JPH04265091A - Monitor picture receiver - Google Patents

Abstract

PURPOSE:To display white and black of a monochromatic component in a device provided with a white balance automatic control circuit. CONSTITUTION:A switch circuit 8R is provided between a signal level automatic adjustment circuit 4R and a cathode drive circuit 5R, and the signal from a signal level automatic adjustment circuit 4B of the signal component of B is supplied to the switch circuit 8R through a white level adjustment circuit 9R and a black level converting circuit 10R. The switch circuit 8R is switched to the side of the signal level automatic adjustment circuit 4R only in the period when a reference signal is inserted. The signal from the signal level automatic adjustment circuit 4R is supplied to a black level detecting circuit 11R, and the black level converting circuit 10R is controlled in accordance with this detected value.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monitor receiver used in broadcasting stations and the like.

0002

2. Description of the Related Art One of the functions of a so-called monitor receiver is to display only a monochromatic component in a video signal and use it for various checks. Particularly recently, this display has also been performed as a black and white image. In order to display only the monochrome component in black and white, the video signal is converted into each primary color signal, and then only the monochrome component is supplied to each primary color signal processing circuit.

By the way, recent monitor receivers are equipped with a circuit that detects the cathode current of the cathode ray tube due to each primary color signal and maintains the value in its initial state in order to suppress changes in white balance over time. Many have been adopted. However, in a device equipped with such an automatic white balance control circuit, when attempting to display monochromatic components in black and white as described above, only the monochromatic components are supplied to each cathode during monochromatic component display, so Automatic white balance control using signal control becomes impossible.

0004

The problem to be solved is that a device equipped with a conventional automatic white balance control circuit cannot perform black and white display of monochromatic components.

[0005]

[Means for Solving the Problems] The present invention includes inserting a predetermined reference signal into each primary color signal (circuits 3B, 3R, 3G).
) and detect the cathode current during this period (circuit 7B
, 7R, 7G) and automatically adjust the signal level (circuit 4B,
4R, 4G) in a monitor receiver that performs
A switch circuit (8R, 8G) that switches the reference signal period and video signal period for each of the primary color signals, and a black level detection and black level conversion circuit (11R, 11G).
and 10R, 10G), and is capable of displaying monochromatic components of each of the primary color signals.

[0006]

[Operation] According to this, the signal from the circuit for each primary color signal is supplied to the cathode only during the reference signal period, and the signal level is automatically adjusted, and the black level of this adjusted signal is detected and the monochrome color is By converting the black level of the signal for component display, the signal level is automatically adjusted even during monochrome component display, and good monochrome component display can be performed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example configuration. Although this figure shows the case of monochrome display of the monochrome component of blue (B), it is also possible to display monochrome components of other colors (red: R, green: G) by mutually providing similar circuits. This is something that can be achieved.

In this figure, 1 is an input terminal for a video signal. The video signal from this input terminal 1 is supplied to an R, G, B conversion circuit 2, and three primary color signals of R, G, and B are extracted. Of the three primary color signals of R, G, and B, the B signal component is supplied to the reference signal insertion circuit 3B,
A reference signal having a certain level near a predetermined black level that is not influenced by the input signal is inserted. The B signal component into which the reference signal has been inserted is supplied to the signal level automatic adjustment circuit 4B. The signal from this automatic signal level adjustment circuit 4B is taken out via a cathode drive circuit 5B to a terminal 6B connected to the blue (B) cathode. Further, the cathode current during the period in which the above-mentioned reference signal of the cathode drive circuit 5B is inserted is detected by the cathode current detection circuit 7B, and the automatic signal level adjustment circuit 4B is controlled according to this detected value. Therefore, by controlling this signal level automatic adjustment circuit 4B,
The emission level of the cathode ray tube is maintained near the black level of the B signal component.

Similarly, regarding the R and G signal components,
The signal components are supplied to reference signal insertion circuits 3R and 3G, where a reference signal is inserted, and the R and G signal components into which the reference signal has been inserted are supplied to signal level automatic adjustment circuits 4R and 4G. Signals from the signal level automatic adjustment circuits 4R and 4G are taken out via cathode drive circuits 5R and 5G to terminals 6R and 6G connected to the red (R) and green (G) cathodes. Further, the cathode currents of the cathode drive circuits 5R, 5G during the period in which the reference signals are inserted are detected by the cathode current detection circuits 7R, 7G, and the signal level automatic adjustment circuits 4R, 4G are controlled according to the detected values.

In this circuit, signal level automatic adjustment circuits 4R, 4G and cathode drive circuits 5R, 5G
Switch circuits 8R and 8G are provided between the above-mentioned B
The signal from the signal level automatic adjustment circuit 4B of the signal component is transmitted to the white level adjustment circuits 9R, 9G and the black level conversion circuit 10R.
, 10G to the switch circuits 8R and 8G. Therefore, when performing monochrome display of the monochromatic component of blue (B), the switch circuits 8R and 8G are switched to the black level conversion circuits 10R and 10G. At the same time, the switch circuits 8R and 8G are switched to the signal level automatic adjustment circuits 4R and 4G only during the period when the reference signal is inserted. Furthermore, signal level automatic adjustment circuit 4R
, 4G are supplied to black level detection circuits 11R and 11G, and black level conversion circuits 10R and 10G are controlled according to the detected values. The processing circuit for the single color component of green (G) is omitted due to space limitations, but the processing circuit for the single color component of red (R
) is similar to the circuit.

Therefore, in this circuit, the switch circuit 8
During the period when the reference signal is inserted in R and 8G, the signal level automatic adjustment circuit is switched to the 4R and 4G side. As a result, during this period, the signal level automatic adjustment circuit 4R
, 4G, cathode drive circuits 5R, 5G, and cathode current detection circuits 7R, 7G form a loop.
, G signal components are maintained near the black level of the cathode ray tube. At the same time, the black levels of the R and G signal components are detected by black level detection circuits 11R and 11G,
Switch circuit 8R with black level conversion circuit 10R and 10G
By making the black level of the B signal component selected by , 8G equal to the black level of the R and G signal components, the light emission level of the R and G cathode cathode ray tubes due to the B signal component is near the black level. Automatically adjusted to always match the set value. In this embodiment, settings near the white level are adjusted by white level adjustment circuits 9R and 9G.

[0012] According to the above-mentioned device, the signals from the original primary color signal circuits are supplied to the cathode (switch circuits 8R, 8G) only during the reference signal period, and the signal level is automatically adjusted (circuits 4R, 4G). At the same time, detect the black level of this adjusted signal (circuits 11R and 11G)
Black level conversion of a signal displayed as a monochromatic component (Circuit 10
R, 10G), the signal level is automatically adjusted even during monochromatic component display, and good monochromatic component display can be performed.

Furthermore, according to the above-mentioned device, since a monochromatic component display circuit can be configured in the feedback loop of auto white balance, it is possible to use an IC in which an RGB matrix and auto white balance are integrated on one chip. The circuit can be streamlined.

[0014]

According to the present invention, the signal from the circuit for each primary color signal is supplied to the cathode only during the reference signal period, and the signal level is automatically adjusted, and the black level of this adjusted signal is detected. By converting the black level of the signal for monochrome component display, automatic adjustment of the signal level is performed even during monochrome component display, making it possible to perform good monochrome component display.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of essential parts of an example of a monitor receiver according to the present invention.

[Explanation of symbols]

1 Video signal input terminal 2 R, G, B conversion circuit 3B, 3R Reference signal insertion circuit 4B, 4R
Signal level automatic adjustment circuit 5B, 5R Cathode drive circuit 6B, 6R, 6G Terminal 7B connected to cathode,
7R Cathode current detection circuit 8R Switch circuit 9R White level adjustment circuit 10R Black level conversion circuit 11R Black level detection circuit

Claims (1)

[Claims] 1. A monitor receiver in which a predetermined reference signal is inserted into each primary color signal, and the signal level is automatically adjusted by detecting the cathode current during this period, wherein the reference signal period is inserted into each of the primary color signals. and a switch circuit for switching video signal periods, and a black level detection and black level conversion circuit, and is capable of displaying monochromatic components of each of the primary color signals.