KR940007017Y1 - Catv apparatus - Google Patents

Abstract

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Description

Frequency conversion module for cable TV converter and decoder connection

1 is an example of video audio processing means in a conventional cable TV converter.

2 is a circuit block diagram according to the present invention.

* Explanation of symbols for main parts of the drawings

1: frequency conversion module 12: IF-channel conversion module

14 Channel-IF Conversion Module 3 Channel Decoder

The present invention relates to a wired TV converter having a frequency conversion module interconnected with a decoder capable of decrypting encryption in a wired TV converter with encryption and decryption functions.

In the cable TV converter in this technical field, when a cable TV station adds an encryption means for a specific channel, there is no circuit in the converter that connects the decoder to decrypt the subscriber. Could not.

As an example, the system for the cable TV converter of the above example usually has the form of FIG.

In general, the tuner 2 generates an IF signal using an IF tuner to separate an audio and video signal from an RF signal having an RF frequency band of 54 MHz to 890 MHz. To be separated.

In other words, here, the tuner 2 to which the RF signal is inputted and the IF signal outputted therefrom are processed by the video audio processing block 5 to process the signal.

Therefore, in the above-described prior art, such a disadvantage has been caused because the cable TV converter does not smoothly grant a viewing function for a specific channel transmission to which an encryption means is added.

That is, if an interference signal having a carrier corresponding to a CH-3 signal of an RF signal transmitted from a wire broadcasting station, that is, a CH3 signal at a frequency of 60 to 66 MHz is superimposed and transmitted, the content containing such interference signal must be removed. You can watch TV channels. However, it can be seen that no specific RF signal can be selected by the IF signal alone.

The present invention has been made to improve the above problems.

The present invention is characterized in that a signal conversion module is provided in the CATV converter so that decryption processing can be performed even if an encryption means is added to any arbitrary channel.

This will be described in more detail below.

That is, Figure 2 shows the circuit system of the cable TV tuner according to the present invention.

Here, channel 3, which is an RF signal band of 60 to 66 MHz, is used to convert the IF signal into an RF signal. However, another channel may be used according to the RF signal band transmitted from the cable broadcasting station. A conversion module 1 is provided between the output shaft of the conventional cable TV tuner 2 and the video audio processing block 5, which is connected to the output of the tuner by the IF-channel conversion module 12. The output of the IF-channel 3 conversion module 12 is connected to the channel 3 decoder 3 outside the tuner 2 and its output is applied to the channel 3-IF module 14, which in turn is the channel 3 IF module. It is a system from 14 to the normal video and audio processing block 5.

The RF coding scheme consisting of the IF channel 3 -conversion module 12, the channel 3 -decoder 3, and the channel 3 -IF module 14 cannot select any specific RF signal only with the IF signal for video and audio signals. Therefore, this is to remove the interference signal included in the carrier corresponding to the CH-3 signal, that is, the CH-3 signal of 60 to 66MHz frequency from the RF signal transmitted from the wire broadcasting station. Therefore, it may be usefully used for paying broadcasting on a fixed channel in a cable TV broadcasting.

The present invention of this configuration is as follows.

In other words, if the IF signal is output from the cable TV tuner 2 according to the present invention, the IF-channel 3 conversion module 12 of the signal conversion module 1 is IF, since the IF signal cannot be selected as a specific RF signal only. The signal is once converted to the frequency band of channel 3 of the 60 to 66 MHz frequency, which is an RF signal. Since the RF signal converted into the RF signal through the IF-channel 3 conversion module 12 includes the encryption content included in the carrier corresponding to the channel 3 signal, that is, the interference signal, the channel 3 frequency signal is In order to remove the interference signal included in the signal is input to the channel 3-decoder outside the converter. Here, the channel 3 frequency signal from which the encrypted content has been removed is inputted to the channel 3-IF conversion module 14 to convert the IF signal to the IF signal for processing into an audio and video signal, followed by the IF signal in the decrypted state. It is sent to the video audio processing block 5 of the stage.

The present invention has an advantageous feature that the signal conversion module is provided in the cable TV converter, thereby giving a means for easily decrypting the encrypted channel when it is received in such a device.

Claims (1)

A wired TV converter including an IF tuner 2 for tuning an input RF signal to an IF signal, and a video audio processing block 5 for processing video and audio signals from the IF signal drawn from the tuner 2. An IF-channel conversion module 12 for converting an IF signal drawn from the IF tuner 2 into an RF signal of an RF frequency band applied to a corresponding channel, obtained from the IF-channel conversion module 12 A channel-decoder 3 for removing the interference signal included in the RF signal, and a channel-IF for converting the RF signal from which the interference signal is removed from the decoder 3 into an IF signal for video and audio signal processing. And a conversion module (14) to provide the IF signal with the interference signal removed to the video audio processing block (5).