JP2961847B2 - Channel selection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a channel selection device effective for a receiver such as a satellite television broadcast.

2. Description of the Related Art In satellite video distribution such as communication satellite broadcasting (hereinafter, referred to as CS broadcasting), a receiver contracts with a program supplier such as a broadcasting company, and only the contractor supplies the program. In order to be able to receive the program and prevent anyone other than the subscriber from watching it,
The supplied programs are scrambled. For this reason, the subscriber is provided with a decoder unit for returning the scrambled television signal to a viewable state.

Normally, scramble for allowing only a contractor to receive a supplied program sends a key for descrambling the scramble corresponding to the contractor for the purpose. Only the decoder unit that has received this key is specified, and the program supplied from the program supplier can be previewed.

Problems to be Solved by the Invention By the way, since CS broadcasting is a broadcasting for communication, the broadcasting time tends to fluctuate according to the convenience of the sender, and the CS broadcasting is often used as intra-company communication. The equipment is often installed in a location remote from the contractor, for example, in a conference room or auditorium. Therefore, it is difficult for the receiver to know the broadcast time in advance. In CS broadcasting, the number of channels is as large as 32 and it takes a lot of time to select a channel.
This is inconvenient when timer recording is performed.

The present invention relates to a channel selection method for receiving a scrambled broadcast without requiring the receiver to be at the receiver and automatically selecting a program that can be viewed by the subscriber. It is intended to provide a device.

Means for Solving the Problems The present invention, in order to achieve the above object, a signal detecting means for determining the presence or absence of a transmission signal, and whether or not it can be decoded by the scramble related information included in the scrambled transmission signal Determining means for determining, and enabling reception of only readable channels. In addition, a channel that can be decrypted among scrambled signals and a channel of a non-scrambled signal that is broadcast free of charge are available as channels that can be viewed. Automatic channel control means for preferentially selecting a channel. Further, the automatic channel control means is provided with a determination channel selection means capable of setting a specific channel in advance as a channel for performing signal determination for selecting a channel.

Operation The present invention can select a program specified by scramble information included in a transmission signal scrambled by a transmission station as a reception channel as a channel selection without receiving any advance notice. A broadcast intended by the receiver is performed, and important programs are automatically selected even when the subscriber is not present, thereby preventing recording errors.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an outline of an SHF band satellite television signal receiving system according to an embodiment of the present invention. FIG. 2 is a flowchart of channel selection in the embodiment of the present invention.
FIG. 3 is a diagram showing an example of another processing device, FIG. 4 is a diagram showing a satellite television signal frequency spectrum, FIG. 5 is a block diagram showing a configuration of a signal discriminating device, and FIG. FIG.

The SHF band signal transmitted from the satellite is converted into a digital signal with a subcarrier of 5.73 MHz, packetized at predetermined time intervals, and a voice signal to which an error correction code is added and an analog voice signal are multiplexed. Is FM modulated to 12GH
It is a z-band SHF signal.

The signal in the SHF band is received by the receiving parabolic antenna 1 shown in FIG. 1, and the SHF band signal received by the parabolic antenna 1 is output to the outside by a waveguide or the like.
The frequency is converted by the door unit 2 as a first intermediate frequency signal of, for example, about 1 GHz. Then, the first intermediate frequency signal is supplied to the tuner 4 through the coaxial cable 3. A tuning signal corresponding to the output of the automatic channel control device 22 is supplied from the tuning circuit 5 to the tuner 4. The tuner 4 converts the selected broadcast wave first intermediate frequency signal into a second intermediate frequency signal. It is obtained by frequency conversion into a frequency signal. This second intermediate frequency signal is input to the FM demodulation circuit 7.
FM demodulation is performed and an FM demodulated signal is obtained. The FM demodulated signal is separated by the band pass filter 8 into an audio subcarrier and a video signal. The voice subcarrier obtained here is 4-phase PS
The digital data signal supplied to the K demodulation circuit 9 is demodulated and supplied to the decoding circuit 10. In the decoding circuit 10, an error that can be corrected by the error correction code is corrected and sent to the signal discriminating device 21 and the decoder unit 11. Here, the presence / absence of scrambling of the received signal is recognized by the type identification code 63 by the scramble presence / absence determining means 52, and the scramble decryption determination means 53 determines by the scramble-related information 64 whether or not the scramble can be decrypted. The signal supplied to the decoder unit 11 is restored to the original signal using the scramble-related information 64.

Next, an automatic channel selection method according to an embodiment of the present invention will be described with reference to FIG.

First, in step sp.1, the presence / absence of a received signal is determined by a signal detecting means.
51 decides. Next, in step sp.2, if the signal detection means 51 determines in step sp.1 that there is a signal, the scramble presence / absence determination means 52 determines whether or not the signal is scrambled. This step sp.2
In other words, a signal that is a viewable broadcast signal is determined without performing descrambling.

Next, in step sp.3, in step sp.2, if the scramble presence / absence determination unit 52 determines that the signal is scrambled, the scramble decryption determination unit 53 determines whether the signal can be decrypted. .

Here, the signal whose scramble can be deciphered is a contract program (specified program) with the receiver's program supply company, so that it is determined whether or not the receiver's target program.

Next, in step sp.4, when the scramble decoding determination device 53 determines in step sp.3 that the signal is a readable signal, the channel is selected as a reception channel.

In addition, in step sp.1, step sp.2, and step sp.3, if no, the channel is not selected as the reception channel, but in that case, the channel is switched for all other channels, and the process returns to the start and satisfies the above conditions. Repeat until tuning. Here, if any of the channels does not satisfy the above conditions, the first selected channel is set.

In the present embodiment, since a channel having no signal and a channel in which scramble cannot be deciphered are not selected, only those which can be deciphered can be selected from the scrambled channels to select a channel.

FIG. 3 is a block diagram showing an example of a processing device in which a channel selection channel selecting means device 31 is added to the processing device 6. The processing device 6 receives the scramble information from the terminal 14, performs channel selection processing, and sends the information to the channel selection circuit 5 via the terminal 15. When selecting a channel, it takes time to determine signals for all channels. However, if the channel selection channel selection means 31 is used as shown in FIG. 3, the channel selection time is short.

In the example of FIG. 3, the channel selection channel selection means 31 is used to limit the channel selection. However, a device having a learning function for remembering frequently received channels is used. Is also good.

According to the present invention, at power-on and at the end of a program that can be viewed on the same channel, the viewable channel is automatically selected.
The scrambled broadcast can be automatically received, and recording mistakes can be prevented.

Also, it is not necessary to prevent the screen from being unscrambled or no signal, and to prevent the screen from becoming unsightly.

In addition, the channel selection time can be shortened by previously setting the channel for performing the channel selection determination.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a receiver according to the present invention.
Fig. 3 is a flowchart showing an embodiment according to the present invention. Fig. 3 is a block diagram of an example of a processing device in which a channel selection channel selecting means 31 is added to the processing device. Fig. 4 illustrates a television signal of a satellite broadcast television wave. FIG. 5 is a block diagram showing a configuration of a signal discriminating apparatus, and FIG.
The figure shows an example of the packet configuration of CS broadcast. 6 processing device 21 signal discriminating device 22 automatic channel control device 31 channel selection channel selection means
51 ... signal detection means, 52 ... scramble presence / absence determination means, 53 ... scramble decryption determination means.

Claims (3)

(57) [Claims] 1. A receiving apparatus capable of receiving a transmission signal scrambled by a transmission station, comprising: signal detection means for determining the presence or absence of a transmission signal; and scramble-related information included in the scrambled transmission signal. And a determination means for determining whether or not the channel can be decoded, and enabling only a channel which can be decoded to be received. 2. A scrambled signal among scrambled signals and a non-scrambled signal channel broadcast free of charge as a viewable channel. 2. The channel selection device according to claim 1, further comprising an automatic channel control means for preferentially selecting the selected channel. 3. The channel selection device according to claim 2, further comprising a judgment channel selection means capable of setting a specific channel in advance as a channel on which the automatic channel control means makes a signal judgment for performing a channel selection.