JPH03132266A - Waveform distortion eliminating device - Google Patents

Abstract

PURPOSE:To extract selectively a video signal before and after waveform distortion processing without stopping the operation by implementing the changeover of insertion and input/output connection of a matching means with respect to the input side of a waveform distortion elimination power consumption system and keeping the video signal input independently of the state of a switch means for the waveform distortion elimination processing system. CONSTITUTION:Switch means 46, 48 are switched as required and either a video signal subject to waveform distortion elimination or a video signal not subject to waveform distortion elimination is selectively outputted to an external opposite device. The inputted video signal is inputted to a waveform distortion elimination processing system 40 independently of the operation of the switch means 46, 48 and the operation of the elimination processing is continued. Thus, the video signal before and after the elimination processing is extracted selectively without stopping the function of the waveform distortion elimination processing system 40 and the video signal before and after the elimination processing to confirm the ghost elimination effect is switched without giving effect onto the ghost elimination processing function.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a waveform distortion removal device that removes waveform distortion such as ghosting in video equipment such as a television, and particularly relates to a waveform distortion removal device that removes waveform distortion such as ghosting in video equipment such as a television. It is about improvement.

[Conventional technology] In the field of handling television video signals, etc.

Waveform distortion such as ghosting occurs due to reflection of radio waves due to multipaths in the transmission system. For this reason, devices are used that remove ghosts and the like by using a predetermined, controlled signal waveform portion of a television video signal as a reference signal.

By the way, with respect to such a waveform distortion removal device, (1) In order to confirm the effectiveness of the removal device, a comparison is made between before and after ghost removal processing.

(2) The period after the power is turned on until the system stabilizes is kept in the same apparent state as before the removal process.

(3) When resetting to the initial state at the time of switching broadcast reception channels, the video signal before the removal process is temporarily output.

(4) In order to converge when the removal processing operation falls into an irreversible state due to some disturbance, -
A reset start is performed after temporarily returning to the state before the removal process.

(5) Start the removal processing operation and output the processed video signal after the operation is almost completed.

(6) In an adapter one-type ghost removal device.

To make it possible to extract the minimum necessary video signal before removal processing even if the power is not turned on.

Turning on the ghost removal operation for various reasons such as.

An off switching function is provided.

As a conventional waveform distortion removing device having such a function, there is one shown in FIG. 3, for example. In the figure, a terminal 10 to which a video signal is input from the outside is connected to the input side of a filter part 12. The output side of this filter part 12 is connected on the one hand to an output terminal 14 and on the other hand to the input side of a waveform acquisition section 16 . The output side of this waveform acquisition section 16 is connected to the input side of a calculation section 18 , and the output side of the calculation section 18 is connected to the input side of the filter part 12 .

Of these, the filter portion 12 is composed of a transversal filter or the like, and has a configuration as shown in FIG. 4, for example. The waveform acquisition section 16 is for extracting a reference signal for ghost detection included in the video signal. Further, the calculation unit 18 is for calculating and setting the tap count in the filter part 12.

An overview of the operation of such a waveform distortion removal device is as follows.
A video signal is input from the outside to the terminal 1O, and the filter section 12 performs filter processing to remove waveform distortion on the video signal. The video signal after the filter processing is manually input to the waveform acquisition section 16.

Here, the waveform of the reference signal line for ghost detection is captured.

Next, the operation unit 18 performs an operation of pulsating this captured signal by waveform conversion processing such as differentiation or difference to obtain a reference pulse, and extracting waveform distortion such as ghosts based on this pulse. It will be held in Furthermore,
The calculation unit 18 calculates the filter part 1 from the extracted waveform distortion.
The optimum value of tap coefficient 2 is calculated and set.

Next, the filter part 12 will be explained with reference to FIG. In the figure, an input terminal 20 is connected to the input sides of a delay circuit 22 and a transversal filter 24, respectively. The output side of the delay circuit 22 is an adder 26
The output side of the transversal filter 24 is connected to the input side of the switch circuit 28 . The input side of this switch circuit 28 is connected to the other input side of the adder 26.

Next, the output side of the adder 26 is connected to the plus input side of the subtracter 30. The output of this subtracter 30 is connected on the one hand to the output of the filter part 12 and on the other hand to the input of a delay circuit 32. The output side of this delay circuit 32 is connected to the minus input side of the subtracter 30 via a transversal filter 34 and a switch circuit 36, respectively. Among these, the switch circuit 28 is for rONJ and rOFFJ the output of the transversal filter 24 to the adder 26, and the switch circuit 36 is for subtracter 30.
The output of the transversal filter 34 for rON
J.

This is for roFFJ.

The transfer function G (Z) between the input and output of the filter part 12 having such a configuration is as follows, where Z-1 is the unit delay time T (T=1
)/4) f − c, f sc = 3.58MH
++ a representing the delay of z (color subcarrier frequency)
l is the tap coefficient value of the transversal filter 24, and bJ is the tap coefficient value of the transversal filter 34.

At this time, the delay times of the delay circuits 22 and 32 are each NT
(=Z″″N), and the transversal filter 24
The number of taps is 2N+1. The number of taps of the transversal filter 34 is M−N. The coefficient values a, b7 of these taps are optimized based on the reference signal as described above, thereby removing waveform distortion.

By the way, either the tap coefficient value al+b is "
0'', the filter portion 12 does not function and the input video signal is output as is. However, when comparing waveforms before and after ghost removal, the tap coefficient values a + and b
Since it would take a lot of effort to return 4 to ``0'', the waveform comparison operation is performed by performing rONJ and rOFFJ by the switch circuit 28.36.

[Problems to be Solved by the Invention] However, in the prior art as described above, what is disconnected by operating the switch circuits 28 and 36 is a part of the ghost processing system, and the ghost removal operation continues. Therefore, if such separation is performed while the ghost removal operation is in progress, the video signal output will be the same as before removal, so the ghost processing will proceed further.

Therefore, if the switch circuits 28 and 36 become rONJ again and are returned to their original state, divergence may occur due to excessive correction. Therefore, even temporarily, the ghost removal operation must be stopped and rONJ and rOF of the switch circuits 28 and 36
It is necessary to perform FJ.

Furthermore, if the waveform distortion removal device is of the attack type, the rO of the power supply is
If NJ and rOFFJ are not shared, a situation may arise in which no signal is supplied to the other party's equipment. Especially when receiving channels with few ghosts.
It is often troublesome to use the adapter's waveform distortion removal device.

The present invention has been made in view of the above points, and is capable of selectively extracting video signals before and after ghost processing without stopping the operation of the ghost removal system.
It is an object of the present invention to provide a waveform distortion removing device that can be controlled both electrically and manually, has a simple configuration, and is advantageous in terms of cost.

[Means for Solving the Problems] One aspect of the present invention provides a waveform distortion removal device that uses a reference signal extracted from a video signal to set tap coefficients of a filter section of a waveform distortion removal processing system. A first state in which a matching means is inserted into the video signal input side of the waveform distortion removal processing system and the output side of the waveform distortion removal processing system is connected to the output side of the waveform distortion removal device; a second state in which the input side of the waveform distortion removal device is connected to the output side without being removed from the video signal input side of the processing system, and the input side of the waveform distortion removal device regardless of the operation of the switch means; and connecting means for connecting the waveform distortion removal processing system to the input side of the waveform distortion removal processing system.

In another aspect of the invention, the switch means is an electrically driven electronic switch, the drive power source is shared with the drive power source of the waveform distortion removal processing system, and when the drive power source is cut off, the electric switch is activated. It is characterized in that it can be switched to the second state.

[Function] According to the present invention, the switch means is switched as necessary, and either the video signal that has undergone waveform distortion removal processing or the video signal that has not been subjected to removal processing is selectively output to an external partner device. be done. The input video signal is input to the waveform distortion removal processing system regardless of the operation of the switch means, and the operation of the removal processing is continued.

According to another invention, the drive power source is commonly configured by the waveform distortion removal processing system and the switch means. When the driving power source is cut off, the input video signal is output as is by the operation of the switch means, and the video signal output does not stop due to the waveform distortion removal processing system not operating.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings.

<Overview of this embodiment> First, an overview of this embodiment will be described with reference to FIG. FIG. 1 shows the main parts of a waveform distortion removing device according to one embodiment. In the figure, the waveform distortion removal device 40 includes a switching section 42 and a ghost removal processing system 44.
Each has

Among these, the switching unit 42 includes switch circuits 46 and 48.
and a matching resistor 50, respectively. An input terminal 52 to which a video signal is supplied from the outside is connected to the input side of the ghost removal processing system 44, and a matching resistor 50. and the switching terminal f of the switch circuit 48, respectively. The matching resistor 50 is connected to the common terminal a of the switch circuit 46. The switching terminal C of the switch circuit 46 is open, and the switching terminal C is grounded. The output side of the ghost removal processing system 44 is connected to the switching terminal e of the switch circuit 48, and the common terminal d thereof is connected to the output terminal 54.
It is connected to the.

Among the above-mentioned parts, the ghost removal processing system 44 is configured as shown in FIG. 3, for example, and a part of its filter is configured as shown in FIG. 4, for example. In addition,
From the configuration of the filter part 12, the switch circuit circuit 2
A video signal is always inputted from the input terminal 52 to this ghost removal processing system 44, which may be configured to remove the signal 8.36.

Next, the switch circuit 46 is for taking out the matching resistor 50 connected to the input side of the ghost removal processing system 44 to the outside and switching whether or not to ground it. Further, the switch circuit 48 outputs either the video signal from the input terminal 52 before ghost removal or the video signal after ghost removal output from the ghost removal processing system 44 as an output from the output terminal 54 to the partner device. It is for selection.

These switch circuits 46 and 48 are designed to be switched in conjunction and have the following two states.

(1) First state (state shown) In the switch circuit 46, the switching terminal is connected to the common terminal a. In the switch circuit 48, the switching terminal e is connected to the common terminal d.

(2) In the second state switch circuit 46, the switching terminal C is connected to the common terminal a. In the switch circuit 48, the switching terminal f is connected to the common terminal d.

Next, the matching resistor 50 is originally a ghost removal device (
(see FIG. 1), and in this embodiment, it is taken out and provided on the switching section 42 side.

As this matching resistor 50, a resistor of approximately 75Ω is normally used.

Next, the operation of the device shown in FIG. 1 will be explained - a. First state First, in the first state described above, the switch circuit
8 is switched as shown. Therefore, one end of the matching resistor 50 is connected to the ground, and as a result, the matching resistor 50 is connected to the input side of the ghost removal processing system 44.

The device will be matched with the other device. On the other hand, the output side of the ghost removal processing system 44 is connected to the switch circuit 4
8 to the output terminal 54.

That is, in this first state, the ghost removal processing system 4
A matching resistor 50 is connected to the input side of 4, and the ghost removal processing system and the other device are connected. Therefore, the video signal supplied from the destination device is input to the ghost removal processing system 44, and the video signal from which the ghost has been removed is supplied from the output terminal 54 to the destination device.

b. Second state Next, in the second state described above, first, the switch circuit 4
6 removes the matching resistor 50 from the circuit. Furthermore, by switching the switch circuit 48,
The input terminal 52 is connected to the output terminal 54, and the connection between the output side of the ghost removal processing system 44 and the output terminal 54 is cut off.

Therefore, the video signal supplied from the other device is sent to the other device as is. A matching resistor similar to the matching resistor 50 is inserted on the input side of the other device, so the matching resistor 50 is connected to the switch circuit 4.
Naturally, it is removed by switching 6.

On the other hand, since the video signal is input to the ghost removal processing system 44 from the input terminal 50 in the same manner as in the first state, the ghost removal operation continues without interruption in any state. It will be done.

Therefore, even if the state changes due to switching of the switch circuits 46 and 48, there is no intervention in the ghost removal operation, and the removal operation continues stably.

In this manner, by switching the switch circuits 46 and 48, the first state in which the video signal is ghost-removed and output, and the second state in which the video signal is output without ghost removal are selected. Because you can
The effect of ghost removal can be easily confirmed.

<Configuration of Example> Next, the specific configuration of this example will be described with reference to FIG. 2. The device shown in FIG. 2 is a more specific version of the device shown in FIG. 1, and can also be adapted to an adapter format. That is,
The switch circuit is configured to be linked by a relay circuit, and the power supply for this relay circuit and the ghost removal processing system is shared, so that when the ghost removal processing system is not using the power supply, it is automatically switched to the second state. It is configured to be.

In the figure, each relay circuit 60 has terminals 01 to Q8, respectively, and terminals Q1 to Q8. Relay coil 62 is installed between Q5.
is connected. Also, terminal Q3. Q7 are respectively connected to contacts 64, and terminals Q4. Q8 are each connected to a contact 66.

Terminal Q2. Q6 is connected to one of the contacts 64 and 66 depending on whether the relay coil 62 is energized or not.

Next, the external connections of the relay circuit 60 will be explained.
Terminal Q1. A diode 68 for absorbing reaction pulses in the relay coil 62 is connected between Q5, and a diode 68 for driving the relay coil 62 is connected to the terminal Ql.
The collector side of a PN type transistor 70 is connected. The emitter side of this transistor 70 is grounded, and the base side has a bias resistor. 2.74°76 are connected to each other. Also, these bias resistors? 2.
A transistor 70 is connected between 74.76 and ground.
A switch 78 for driving ``ON'' and rOFFJ is connected. By switching the transistor 70 by operating the switch 78, the energization state of the relay coil 62 is changed.

Next, the terminal Q2 is connected to the output terminal 54, the terminal Q3 is connected to the input side of the ghost removal processing system 44, and the terminal Q4 is connected to the output side of the ghost removal processing system 44. In addition, the terminal Q5 is a DC power supply Vc for operation.
The terminal Q6 is connected to the matching resistor 50. Further, the terminal Q7 is an oven, and the terminal Q8 is grounded. In addition, the DC power supply Vc
C is also used as a driving power source for the ghost removal processing system 44, and when the ghost removal processing system 44 is cut off, the power supply to the relay coil 62 is also cut off.

<Operation of this embodiment> Next, the operation of the above embodiment will be explained.

a. Case of the first state First, the case of the first state shown in FIG. 1 will be explained. The state shown in FIG. 1 is this first state. In this case, switch 78 is operated to roFFJ. Therefore, the DC power supply Vcc is voltage-divided by the bias resistors 72 and 76, so that a current flows to the base of the transistor 70 via the bias resistor 74. Therefore, the transistor 70 is in the "ON" state.

Then, current also flows through the relay coil 62 due to the DC power supply Vcc, and the terminal Q3. Q7 is contact 6
Connected to the 6th side. This results in a matching resistance of 50
is connected to ground, and the ghost removal processing system 4
The output side of 4 is connected to the output terminal 54. Therefore, as described above, the video signal supplied to the input terminal 52 is
The video signal is input to the ghost removal processing system 44 and subjected to the processing, and furthermore, the video signal after the removal processing is supplied to the partner device via the output terminal 54.

b. In the second state In this case, the switch 78 is turned "ON".

Therefore, the voltage divided by the bias resistors 72 and 76 of the DC power supply Vcc is grounded, and a sufficient current does not flow through the base of the transistor 70.
The transistor 70 enters the roFFJ state, and no current flows through the relay coil 62 either.

In this case, terminal Q3. Q7 is connected to the contact 64 side. As a result, the matching resistor 50 is not grounded, and the input side of the ghost removal processing system 44 is connected to the output terminal 54. Therefore, as described above, the video signal supplied to the input terminal 52 is inputted to the ghost removal processing system 44 on the one hand, and the processing is performed at t.
aM, and output terminal 5 as it is on the other side.
4 to the other party's device.

When the C0 DC power supply Vcc is cut off Second, the operation when the DC power supply Vcc is cut off will be explained. In this case, the operation of the ghost removal processing system 44 is stopped. Further, the energization to the relay coil 62 is also stopped. Therefore, the state is similar to the second state described above, and the terminals Q3 to Q7 are connected to the contact 64 side. Therefore, the input video signal will be output as is to the other party's device.

For example, when receiving a channel where ghosts are not a problem, the ghost removal processing system 44
Even if the power is turned off (in the case of the Agebuta format, the power is turned off), the video signal will still be supplied to the other device. This makes it possible to save power and resources.

<Effects of the Example> As described above, according to the present example, the video signals before and after the ghost removal process can be selectively extracted without stopping the functions of the ghost removal processing system, and the electrical (1) Switching of the video signal before and after the ghost removal process to check the ghost removal effect can be performed without affecting the ghost removal processing function. Can be done.

(2) When changing the switch, impedance matching of the video signal system is achieved, so unnecessary fluctuations in the video signal and deterioration of frequency characteristics do not occur.

(3) The configuration is simple and cost-effective.

There is an effect.

In addition, in the case of the adapter format, the power supply for the ghost removal processing system and the switching power supply for the switching section are common, and the configuration is such that when the power is cut off, the input video signal is output as is, so ghost removal can be performed as necessary. You can save electricity by doing this.

<Other Embodiments> Note that the present invention is not limited to the above-mentioned embodiments. For example, in the above-mentioned embodiments, the case where ghosts are mainly removed has been described, but the present invention also applies to similar waveform distortions. It is valid. Furthermore, the circuit configuration can be modified in various ways so as to achieve the same effect, and these modifications are also included in the present invention.

Further, in the apparatus of FIG. 2, the switch 78 is driven manually, but it can be configured to be driven electronically by a digital circuit. In this way, the entire switching group can be placed under the control of the calculation section 18 shown in FIG. 3.

As a result, for example, immediately after the tll power is turned on, the operation is performed in the second state until the many tap coefficients of the filter part 12 are rewritten to the initial values, and the transient output image of the ghost removal processing system is To prevent signal disturbances from being output to the outside.

(2) In the case of a feed-forward type ghost removal method in which the reference signal is detected not at the output side of a part of the filter but at its input side as shown in Figure 3, a filter value that can cancel out the ghost is calculated. After setting the second
state to the first state.

You can perform actions such as:

[Effects of the Invention] As explained above, according to the present invention, the switching means inserts the matching means to the input side of the waveform distortion removal processing system and switches the input/output connection, and also performs the waveform distortion removal processing. Since the system continues to receive video signals regardless of the switching state, it is possible to selectively extract video signals before and after waveform distortion processing without stopping the operation of the waveform distortion removal processing system. effective.

Further, since the operation is performed by switching the switching means, it can be controlled both electrically and manually, and the structure is simple and advantageous in terms of cost.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an outline of an embodiment of the present invention, FIG. 2 is a circuit diagram showing a detailed configuration example of the embodiment, FIG. 3 is a configuration diagram showing a general waveform distortion removal device, and FIG. FIG. 4 is a configuration diagram showing an example of a part of the filter of the waveform distortion removing device. 12--Filter part, 16--Waveform acquisition section, 18
... Arithmetic unit, 40... Waveform distortion removal device, 42...
Switching unit, 44... Ghost removal processing system (waveform distortion removal processing system), 46.48... Switch circuit (switch means), 50... Matching resistor, 60... Relay circuit (electrical switch). Engraving of the drawings: Figure 1: January 1995, Oda

Claims (2)

[Claims] (1) In a waveform distortion removal device that sets tap coefficients of a filter section of a waveform distortion removal processing system using a reference signal extracted from a video signal, a matching means is provided on the video signal input side of the waveform distortion removal processing system. A first state in which the output side of the waveform distortion removal processing system is connected to the output side of the waveform distortion removal device by inserting the matching means, and a first state in which the matching means is removed from the video signal input side of the waveform distortion removal processing system to remove waveform distortion. A switch means for switching between a second state in which the input side of the device is directly connected to the output side; and a connection for connecting the input side of the waveform distortion removal device to the input side of the waveform distortion removal processing system regardless of the operation of the switch means. A waveform distortion removing device characterized by comprising: means. (2) In the waveform distortion removal device according to claim 1, the switch means is an electrically driven electric switch, and the drive power source is common to the drive power source of the waveform distortion removal processing system, and the drive power source is A waveform distortion removing device characterized in that when the electronic switch is cut off, the electronic switch is switched to the second state.