JPH02249387A - 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 the 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 receives television signals A, B of different signal forms, amplifies and detects them and outputs a video signal of a basic frequency band. A converter 2 provided with a descrambler function receives the video signal to convert the television signal B into the television signal A and outputs the descrambled signal when the television signal B is descrambled. A switching circuit 5 inputs a converter output signal and the television signal A to output any of them 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 0ATV 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 these various transmission systems, the switching of 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 switching by acquisition 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.

The present invention overcomes the above-mentioned problems, allows TV signals of different signal formats to be viewed on one type of display device, and automatically operates a switching circuit as the received signal changes. The object of the present invention is to provide a signal switching device that can perform the following steps.

Means for Solving the Problems In order to solve the above problems, the signal switching device of the present invention has the following features:
This system is configured to convert television signals of different signal formats into the same signal format, and to detect waveforms specific to the signal format and automatically change the KI71.

Effects of the Invention With the above-described configuration, the present invention can automate signal input switching to a television monitor, which was conventionally performed by one person by manually 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 are expected to be able to receive television signals from multiple channels using the same parabolic antenna (same direction). Therefore,
Since there are many cases where different signal formats are received,
Here, we will discuss the case of receiving satellite signals.

FIG. 1 is a block diagram of one embodiment. 1 in the figure is F
For example, a 12 GH band signal is received by an antenna ANT and a low noise converter LNB in an M signal receiver, and a 1G signal is received by an antenna ANT and a low noise converter LNB.
H2, down-converted to band and input. Therefore, unlike an FM receiver for terrestrial broadcasting, the performance is similar to that of a so-called satellite television broadcast reception tuner (BS tuner). As the output of receiver 1, the FM detection output is connected to terminal Pa.
, Pb. Let us now assume that signal A is a signal currently being transmitted from BS2, that is, an NTSC television signal, and signal B is a so-called MUSE television signal.

2 is a down converter that converts MUSE TV signals to NTSC TV signals, and if the Pb output is scrambled, it has a paid reception function that allows descrambling only to viewers who have paid a fixed fee and signed up for reception. We are prepared. 3 inputs an NTSC video signal,
This is a circuit that converts RGB signals, and is the same as the equivalent circuit of a normal television receiver. 4 is a circuit that detects a synchronization signal from the video signal output from the P1 terminal.

6 is an analog switch, and when a switching signal of L or H is applied to the switching terminal ite, the inputs of C1 to C6 change to C1 to C6.
It is possible to switch between whether output is output to b1 to b6 or b1 to b6 are output. θ is a monitor television with an RGB input terminal.

The operation in Figure 1 is that when the FM tuner 1 receives the MUSE TV signal in tune, the downverter 2 with a descrambler function determines whether or not there is an input MUSE TV signal, and the MUSE TV signal is received. Sometimes the output φ of the converter 2 becomes high (H) and the switch 6
b1~'11b2~C...)y=c
is conductive, a1~CI, a22 l
6 6 -C2,...a6-C6 are blocked.

Further, the converter 2 inputs the FM detection output output to the Pb terminal, performs appropriate processing on the USE television signal, and outputs the RGB output of the NTSC television signal and the L.

Outputs an H audio signal and H and V synchronization signals. In other words,
The monitor television 6 outputs an image obtained by converting the MUSE television signal to an NTSC television signal, as well as left and right audio.

When the tuning frequency of the tuner 1 is changed and a signal other than the MUSE television signal, for example, an NTSC television signal, is received, the output φ of the converter 2 becomes low and becomes Iv(L), and the switches 6 are set to a1 to C1, . . . ......a6~
c6 becomes conductive and b1 to c1.・River... b6 to c6 are blocked. Note that the output φ of the converter 2 is, for example, when the trev signal B is a MUSE TV signal, the down converter receives and detects the synchronization signal waveform peculiar to the MUSE system, and detects the presence or absence of the MUSE TV signal input as a status signal. Since it can be output as the switching signal φ, the voltage at the se terminal can be set. Further, even when the television signal B is in a format other than the MUSE television signal, such as a MAC television signal, the switching signal to the 8θ 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. Connect to S.

On the other hand, from the synchronization detection circuit section 4, the television signal A, that is, NT
A detection signal indicating that an SC television signal is being received is taken out as a low level (L) status signal and connected to the set terminal R of the flip-flop 7. In this way, TV signal B
When receiving signal A, flip-flop 7 is set, and when receiving signal A, flip-flop 7 is set.
is reset, so its Q output can be used as the se terminal input of the switching circuit 6.

Next, FIGS. 3 and 4 show cases where the television signal is a composite video signal and an RF multiplied signal. In FIG. 3, 2V is an additional circuit that converts the RGB output signal of the converter 2 of FIG. 1 into a video signal and outputs the video signal. The operation is as described above. 6v is the same as in Fig. 1, and the 80 terminal is used to switch between the 2v video output signal and the video output signal from the Pa and P8 terminals, and 6v is the same as in Fig. 1. and a TV monitor with left and right audio inputs.

Figure 4 is an example of a case where it is thought that the largest number of television receivers will be connected.The 2v and 3v video signals and audio signals are converted into RF signals by RF modulators 8 and 9, and the normal It is connected to the antenna input terminal of the television 6R, and SR is an RF switch that controls the pse terminal by φ and determines which of τ1 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, it is possible to automate input switching of two types of television signals having different signal formats to a television receiver.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a signal switching device according to a first embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of main parts in this embodiment, and FIG. 3 is a block diagram of a signal switching device according to a second embodiment of the present invention. Block Diagram,
FIG. 4 is a block diagram of a third embodiment of the present invention. 1...FM signal receiver, 2...Down converter, 3...μ degree signal...color signal processing circuit (RGB signal conversion circuit), 4... ...Synchronization signal detection circuit, 5...Switch, 6...RG
Monitor with B input Tv0 Name of agent: Patent attorney Shigetaka Awano and one other person Ninioka

Claims (6)

[Claims] (1) 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 are received, and after amplification and detection, the base An FM signal receiver that outputs the video signal V_S in the frequency band, and an FM signal receiver that receives the video signal V_S as input and converts the TV signal B into the TV signal A, and outputs a descrambled signal if the TV signal B is scrambled. a converter with a descrambler function for signal format B, and a switching circuit that inputs the converter output signal C and the television signal A and outputs either the converter output signal C or the signal A 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) As a switching signal, a signal indicating that the FM signal receiver is receiving TV signal B output from a converter that converts TV signal B to TV signal A with a descrambler function, and a synchronization detection circuit Claim 1 or 2, characterized in that the output of a flip-flop is used which is set and reset by two signals, including a signal indicating that the FM signal receiver is receiving the television signal A output from the FM signal receiver.
The signal switching device described. (4) RGB signals are used as the output of TV signal A, and the output of the converter that converts TV signal B to TV signal A, which is equipped with a descrambler function, is also an RGB signal, and two types of RGB signals are input to the switching circuit. The signal switching device according to any one of claims 1 to 3, characterized in that: (5) As the output of the TV signal A, the synchronization signal and the audio signal are also input to the switching circuit at the same time as the RGB signal, and as the output of the converter that converts the TV signal B to the TV signal A, which is equipped with a descrambler function, the synchronization signal, Audio signal is also RG
2. The signal switching device according to claim 1, wherein the signal is input to the switching circuit at the same time as the B signal. (6) As the output signal of the output terminal in the tuner,
A converter that outputs a UHF or NTSC signal and has a descrambling function that converts signal format B to signal format A also outputs a UHF or VHF signal, and with both as input, RF that switches and outputs either one. The signal switching device according to any one of claims 1 to 3, comprising a switching circuit.