JPH0310575A - Recording and reproducing device - Google Patents

Abstract

PURPOSE:To reduce cost and the number of components by using a delay circuit used for a color noise reduction circuit of a reproducing system so as to select it by a switch and using the delay circuit of the 2nd stag of a 3-line comb-line filter of a recording system in common. CONSTITUTION:An output of a 1H delay circuit 12 at recording is given to a noninverting output of a subtractor 26 via an LPF 14, a recording terminal of a switch SW and an input of other BPF 16. Three inputs of comb-line filter arithmetic section 24 respond to each output of BPFs 22, 16 and an output of a time matching delay compensation circuit 34 and its outputs is a color signal output. On the other hand, a reproduced color reproduced and separated from a video tape is subjected to frequency conversion and given to a CNR IC 30 and the 1H delay circuit input connection terminal 30a is connected to other terminal of the switch SW. An input terminal of a CNR 1H delay circuit 32 is connected to an output terminal of the switch SW and an output of the CNR IC 30 is used as a color signal output.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a video signal recording and reproducing device, and particularly relates to an improvement of a recording and reproducing device that uses a logical comb filter in the recording system and has a color noise reduction circuit in the reproducing system. .

[Prior Art] Some VTRs, which are recording and reproducing devices that record video signals, use a 3-line logical comb filter in the recording system to separate luminance signals and color signals, and in the reproducing system. Some have a color noise reduction circuit.

FIG. 2 is a block diagram showing the main parts of the recording system and reproduction system of such a conventional VTR. The recording system's logical comb filter IO converts the input composite video signal into IH (
1 horizontal period), and a CCD delay circuit 18 that further delays the output by IH.
A comb filter operation unit 24 that separates the color signal C using the non-delayed input composite signal, its IHH extended signal, and the 2H delayed delay bone, and a subtracter 26 that subtracts the color signal C from the IHH extended signal and sends out a luminance signal Y. have. Some devices use a glass delay line instead of the CCD delay circuit 18.

On the other hand, the color noise reduction circuit (CNR) 28 of the reproduction system is C
IH delay circuit 3 consisting of NR IC30 and glass delay line
It has 2.

[Problems to be Solved by the Invention] In such a conventional recording and reproducing device, in addition to one delay circuit made of a relatively inexpensive glass delay line as a delay element, two relatively expensive CCD delay circuits or a glass delay line are used. This requires two delay circuits consisting of a CCD delay circuit and one CCD delay circuit, making a total of three delay circuits, resulting in a problem that the overall circuit configuration is complicated and the cost is high.

Therefore, an object of the present invention is to reduce the number of relatively expensive CCD delay circuits to reduce costs, and to provide a recording/reproducing apparatus having a simple circuit configuration.

[Means for Solving the Problems] In order to achieve the above object, the present invention adopts a configuration in which an inexpensive glass delay element for CNR is commonly used as a subsequent delay element in a logical comb filter.

That is, according to the present invention, there are three lines including a first delay means for delaying an input video signal by an integral number of one horizontal period, and a second delay means for further delaying the output signal of the first delay means by an integral number of one horizontal period. A recording/reproducing apparatus having a type Y/C separation filter in the recording system and having a color noise reduction circuit using line correlation of reproduced color signals in the reproduction system and equipped with a third delay means, The second and third delay means are a single delay means, and the output signal of the first delay means is given as an input to the single delay means during recording, and the signal of a predetermined portion of the color noise reduction circuit is given during playback. A recording/reproducing device is provided which is characterized by being provided with a switching means.

[Function] In the recording/reproducing apparatus of the present invention, during recording, the switching means applies the output signal of the first delay means to the shared single delay means, and after further delaying, the output signal is applied to the comb filter operation section, so that the color signal is Made. On the other hand, during reproduction, the switching means connects the input terminal of the shared single delay means to a predetermined terminal of the CNR IC, thereby performing a color noise reduction effect.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the main parts of a recording system and a reproducing system of a recording/reproducing apparatus as an embodiment of the present invention.

In this embodiment, the delay circuit 32 made of a glass delay line used in the conventional CNR circuit of the reproduction system is also used as the second stage delay circuit of the recording system.

That is, the input signal of the delay circuit 32 is switched by a switch SW, which is a switching means that is switched by a predetermined control signal during recording and reproduction.

In the figure, the same parts as in FIG. 2 showing the conventional example are designated by the same numbers.

Input composite signal is IH delay circuit 12 and BPF 22
is given to. The output of the IH delay circuit 12 is LPF1
4 to the output of the subtracter 26, the recording side terminal of the switch SW, and the input of the other B P F 16. The three inputs of the comb filter calculation unit 24 are BPF 22.
16 outputs and a delay compensation circuit 34 for time adjustment, which will be described later.
In response to the output of the subtractor 26, the output becomes a color signal output and is also applied to the subtracter 26. The output of the subtracter 25 is a luminance signal output. These luminance signal outputs and chrominance signal outputs are sent to the head via a recording amplifier (not shown) after passing through a known processing circuit and are recorded on a videotape.

On the other hand, the reproduced color signal reproduced and separated from the video tape is frequency-converted and then applied to the CNR IC 30, whose IH delay circuit input connection terminal 30a is connected to the switch S.
Connected to other terminals of W.

The input terminal of the IH delay circuit 32 for CNR is connected to the output terminal of the switch SW, and the output terminal is connected to the IH delay circuit 32 for CNR.
It is applied to the H delay circuit output connection terminal 30b and the input of the time adjustment delay compensation circuit 34. The output of the CNR IC 30 is used as a color signal output.

In the circuit configuration shown in Figure 1, unlike the conventional example shown in Figure 2, the BPF1
6, but the output of the LPF 14 at the preceding stage is provided to the IH delay circuit 32 via the switch SW. This is because the IH delay circuit 32 is made of a glass delay circuit and therefore has BPF characteristics.

In the above embodiment, the delay circuit 3 is arranged after the switch SW.
Although 2 is a glass delay line, the present invention is not limited to this, and a CCD delay circuit may also be used. In this case, the delay compensation circuit 34 for time adjustment becomes unnecessary, but instead, the conventional B
It is necessary to insert a BPF similar to PF16. Also, each delay circuit performs an IH delay, but this is compatible with the NTSC system, and the PAL system requires a 2H delay, and depending on the system, a delay of an integral multiple of IH is required. It can be a circuit.

As is clear from the detailed explanation above, in the recording and reproducing apparatus of the present invention, the delay circuit used in the color noise reduction circuit of the reproduction system is switched by a switch, and the delay circuit used in the second stage of the three-line comb filter of the recording system is switched. Since it is used for both purposes, it is possible to reduce the number of parts and reduce costs.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the main parts of the recording system and playback system of an embodiment of the recording/playback apparatus of the present invention, and FIG. 2 is a block diagram showing the main parts of the recording system and playback system of a conventional recording/playback apparatus. be. 12, 32...Delay circuit, 14...LPF,
16.22... BPF, 24... Comb filter calculation unit, 26... Subtractor, 30... I for CNR
C, SW...Switch. Inventor: Mikiju Ishii

Claims (1)

[Claims] (1) A 3-line Y/R having a first delay means for delaying an input video signal by an integral number of one horizontal period, and a second delay means for further delaying the output signal of the first delay means by an integral number of one horizontal period. In the recording and reproducing apparatus, the recording system includes a C separation filter, and the reproducing system includes a color noise reduction circuit that utilizes line correlation of reproduced color signals and is equipped with a third delay means. The third delay means is a single delay means, and a switching means is provided for supplying the output signal of the first delay means as input to the single delay means during recording and the signal of a predetermined portion of the color noise reduction circuit during reproduction. A recording/reproducing device characterized in that: