JPH03237882A - Ghost elimination device - Google Patents

Abstract

PURPOSE:To reduce a ghost elimination time by detecting a transmission identification number from a teletext broadcast signal, discriminating a reception channel from the identification number, reading a ghost elimination processing data accordingly and giving the data to a ghost elimination processing section. CONSTITUTION:A ghost elimination processing section 13 calculates a difference between a reference signal and a GCR signal included in a video signal from an A/D converter circuit 12 to extract a ghost component and repeats the calculation so that the result of difference calculation is converged to zero thereby outputting a video signal from which ghost is eliminated to a D/A converter circuit 14. A memory 16 stores a ghost elimination processing data for each channel. A CPU 17 for ghost elimination processing receives transmission identification information from a transmission identification number processing section 20 and reads the ghost elimination processing data of a channel corresponding to the transmission identification information from the memory 16 and the ghost elimination processing section 13 uses the ghost elimination processing data to apply calculation. Thus, the calculation time of the ghost elimination processing section is reduced and the time required for ghost elimination is decreased.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a ghost signal removal device, and more particularly, to a ghost signal removal device for recording broadcast signals of each channel on a VTR and reproducing the recorded broadcast signals. The present invention relates to a ghost signal removal device that enables ghost removal processing for each channel and shortens the time required for ghost removal even when there is no channel information indicating how many channels a signal belongs to, as in the case of the present invention.

(Prior Art) Recently, in television broadcasting, GCR (ghost cancel) is used as a reference signal for ghost cancellation.

r reference ) signal is inserted into the vertical retrace period. The ghost signal removal device performs waveform equalization using this OCR signal to remove ghosts.

In such a conventional ghost signal removal device, a reference signal having the same waveform is generated at the same insertion position as the OCR signal inserted into the received signal.

Then, the calculation means performs a difference calculation between the transmitted GCR signal and the reference signal to extract a distortion component (ghost component), and based on the result of this difference calculation, the received signal is delayed and the amplitude is changed to l1fllllL. A ghost cancellation signal is generated.The ghost cancellation signal is subtracted from the received signal to obtain a signal from which ghost components have been removed.

By the way, the calculation process for extracting the ghost component,
In order to reduce the time required for arithmetic processing to determine the delay amount and amplitude control amount based on the extracted distortion components, and to reduce the time required for ghost removal, the -degree processed data is stored and the next When receiving data, the previously stored data is used. Since the amount of ghost differs depending on the receiving channel, it is necessary to store the amount of ghost and processing data for each channel.

Therefore, channel information is required to manage processing data for each channel. The tuner is given channel information from a tuning processing circuit to control tuning, and the channel information from this tuning processing circuit is also used in ghost removal. However, when a broadcast signal is once recorded on a VTR and then reproduced and displayed, there is a problem in that channel information cannot be obtained and processing for each channel is impossible.

(Problem to be Solved by the Invention) As described above, in the conventional ghost signal removal device described above, if there is no channel information, processing for each channel is impossible, and the time required for ghost removal increases. There was a problem.

The present invention has been made in view of such problems, and includes:
It is an object of the present invention to provide a ghost signal removal device that can perform processing for each channel and shorten ghost removal time by obtaining channel information from a received signal.

[Structure of the Invention] (Means for Solving the i! Problem) A ghost signal removal device according to the present invention includes a ghost removal processing unit that removes a ghost included in a received video signal by calculation, and a method that reduces the calculation time. a memory in which ghost removal processing data for each channel is stored;
a transmission identification number processing unit that detects a transmission identification number from a teletext signal multiplexed within a vertical retrace period of a video signal of a receiving channel; and a transmission identification number processing unit that determines a reception channel from the transmission identification number and corresponds to the reception channel from the memory. 6111111 means for reading out the ghost removal processing data and applying it to the ghost removal processing section.

(Function) In the present invention, ghost removal processing data for shortening the calculation time of the ghost removal processing section is stored for each channel in the memory. The transmission identification number processing unit detects the transmission identification number from the teletext signal multiplexed with the received video signal.

The IIIm means determines the reception channel from this transmission identification number, reads out ghost removal processing data corresponding to the reception channel from the memory, and supplies it to the ghost removal processing section. As a result, the calculation time of the ghost removal processing section is shortened, and the time required for ghost removal is shortened.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings. FIG. 1 is a block diagram showing an embodiment of a ghost signal removing device according to the present invention. This embodiment is designed to remove ghosts from the video signal from the television receiver 1.

The RF signal induced in the antenna 2 of the television receiver 1 is given to the reception detection circuit 3. The reception detection circuit 3 selects a channel based on the channel information from the channel selection processing circuit 4 and outputs a video signal from the video output terminal 5. Note that the channel selection processing circuit 4 is controlled by a user operating a channel selection remote control 6. The video signal derived from the video output terminal 5 is applied to the video input terminal 8 of the ghost signal removal device 7.

This video signal is input to the clamp circuit 9 and the oscillation circuit 10, and is also given to the character data acquisition escape section 11. The clamp circuit 9 clamps the video signal to the input level of the A/D conversion circuit 12. The A/D conversion circuit 12 converts the video signal into a digital signal and processes it into the ghost removal processing section 1.
Give to 3. The ghost removal processing section 13 includes a reference signal memory, a calculation means, a delay device, a multiplier, an adder, etc. (not shown), and combines the GCR signal included in the video signal from the A/D conversion circuit 12 with the reference signal. A ghost component is extracted by calculating the difference, and based on this ghost component, the delay amount and amplitude of the received signal are controlled to generate a ghost cancellation signal, which is added to the video signal from the A/D conversion circuit 12. . Then, the ghost removal processing unit 13 repeats the calculation so that the difference calculation result converges to O, and outputs the video signal from which the ghost has been removed to the D/A conversion circuit 14. D/A
The conversion circuit 14 converts the video signal from the ghost removal processing section 13 into digital-to-analog and outputs it to the video output terminal 15.

The memory 16 stores ghost removal processing data for each channel. CpU for ghost removal processing
17 is provided with transmission identification information from a transmission identification number processing section 20 (described later), reads ghost removal processing data of a channel corresponding to this transmission identification information from the memory 16, and supplies it to the ghost removal processing section 13. The ghost removal processing unit 13 can shorten the convergence time of the difference calculation results by performing calculations using the ghost removal processing data.

The oscillation circuit 10 multiplies the color subcarrier of the input video signal by 4 to generate a sampling clock, and this clock is sent to the A/D conversion circuit 12, the ghost removal processing section 13, and the D/D/D conversion circuit 12.
The signal is supplied to the A conversion circuit 14 for control.

On the other hand, the character data import processing section 11 samples the teletext signal multiplexed during the horizontal scanning period of the vertical blanking period of the video signal input via the video input terminal 8 and stores it in the memory 18 . The CP LJ 19 for character signal processing reads the data stored in the memory 18, decodes it, and transfers the character data to the transmission identification number processing section 20. The transmission identification number processing unit 20 detects the transmission identification number from the character data and sends the transmission identification information to the CP for ghost removal processing.
It will be forwarded to U17. As shown in the correspondence between the transmission identification number and the broadcasting station name in Table 1 below, the transmission identification number is set for each broadcasting station, and as mentioned above, the CPU 17 determines the receiving channel from the transmission identification information. to judge.

Next, the operation of the ghost signal removing device configured as described above will be explained.

The user operates the channel selection remote control 6 to specify a desired channel. Then, the channel selection processing circuit 4 provides channel information to the reception detection circuit 3.

The reception detection circuit 3 detects the RF signal of the desired channel and sends it to the ghost signal removal device 17 via the video output terminal 5.
A video signal is given to the video input terminal 8 of the .

This video signal is clamped by the clamp circuit 9 to the input level of the A/D conversion circuit 12, converted to a digital signal by the A/D conversion circuit 12, and provided to the ghost removal processing section 13. Further, the oscillation circuit 10 generates a sampling clock based on the input video signal, and generates a sampling clock based on the input video signal.
The signal is supplied to the D conversion circuit 12, the ghost removal processing section 13, and the D/A conversion circuit 14.

The ghost removal processing unit 13 calculates the difference between the GCR signal and the reference signal, and calculates the delay amount and amplitude IIJIII of the received signal by processing the difference calculation result! A ghost cancellation signal is generated by determining the amount of l. The ghost removal processing section 13 adds the ghost cancellation signal to the video signal from the A/D conversion circuit 12, and repeats the calculation so that the difference calculation result converges to O.

The video signal from the ghost removal processing section 13 is converted into an analog signal by the D/A conversion circuit 14 and output from the video output terminal 15.

In this embodiment, the video signal input to the video input terminal 8 is also provided to the character data capture processing section 11 . The text data capture processing section 11 captures the text broadcast signal multiplexed with the video signal and stores it in the memory 18. CPU 19
reads the data from the memory 18, decodes it, and provides it to the transmission identification number processing section 20. The transmission identification number processing section 20 detects the transmission identification number from the character data transferred from the CPU 19 and outputs the transmission identification information to the CPU 17. The CPU 17 determines the receiving channel from this transmission identification information. For example, if the prefecture code of the transmission identification number of teletext multiplexed multiplexed with the video signal of the channel selected by the user is 13, and the tenth place of the transmission station code is 1 (see Table 1), the CPU 17
The broadcasting station of the receiving channel is “Nippon Television Broadcasting Network Co., Ltd.”
”(4 channels in Tokyo).C
The P U 17 reads ghost removal processing data corresponding to the reception channel from the memory 16 and supplies it to the ghost removal processing section 13 . As a result, the ghost removal processing section 13
The time required for arithmetic processing is shortened, and the time required for ghost removal is shortened.

In this way, in this embodiment, the ghost removal processing data for each channel is provided to the ghost removal processing section 13 by detecting the transmission identification number of the teletext multiplexed on the video signal and determining the receiving channel. This shortens the ghost removal calculation, and the time required for ghost removal can be shortened even when reproducing broadcast signals recorded on a VTR.

[Effects of the Invention] As explained above, according to the present invention, it is possible to detect the transmission identification number and perform ghost removal processing for each channel, thereby reducing the time required for ghost removal. .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a ghost signal removing device according to the present invention. 11...Character data import processing unit, 13...Ghost removal processing unit, 16...Memory, 1
7...CPU, 2G...Sending identification number processing unit. 1st rlA

Claims (1)

[Scope of Claims] A ghost removal processing unit that removes ghosts included in a received video signal by calculation; a memory that stores ghost removal processing data for each channel to shorten the calculation time; a transmission identification number processing unit that detects a transmission identification number from a teletext signal multiplexed within a vertical blanking period of a video signal; and a ghost removal unit that determines a reception channel from the transmission identification number and removes ghosts corresponding to the reception channel from the memory. A ghost signal removal device comprising: a control means for reading out processed data and applying it to the ghost removal processing section.