JP2003250167A - Test video signal generator and high frequency signal generator using the same - Google Patents

Abstract

(57) [Problem] To provide a test video signal generator capable of reducing a circuit scale and cost. SOLUTION: A storage means 51 for storing a code of a pattern to be displayed in each of a plurality of cells obtained by dividing a screen in units of cells, a reading means 50 for reading out a code of a pattern in accordance with a display position of the screen in units of cells, A pattern video signal generating means 21 for generating a pattern video signal corresponding to the output code; and a pedestal signal generating means 22 for generating a pedestal signal including a synchronizing signal and having a video portion of a black level.
And superimposing means 23 for superimposing a pattern video signal on a pedestal signal to output a test video signal, thereby greatly reducing the storage capacity of the storage means compared to a conventional device that stores video information in pixel units. Thus, the circuit scale can be reduced and the cost can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a test video signal generator and a high frequency signal generator using the test video signal generator.
The present invention relates to a test video signal generator that generates a simple test video signal and a high-frequency signal generator using the test video signal generator.

[0002]

2. Description of the Related Art Conventionally, in an apparatus for generating a video signal, a video luminance signal and a carrier color signal are generated for each horizontal scanning line of a composite video signal, and both are superposed to obtain a color video signal. Therefore, even if a plurality of continuous horizontal scanning lines have the same signal content, a luminance signal and a carrier color signal are repeatedly generated for each horizontal scanning line, and both are superimposed to obtain a color video signal.

When a test video signal is generated, video information (R, G, B) for one field or one frame is stored in a field memory or a frame memory for each pixel and read from the memory. After the video information is D / A converted, a matrix operation is performed to generate a luminance signal and a carrier color signal, and both are superimposed to obtain a color video signal.

[0004]

The conventional test video signal generator requires a field memory or a frame memory, which causes a problem that the circuit scale becomes large and the cost becomes high.

The present invention has been made in view of the above points, and an object of the present invention is to provide a test video signal generator capable of reducing the circuit scale and cost, and a high frequency signal generator using the same.

[0006]

According to a first aspect of the present invention, in a test video signal generator for generating a test video signal, a code of a pattern to be displayed in each of a plurality of cells into which a screen is divided is cell by cell. Stored storage means, reading means for reading a code of a pattern corresponding to the display position of the screen from the storage means in cell units, and a pattern video signal for generating a pattern video signal corresponding to the code read by the reading means Generating means, a pedestal signal generating means for generating a pedestal signal having a black level in a video portion including a synchronizing signal, and a pedestal signal generated by the pedestal signal generating means for generating a pattern video signal generated by the pattern video signal generating means. Storing video information on a pixel-by-pixel basis by having superimposing means for superimposing and outputting a test video signal That the storage capacity of the storage means relative to the conventional apparatus is significantly reduced, the cost can be reduced can reduce the circuit scale.

According to the invention described in claim 2, by using the test video signal generator according to claim 1, the circuit scale of the high frequency signal generator can be reduced and the cost can be reduced.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A test video signal generator according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a high frequency signal generator using the test video signal generator of the present invention. In the figure, a carrier signal generator 10 and a video signal generator 2
0, a modulator 30, an audio signal generator 40, a controller 50, and a low-pass filter 60. The carrier wave signal generator 10, the video signal generator 20, the modulator 3
0, the audio signal generator 40 and the controller 50 are connected by a control bus 70. Well-known techniques can be used for the carrier signal generation unit 10, the modulator 30, and the audio signal generation unit 40. However, the carrier signal generation unit 1 shown in FIG.
For 0, it operates as follows.

The carrier signal generator 10 has frequencies of 450-
An oscillator 11 that generates a variable oscillation frequency in a band of 850 MHz and supplies it to the mixer 12, and a frequency 890 to 105.
Oscillator 13 is generated by varying the oscillation frequency in the band of 0 MHz and is supplied to mixer 12 via switch 14, and oscillator 13 is generated by varying the oscillation frequency in the band of frequency 1050 to 1270 MHz and is supplied to mixer 12 via switch 16. And an oscillator 15 that operates.

The control unit 50 controls the oscillation frequency of each of the oscillators 11, 13, 15 and the ON / OFF control of each of the switches 14, 16. For example, the control unit 5
0 causes the oscillator 11 to oscillate at a frequency of 800 MHz, the oscillator 13 to oscillate at a frequency of 1000 MHz, and the switch 1
Only the signal No. 4 is turned on, and the mixer 12 outputs a carrier signal having a frequency of 200 MHz, which is the difference frequency between the two oscillation signals.

The video signal generating section 20 comprises a pattern generator 21, a pedestal signal generating section 22 and a superimposing circuit 23. When the pattern code and the display position are designated by the control unit 50, the pattern generator 21 generates a pattern video signal in which the carrier color signal is superimposed on the luminance signal for displaying the pattern indicated by the code at the display position. It is generated and supplied to the superimposing circuit 23. In addition, as the pattern to be displayed,
It is a color and a background color that represents letters / numbers or an arbitrary shape, or a fill (only the background color). Further, the horizontal and vertical synchronization of the pattern video signal is performed in synchronization with the control from the control unit 50.

The pedestal signal generator 22 is a pedestal signal as a composite video signal including a horizontal synchronizing signal and a vertical synchronizing signal having a color burst signal in the back porch when the luminance signal and the carrier color signal are 0, that is, a black level. Is generated and supplied to the superimposing circuit 23. Horizontal and vertical synchronization of the pedestal signal is performed in synchronization with the control from the control unit 50.

The superimposing circuit 23 superimposes the pattern video signal from the pattern generator 21 on the video period of the pedestal signal from the pedestal signal generator 22 and supplies it to the modulator 30.

The audio signal generator 40 generates an audio signal according to an instruction from the controller 50 and supplies it to the modulator 30. The modulator 30 amplitude-modulates the carrier signal with a composite video signal for displaying a pattern, and at the same time, the carrier signal generator 1
The frequency is 4.5M based on the high frequency signal supplied from 0
An audio carrier with a high frequency of Hz is generated and frequency-modulated with an audio signal. The modulated signal obtained here is output after the unnecessary high frequency component is attenuated by the low pass filter 60.

In this embodiment, as shown in FIG. 2, one screen is divided into 21 columns × 16 rows of cells. The number of cell divisions is arbitrary. C (1,1), c (16,
21) and other cell numbers are attached. In FIG. 2, symbols are displayed only for some cells.

The control unit 50 is composed of a microprocessor having a built-in ROM 51. The ROM 51 stores the cell number of each cell shown in FIG. 2 and the code of the pattern displayed in each cell. There is a one-to-one relationship between each cell number and the display position, and the control unit 50 controls the video signal generation unit 2
The code of the pattern corresponding to the cell number is supplied from the ROM 51 to the read pattern generator 21 in accordance with the cell number on the screen synchronized with the horizontal and vertical synchronization control for 0.

When the color bar shown in FIG. 3 is displayed on the screen, the ROM 51 has three cell numbers c in the column.
A code of a fill pattern having a white background color is stored for (i, 1) to c (i, 3) [where i is an integer of 1 to 16]. Similarly, for the cell numbers c (i, 4) to c (i, 6) of the next three columns, the code of the filling pattern with the yellow background color is stored, and the cell numbers c (i, For 7) to c (i, 9), the code of the fill pattern whose background color is cyan is stored.
For the cell numbers c (i, 10) to c (i, 12) of the columns, the code of the fill pattern with the green background color is stored, and the cell numbers c (i, 13) to c (i, 1) of the next three columns are stored.
For 5), the code of the fill pattern whose background color is magenta is stored, and the cell number c (i, 16) of the next three columns is stored.
~ C (i, 18) stores the code of the fill pattern whose background color is red, and the cell number c of the next three columns
The code of the fill pattern having a blue background color is stored for (i, 19) to c (i, 21).

Then, the control unit 50 sequentially reads out the code of the pattern from the ROM 51 on the basis of the horizontal and vertical synchronizations and supplies it to the pattern generator 21, whereby the pattern generator 21 displays the pattern indicated by the code. To generate a pattern video signal in which the carrier color signal is superimposed on the luminance signal for performing.

The pattern generator 21 incorporates a code-pattern correspondence table as shown in FIG. 4, and generates a pattern video signal using this correspondence table.
In FIG. 4, each pattern is composed of n × m dots (n and m are predetermined integers). For example, code 001 is a fill pattern whose background color is blue, and code 022
Has a pattern in which the left half is black and the right half is white. Code 0
30 is a pattern in which the left half is red and the right half is yellow, and the code 040 is a number pattern.

The pattern generator 21 and the superimposing circuit 23 constituting the above-mentioned video signal generating section 20 are existing circuits, and the ROM 51 of the control section 50 is, for example, 2
It only needs to have a small capacity to store the codes of cells in 1 column x 16 rows, and the large-capacity frame memory and field memory that were required in the past are not required, and the circuit scale can be reduced and the cost can be significantly reduced. it can.

If the control unit 50 is provided with a non-volatile memory instead of the ROM 51 and the code of the pattern of all cells is stored in the non-volatile memory, the test image is changed by rewriting the code of the non-volatile memory. It is possible.

The ROM 51 corresponds to the storage means described in the claims, the control unit 50 corresponds to the reading means, the pattern generator 21 corresponds to the pattern video signal generating means,
The pedestal signal generator 22 corresponds to the pedestal signal generating means, and the superimposing circuit 23 corresponds to the superimposing means.

In the above embodiment, the test video signal generator is incorporated for generating the modulation signal of the high frequency signal generator, but naturally it can operate as a single test video signal generator.

[0025]

As described above, the invention according to claim 1 is
Storage means for storing, for each cell, a code of a pattern to be displayed in each of a plurality of divided cells of the screen, reading means for reading the code of the pattern corresponding to the display position of the screen from the storage means for each cell, and read by the reading means. A pattern video signal generating means for generating a pattern video signal according to the issued code, a pedestal signal generating means for generating a pedestal signal of a video portion including a sync signal and having a black level, and a pattern video signal generating means By including superimposing means for superimposing the pattern video signal on the pedestal signal generated by the pedestal signal generating means and outputting the test video signal, the storage capacity of the storage means is different from that of the conventional apparatus for storing the video information in pixel units. Is significantly reduced,
The circuit scale can be reduced and the cost can be reduced.

The invention described in claim 2 is the same as claim 1
By using the described test video signal generator, the circuit scale of the high frequency signal generator can be reduced and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a high frequency signal generator using a test video signal generator of the present invention.

FIG. 2 is a diagram for explaining cells obtained by dividing a screen.

FIG. 3 is a diagram showing a color bar displayed on a screen.

FIG. 4 is a diagram showing a correspondence table between codes and patterns.

[Explanation of symbols]

10 Carrier wave signal generator 11,13,15 oscillator 12 mixers 14, 16 switch 20 Video signal generator 21 pattern generator 22 Pedestal signal generator 23 Superimpose circuit 30 modulator 40 Audio signal generator 50 control unit 60 low pass filter 70 control bus

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tsuyoshi Nakatogawa             2-2-1 Jinnan 2-chome, Shibuya-ku, Tokyo             Sending Association Broadcast Center (72) Inventor Rei Suzuki             2-2-1 Jinnan 2-chome, Shibuya-ku, Tokyo             Sending Association Broadcast Center (72) Inventor Ryu Ezaki             1-6-26 Daimon, Kokurakita-ku, Kitakyushu City, Fukuoka Prefecture             Japan Broadcasting Corporation Kitakyushu Broadcasting Station (72) Inventor Mitsuo Kusuhara             Sanya Electronics Co., Ltd. 1 Toyacho, Ueno City, Mie Prefecture             Within F-term (reference) 5C061 BB02 CC01

Claims (2)

[Claims] 1. A test video signal generator for generating a test video signal, wherein: storage means for storing a code of a pattern to be displayed in each of a plurality of divided cells of the screen in cell units; and display of the screen from the storage means. Read-out means for reading out the code of the pattern corresponding to the position on a cell-by-cell basis, pattern video signal generating means for generating the pattern video signal according to the code read by the read-out means, and the video portion including the synchronizing signal has a black level. Pedestal signal generating means for generating the pedestal signal, and a superimposing means for superimposing the pattern video signal generated by the pattern video signal generating means on the pedestal signal generated by the pedestal signal generating means to output a test video signal. A test video signal generator having: 2. A high-frequency signal generator using the test video signal generator according to claim 1.