JPS6243995A - Video recording and reproducing device - Google Patents

Abstract

PURPOSE:To reduce a low frequency converting color noise by providing a low frequency converting chrominance signal delay device, an inverse equipment for inversing a delay signal every field, and a noise reducing device. CONSTITUTION:During reproducing, reproducing chrominance signals 201, 202 including cross talk components are delayed by 1H with a delay device 17. A switch 15 is changed over to the C side of the drawing when a field in which a phase of the reproducing chrominance signal is not inversed every 1H is reproduced, an output of the delay device 17 passes through an LPF 16 as it does, is mixed with a signal which is not delayed in a MIX 5 and a cross talk component is removed. When a field in which the phase of the reproducing chrominance signal is inversed every 1H is reproduced, the switch 15 is changed over to the (d) side, the output of the delay device 17 is inversed by 180 deg. in an INV 14, passes through the LPF 16, is mixed with the signal which is not delayed in the MIX 5 and the cross talk component is removed. Thereby, a low frequency converting color noise can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for converting a low-band converted reproduced color signal to a subcarrier frequency.
T! The present invention relates to a video recording and reproducing apparatus using a guard panless recording method that can reduce noise without causing noise.

BACKGROUND OF THE INVENTION In recent years, video recording and reproducing devices have grown significantly, centering on VTRs, and especially in the field of home and business VTRs, guard panless recording type VTRs, which have low running costs, have become widespread. Currently, guard panless recording method V
In part of the TR, the PJ4 color signal is V
There are 11 types of T'R that can be output to the outside.

Hereinafter, an example of a conventional video recording and reproducing apparatus of 1-34 will be described with reference to the drawings. Here, the VIIS method that employs the PS color @sign processing method will be described.

Figure 5 shows the color signal noise reduction V of a conventional video recording and reproducing device.
1 is a simplified block diagram of an i-device; FIG. In Fig. 5, 1 is the f relay line (hereinafter referred to as D
(referred to as L)゛, 2 converts the frequency of the low-pass conversion color signal to the passband of [)Ll! Balanced modulator (hereinafter referred to as r3M), 3 converts the signal that has passed through the DLI back to a low frequency *I
4 is a low-pass filter (hereinafter referred to as LPF); and 5 is a signal mixing device (referred to as 1-step MIX).

ff16 shows the principle of the color signal noise reduction device shown in FIG. 6 indicates the phase vector of the color signal in the tape pattern during recording. 7゜8, 9.10.
11 shows the phase vector of the reproduced color signal input to the PS low-pass conversion reproduced color signal input, 8M2 output, DI-1 output, LPF4 output, and MIX5 output in Fig. 5. The operation of the conventional video recording/playback system will be explained below. First, at the same time as converting the color signal to low frequency during recording, the phase of the color signal of the field to be recorded on the adjacent track is adjusted by 90 degrees in 1].
It records data while rotating in the opposite direction (6). Approximately 629KH whose phase rotates by 90 degrees every day during playback.
The low frequency conversion reproduced color signal (large arrow) of z is 9 for every 1]-1.
The crosstalk component (small arrow) from the adjacent track whose phase is rotated in the opposite direction by 0° is included and input to F3M2 (7). On the other hand, to nM2, a continuous wave 12 of about 4.2 HIIz whose phase is rotated by 90° in the same direction as the low-pass conversion reproduced color signal every 11-1 is input, and a color of about 3.58 Htlz whose phase has been restored is input. A signal is output (8). F
The output signal of 3M2 is delayed by one day by I)Ll and f9)
, F3M3. On the other hand, EIM3 has F3M2
The same continuous wave 12 of 4.2HIIz as that inputted to is inputted. When the output of 11M3 is passed through l P F 4,
It is possible to extract eight low-pass converted signals that have the same 47 phases as the low-pass converted reproduced color signal, are rotated by 90 degrees every 111, and are extended by 1118 (10). M r X 5 t-
, Toki 111i1! The extended low frequency converted color signal and the low frequency converted reproduced color signal without 8 extension are mixed to obtain a low frequency converted color signal from which the R&Stoke component (small arrow) has been removed (11).

Problems to be Solved by the Defense However, since the above-mentioned 4M component converts the frequency twice using a balanced modulator, the S/N ratio deteriorates significantly. In addition, in this example, the balanced modulator outputs not only the required difference frequency signal, but also the sum frequency signal and other signals with unnecessary frequencies, so the balanced modulator is passed through a steep low-pass filter. (If not, the frequency band of the color signal will become narrower, and the A☆ phase characteristics will also deteriorate. Also, in order to overcome the phase operation with a balanced modulator, the phase is rotated by 90' for every 111, and the frequency band of the color signal becomes narrower. There is a problem that if you make a reverse rotation 4.2 Htlz, you will not be able to use GJ.
The purpose of this invention is to solve the problem mentioned above, and by delaying the low frequency conversion color (II) without performing frequency conversion and phase restoration, the deterioration of the S/N ratio is small. To provide a video recording and reproducing device having a noise reduction B1 with a relatively simple circuit configuration, which allows a wide frequency band because a steep low-pass filter is not required, and does not deteriorate phase characteristics.

Step 1 to Solve the Problems In order to solve the above problems, the video recording/reproducing apparatus of the present invention delays the low frequency conversion color signal and inverts the color signal for each field. and a device for mixing the delayed signal and the inverted signal into the low frequency converted color signal.

Effect of the Invention With the above-described configuration, the present invention makes it possible to reduce the noise contained in the low-frequency converted color signal without frequency conversion and phase restoration, and as a result, compared to the conventional example, it is possible to reduce the noise contained in the low-frequency conversion color signal. Low-frequency conversion color 4g with excellent S/N ratio, frequency characteristics, and phase characteristics, and reduced noise.
You will get @.

Embodiment Below, a video recording and reproducing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a simplified block diagram of a color noise reduction device in a PS color signal processing method according to a first embodiment of the present invention. In Fig. 1, 13 indicates the low frequency conversion color signal by 1 fl
A delay B1 (hereinafter referred to as 1 (1+90°Dl)) delays by +90°, 14 is an inverter (hereinafter referred to as INV) that inverts the signal by 180°, 15 is a switch that is switched for each field, and 16 is a low-pass filter.

FIG. 2 shows the principle of this embodiment shown in FIG. In FIG. 2, 6 is the a-phase vector of the color signal in the tape pattern during recording, similar to the conventional example shown in FIG. 101. 102.111゜112.12
1. 122 is the PS low-pass conversion reproduction color signal input shown in FIG.
1) 1+90°DI-13 output, switch 15 output, M
The phase vector of the color signal in the IX5 output is shown. However, 101. 111. 121. 131, the phase vector of the reproduced color signal rotates 90" clockwise every 111,
If the crosstalk components rotate around the same time, 102
．． 112. 122. 132 indicates a phase vector in the opposite case.

``About the video recording and reproducing device configured in this way, J
Below, the operation will be explained using FIGS. 1 and 2. First, during recording, as in the conventional example, the color signal is low-frequency converted, and at the same time, the phase of the color signal of the field recorded on the adjacent track is recorded while rotating in opposite directions by 90 degrees every 1]-1. (6). During reproduction, the reproduced color signals 101 and 102 (large arrows) whose phase is rotated in the opposite direction and which include losstalk components (small arrows) are 11-1.
+90″'r) 11-1-1-90° by I-13
Delay (111.112). The phase of the reproduced color signal is 11
In a field where the blade rotates clockwise every -1, set switch 15 to the a side in Fig. 1, and set I N + 90"1')1
The output of 13 passes through L P F 16 as it is (121
), is mixed with a non-delayed signal at MIX5, and crosstalk components (small arrows) are removed (131). In a field where the (M phase) of the reproduced color signal rotates around h every 111, the switch 15 is set to the b side in Fig. 1, and the 11-190
°r) 11317) The output is INV14'C- inverted (
122), passes through the LPF 16, is mixed with a signal that is not delayed by MIX 5, and crosstalk components (small arrows) are removed (132). In addition, the low-pass filter 16 is I H+9
This is for clock removal when a CCO is used for 0"11113, and steep characteristics are not required.

As described above, according to the present embodiment, there is provided a delay device for delaying the low-frequency conversion color signal, an inverting device for inverting the delayed signal for each field, and a delay device for delaying the low-frequency conversion color signal. By providing a noise reduction device having a signal mixing device and a noise reduction device having a signal mixing device, it is possible to reduce the color noise of the PSS color signal prescription method video recording/reproduction WA@ while keeping the low line conversion signal.

In the first embodiment, 13 is a delay device that delays the signal by IH + 90 degrees, but it may also be a delay device that delays the signal by IH-90°.However, in this case, when reproducing a field whose phase is clockwise, When reproducing a field whose phase is around h, the switch 15 must be set to the b side in FIG.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a simplified block diagram of a color noise reduction device in a PT color signal processing method according to a second embodiment of the present invention. In FIG. 3, 17 is a delay device that delays the low frequency conversion color signal by one day, and 14, 15, and 16 are the same as those in the first embodiment shown in FIG. FIG. 4 shows the principle of the second embodiment shown in FIG. In FIG. 4, reference numeral 18 indicates the phase vector of the color signal in the i-p pattern during recording. 201. 202.211. 2
12.221°222.231. 232 is P in Figure 3
The phase vector of the reproduced color signal at the I low-pass conversion reproduced color signal input, IHI') 117 output, switch 15 output, and MIX5 output is shown. However, 201. 211. 221
．． 231 is a field in which the color signal phase is inverted every 1]], 202°212, 222. 232 indicates the color signal phase of the non-inverted field.

The operation of the video recording and reproducing apparatus configured as described above will be explained below with reference to FIGS. 3 and 4. First, during recording, one of the two fields to be recorded on the adjacent track is recorded with the phase of the color signal inverted every 11-1, and the other is recorded with the color signal (of No. f1 (O phase remains as it is). Record it (18). At 11 o'clock again, ri [one color Oi month 201, 202 (large arrow) containing one stroke component (small arrow) is extended to 111i!! with if!M device 17. (211.
212). The switch 15 is again 1 - the phase of the color signal is 111
When re-inverting the field that is not inverted every time, it is set to the C side in Fig. 3, and the output of the delay device 17 passes through the LPF 16 as it is (221), is mixed with the signal that is not delayed in the MIX 5, and the crosstalk component ( small arrow) is removed (231)
. When reproducing a field in which the phase of the first color signal is inverted to 1110, set it to the d side in figure W43, and the output of the delay device 17 is inverted by 180 degrees at INV14 (222), and the L
It passes through P F 16 and is mixed with the undelayed signal at MIX 5, and the crosstalk component (small arrow) is removed (2
32).

As described above, according to this embodiment, P
Video recording and playback using the I color signal processing method can reduce color noise in the stomach.

Effects of the Invention According to the present invention, as in the Song Dynasty, the S/N ratio by the balanced modulator is
It has excellent features such as no ratio deterioration, no need for a steep n-pass filter, a wide frequency band, no abrupt termination of phase characteristics, and low-frequency conversion color noise reduction with a relatively simple circuit configuration. You can get benefits.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of the present invention;
The figure shows the principle of the first embodiment of the invention shown in Fig. 1, and Fig. 3 shows the second embodiment of the invention (block diagram). 5th principle diagram of the second embodiment of
The figure is a block diagram of a conventional video recording and reproducing apparatus, and FIG. 6 is a principle diagram of a conventional video recording and reproducing apparatus. 5... Mixed loading, 13... 111+90" slow reddening device, 14... 180° reverse charging, 15... Switch that changes for each field, 16... 0-bass filter,
17...1 day delay device

Claims (1)

[Claims] 1. A noise reduction device having a delay device that delays a low-band converted color signal, an inverter that inverts the delayed signal for each field, and a device that mixes the delayed signal and the inverted signal into the low-band converted color signal. A video recording and playback device equipped with