JPH0514617Y2 - - Google Patents

Description

[Detailed Description of the Invention] The video monitor device of the present invention will be explained according to the following items.

A. Field of industrial application B. Outline of the invention C. Prior art [Figure 3] D. Problem that the invention attempts to solve E. Means for solving the problem F. Effect G. Example [Figures 1 and 2] a One embodiment [Figure 1] b Another embodiment [Figure 2] H Effects of the invention (A Field of industrial application) The present invention is a new video monitor device, especially compatible with multiple types of input signals. The present invention relates to a video monitor device.

(B. Summary of the invention) The present invention inputs primary color signals to three input terminals in order to reduce the number of input terminals in a video monitor device that can handle multiple types of input signals, and One of them is also used as a composite video signal input terminal, and a detection circuit provided for each input terminal in the discrimination circuit determines whether the three detection outputs are present at the same time or not as a primary color signal. According to the present invention, the discrimination circuit determines whether the signal input to the input terminal is a primary color signal or a video signal. Since the signal can be detected and sent to different places accordingly, it is possible to input the primary color signal and the video signal to a common input terminal, and separate input terminals are provided for the primary color signal and the video signal. There's no need.

(C Prior Art) [Figure 3] A video monitor device called a monitor television or the like is generally capable of receiving video signals from a tuner, video tape recorder, etc. and reproducing the video, and can also be a microcomputer. It is also possible to play video by receiving RGB signals from a computer, a game device using the same, a text broadcasting decoder, etc. The conventional video monitor device generally receives signals from various devices a, b, c, and d via a centralized control center e, as shown in FIG. Three transmission lines for RGB signals and one transmission line for video signals are provided between them.

(Problem that invention D aims to solve) In this way, conventional video monitor devices that support multiple types of signals had to have separate input terminals for each type of signal, so it was necessary to provide input terminals for each type. The number of transmission lines between the central control sensor and the video monitor device also increases. However, in order to reduce costs and reduce the size of the device, it is preferable to minimize the number of input terminals of the video monitor device and the number of transmission lines connecting it to the central control center.

The present invention has been devised to solve these problems, and its purpose is to reduce the number of input terminals in a video monitor device that supports multiple types of input signals.

(Means for Solving Problem E) In order to solve the above problem, the video monitor device of the present invention has three terminals into which primary color video signals are input and one of which is also used as a composite video signal input terminal. It has an input terminal and a detection circuit that is provided corresponding to each of the three input terminals and detects the signal input from the input terminal. It is characterized by comprising a discrimination circuit that discriminates whether the input signal is a primary color signal or a composite video signal, and a switching circuit that switches the path of the signal input to the input terminal according to the discrimination result of the discrimination circuit. shall be.

(F Effect) Therefore, according to the video monitor device of the present invention, it is possible to detect whether the input signal input to the input terminal is a primary color signal or a composite video signal, and to detect whether the input signal is a primary color signal or a composite video signal. Since processing can be performed depending on whether the input signal is a primary color signal or a video signal, one input terminal can be used in common for inputting the primary color signal and the video signal. Therefore, there is no need to provide separate input terminals for each type of input signal, and the number of input terminals can be reduced.

(G Embodiment) [FIGS. 1 and 2] The video monitor device of the present invention will be described in detail below according to the embodiment shown in the accompanying drawings.

(A One Embodiment) [FIG. 1] FIG. 1 shows an example of the implementation of the video monitor device of the present invention.

T1, T2, and T3 are input terminals, and each signal inputted from each input terminal T1, T2, and T3 is inputted to the signal discrimination circuit 1. The signal discrimination circuit 1 includes synchronous separation circuits 2, 3, and 4, a detection signal hold circuit consisting of diodes D1, D2, D3, and capacitors C1, C2, and C3 for holding the peaks of their outputs, and the detection signal hold circuit. Three transistors Q1, Q2, Q3 driven by the output of the circuit and connected in series;
2 and Q3, and a resistor R1 that serves as a collector resistance for the series circuit consisting of Q2 and Q3. Synchronous separation circuit 2,
3, 4, diodes D1, 2, 3, and capacitors C1, 2, 3 form a detection circuit that detects whether the signal is a video signal or not.

Reference numeral 5 designates a switching circuit, which is driven by the output signal of the signal discrimination circuit 1 and includes a transistor Q4 whose collector is connected to the power supply terminal Vcc, and a grounded emitter transistor Q5 whose base is connected to the emitter of the transistor Q4 via a resistor R2. and a transistor Q6 driven by the output of the transistor Q5.
Consisting of The collector of the transistor Q6 is connected to the power supply terminal. Note that R3 is a resistor forming the collector resistance of the transistor Q5.

6 is a signal processing circuit, which includes transistors Q7 to
Q12, resistors R4 to R9, a Y chroma circuit 7, and a video out circuit 8. Transistor Q7 is an emmic floor transistor whose base receives a signal from input terminal T1, transistor Q8 is an emmic floor transistor whose base receives a signal from input terminal T2, and transistor Q9 is an emmic floor transistor whose base receives a signal from input terminal 3. The ground floor transistors R4, R5, and R6 are resistors connected between the emitters of the emotic floor transistors Q7, Q8, and Q9 and ground. The collectors of the transistors Q7, Q8, and Q9 are connected to the emitter of the transistor Q4. Also, Y
The power supply terminal of the chroma circuit 7 is also connected to the emitter of the transistor Q4. The output of the emitter floor circuit by transistor Q7 is Y microcircuit 7.
The output of each emitter floor circuit formed by transistors Q8 and Q9 is connected to an audio playback device (not shown) outside the video monitor device (two left and right), for example.
channel) is connected to the input side of the channel. Incidentally, Y consisting of resistors R5 and R6 of these transistors Q8 and Q9
Sometimes there is no circuit. In such a device, when a video signal is input, no signal is received at the input terminals T2 and T3.

The transistor Q10 is an emitter floor transistor that receives a signal from the input terminal T1 at its base.
Transistor Q11 is an emitter floor transistor whose base receives a signal from input terminal T2, transistor Q12 is an emitter floor transistor whose base receives an input signal from input terminal T3, and the collectors of transistors Q10 to Q12 are all connected to transistor Q6. Connected to Emitsuta. R7-R9 are transistors Q10-Q1
This is a resistor connected between the emitter of No. 2 and ground.

The output terminal of the emitter floor circuit formed by the transistor Q10 and the R output terminal of the Y chroma circuit 7 are connected to the R input terminal of the video out circuit 8, and the output terminal of the emitter floor circuit formed by the transistor Q11 and the G output terminal of the Y chroma circuit 7 are connected to the video output terminal. A transistor Q is connected to the G input terminal of the out circuit 8.
The output terminal of the emitter floor circuit 12 and the B output terminal of the Y chroma circuit 7 are connected to the B input terminal of the video out circuit 8.

Next, the operation of the video monitor device shown in FIG. 1 will be explained.

First, the operation when RGB signals are input will be explained.

Since each RGB signal has a synchronization signal,
When RGB signals are input, signals R, G, and B having synchronization signals are input to each input terminal T1 to T3, and therefore each synchronization separation circuit 2 to
4 outputs a synchronization detection signal, which is held by a detection signal hold circuit consisting of diodes D1-D3 and capacitors C1-C3. As a result, transistors Q1 to Q3 all remain on. When all transistors Q1 to Q3 are on, transistor Q4 is turned off. When the transistor Q4 is turned off, the power supply voltage Vcc is not supplied to the transistors Q7 to Q9 and the Y chroma circuit 7, and these circuits do not operate. When transistor Q4 turns off, transistor Q5 also turns off, and as a result, transistor Q
When transistor Q6 is turned on, power supply voltage Vcc is applied to the collectors of emitter floor transistors Q10 to Q12.
Each emitter floor transistor Q10-12 remains in an operating state. That is, transistors Q10-12
Signals having almost the same level as the R, G, and B signals received by the receiver are input to the video out circuit 8, and the input RGB signals are reproduced and processed by the video out circuit 8. Become.

Next, the operation when a video signal is input will be explained.

When a video signal is input, the video signal is input to the input terminal T1, and the audio left signal L is input to the input terminal T2.
However, the audio right signal R is input to the input terminal T3. Among the signals input to the input terminals T1 to T3, the audio signals R and L do not have a synchronization signal. Only the video signal input to input terminal T1 has a synchronization signal. Therefore, transistor Q1 is turned on, but transistors Q2 and Q3 are turned off. Then, transistors Q4 and Q5 are turned on, and transistor Q6 is turned off. Then, by turning on transistor Q4, transistors Q7 to
The Q9 and Y chroma circuits 7 are now receiving the power supply voltage Vcc. On the other hand, transistor Q10~
Since transistor Q6 is turned off, Q12 cannot receive the power supply voltage Vcc and becomes inoperative.

Thus, the video signal input to the input terminal T1 passes through the emitter floor Q7 to the Y chroma circuit 7.
A Y chroma circuit 7 generates an RGB signal based on the video signal, and the RGB signal is input to a video out circuit 8 for reproduction on a CRT.

Further, the audio signals L and R input to the input terminals T2 and T3 are provided for audio reproduction by an external audio reproducing device (not shown) via emitter floors Q8 and Q9. Note that when a video signal is input, if no other type of signal is received (that is, if there is no circuit consisting of transistors Q8 and Q9 and resistors R5 and R6), only the video signal is naturally processed. .

As described above, according to the illustrated video monitor device, when a signal is input to the input terminals T1 to T3, the signal discrimination circuit 1 discriminates whether the signal is an RGB signal or a video signal, and the RGB signal is When this is the case, the switching circuit 5 stops the operation of the Y chroma circuit 7 and the transistors Q7 to Q9, and sends the RGB signals input to the input terminals T1 to T3 to the video out circuit via the emitter floor transistors Q10 to Q12. The state is that it has been transmitted to 8.
In addition, when the input signal is a video signal or an audio signal, the switching circuit 5 switches the transistors Q10 to Q
12 is stopped, and the video signal input to the input terminal T1 is transmitted to the video out circuit 8 via the emitter floor transistor Q7, and the video out circuit 8 outputs the video signal based on the video signal.
Creates RGB signals and uses them for image reproduction. Then, the audio signals L and R input to input terminals T2 and T3 are transferred to emitter floor transistors Q8 and Q9.
is used for audio reproduction by an audio reproduction process (not shown).

Note that the above embodiment has three input terminals, and in some cases, RGB signals are received at the three input terminals,
At other times, one of the input terminals received a video signal. However, the present invention has two
The two input terminals receive color difference signals R-Y, B-Y and are used for image reproduction, and at other times, one of the two input terminals receives a video signal. , the video signal may be used for image reproduction. This is because two color difference signals, for example R
-Y, B-Y, color difference signal G-Y can also be created by providing a matrix circuit. Therefore, by providing a matrix circuit in the video monitor device to create another color difference signal from two color difference signals. , two input terminals are provided, and the second
This makes it possible to obtain a video monitor device that receives a color difference signal at one input terminal and reproduces it, or receives a video signal at one of two input terminals and reproduces it.

Incidentally, instead of the synchronization separation circuits 2 to 4 of the signal discrimination circuit 1, a blanking separation circuit for separating blanking signals may be used.

(b Other Embodiments) [Figure 2] Figure 2 shows an embodiment in which the input terminals T2 and T3 to which no video signals are input are used to transmit deflection pulses to the central control center when a video signal is input. FIG. 3 is a circuit diagram showing a state when a video signal is input.

In this video monitor device, when a video signal is input, a signal having a synchronizing signal is input only to the input terminal T1, and the other input terminals T2,
A signal (or rather, a signal itself) having a synchronization signal is not input to T3. When this is detected by the signal discrimination circuit 1, the switching circuit 5 becomes in a state of transmitting the video signal received at its input terminal T1 to the Y chroma circuit 7. In this respect, it is no different from the video monitor device shown in FIG. However, in the video monitor device shown in FIG. 1, the input terminals T2 and T3 are not used for inputting audio signals; Used to send vertical deflection pulses to a central control center.
The deflection pulse sent out from the video monitor device is processed appropriately by the deflection pulse processing circuit 10 and then input to the character signal generation circuit 11, which is used to generate character symbols for channel display, volume display, etc. Used as a timing signal. The character signal output from the character signal generating circuit 11 is superimposed on a video signal from a tuner or the like in a video signal circuit 12, and appears on the CRT screen as, for example, a channel display or a volume display.

It should be noted that this video monitor device operates in exactly the same way when RGB signals are input as shown in FIG. 1.

As mentioned above, the video monitor device shown in Figure 1 or Figure 2 both has an RGB input terminal T1.
When the signals or color difference signals R-Y, R-B are input, one of them, for example, the R signal or R
- It functions as a terminal that receives the Y signal, and when a video signal is input, it also functions as a terminal that receives the video signal, so it can receive RGB signals or R-Y,
It is not necessary to use four or three transmission lines just because it corresponds to both B-Y and video signals, and it is not necessary to use four or three transmission lines to handle both B-Y and video signals.
As with the type of video monitor device that receives only -Y and B-Y (that is, does not receive video signals), three or two transmission lines can be used.

(H Effect of the invention) As is clear from the above description, the video monitor device of the invention inputs primary color signals to three input terminals, and inputs one of them to a composite video signal. It is also used as an input terminal, and a detection circuit provided for each input terminal in the discrimination circuit discriminates whether the three detection outputs are present at the same time or not to determine whether it is a primary color signal or a video signal. This feature is characterized in that the transmission path of the transmission path is switched.

Therefore, according to the video monitor device of the present invention, the discrimination circuit detects whether the signal input to the input terminal is a primary color signal or a video signal, and the signal can be sent to different locations accordingly. It becomes possible to input the video signal to a common input terminal, and there is no need to provide separate input terminals for the primary color signal and the video signal, and the number of input terminals can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of the implementation of the video monitor device of the present invention, and FIG. 2 is a circuit block diagram showing the main part of the substantial circuit configuration when a video signal is input in another embodiment of the video monitor device of the present invention. , 3rd
The figure is a circuit block diagram showing a conventional example of a video monitor device. Explanation of symbols, 1...Signal discrimination circuit, 2, 3,
4, D1, D2, D3, C1, C2, C3...detection circuit, 5...switching circuit.

Claims (1)

[Claims for Utility Model Registration] Three input terminals into which primary color video signals are input, one of which is also used as a composite video signal input terminal, and an input terminal provided corresponding to each of the above three input terminals. It has a detection circuit that detects the signal input from the terminal, and determines whether the signal input to the input terminal is a primary color signal or a composite video signal depending on whether three detection outputs exist simultaneously. A video monitor device comprising: a discrimination circuit; and a switching circuit that switches a route of a signal input to the input terminal according to a discrimination result of the discrimination circuit.