JPH09139889A - Signal switching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain correct switching processing even when a television signal whose picture element is shifted and a television signal whose picture element is not shifted are in existence in mixture. SOLUTION: The object of the device is a television signal in which a reinforcement signal is inserted to an upper part and a lower part of a main image signal. The picture element of the television signal is shifted for color frame synchronization to take in-station synchronization. An interpolation processing is conducted for a reinforcement signal whose picture element is shifted by using an interpolation circuit 8. The picture element position of the reinforcement and the picture element position of the main image signal are completely in matching by the interpolation processing. Then the signal is given to a delay means 90 to festore a reference signal whose picture element is shifted to the original position, The reference signal is restored to the correct position by selecting a delay of the delay means to be (1H-n). Since the 22nd H reference signal is shifted by the same amount when the picture element is shifted, the reinforcement signal and the 22nd H reference signal are restored by the picture element shift.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a next-generation EDTV.
The present invention relates to a signal switching device that uses a wide-screen directional high-definition television signal such as (EDTV-II) as an external television signal and uses it in a state of being color-frame synchronized with an in-station television signal.

More specifically, when switching an external television signal that is shifted by n pixels and a local television signal that is not pixel-shifted for color frame synchronization, only the screen enhancement signal that constitutes the external television signal is switched. A signal switching device is proposed in which interpolation is performed in a state where n pixels have been returned to the original state so that the pixel positional relationship with the main screen signal forming the external television signal is matched and then switching is performed. is there.

[0003]

2. Description of the Related Art Broadcast television cameras installed in a station are driven so that their color frames are synchronized with each other, so that there is no problem in frame synchronization, but a television signal transmitted from outside the station. When switching between the in-station television signal and the in-station television signal, a signal switching device considering this frame synchronization is used.

FIG. 7 shows a signal switching device 1 showing an example thereof.
0 is a specific example, and terminals 11a to 11c are input terminals for in-station television signals Sa to Sc obtained from three television cameras installed in the station in this example, and these are supplied to the switcher 14. .

The terminal 13 is an input terminal to which the outside television signal is supplied, and is an external signal transmitted through various transmission systems. The out-of-station television signal (hereinafter, referred to as an external television signal) So includes a VTR reproduction signal which is not synchronized with the television camera.

Since the external television signal and the in-station television signal are not generally synchronized with each other, the normal input terminal 13 is used.
A frame synchronizer (FS) 18 for synchronizing color frames is provided between the switcher 14 and the switcher 14 and is supplied to the switcher 14 in a state of being frame-synchronized with the in-station television signal.

A read / write signal is given from the control CPU (control section) 16 to the frame synchronizer 18, and a switching signal SW is used as a switching signal SW when a target television signal is selected.
Given to. The control CPU 16 is supplied with color frame signals inside and outside the station via terminals 13 and 17.

In the case of the NTSC system, since the phase of the color subcarrier is completed in 4 fields, the color video signal may be delayed so that the phase of the color frame is matched in units of 4 fields. Since it is opened too much, the delay of the audio gives a sense of incongruity, especially at the time of simultaneous broadcasting that connects the inside and outside of the station.

In consideration of the above, the conventional frame synchronizer is used in order to reduce the delay amount of the video signal as much as possible to eliminate the discomfort at the time of simultaneous relaying and to achieve the frame synchronization with the in-station television signal. In 18, a 2-field delay plus a 2-pixel shift process is performed.

This is an example when a color video signal is digitally converted by 4fsc (fsc is a color subcarrier frequency). If the digital conversion is performed by 4fsc in this way, the color phase becomes one cycle in 4 pixels. By shifting the color phase by 180 ° due to the field delay and further shifting it by 2 pixels (180 ° phase),
This is because the color phase can be matched with the color phase in the station only by delaying two fields.

A television signal directed to high definition may be applied as the external television signal. This high definition television signal refers to the following signal.

The current television broadcast signal is an interlaced signal, but as one of the television broadcast signals which can achieve high resolution while maintaining compatibility with the interlaced signal, 525 scanning lines per field are provided. (NTSC
EDTV system) is known.

Among the EDTV systems, there is proposed a television system (called a next-generation EDTV system, which is referred to as EDTV-II) which aims to widen the screen like high-definition broadcasting.

The aspect ratio of the screen of high-definition broadcasting is 16: 9. The EDTV-II system also has the same aspect ratio. Since the EDTV-II system aims to achieve high resolution while achieving compatibility with the current television system, even an EDTV-II system television signal can be adapted to a screen with the current aspect ratio (4: 3). The signal form (letterbox type such that part of the upper and lower screens are non-screen parts) is adopted.

FIG. 8 shows an example thereof. The figure shows the screen configuration when an image of the EDTV-II system is projected on the screen 20 of the current aspect ratio. There is a main screen portion 21 in the center of the screen, and the image of the main screen portion 21 has the current aspect ratio. It becomes the image when projected on the screen.

The upper and lower blank portions of the main screen portion 21 are the upper and lower non-screen portions 22A and 22B, and are processed so as to be a non-screen (actually a gray color close to black) so as not to adversely affect the video of the current aspect ratio. Has been done.

The video signals constituting the upper and lower non-screen sections 22A and 22B are called reinforcement signals, which are signals used for high definition video, and vertical high frequency signals and the like are used. .

The main screen portion 21 has 180 horizontal lines, whereas the upper and lower non-screen portions 22A and 22B each have 30 horizontal lines. Since it is necessary to allocate the reinforcement signal of the video signal forming the main screen to the total number of 60 horizontal lines,
It is compressed to 3 and inserted in the upper and lower non-screen portions 22A and 22B.

In FIG. 8, the upper and lower non-screen sections 22A and 22B are divided into three parts in the horizontal direction, and the upper non-screen section 22A is provided with three reinforcement signals for the number of horizontal lines of, for example, 90 upper lines in the main screen section 21. It is divided into two and inserted. As shown in FIG. 9, for example, the reinforcement signal (compressed image data) associated with the first to thirtieth horizontal lines is stored in the divided area 23A in the 31st
~ The reinforcement signal for the 60th horizontal line is the divided area 23B.
In addition, the reinforcement signals for the 61st to 90th horizontal lines are respectively inserted into the divided areas 23C to form the upper and lower non-screen portions 22A. There is a lower 90
Similar processing is performed for the horizontal line and the horizontal line is inserted.

[0020]

When the same number indicating the pixel position of the main screen signal is used as the number indicating the pixel position of the corresponding reinforcement signal, the main screen section is clear as shown in FIG. The pixel position in the horizontal direction of 21 does not match the pixel position of the reinforcement signal inserted in the divided areas forming the upper and lower screenless portions 22A. This is nothing but the compression processing of the reinforcement signal and the distributed insertion processing into the divided areas as described above.

FIG. 10 shows the pixel position relationship between the main screen signal and the reinforcement signal, and FIG. 10A shows the pixel position between the main screen signal and the compressed reinforcement signal. When the color frame synchronization is performed and the n pixels, for example, 2 pixels are shifted in this pixel relationship, the result is as shown in FIG. In the two-pixel shift processing, in actuality, as shown in FIG. 9B, a meaningless signal (indicated by "x" mark) is output for two pixels, and then the readout processing is performed so as to output the actual compression reinforcement signal. Is equivalent to

Such an external television signal shifted by 2 pixels and an in-station television signal which holds a normal pixel relationship not shifted by 2 pixels are switched by the switcher 14 shown in FIG. , Mix, etc.) causes the following problems.

For example, when the external television signal is to be replaced with the in-station television signal, the two-pixel shift processing and the other one are not mixed. When the decoder side of the receiver performs the processing in accordance with the in-station television signal, the restoration processing for the two-pixel shift is not performed, so that the reinforced image for the external television signal is not correctly decoded and displayed. On the contrary, when the processing according to the external television signal is performed, the reinforced image for the in-station television signal is correctly decoded and is not displayed.

To this end, a signal processing device may be provided in each of the signal transmission systems that may be pixel-shifted and output, and processing for undoing the two-pixel shift may be performed. For that purpose, the external television signal may be once decoded to restore the pixel shift, and then encoded again and supplied to the switcher 14.

However, in order to do so, this signal processing device must be inserted into all the transmission systems in which the pixel-shifted external television signal may be transmitted, resulting in high cost. In addition to this, the image quality is deteriorated because the decoding and encoding processes are performed.

Therefore, the present invention solves such a conventional problem, and makes it possible to correctly decode a reinforcement signal related to an external television signal shifted by n pixels without deteriorating the image quality and increasing the cost. It proposes a signal switching device capable of reproducing a correct image by using.

[0027]

In order to solve the above problems, in the invention described in claim 1, in the signal switching device for switching between the external television signal and the in-station television signal, the main screen signal is When a reinforcement signal is inserted and an external television signal that is shifted by n pixels for frame synchronization with the in-station television signal is input, the reinforcement signal is restored to n pixels and the reinforcement signal is restored. It is characterized in that the interpolation is performed to match the pixel position with the main screen signal and the pixel position is supplied to the switcher.

In the invention according to claim 2, a television signal composed of a main screen signal, a horizontal high frequency signal, and a reinforcement signal such as a vertical high frequency signal is supplied to the pixel shift discrimination means. , The presence or absence of pixel shift and the pixel shift amount are respectively detected, and when the pixel shift is detected,
The main screen signal is supplied to the delay means selected for the delay time corresponding to the pixel shift, and the vertical high frequency reinforcing signal is supplied to the interpolation means.

According to a third aspect of the present invention, a letterbox type high definition television signal is used as the external television signal, and a data-compressed signal is used as the reinforcing signal.

In the fourth aspect, the interpolation means is
It is characterized by comprising a pair of variable coefficient units, a delay element for one pixel or more, and an adder to which a pair of variable coefficient outputs are supplied.

According to a fifth aspect of the present invention, there is provided 1H (H is one horizontal period) delay means to which a television signal having no pixel shift is supplied, and a television signal pixel-shifted by n pixels, the interpolation processing being performed. (1H-n) delay means to which the subsequent television signal is supplied.

Consider a case where an external television signal, which is frame-synchronized with the in-station television signal by further shifting by two pixels from two fields, is input. The 22H (H is a horizontal period) and 285 are included in the television signal.
The identification signal CTL is inserted in the Hth position, and the reference signal (pulse) serving as the reference phase is located at the beginning thereof. When the pixel is shifted, this reference signal is also shifted and inserted by the same amount, so the pixel shift amount is calculated by measuring the time from the horizontal synchronizing signal to the reference signal. Only the reinforcement signal is restored to the original amount by this pixel shift amount.

Interpolation interpolation processing is performed on the restored reinforcement signal. By the interpolation processing, the pixel position of the reinforcement signal and the pixel position of the main screen signal completely match. Then, the pixel-shifted reference signal is passed through delay means to return it to its original position. By selecting the delay amount of this delay means to be (1H-n), the reference signal can be returned to the correct position.

By carrying out these processes, the reinforcement signal of the external television signal can be correctly decoded even if the television signal with pixel shift and the television signal without pixel shift are mixed.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a case where an example of a signal switching device according to the present invention is applied to an EDTV-II compatible video processing device will be described in detail with reference to the drawings.

FIG. 1 shows a signal switching device 1 according to the present invention.
8 is a system diagram showing one mode of implementation of No. 0, and basically follows the conventional circuit configuration shown in FIG. 7. In FIG. 1, for the sake of convenience of explanation, two TV cameras 32 and 34 in the station and two VTs
R36, 38 and one frame synchronizer 4
A switching device using 0 (40a indicates its input terminal) is shown. These are all in-station synchronization signal generator 4
It is designed to be driven in synchronization with the sync signal from the No. 2.

Encoders 33 and 35 are provided at the subsequent stages of the in-station television cameras 32 and 34, respectively, and high-definition television signals having the reinforcing signals as described above are generated here. Therefore, the switcher 14 switches between high definition television signals. It is assumed that these television signals have been digitally converted as described above.

With respect to the in-station television signal output from the television camera 32 or the like, the probability that the television signal reproduced by the VTR 36 or the television signal input from the terminal 40a is in-station synchronization is 50. %
It is. When the intra-station synchronization is not established, all of them are internally processed so that the intra-station synchronization is established, and a television signal shifted by n pixels is output. These become the external television signal So. The pixel shift amount is either advanced by 2 pixels or delayed by 2 pixels, advanced by 4 pixels or 6 pixels, or delayed. The following example shows a case where intra-office synchronization is achieved with a delay of 2 pixels.

A delay means 44 is provided in the switcher 14 between the system for outputting the external television signal and the system for outputting the in-station television signal, which is the route through which the intra-station synchronization signal is supplied. The in-station synchronization signal is delayed by the amount of (4F-m) fields so that the frame phases of the input external television signal and the in-station television signal are completely matched and then supplied. m corresponds to the delay amount generated by the interpolation processing to be described later. (4F-
Since the delay of m) fields is equivalent to the advance of m pixels from the intra-station synchronization signal, the delay associated with the interpolation processing can be eliminated.

According to the present invention, when an external television signal shifted by n pixels is input, the augmentation signal and the identification signal CTL are restored to the original values for n pixels, and the augmentation signal is interpolated and interpolated to the main screen. A switcher 1 for an external television signal whose pixel positions match those of the signal.
4 is input. The signal processing will be described with reference to FIG. 10 again. The pixel shift amount n is 2 pixels.

FIG. 1 shows the pixel positional relationship between the main screen signal and the reinforcement signal which form the external television signal shifted by two pixels.
As shown in 0B. When two pixels are returned to the original with respect to the reinforcement signal, it becomes as shown in FIG. On the other hand, the pixel relationship between the main screen signal shifted by 2 pixels and the reinforcement signal corresponding to this main screen signal is as shown in FIG.

Considering the reinforcement signal, the pixel positional relationship in FIG. 3C is indicated by solid arrows in FIG. On the other hand, FIG. 10D
The pixel positional relationship of the reinforcement signal shown by is shown by the broken line arrow in FIG.
To return the pixel position of the solid line position to the pixel position shown by the broken line,
The reinforcement signal shown by the solid line may be interpolated. for that reason,
As shown in FIG. 1, a signal transmission system in which pixels may be shifted and input to the switcher 14, a VTR3 in this example.
An interpolation interpolator 50 is provided in each of the output systems of 6, 38 and the frame synchronizer 40.

FIG. 2 shows a concrete example of the interpolation device 50. In this example, the main screen signal is delayed by 2 pixels instead of returning the reinforcement signal by the pixel shift (2 pixels), and the interpolation signal is subjected to the interpolation processing.

The external television signal is supplied to the pixel shift discriminating circuit 52 through the terminal 51 to discriminate whether or not it is a pixel-shifted television signal, and when the pixel is shifted, the pixel shift amount is obtained. As shown in FIG. 4, it is determined whether the pixel shift processing is performed or not.
Identification signal CT inserted at 2H and 285H, respectively
It is determined using L. 23H or later and 286H
After the eyes, there is video information, where SM is the main video information and SS is the reinforcement video information.

The above-mentioned identification signal CTL is as shown in FIG. The same figure A shows the video signal (television signal) of the 22nd H. The horizontal synchronizing signal PH is used as the video signal.
Then, the color burst signal CB is inserted, and the identification signal CTL is inserted in a predetermined period thereafter. Identification signal CT
L is composed of 27 bits, and the reference signal CTL1 of bit "1" is inserted in the first bit B1. The reference signal CTL1 is used as all reference phases.

An identification signal CTL2 which becomes a bit "1" when EDTV-II is inserted into the bit B3. An even parity bit is added to this bit as bit B4. After that, various identification signals CT from bit B6 to bit B23 and bit B25 to bit B27
L3 and CTL4 are to be inserted. 23H
A reinforcement signal (reinforcement video information SS) is inserted from the eye to the 52nd eye, and normal video information Sv (SM) is inserted thereafter as shown in FIG. 5B.

The time Ta from the leading edge of the horizontal synchronizing signal PH to the trailing edge of the reference signal CTL1 is strictly defined. On the other hand, when the pixel shift is performed, the identification signal CTL is also shifted by the pixel shift.
By measuring, it is possible to know the presence or absence of pixel shift and the shift amount. For example, as shown in FIG. 5C, Δ
When the pixel is shifted by (= 2 pixels), the time Tb at that time is Tb = Ta + Δ.

In FIG. 2, when the discriminating circuit 52 determines that the pixel shift is not performed, the discriminating circuit 52.
The determination pulse Pd of a lower level is output, and the first switch 54 holds the switching state of the terminal a.
At this time, the external television signal is 1H delay means 56.
Is supplied to the second switch 58 via the
The side is selected and supplied to the output terminal 60. In other words, it is output with a mere 1H delay. Delay means 5
Reference numeral 6 is provided to make the time relationship of the external television signals input to the a terminal and the b terminal of the second switch 58 uniform.

When the discriminating circuit 52 detects the pixel shift, the discriminating pulse Pd becomes high level, the first and second switches 54 and 58 are switched to the terminal b side, and the external television signal is the third. It is supplied to the switch 64 side. The third switch 64 and the subsequent fourth switch 70 are provided for the interpolation processing, so that the external television signal is further supplied to the switching signal generation circuit 62.

In the generating circuit 62, a switching pulse (reinforcing side pulse) Pb corresponding to the reinforcing signal shown in FIG. 4 and a switching pulse (discriminating side pulse) Pc corresponding to the identification signal CTL are respectively generated from the input composite synchronizing signal. To be done.

By the reinforcement side pulse Pb given to the third changeover switch 64, the terminal c is output in the case of the main screen signal.
And is supplied to the fourth switch 68 through a predetermined variable delay means 66. This fourth switch 6
Since the reinforcement side pulse Pb is also given to 8, the output of the delay means 66 is selected by this. In this example, instead of the process of returning the reinforcement signal to the original amount by the pixel shift, the process of delaying the main screen signal side by the pixel shift n by the variable delay means 66 is performed.

Third switch 6 except for the main screen signal
4 is switched to the terminal d side, and interpolation processing is performed. Even in this case, the interpolation process is not necessary for the identification signal CTL. Therefore, the fifth switch 70 is provided, and when the discrimination-side pulse Pc is obtained, it is switched to the terminal e side, and the signals at the 22nd and 285Hths are directly supplied to the fourth switch 68. Fourth switch 68
Also, the discrimination-side pulse Pc is given to this discrimination signal CT.
L is selected.

On the other hand, the section in which the reinforcement signal is inserted is switched to the terminal f side, and the interpolation signal is interpolated by the interpolation circuit 80. The interpolating / interpolating circuit 80 is for giving a low-pass characteristic to the reinforcement signal, and has a delay element 82 selected for a delay time of one pixel, the output of which is the first variable coefficient unit 84. Is multiplied by a coefficient K1 of. Similarly, the reinforcement signal is supplied to the second variable coefficient unit 86 and is multiplied by the second coefficient K2, and the respective multiplication outputs are added by the adder 88.

In the case of an external television signal which has been delayed by two pixels and subjected to color frame synchronization processing as described above, the values shown in broken lines (pixel positions 0, 3, 6) as shown in FIG. Therefore, addition processing is performed with an internal division ratio of 1: 2. Therefore, in the case of 2-pixel shift, the first coefficient K1 is selected to be 2/3 and the second coefficient K2 is selected to be 1/3, and the first pixel is zero and the second pixel is the third pixel. And the value corresponding to the sixth pixel position is output for the third pixel.

Since the pixel shift amount can be obtained by the discrimination circuit 52, the control signal Pe corresponding to the pixel shift amount is supplied to the coefficient units 84 and 86 described above. The control signal Pe is also supplied to the variable delay unit 66 described above, and the delay amount is controlled so that the main screen signal is delayed by the calculated pixel shift amount n.

The interpolated and interpolated reinforcement signal is supplied to the fourth switch 68. Since the reinforcement side pulse Pb and the discrimination side pulse Pc are supplied to the fourth switch 68, the terminal e is selected in the horizontal section of the discrimination signal CTL and the terminal f is selected in the reinforcement signal section, and the main screen is displayed. In the signal section, the terminal c is selected, and the fourth switch 68 causes the terminal shown in FIG.
An external television signal corrected to have a pixel relationship as shown in is output.

This external television signal is the identification signal CT.
With respect to the relationship with L, the pixel is still shifted by 2 pixels as shown in FIG. 10C, so that the variable delay means 90 in the next stage returns the identification signal CTL by 2 pixels. Actually (1H-n)
By delaying by (H is a horizontal period), the identification signal CTL can be read in a state of advancing by n pixels, and therefore this delaying process is performed in FIG. Since n changes depending on the pixel shift amount, the delay amount of the variable delay means 90 is controlled by the control signal Pe.

Therefore, by interposing the variable delay means 90, the identification signal CT satisfying the normal phase relationship while the intra-station television signal supplied to the terminal a side of the second switch 58 and the color frame are in synchronization with each other.
An external television signal having L can be output to the terminal b side.

When the pixel shift is shifted by 2 pixels toward the phase advance side, the same processing as that in the case of the external television signal in which the color frame synchronization is obtained in the state of being delayed by 4 pixels is performed. When the 4-pixel shift is illustrated, the relationship is as shown in FIGS. 6A and 6B. In this case, therefore, if the reinforcement signal as shown in FIG. The pixel positional relationship with the main screen signal is satisfied even with the shift of 4 pixels. Therefore in this case 4
The coefficient value and each delay amount are selected so as to shift by the pixel.

Electronic switches can be used as the switches 54, 64, 70 and the like described above. The connection relationship will also be simplified if it is a logical changeover switch configuration.

[0061]

As described above, in the signal switching device according to the present invention, the processing for correcting the pixel shift is performed on the reinforcement signal for the main screen signal, and the interpolation for the main screen signal is performed. The pixel positions of the reinforcement signals are made to match.

According to this, the pixel-shifted external television signal can be subjected to switching processing in a state in which the intra-station television signal not subjected to the pixel shift processing is color frame synchronized, so that there is no pixel shift. Regardless of the above, it is possible to perform switching processing for a plurality of television signals in a normal state for a video special effect.

In this case, since only the interpolation device and the circuit system associated with it are used, the cost is much lower than that of the signal processing device for encoding and decoding, and the image quality deterioration caused by encoding and decoding is caused. It has features that can be prevented. Therefore, the present invention is suitable for application to the above-mentioned EDTV-II-compatible in-station broadcasting facility and the like.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an outline of a signal switching device according to the present invention.

FIG. 2 is a system diagram showing an example of an interpolation interpolation device used for this.

FIG. 3 is a diagram showing a pixel position correction state for restoring a reinforcement signal.

FIG. 4 is a diagram showing a relationship between a signal and a switching pulse.

[Fig. 5] Fig. 5 is a diagram illustrating a relationship between two-pixel shifted television signals.

FIG. 6 is a diagram showing a pixel positional relationship of a television signal in a 4-pixel shift state.

FIG. 7 is a system diagram showing an example of a signal switching device used in a station.

FIG. 8 is a diagram showing a signal configuration of an EDTV-II system.

FIG. 9 is a diagram showing a relationship between main screen image data and upper and lower non-screen compressed data.

FIG. 10 is an explanatory diagram of 2-pixel shift processing and its restoration.

[Explanation of symbols]

 14 switcher 50 interpolation interpolator 52 discrimination circuit 56, 66, 90 variable delay means 62 switching signal generation circuit 80 interpolation interpolation circuit

Claims (5)

[Claims] 1. A signal switching device for switching between an external television signal and an in-station television signal, wherein a reinforcement signal is inserted into a main screen signal, and n pixels are shifted for frame synchronization with the in-station television signal. When an external television signal is input, it is returned to the original by n pixels with respect to the augmented signal, and the augmented signal is interpolated and interpolated to match the pixel position with the main screen signal and supplied to the switcher. A signal switching device characterized in that 2. A television signal composed of a main screen signal, a horizontal high frequency signal, and a reinforcement signal such as a vertical high frequency signal is supplied to the pixel shift discriminating means, and the presence or absence of pixel shift and the pixel shift amount are respectively determined. When the pixel shift is detected and the pixel shift is detected, the main screen signal is supplied to the delay means selected for the delay time for the pixel shift, and the vertical high frequency reinforcement signal is supplied to the interpolation means. A signal switching device characterized by being made. 3. The high definition television signal of letterbox format is used as the external television signal, and the data-compressed one is used as the reinforcing signal. The signal switching device described. 4. The interpolation means comprises a pair of variable coefficient units, a delay element for one pixel or more, and a pair of adders to which variable coefficient outputs are supplied. Item 2. The signal switching device according to item 2. 5. A delay means of 1H (H is 1 horizontal period) to which a television signal without pixel shift is supplied, and a television signal pixel-shifted by n pixels.
The television signal after the interpolation processing is supplied (1H
-N) delay means.
The signal switching device described.