JPH05191804A - Descramble device - Google Patents

Abstract

PURPOSE:To reduce the unncessary repair requests, etc., by enabling the judgment whether the cause when a scramble processing signal can not be decoded is atrributed to the wrong reception condition of broadcasting radio wave or the fault of a descramble device or not by a user. CONSTITUTION:A scramble processing signal for which a PSK demodulation is performed from a PSK demodulation circuit 11 is supplied to a sound descramble processing circuit 12. The descramble processing signal is supplied from this sound descramble processing circuit 12 to a PCM demodulation circuit 13. The number of times of error detection in a bit string of digital data from this PCM demodulation circuit 13 is counted by a counter 15. When the number of times of error during a fixed time exceeds a prescribed value, a LED 11 is made to turn on via a LED driver 16 and the reception status of broadcasting radio wave is displayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a descrambler for performing a descramble process on an information signal such as a scrambled video signal, audio signal or general data signal.

[0002]

2. Description of the Related Art Recently, information signals such as video signals, audio signals, general data, etc. are not paid to an unspecified large number of viewers by using a broadcasting satellite or a communication satellite, but a specific receiving subscriber is charged. Pay broadcasting such as so-called pay television provided by has become popular. In this case, in order to prevent non-contractors other than the contractor who has made a value contract with the information provider from viewing the information signal such as the above-mentioned video signal, audio signal, general data, etc. Is scrambled and transmitted. In addition, among subscribers, when viewing a specific information signal, there is a separate charge, or when different types of receivable information signals are used depending on the contract content, different types of scrambling processing are performed depending on the information signal. Is applied. On the other hand, on the receiving side, the descrambler is used to restore the scrambled information signal to obtain the original signal.

There are various methods for scrambling the information signal depending on the type of the information signal. In general,
It is often controlled by a pseudo-random signal sequence (scramble sequence). On the other hand, the descrambling process restores the original signal with the same signal sequence (descramble sequence) as the scrambling process.

For example, in the scrambling process of a voice signal, a method of continuously adding pseudo random signals is generally used, and in the descrambling process, the same pseudo random signal is generated.
A general method is to restore the original audio signal by adding it to the received signal sequence. Further, the scramble processing of the video signal includes a method of inserting a cutting point in each scanning line and exchanging the cutting points before and after it, and a method of changing the order of the scanning lines in a plurality of scanning lines or one field. For the former, there is a method of reproducing a pseudo-random signal and returning before and after the cutting point, and for the latter, there is a method of reproducing a pseudo-random signal and returning the scanning line order.

The descrambling device for performing the above descramble processing may be, for example, a BS tuner, a separate type from the CS tuner, an integrated type, or a built-in type in which a television receiver has a BS tuner and a descramble function. Some BS tuners, CS tuners, etc. display the reception level of received broadcast radio waves. Based on this reception level, the BS antenna and CS antenna can be adjusted to an appropriate direction and elevation angle.

[0006]

When the scrambled broadcast wave is received and descrambled, it may not be descrambled (decipherable). If the descrambler is out of order,
This is when the descramble device is not authorized (registered) and the broadcast wave condition is bad.

As described above, if the BS tuner, the CS tuner, etc. have the function of displaying the reception level, it is possible to grasp the situation where the broadcast radio wave condition has deteriorated based on the function. However, when a descrambler is connected to a tuner that does not have the function of displaying the reception level or a tuner that has the function but is not used correctly, when the scrambled broadcast signal cannot be decoded. It is impossible to distinguish whether the reason is that the descrambler is out of order or the radio wave condition is bad. As a result, the user will judge as if the descrambler has failed even though it is not.

Therefore, the present invention has been made in view of the above situation, and an object thereof is to provide a descrambling device capable of displaying the reception status of broadcast radio waves.

[0009]

A descrambling device according to the present invention is a descrambling device that restores a scrambled signal to an original signal, counts the number of error detections in a bit string, and The problem is solved by displaying the reception status of broadcast radio waves by the display means in response to the case where the number of errors exceeds a predetermined value.

The descrambling device according to the present invention is a descrambling device that restores a scrambled signal to an original signal, and uses an output in which a pulse width of an error detection output is expanded to display a radio wave by display means. The above problem is solved by representing the reception status of

The reception status of the broadcast radio wave represented by the display means described in the above two means is when the reception status of the broadcast radio wave is deteriorated, and is like a so-called alarm.
In the former case, the display means which is a so-called alarm is, for example, an LED when the number of errors during a certain time exceeds a predetermined value.
In the latter case, the pulse width of continuous error (double error) is expanded, and as the number of double errors increases, for example, the frequency of LED lighting is increased so that it can be caught by human eyes. Is.

[0012]

The descrambling device according to the present invention counts the number of error detections in the bit string during a certain period of time, and displays the count to notify the reception status of broadcast radio waves. In addition, the pulse width of the error detection output is expanded, and the expanded output is used to notify the reception status of the broadcast wave.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a descrambling device according to the present invention will be described below with reference to the drawings. FIG. 1 is a block circuit diagram of a first embodiment of a descrambling device according to the present invention. Here, this embodiment is separately connected to the outside of a communication satellite (communication satellite: CS) tuner.

In FIG. 1, the descrambling device according to the present invention comprises an audio section (audio signal + data) and a video section. The audio section and the video section each include an audio descrambling processing circuit 12 and a video descrambling processing circuit 19 that perform descramble processing.

The PSK demodulation circuit 11 supplies the PSK (Phase Shift Keying) demodulated scrambled signal to the voice descramble processing circuit 12 of the voice section. The voice descrambling circuit 12 has a PCM
The demodulation circuit 13 is connected, and the PCM demodulation circuit 13 is also connected to the D / A converter 14 and the counter 15.
The output of the D / A converter 14 is derived from the output terminal 22. The counter 15 is connected to, for example, the LED 17 via the LED driver 16. Further, a reset signal is supplied to the counter 15 via the reset terminal 23.

The de-emphasis processing signal from the de-emphasis circuit 18 is supplied to the video descrambling circuit 19 of the video section. The output signal of the video descramble processing circuit 19 is derived from the output terminal 24.

The PCM demodulation circuit 13 of the voice section has a function of detecting a code error during transmission of the digital signal transmitted from the transmitting side and correcting it to the original correct code.

For example, in a transmission system using a communication satellite (CS), the decoded data for voice and descramble is transmitted as 4PSK-modulated digital data as shown in FIG. That is, the decoded data for voice and descramble is converted into a digital signal by the PCM processing circuit on the transmission side, and the signal is combined with the video signal (frequency division multiplexing) and transmitted in one radio wave.
Phase-modulates a carrier of 5.73MHz with a digital audio signal (4
PSK modulation) is performed to obtain a carrier voice signal. This carrier voice signal is transmitted to the receiving side. Even if the 1-bit code is erroneous during the transmission, it has a great influence. Therefore, the receiving side has a function of detecting the code error during the transmission and correcting it to the original correct code. Specifically, even if the bit code of a signal is wrong during transmission, a signal called an error correction code is added on the transmitting side so that the receiving side can detect it and correct it to a correct code. The error correction code used for CS and satellite broadcasting (BS) is called BCH (63,56) code, and the error correction circuit of the PCM demodulation circuit 13 on the receiving side detects an error of up to 2 bits, One bit error can be corrected. For example, code errors increase as the broadcast wave condition deteriorates. At this time, 2-bit errors (double errors) due to 2-bit error detection also increase. Therefore, if this double error exceeds a certain amount within a certain time, there is a possibility that the descrambling operation cannot be performed. Therefore, the radio wave condition is displayed by displaying this.

Specifically, the counter 15 shown in FIG.
The double error in the bit string of the digital data of the demodulation circuit 13 is counted up by the double error flag, and when the count exceeds a certain value, the LE is passed through the LED driver 16.
Turn on D17. Further, a reset signal is supplied from the terminal 23 to the counter 15 at regular intervals to reset the counter 15.

As described above, in the first embodiment of the descrambler according to the present invention, the number of error detections output from the error correction circuit of the PCM demodulation circuit 13 is counted by the counter 15 within a fixed time. If the number is exceeded, LE
Turn on D17. This allows the user to confirm the deterioration of the radio wave condition.

Next, FIG. 3 shows a block circuit diagram of a main part of a second embodiment of the descrambling device according to the present invention. Each block having the same configuration as that in FIG. 1 will be described using the same reference numerals as those in FIG. In FIG. 3, the second embodiment of the descrambling device according to the present invention has a video part and an audio part as in the first embodiment, but only the audio part will be described here.

The double error in the bit string of the digital data of the PCM demodulation circuit 13 of the voice part of FIG.
Monostable flip-flop 25 connected to demodulation circuit 13
Is supplied to. This monostable flip-flop 25 detects the above double error by the double error flag,
Increase the pulse width. Then, the LED 17 is turned on by using the enlarged output. Here, when the reception condition of the broadcast wave is bad, the above double error increases,
The frequency of lighting the LED 17 also increases.

As described above, in the second embodiment of the descrambling apparatus according to the present invention, the number of times the LED 17 is turned on increases as the reception status of the broadcast radio wave deteriorates, and thus the reception status of the broadcast radio wave deteriorates for the user. Let me know.

Needless to say, the present invention is not limited to the above-mentioned embodiments.

[0025]

The descrambling apparatus according to the present invention counts the number of error detections in the bit string, and displays the reception status of broadcast radio waves by the display means when the number of error detections within a certain time exceeds a predetermined value. Notify the user of the reception status of broadcast waves. In addition, the output of the error detection output with the expanded pulse width is used to indicate the reception status of the broadcast radio wave by the display means to inform the user of the reception status of the broadcast radio wave. Therefore, when the scrambled signal cannot be decoded, it is possible for the user to judge whether the cause is the bad reception of the broadcast wave or the descrambler is out of order, and unnecessary repair requests are reduced.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of a first embodiment of a descrambling device according to the present invention.

FIG. 2 is a characteristic diagram of modulation signal frequency versus main carrier frequency deviation used to describe transmission of voice and descrambling deciphered data on a communication satellite (CS).

FIG. 3 is a block circuit diagram of a second embodiment of the descrambling device according to the present invention.

[Explanation of symbols]

 11-PSK demodulation circuit 12-voice descrambling circuit 13-PCM demodulation circuit 14-D / A converter 15-counter 17-・ ・ ・ LED 25 ・ ・ ・ Monostable flip-flop

Claims (2)

[Claims] 1. A descrambling device for restoring a scrambled signal to an original signal, counting the number of error detections in a bit string, and displaying when the number of error detections within a certain time exceeds a predetermined value. A descrambling device characterized in that the reception status of broadcast waves is represented by means. 2. A descrambling device for restoring a scrambled signal to an original signal, wherein the display means indicates the reception status of broadcast radio waves by using an output in which a pulse width of an error detection output is expanded. Descrambling device.