JPH02249386A - Signal switching device - Google Patents

Abstract

PURPOSE:To automate signal input changeover to a television monitor by converting television signals of different signal forms into a same signal form and detecting a waveform or the like specific to the signal form so as to switch the signals automatically. CONSTITUTION:An FM signal receiver 1 receives television signals A, B of different signal forms and outputs a video signal of a basic frequency band. A descrambler DB 4 inputs an output C1 being the television signal B of a converter 3 when the television signal B is scrambled and returns the descrambled output C2 to the converter 3 and converts the signal C2 into the television signal A. A descrambler DA2 inputs the television signal A when the television signal A is scrambled to output the descrambled signal D. A switching circuit 5 inputs the output signal C3 of the descrambler DB and outputs any of the television signal by using a switching signal phi. Thus, the input changeover of the 2 kinds of television signals with different signal forms to the television receiver 6 is automated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides for receiving two or more scrambled television signals of different signal formats so that they can be viewed on a single television signal display device. The present invention relates to a signal switching circuit for

Conventional technology Recently, in addition to general television broadcasting, CATV
Broadcasting and satellite television broadcasting have begun to take place. In general broadcasting, signals are transmitted using the standard television system (NTSC system), but in CATV broadcasting and satellite television broadcasting, signals are transmitted using high-definition systems such as the MUSE system and the MAC system. When receiving television signals using different transmission systems among these popular systems, switching the receiving circuit according to the television system to be received has been done manually by connecting and disconnecting connectors.

Problems to be Solved by the Invention However, such manual switching is troublesome to operate, requires a lot of space if the TV receiver itself is separate, and has many display screens, making it difficult to use. was there.

In view of the above-mentioned problems, the present invention allows TV signals of different signal formats to be viewed on one type of display device, and also allows a switching circuit to be automatically operated in accordance with changes in the received signal. The object of the present invention is to provide a signal switching device that can perform the following functions.

Means for Solving the Problems In order to solve the above problems, the signal switching device of the present invention converts television signals of different signal formats into the same signal format, and also converts television signals of different signal formats into the same signal format. It has a configuration that detects waveforms, etc. and automatically switches.

Function: With the above-described configuration, the present invention can automate the switching of signal input to a television monitor, which was conventionally done manually by connecting and disconnecting connectors.

Example In satellite communication, satellite broadcasting, etc., television signals are NTSC.
formats other than the MAC method (for example, MAC method).

(MUSE method, etc.). In particular, communication satellites receive television signals from many channels using the same parabolic antenna (same direction).

Therefore, since there are many cases where different signal formats are received, the case where satellite signals are received will be described here.

FIG. 1 is a block diagram of one embodiment. In the figure, 1 is F
In the M signal receiver, for example, a 12 GH band signal is received by the antenna ANT and the low noise converter LNB, and the IGH
It is down-converted into one band and input. Therefore, the performance is similar to that of a so-called satellite television broadcast reception tuner (BS tuner), which is different from an FM receiver for terrestrial broadcasting. As the output of receiver 1, the FM detection output is sent to terminals Pa and P.
It is output from b. Now, suppose that TV signal A is currently 1
Let us assume that the television signal section JFJTSC television signal and the television signal B transmitted from 3S2 are the so-called MUSE television signals.

2 is an NTSC pay receiver that allows descrambling only to viewers who have paid a fixed fee and signed a reception contract when the outputs of Pa and PIl are scrambled. In other words, the receiver 2 receives the F output to the Pa terminal.
Scrambled NTSC with M detection output as input
Appropriate descrambling processing is applied to the TV signal, and NT
Outputs SC type RCiB output and H, V synchronization signals. Further, the scrambled pit stream output including the audio signal outputted to the Pa terminal is input, and after performing appropriate descrambling processing, right and left audio signals are output.

3 is a down converter that converts a MUSE TV signal into an NTSC TV signal. 4 is M.U.
This is an SE system paid receiver, and only viewers who have paid a predetermined fee and subscribed to the scrambled MUSE television signal are allowed to descramble the scrambled MUSE television signal.

5 is an analog switch, and when an L or H switching signal is applied to the switching terminal se, the inputs of a1 to a6 are changed to 01 to C6.
It is switched whether the inputs of b1 to b6 are output.

6 is a monitor television with an RGB input terminal.

The operation in FIG. 1 is such that when the FM tuner 1 tunes to the carrier wave modulated by the MUSE television signal, the input MU
The downverter 3 determines the presence or absence of the SE TV signal, and the MU
When the SE signal is received, the output φ of the down converter 3 becomes high (B) V (C), and the switches b1 to C1, b2 to
C2,... b6 to C6 are electrically connected, and a1 to 01.
a2-C2t...a6-C6 are blocked.

In addition, the down converter 3 outputs the FM signal to the Pb terminal.
Using the detection output as input, it performs appropriate processing on the MUSE television signal and outputs NTSC RGB output, left and right audio signals, and H and V synchronization signals.

Tsumashi, connect the MUSE TV signal to monitor TV 6.
The image converted to the TSC format and left and right audio are output.

When the tuning frequency of the tuner 1 is changed and a carrier wave modulated with a television signal other than the MUSE system, for example, an NTSC television signal, is received, the output φ of the down converter 3 becomes low and becomes /l/ (L). 6 is 61~CI
, "・"' as "-06 conducts, and b1 to C
1°... b6 to c6 are blocked. Therefore, the switching circuit 6 operates in response to channel switching of the tuner.
Images are always displayed on the monitor television 6 using NTSC signals.

Note that the output φ of the down converter 3 is, for example, when the television signal B is a MUSE television signal, the down converter 3 receives and detects a synchronization signal waveform peculiar to MUSE, and determines whether or not the MUSE television signal is input. Since it can be expressed as a signal, it can be used as the switching signal φ to determine the voltage at the Be terminal. Also, TV signal B
Even when the signal is in a format other than the MUSE format such as the MAC format, the voltage at the Be terminal can be set using the detection signal φ obtained by determining the signal specific to the television signal B.

As another method, as shown in Fig. 2, the detection signal indicating that the TV signal B is the MUSE TV signal is extracted from the down converter 3 as a state signal of V/v (L), and the flip-flop Connect to set terminal S of 7. On the other hand, a detection signal indicating that the television signal A, that is, the NTSC television signal is being received, is extracted from the NTSC pay receiver 2 as a low level signal (L) and connected to the reset terminal R of the flip-flop 7. . In this way, when the TV signal B is being received, the flip-flop 7 is set, and when the TV signal A is being received, the flip-flop 7 is reset, so the Q output is set to the go high of the switch 6. It can be input and used.

Next, let us consider the case where the signal is a composite video signal and an RF multiplied signal.
It is shown in Fig. 4. In FIG. 3, 2v and 3v are circuits that convert the RG and B output signals of the receiver 2 and down converter 3 shown in FIG. 1 into video signals and output the video signals, respectively. The operation is as described above. 6V is the same as in Fig. 1, and the 8e terminal is the same as in Fig. 1 in that the 2V video output signal and 3V video output signal are switched. 6■ is the video signal input and the left and right terminals. This is a TV monitor with an audio input terminal.

Fig. 4 is an example of a case where it is thought that the largest number of television receivers will be connected. In this method, it is connected to the antenna input terminal of 6R, and 5R is an RF switch that controls the Be terminal by φ and determines which of rl and r2 is connected to r3.

Therefore, the configuration of FIG. 4 is basically the same as that of FIG. 1.

Effects of the Invention As described above, according to the present invention, input switching of two or more types of television signals having different signal formats to a television receiver can be automated.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the main parts in an embodiment of the present invention, FIG. 2 is a block diagram of the main parts of a modification of FIG. 1, and FIG. Block diagram of main parts,
FIG. 4 is a block diagram of main parts of a third embodiment of the present invention. 1...FM signal receiver, 2...NTS
C-system paid receiver, 3...down converter,
4...MUSE system paid receiver, 6...
・Analog switch, 6...Monitor TV.

Claims (6)

[Claims] (1) Receiving a signal modulated by a television signal A having a first signal format and a television signal B having a second signal format different from the first signal format, and an FM signal receiver that outputs a signal V_S, a converter that receives the video signal V_S and converts the television signal B into a television signal A, and a first television signal B of the converter when the television signal B is scrambled. The output C_
a descrambler D_B for television signal B which returns the descrambled output C_2 with input C_1 to the converter and converts C_2 into television signal A; A descrambler D_A for the television signal A that outputs the signal D obtained by the descrambler D_B, and a switching circuit that receives the output signal C_3 and the signal D of the descrambler D_B and outputs either the signal C_3 or the signal D according to a switching signal. A signal switching device characterized by: (2) The signal switching device according to claim 1, wherein the switching signal is a signal that determines whether or not the FM signal receiver is receiving the television signal B. (3) A signal indicating that the FM signal receiver is receiving TV signal B output from the converter that converts TV signal B to TV signal A as a switching signal, and a signal output from the descrambler of TV signal A. TV signal A to FM
2. The signal switching device according to claim 1, wherein the output of a flip-flop is used which is set and reset by two signals, including a signal indicating that the signal receiver is receiving the signal. (4) The signal switching device according to any one of claims 1 to 3, wherein an RGB signal is used as an output signal of a converter that converts television signal B to television signal A and a descrambler D_A of television signal A. (5) The signal according to claim 4, characterized in that a synchronization signal and an audio signal are output simultaneously with the RGB signal as output signals of the converter that converts the television signal B to the television signal A and the descrambler D_A of the television signal A. Switching device. (6) Convert the output of the converter to a UHF or VHF signal, and also convert the output of the descrambler D_A to a UHF or VHF signal.
4. The signal switching device according to claim 1, further comprising an RF switching circuit that converts the signal into an HF signal, takes both as input, and switches and outputs one of them.