JPH0641429Y2 - Y / C separation circuit compatible with separated Y and C signal inputs - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention provides a high-quality digital television receiver of a type in which a luminance signal and a color signal are separated in addition to a normal NTSC composite video signal. The present invention relates to a receiver capable of inputting and processing a system video signal, particularly a Y / C separation circuit.

[Conventional technology]

In recent years, as a high-quality digital television receiver, a receiver has been developed that is equipped with a motion adaptive Y / C separation circuit by digital technology processing and converts interlaced scanning to progressive scanning to obtain high-quality images. Has been done. By the way, it has become common for television receivers to have a function of receiving not only broadcasting but also video signals from other media so as to make advanced use thereof. In particular, high image quality digital television receivers are required to have multiple functions in order to positively utilize their high image quality.

[Problems to be solved by the invention]

However, at present, in high-quality digital television receivers, like the so-called S-VHS signal of VTR,
It is not known that a video signal in a format in which a luminance signal and a chrominance signal are separated is input and processed. When a video signal processing circuit of this type is incorporated in a high quality digital television receiver, it is necessary to share the circuits so that the number of required parts is reduced as much as possible.

In view of the above circumstances, the purpose of the present invention is to perform the Y / C separation stage,
It is an object of the present invention to provide a Y / C separation circuit that incorporates a video signal processing circuit in which a luminance signal and a chrominance signal are separated.

[Means for solving problems]

The Y / C separation circuit of the present invention comprises a motion adaptive Y / C separation unit and its pre-stage unit. In addition to an NTSC composite video signal (NTSC signal) input, a luminance signal (Y ₀ signal) / color signal ( (C ₀ signal) is a part of the circuit is shared for separate system video signal input in a separate format.

The front part uses NTS as a transmission path to the motion adaptive Y / C separation part.
The signal after the changeover switch of the first path, the second path for A / D converting the C ₀ signal, the second path for A / D converting the C signal and the Y ₀ signal, and the signal after the changeover switch of the first path are input and synchronized. It has a synchronization generation circuit that generates signals and timing pulses, and the input to the APC circuit in the synchronization generation circuit is C
_The signal can be switched to ₀ .

The motion adaptive Y / C separation unit is provided with a comb filter that uses two 1-line memories and 1-field memory, separates and outputs the C signal in accordance with the motion, and outputs the C signal from the NTSC signal. A circuit that subtracts and outputs a Y signal, and when the video signal of another system is input, the subtraction is stopped and the Y ₀ signal input through the first path / the second path is input.
Equipped with a switching means that directly outputs the C ₀ signal to the output terminal, and supports various switches of the front stage, motion adaptive Y / C separation part for each input of NTSC signal / video signal of another system Then, it works together.

[Action]

Although details will be described in the embodiments, for the signals of the Y ₀ signal / C ₀ signal separation format, the Y ₀ signal shares the main part of the A / D converter and the synchronization generation circuit with the NTSC signal and the C ₀ signal. Only the ₀ signal is separately guided to the motion adaptive Y / C separation unit via the A / D converter.
When the C ₀ signal is input, the f _sc signal (color subcarrier signal) of the synchronization generating circuit is extracted from the C ₀ signal by the changeover switch. In the motion adaptive Y / C separation unit, Y / C
Stop the operation of the circuits involved in the separation.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the entire circuit configuration, and FIG. 2 is a block diagram of the main part of the motion adaptive Y / C separation unit. The circuit of the present invention comprises a front stage section 100 to which the Y ₀ signal / C ₀ signal of the NTSC signal and the video signal of a different system is inputted, and a motion adaptive Y / C separation section 200. FIG. 1 is an overall configuration diagram. In particular, the front part 100 is shown in detail.

In Fig. 1, the NTSC composite video signal (hereinafter referred to as NTSC signal) is at terminal 1, and the Y ₀ signal of the S-VHS signal is at terminals 2 and C.
_{The 0} signal is input to the terminal 3. The S-VHS control signal for switching to S-VHS signal input is input to terminal 4. The S-VHS control signal controls all switches in the circuit of the present invention. In the following figures, the switches are shown to show the contact state when the S-VHS control signal is not applied.

When the S-VHS control signal is not input, that is, when the NTSC signal is input, the NTSC signal is input to the motion adaptive Y / C separation unit 200 via the A / D converter 5 through the first path 101. At the same time, it is input to the synchronization generation circuit 11 through the path 102. The synchronization generating circuit 11 has a well-known circuit configuration because the changeover switch 10B is at the position shown in the figure. a subcarrier f _sc occurs, the clock generation circuit 9 generates HD, VD, 4f _sc, the various clocks required for the digital signal processing such as 8f _sc.

Now, when the S-VHS signal is input, the S-VHS control signal is input, so the changeover switches 10A and 10B are switched, and the Y ₀ signal is input to the first path 101 and the synchronization generation circuit via the path 102. It is also entered in 11. At this time, the changeover switch 10B is changed over, the transmission to the APC circuit 8 is cut off, and only the sync separation circuit 6 is passed through. The C ₀ signal is a motion adaptive Y / C
As shown in the drawing, the signal is transmitted to the separation unit 200 through the A / D converter 12 and the 1-line delay circuit 13 through the second path 103 regardless of the switching of the changeover switches 10A and 10B. On the other hand, when the changeover switch 10B is changed over, it becomes an input to the band pass filter 7 of the synchronization generating circuit 11 and the APC circuit 8, and C
_The color subcarrier synchronized with the ₀ signal and clocks such as 4f _sc and 8f _sc of the clock generation circuit are generated. Since the 1-line delay circuit 13 is a circuit that uses two 1-line memories for a moving image as a separation method of a motion adaptive Y / C separation unit 200 described later, the Y ₀ signal and the C ₀ signal are It is to match the phase of.

Next, the motion adaptive Y / C separation unit 200 will be described. Since it is a motion adaptive type, as is well known, a motion signal is created from the NTSC signal by the motion detection circuit 21, and the separation method is changed depending on whether this is a still image or a moving image. Second
Although the figure is a block diagram of the motion adaptive Y / C separation unit 200, the main part 20 excluding the motion detection circuit 21 is illustrated for the sake of easy understanding.

The Y / C separation in Fig. 2 is the C separation for moving images.
This is performed by a 3-tap comb filter that uses the individual 1-line memories 22A and 22B, the adder circuit 24A and the coefficient adder circuit 24B, and in the case of a still image, C separation is performed using the 1-field memory 23, and both are used as motion signals. Select switch 10
Switch with E. 26 and 28 are bandpass filters that pass the color subcarrier.

Now, when the S-VHS signal is input, the Y ₀ signal, C ₀ is passed through the first path 101 and the second path 103 in the front stage section 100.
The signal is input and the S-VHS control signal is input. By the S-VHS control signal, the changeover switch 10C is changed over through the C ₀ signal, the switch 10D is turned off, and the Y ₀ signal appears at the output terminal 30 without being subtracted by the subtraction circuit 27. The change-over switch 10E for changing over between a moving image and a still image is at the position Q in the figure when no motion signal is inputted as a control input. When the S-VHS control signal is input, the switch 10F is turned off and the motion signal is cut off, so that the C ₀ signal passes through the band pass filter 28 and appears at the output terminal 31.

Y (Y ₀ ) signal output separately from terminals 30 and 31 C
The (C ₀ ) signal is transmitted to the digital signal processing circuit in the next stage, but if it is output via the D / A converters 32 and 33, respectively, as shown in FIG. Signal
As it is, it can be used for S-VHS VTR recording.

[Effect of device]

As described above, the present invention has a signal format in which a luminance signal and a chrominance signal are separated in addition to the standard NTSC signal defined in television broadcasting, for example, an S-VHS type VTR.
It is possible to receive a signal such as the above and share a part of the Y / C separation circuit for the NTSC signal and transmit it as a Y signal / C signal to the digital signal processing circuit in the next stage. This sharing eliminates the need to provide separate A / D converters for S-VHS signals, Y signals, and C signals.
Two converters will suffice. Further, the synchronization generating circuit can be shared by the signals of both systems. In this way, it is possible to support another system video signal in a format in which the luminance signal and the color signal are separated with the minimum number of parts.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of an embodiment of the present invention, and FIG. 2 is a circuit block diagram of a main part of a motion adaptive Y / C separation unit. 100 ... Front stage, 5, 12 ... A / D converter, 6 ... Sync separation circuit, 7 ... Band pass filter, 8 ... APC circuit, 9 ... Clock generation circuit, 11 ... Synchronization generation circuit , 10A, 10B ... Changeover switch, 13 ... 1 line delay circuit, 200 ... Motion adaptive Y / C separation unit, 22A, 22B ... 1 line memory, 23 ... 1 field memory, 24A ... Adder circuit , 24B …… Coefficient addition circuit, 25,27 …… Subtraction circuit, 26,28 …… Band pass filter, 10C, 10E …… Selection switch, 10D, 10F …… switch, 32,33 …… D / A converter .

Claims (2)

[Scope of utility model registration request] 1. A part of a circuit for another system video signal input of a format in which a luminance signal (Y ₀ signal) and a color signal (C ₀ signal) are separated in addition to an NTSC composite video signal (NTSC signal) input. It is a Y / C separation circuit that shares the same function and consists of a motion adaptive Y / C separation unit and its pre-stage, and the front stage is an NTS as a transmission path to the motion adaptive Y / C separation unit.
The signal after the changeover switch of the first path, the second path for A / D converting the C ₀ signal, the second path for A / D converting the C signal and the Y ₀ signal, and the signal after the changeover switch of the first path are input and synchronized. It has a synchronization generation circuit that generates signals and timing pulses, and the input to the APC circuit in the synchronization generation circuit is C
_The motion adaptive Y / C separation unit is provided with a comb filter using two 1 line memories and 1 field memory,
C signal is separated according to the movement and output, and NTSC
A circuit for subtracting the C signal from the signal and outputting the Y signal, wherein when the separate system video signal is input, the subtraction is stopped, and the Y ₀ signal and the C ₀ signal input via the first and second paths are input. The switch is equipped with a switch that directly outputs the signal to the output terminal.
A Y / C separation circuit that operates in conjunction with each input of signal and video signal of another system. 2. A utility model registration claim characterized in that a terminal for outputting the output of the motion-adaptive LAY / C separation section in the first aspect is output through a D / A converter. Item 1 Y / C separation circuit.