoder 3 within one horizontal scanning period. Become. This position decoder 3 has seven NAND gates A to G to which switching signals l, m, and n and those signals passed through an inverter circuit are input, and outputs signals a to g in parallel. These NAND gates from A to G are shown in Figure 2.
As shown in the timing chart, only one output from signals a to g is 0 and all other outputs are 1, and the position where 0 is output is sequentially switched according to switching signals l, m, and n. It is configured so that it is output instead. However, when the switching signals l, m, and n are all 1,
Signals a to g are all 1. Therefore, position decoder 3
From this, a signal uniquely corresponding to each color bar can be obtained. That is, when only signal a is 0, it indicates the position where the color bar signal that displays white on the television receiver is scanned, and when only signal b is 0,
A color bar signal displaying yellow on the television receiver indicates the position to be scanned. Similarly, cyan, green,
The position at which the color bar signals displaying magenta, red, and blue scan on the television receiver corresponds to when only one of the signals b to g is output as 0, and when the signal a
When g is all 1, the black color bar signal indicates the position to be scanned on the television receiver.

Next, the color difference decoder 4 is connected to the position decoder 3.
From the signals a to g output in parallel from (Table 1) and (
8-bit first color difference data and second color difference data corresponding to each color bar shown in Table 2) are created and output. Since the first and second color difference data have the 6th bit to the 0th bit in common, each data is commonly obtained from the output 6 to 0 from the NAND gates C3 to C8 and GND. Note that the reason why the output 0 is grounded is that the color difference data of the 0th bit is all 0. Then, the NA of C1 and C2 is determined for different upper 7th bit data.
Each is obtained as an output 7 from an ND gate. Now, (Table 1
) and (Table 2) to obtain the color difference data shown in the output position, NAN should output 1 for each color difference data.
The output signals of 0 from signals b to g obtained from the position decoder 3 are input to the D gate. For example, yellow number 2
The color difference data is 1000111 starting from the upper 7th bit.
0, so the signal b whose output is 0 when the switching signals l, m, and n are each 001 is set to C2, C6, C7, and C8.
is input to the NAND gate. However, since the color difference data between white and black is all 0, NA
There is no need to input the outputs 0 of the signals a to g to the ND gate, and all the signals a to g are 1 when the switching signal corresponding to black is input.

The luminance decoder 5 also includes a position decoder 3.
The luminance data shown in Table 3 is created from the signals a to g output in parallel. The luminance decoder 5 is composed of NAND gates L1 to L6 which output data from the 7th bit to the 5th bit and from the 2nd bit to the 0th bit of the luminance data to the outputs 7 to 5 and 2 to 0, respectively. It is configured. Note that since the fourth and third bits of luminance data are the same data as the fourth and third bits of the first and second color difference data, the outputs of the NAND gates of C5 and C6 are used. And these NANs from L1 to L6
In order to obtain the desired luminance data from the D gate, for each luminance data, the NAND gate that should output 1,
The configuration is similar to that of the color difference decoder 4 described above, with each of the signals a to g whose output is 0 being input. However, since the black luminance data is all 0 and the signals a to g are all 1, these signals are not input to the NAND gate.

The color bar signal generating device constructed in this manner is much smaller and simpler than conventional ones. For example, the number of gates has been reduced to approximately one-twentieth, and even considering that most of this embodiment is composed of three-input NAND gates, compared to the conventional one, It is possible to realize a device whose circuit area is approximately 1/10th of the scale. As the scale has become dramatically smaller, various types of digital video signal processing I
It can be incorporated into C and provided for testing.

[0015]

Effects of the Invention As described above, the switching signals l, m. Since the decoder means is configured to create and output the first color difference data, second color difference data, and luminance data to be converted from n to each color bar signal each time, the circuit area is very small and simple. It is possible to realize a color bar signal generation device having a circuit configuration, and its power consumption can also be significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a color bar signal generation device according to an embodiment of the present invention.

FIG. 2 is a timing chart illustrating the operation of the device in FIG. 1;

FIG. 3 is a block diagram of a conventional color bar signal generation device.

FIG. 4 is a detailed block diagram of a conventional device.

FIG. 5 is a more detailed block diagram of the block diagram of FIG. 4;

[Explanation of symbols]

1 Pulse generation circuit 2 Decoder means 3 Position decoder 4 Color difference signal decoder 5 Luminance signal decoder

Claims (1)

[Claims] 1. A digital signal processing circuit for displaying color bars divided vertically on the screen of a television receiver, the circuit comprising a pulse generating means and a color bar processing circuit for displaying color bars divided vertically on the screen of a television receiver. and a decoder means for creating first color difference data, second color difference data, and luminance data to be converted into signals, and the decoder means is driven by the pulse generating means to generate each color within one horizontal scanning period. a decoder that sequentially switches and outputs parallel signals that uniquely correspond to the bar; and a decoder group that creates and outputs the first color difference data, second color difference data, and luminance data from the parallel output signals, respectively. A color bar signal generating device characterized by: