JPH0442685A - Recording and reproducing device having waveform equalizing circuit - Google Patents

Abstract

PURPOSE:To reduce the converging time by utilizing plural reference signals inserted in one field so as to apply waveform equalization thereby decreasing time fluctuation among the reference signals. CONSTITUTION:The above device is provided with a reference signal output means 25 extracting a reference signal included in an input video signal in the recording system and outputting it or generating a prescribed reference signal and outputting it and with a reference signal insertion means 24 inserting plural reference signals outputted from the reference signal output means 25 in one field of the input video signal at a prescribed sequence and outputting a recording video signal. Thus, the time fluctuation among the reference signals in one field is comparatively decreased. Thus, the converging time is reduced.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a waveform equalization method that reliably equalizes the waveform of a reproduced video signal that has relatively large time fluctuations, such as a video tape recorder. The present invention relates to a recording/reproducing device having a circuit.

(Prior Art) Recently, there has been a demand for higher image quality in television broadcasting, and EDTV television broadcasting has been started since October 1989. In this EDTV system, an OCR (ghost cancellation reference) signal is superimposed on a television signal and transmitted as a reference signal for ghost removal. That is, in the 18th) 1 (H is the horizontal period) and the 281H within the vertical blanking interval, the 5inx/X integral waveform (hereinafter referred to as WRB (Wide Reverse B) shown in FIG.
ar) waveform) or the Vedestal waveform shown in FIG. 7(b) is inserted. The WRB waveform and pedestal waveform are inserted in an 8-field sequence, and the 1.3
, 6.8 field, the WRB waveform is inserted, and the second .
A hedestal waveform is inserted in the 4.5.7 field. A waveform equalization circuit that performs ghost removal and waveform equalization using this OCR signal has also been commercialized.

FIG. 8 is a block diagram showing a waveform equalization circuit employed in a video tape recorder or the like.

A video signal that has been subjected to ghost interference, waveform distortion, etc. is input to the input terminal 1. An OCR signal is inserted into this video signal. The input video signal is input to a transversal filter (hereinafter also referred to as TF) 2 that performs waveform equalization, and is also input to a four-field difference signal circuit 3. The TF 2 has a delay device, a multiplier, an adder, and a subtracter (not shown), and the gain of each multiplier is controlled by the tap coefficient given from the tap gain memory 4 to equalize the waveform of the input video signal. , the four-field difference signal circuit 3 subtracts the WRB waveform of the first field and the pedestal waveform of the fifth field, and supplies the result to the differentiating circuit 5. The differential (difference) signal from the differential circuit 5 is 5inx
/x waveform, and the input waveform (xk
) is given as On the other hand, the video output from TF2 is output to the output terminal 7 and is also applied to the four-field difference signal circuit 8. 5inx/x obtained by differentiating the output of the 4-field difference signal circuit 8 in the differentiating circuit 9
The waveform is applied to the subtraction circuit 10 as an output waveform (yk). The subtraction circuit 10 receives a reference waveform (
rk) and the output waveform (ykl), and outputs the error waveform (ekl) to the ghost detection circuit 6.

The ghost detection circuit 6 detects the input waveform (xk) and the error waveform (e
k), and correct the tap coefficient given to TF2 so that the error waveform (ek) converges to 0. The calculation result is given to the tap gain modification circuit 12, and the tap gain modification circuit 12 sends and receives data to and from the tap gain memory 4, and updates the tap coefficients in the tap gain memory 4 at predetermined intervals. A tap coefficient is given to the multiplier from the tap gain memory 4, the characteristics of TF2 are changed, and ghost removal waveform equalization is performed.

By the way, in video tape recorders and the like, the time fluctuation of the reproduced video signal is relatively large, as mentioned above.
The OCR signal is inserted in an 8-field sequence, and the OCR signal is detected only once every 8 fields.

Therefore, when an input signal with relatively large time fluctuations is input, such as a VTR playback video signal, the time fluctuations of the OCR signal are large, and it takes a long time for the error waveform (ek) to converge. Furthermore, in order to reduce the influence of noise, a method may be adopted in which OCR signals are synchronously added to extract noise components and distortion components, and these are used to perform tap coefficient correction calculations. However, by synchronous addition, the detected OCR signal is equivalent to being integrated, and if the OCR signal has a large time fluctuation, the influence of the integration effect by synchronous addition becomes large. For this reason, there is a problem in that the characteristics of the transversal filter become overemphasized in high frequencies, resulting in ringing and S/N deterioration.

(Problem to be Solved by the Invention) As described above, in the recording and reproducing apparatus having the conventional waveform equalization circuit described above, since the OCR signal is inserted in an 8-field sequence, the time fluctuation of the OCR signal is The problem is that it takes a long time to converge, and the characteristics of the transversal filter become overemphasized in high frequencies due to the integral effect of synchronous addition, resulting in a deterioration of image quality.

The present invention has been made in view of such problems, and includes:
A waveform equalization circuit that shortens convergence time by inserting an OCR signal in an 8-line sequence during recording, and prevents high-frequency overemphasis during playback to obtain a good playback image. An object of the present invention is to provide a recording/reproducing device having the following functions.

[Structure of the Invention] (Means for Solving the Problems) A recording and reproducing apparatus having a waveform equalization circuit according to claim 1 of the present invention extracts and outputs a reference signal included in an input video signal in a recording system. Alternatively, a reference signal output means for generating and outputting a predetermined reference signal, and a plurality of reference signals outputted by the reference signal output means are inserted into the input video signal in a predetermined sequence in one field to produce a video for recording. A recording/reproducing apparatus having a waveform equalization circuit according to claim 2 of the present invention is equipped with a reference signal insertion means for outputting a signal, and a recording/reproducing apparatus having a waveform equalizing circuit according to claim 2 of the present invention is provided with a reference signal inserting means for outputting a signal. It has an extraction means for extracting a reference signal and a reference signal source for outputting an internal reference signal, and reproduces a reproduced video signal based on arithmetic processing of the reference signal extracted by the extraction means and the internal reference signal from the reference signal source. The waveform equalization section performs waveform equalization.

(Operation) In the present invention, in the recording system, the reference signal insertion means inserts a plurality of reference signals outputted by the reference signal output means into one field of the input video signal in a predetermined sequence. In the reproduction system, an extraction means extracts a reference signal included in the reproduction signal. The waveform equalization unit equalizes the waveform of the reproduced video signal using each reference signal in the extracted field.The time variation between each reference signal in one field is relatively small, and this time variation is used for waveform etc. The effect on the arithmetic processing of the conversion section is low.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing an embodiment of a recording system of a recording and reproducing apparatus having a waveform equalization circuit according to the present invention, and FIG. 2 is a block diagram showing a recording system of a recording and reproducing apparatus having a waveform equalization circuit according to the present invention. FIG. 2 is a block diagram showing an example of the system.

An input video signal is input to the input terminal 20 of the recording system shown in FIG. This input video signal is sent to an OCR detection circuit 21,
Line counter 22, field counter 23 and GC
It is applied to the R insertion circuit 24. field counter 23
counts vertical synchronization signals included in the input video signal and outputs a control signal. The line counter 22 is reset by the control signal of the field counter 23, converts the horizontal synchronizing signal contained in the input video signal, and outputs a control signal. The GCR detection circuit 21 detects the first signal of the input video signal by the control signal from the line counter 22.
Detect the GCR signal included in 88281H. OCR
The output of the detection circuit 21 is given to an 8-line memory 25. The 8-line memory 25 stores the output of the GCR detection circuit 21 and outputs the stored data to the OCR insertion circuit 24. Writing and reading of the 8-line memory 25 is controlled by control signals from the line counter 22 and field counter 23.

FIG. 3 is a block diagram showing a specific refinement of this 8-line memory 25.

The output of the GCR detection circuit 21 is sent to the write address generation circuit 27.
is applied to line memory group 28 via. The line memory group 28 has line memories 28a to 28h, and the write address generation circuit 27 has a field counter 23.
A control signal is applied from the address line memory 28 to sequentially and selectively designate the addresses of the line memory group 28, ie, the line memories 28a to 28h, for each field. In this way, the OCR signals of the first to eighth fields are stored in each of the line memories 28a to 28h, respectively. That is, line memories 28a, 28c, 28f,
The WRB waveform is stored in 28h, and the line memory 28b
, 28d, 28e, and 28g store pedestal waveforms. These line memories 28a to 2
The OCR signal stored in 8h is sent to the read address generation circuit 2.
9 to the OCR insertion circuit 24. The read address generation circuit 29 is a line counter 2
Line memory group 2 is controlled by a control signal from line memory group 2.
O stored in each line memory 28a to 28h of 8
The CR signal is switched and output for each line. That is, the line memories 28a to 2 are stored in the first to eighth lines, respectively.
Outputs the OCR signal stored in 8h. This results in
The WRB waveform is output to the 1st 3.6.8 line, and the pedestal waveform is output to the 2.4 and 5.7 lines. In this way, the OCR insertion circuit 24 is supplied with an 8-line sequence of GCR signals.

The OCR insertion circuit 24 inserts the output of the 8 line memory 25 into the input video signal based on the control signals from the line counter 22 and the field counter 23, and outputs the output from the output terminal 2.
Output to 6. The video signal derived from the output terminal 26 is supplied to a recording section (not shown).

On the other hand, a reproduced video signal is input to the input terminal 1 of the reproduction system shown in FIG. The configurations of the TF 2, the tap gain memory 4, the differentiating circuits 5 and 9, the ghost detection circuit 6, the subtraction circuit 10, the reference signal source 11, and the tap gain correction circuit 12 are the same as the conventional ones. That is, TF2 is a delay device (not shown),
The differentiating circuits 5 and 9 each have a multiplier, an adder, and a subtracter, and the gain of each multiplier is controlled by a tap coefficient to equalize the waveform of an input video signal. By differentiating the signals from the circuits 30 and 31, a signal with a 5inx/x waveform is output. The differential signal from the differentiating circuit 5 is applied to the ghost detection circuit 6 as an input waveform (xk), and the differential signal from the differentiating circuit 9 is applied to the subtraction circuit 10 as an output waveform (yk).

The subtraction circuit 10 receives a reference waveform (γk
) is also given. The subtraction circuit 10 calculates the error between the reference waveform (γk) and the output waveform (yk), and calculates the error waveform (ek).
A ghost detection mouth! Output to @6.

The ghost detection circuit 6 detects the input waveform (xk) and the error waveform (
The tap coefficients are corrected so that the error waveform (ek) converges to zero. The calculation result of the ghost detection circuit 6 is given to the tap gain correction circuit 12. The tap gain correction circuit 12 sends and receives data to and from the tap gain memory 4 to update the tap coefficients in the tap gain memory 4.

Tap gain memory 4 provides tap coefficients to TF2.

In this embodiment, 4-line difference signal circuits 30 and 31 are provided in place of the 4-field difference signal circuit. The 4-line difference signal circuits 30 and 31 subtract the WRB waveform and pedestal waveform inserted before and after the 4 lines of the input video signal, respectively, and extract the sin x/x integral waveform and send it to the differentiating circuits 5 and 9. It is designed to output each.

Next, the operation of the recording/reproducing apparatus having the waveform equalization circuit configured as described above will be explained.

An input video signal input through an input terminal 20 of the recording system is applied to an OCR detection circuit 21. The OCR detection circuit 21 includes a line counter 22 and a field counter 23.
Based on the control signal from
Extract the pedestal waveform included in H. These G.C.
The R signal is applied to an 8-line memory 25. In the 8-line memory 25, the write address generation circuit 27 is controlled by the control signal of the field counter 23, and the OCR signals of the first to eighth fields are stored in the line memories 28a to 28h, respectively. The read address generation circuit 29 of the 8-line memory 25 sequentially reads data from each line memory 28a to 28h line by line in response to a control signal from the line counter 22. In this way, an 8-line sequence of GCR signals is output from the 8-line memory 25 to the GCR insertion circuit 24.

An input video signal is also input to the GCR insertion circuit 1E324. The OCR insertion circuit 24 is a field counter 23
and controlled by a control signal from the line counter 22,
GC from the 8-line memory 25 is applied to predetermined consecutive 8 lines among the 9th to 21H1 272nd to 284H after the equalization pulse during the vertical blanking period of the input video signal.
Insert R signal. In this way, the OCR insertion circuit 24 outputs the video signal into which the OCR signal has been inserted in an 8-line sequence to the recording section via the output terminal 26.

On the other hand, a reproduced video signal is input to the input terminal 1 of the reproduction system. This reproduced video signal is given to TF2, and TF2
performs waveform equalization on the reproduced video signal according to the tap coefficients, and outputs the video signal to the output terminal 7. Tap coefficient is 8
It is created based on the OCR signal inserted in the line sequence. That is, the input and output video signals of TF2 are respectively applied to the 4-line difference signal circuit 11330.31, and the WR, B waveforms and pedestal waveforms of the four lines are subtracted from each other. As a result, a 5inx/x integral waveform is obtained, which is further converted into a 5inx/x waveform by the differentiating circuit 5.9 and output as an input waveform (xk) and an output waveform (yk't).

The output waveform (yk) is given to the subtraction circuit 10.

The subtraction circuit 10 divides the reference waveform (rk) and the output waveform (yk
) and find the error waveform (ek) from the ghost detection port l.
Give to B6. The ghost detection circuit 6 receives the input waveform (xk
) and the error waveform (ek) to output a calculation result that converges the error waveform (ekl).In this way, the tap gain correction circuit 12 sequentially corrects the tap coefficients for each field, TF2 performs waveform equalization of the reproduced video signal.

As described above, in this embodiment, an 8-line sequence OCR signal is inserted into the human-powered video signal in the recording system, and this OCR signal is extracted by the 4-line difference signal circuit 30.31 in the reproduction system. 8 of them
Tap coefficient correction calculations are performed using line sequence GCR signals.

A signal obtained by synchronous addition of OCR signals within one field has sufficiently smaller temporal fluctuations than a signal obtained by synchronous addition of GCR signals between fields. Therefore, even when a playback signal from a video tape recorder or the like that has large time fluctuations is input, the convergence time can be shortened, and the negative effects of the integral effect of synchronous addition can be reduced.
It is possible to prevent F2 from overemphasizing the high frequency range, and it is possible to obtain a good reproduced image.

FIG. 4 is a block diagram showing a recording system according to another embodiment of the present invention. This embodiment is for eliminating distortion in the recording system and reproduction system.

The input video signal is applied to a line counter 36 and a GCR insertion circuit 24 via an input terminal 35. The line counter 36 counts the horizontal synchronization signals of the input video signal to
O
It is output to the CR generation circuit 3γ. The OCR generation circuit 37 is
A GCR signal consisting of an RB waveform and a pedestal waveform is generated, and the generated GCR signal is output to the GCR insertion circuit 24 at the timing of the control signal from the line counter 36.

An input video signal is input to the GCR insertion circuit 24, and the GCR insertion circuit 24 receives the G from the OCR generation circuit 37.
The CR signal is inserted into the input video signal and output to the output terminal 38. The video signal led out to the output terminal 38 is given to a recording section (not shown).

Next, the operation of the embodiment configured as described above will be explained.

The input video signal is given to the line counter 36, and the line counter 36 has the 9th to 21H, the 272nd to 284th
OCR the control signal indicating 8 predetermined continuous lines in H.
The signal is applied to the generation circuit 37 to generate the GCR signal at this timing. That is, the OCR generation circuit 37 outputs the WRB waveform on the 1.3, 6.degree. 8th line among the 8 lines, and the pedestal waveform on the 2.degree. 4.5.7 line. The OCR insertion circuit 24 inserts these GCR signals into each line of the input video signal and outputs them.

As described above, in this embodiment, an 8-line sequence OCR signal is inserted into the video signal during recording, and during playback, the OCR signal is passed through the waveform equalization circuit shown in FIG. waveform distortion can be equalized. Since the OCR signal is inserted in an 8-line sequence, the time fluctuation of the signal detected by synchronous addition is small, which shortens the convergence time and improves the characteristics of the transversal filter, similar to the embodiment shown in FIG. High-frequency overemphasis is prevented and a good reproduced image is obtained.

FIG. 5 is a block diagram showing a recording system according to another embodiment of the present invention. This embodiment enables waveform equalization by a conventional waveform equalization circuit in the reproduction system. In FIG. 5, the same components as in FIG. 4 are given the same reference numerals, and their explanation will be omitted.

This embodiment differs from the embodiment shown in FIG. 4 in that a field counter 39 is provided. The field counter 39 outputs a control signal indicating a predetermined field to the OCR generation circuit 37 by counting the vertical synchronization signal of the input video signal. The OCR generation circuit 37 outputs an OCR signal consisting of a WRB waveform and a pedestal waveform at the timing of control signals from the line counter 36 and field counter 39.

In the embodiment configured in this manner, the OCR signal generation circuit l@37 outputs the WRB waveform and pedestal waveform for each line in an 8-line sequence, and also outputs these waveforms for each field in an 8-field sequence. . Table 1 below shows the number of OCR occurrences! Showing the output of 37, O
The GCR signal from the CR generation circuit 37 is sent to the GCR insertion circuit 2.
4 into the input video signal. Note that in Table 1, the pedestal waveform is indicated by P.

Table 1 As shown in Table 1, an OCR signal is inserted into the input video signal in an 8 line sequence and an 8 field sequence. Therefore, even if the reproduction system employs a waveform equalization circuit that operates in a conventional 8-field sequence, waveform equalization can be performed using the OCR signal inserted into the reproduction video signal.

Other functions and effects are similar to those of the embodiment shown in FIG.

Note that the OCR generation circuit 37 generates an 8-line sequence OC.
It is not necessary to output the R signal, and the WRB waveform and pedestal waveform may be simply inserted and recorded alternately in the input video signal within one field. In this case, in the playback system, each WRB waveform and the pedestal waveform Subtraction is performed for each pair of waveforms to obtain an input waveform and an output waveform. Also, O
Rather than inserting a CR signal, the 5inx shown in Figure 9
/X waveform may be inserted and recorded over several lines, and the DC level of the 5inx/x waveform extracted in the playback system may be adjusted and applied to the ghost detection circuit. In this case, the differentiator circuit may be Not necessary.

[Effects of the Invention] As explained above, according to the present invention, waveform equalization is performed using a plurality of reference signals inserted in one field to reduce the time fluctuation between the reference signals, so that the convergence time is reduced. This has the effect of not only shortening the time, but also preventing high-frequency overemphasis during reproduction and obtaining a good reproduced image.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a recording system of a recording and reproducing apparatus having a waveform equalization circuit according to the present invention, and FIG. 3 is a block diagram showing a specific configuration of the 8-line memory 25 in FIG. 1; FIG. 4 is a block diagram showing another embodiment of the present invention; FIG. is a block diagram showing another embodiment of the present invention, and FIG. 6 is a 5inx/
FIG. 7 is a waveform diagram showing the X waveform, FIG. 7 is a waveform diagram for explaining an OCR signal, and FIG. 8 is a block diagram showing a waveform equalization circuit. 20... Input terminal, 21... GCR detection circuit, 22
... line counter, 23 ... field counter, 24 ... GCR insertion circuit, 25 ... 8 line memory, 26 ... output terminal. Figure 1 Figure 5

Claims (2)

[Claims] (1) A reference signal output means for extracting and outputting a reference signal included in an input video signal in a recording system or generating and outputting a predetermined reference signal; 1. A recording/reproducing apparatus having a waveform equalization circuit, comprising: reference signal insertion means for inserting a plurality of reference signals into one field in a predetermined sequence into an input video signal and outputting a video signal for recording. (2) The reproduction system includes an extraction means for extracting a plurality of reference signals included in one field of a reproduced video signal, and a reference signal source for outputting an internal reference signal, and the reference signal extracted by the extraction means and the 1. A recording/reproducing apparatus having a waveform equalization circuit, comprising: a waveform equalization section that equalizes the waveform of a reproduced video signal based on arithmetic processing with an internal reference signal from a reference signal source.