JP2823308B2 - MUSE / NTSC down converter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-definition MUSE / NTSC down converter.

2. Description of the Related Art In recent years, the muse-type bi-vision reception system is in a state where it can be received by broadcasting using satellite broadcasting.
Accordingly, there has been a strong demand that muse broadcasts have been received by conventional receivers. What makes this possible is the MUSE / NTSC downconverter.

Hereinafter, a conventional MUSE / NTSC down converter will be described with reference to the block diagram of FIG.

First, from the input BS-IF signal, a BSIF demodulator (BS tuner)
The MUSE signal demodulated in is input from terminal A, and A / D
Supplied to a de-emphasis circuit 2 and a synchronization detection circuit 4 which constitute a first signal processing circuit α via a converter 1;
Here, de-emphasis and synchronization detection are performed simultaneously.
In the MUSE system, since nonlinear emphasis processing is performed on the transmission side, it is necessary to configure a filter having an inverse characteristic on the reception side. Also, since the MUSE signal uses positive polarity synchronization,
To keep the clock phase of A / D converter 1 correct, P
LL operation is performed. The image data processed in this manner needs to be converted into an aspect ratio and a scanning line.

The MUSE signal is originally intended to reproduce video on a 16: 9 screen. To play this on a 4: 3 NTSC screen, extract only the data at the center of the screen of 16: 9 video information (zoom-up mode) and shrink the screen and insert it into the 4: 3 screen There is a method (wide mode).

First, the zoom-up mode will be described. The memory 3 is used to extract data at the center of the screen, and the write clock and the read clock are controlled by the memory controller 5 that inputs a synchronization signal from the synchronization detection circuit 4 so that the converted image maintains the correct roundness. Is done. The memory 3 and the memory controller 5 constitute a second signal processing circuit β.

The output signal of the memory 3 is divided into a luminance signal and a chrominance signal by a signal separation circuit 6. In the luminance signal, in a moving image mode, a gap between sample points is interpolated, and reduction of vertical aliasing by a scanning line halving process is reduced. Therefore, a vertical filter 7 is used. Since the color difference signal is sequentially transmitted in a time-division manner such as (RY) and (BY) with the luminance signal (Y) for each line, it is equivalent to synchronization, time extension, and luminance. The interpolation processing is performed by the time expansion circuit 8 and the vertical filter 9. The signal separation circuit 6, the vertical filter 7, the time expansion circuit 8, and the vertical filter 9 constitute a third signal processing circuit γ.

On the other hand, in the wide mode, the processing up to the third signal processing circuit γ is the same as that in the zoom mode, but all the 16: 9 image information of the MUSE signal is written in the write memory 3. Since a vertically long screen can be obtained by time-compressing and reading it out, it is vertically compressed (2/3) and blanking periods are provided at the top and bottom of the screen. The vertical compression circuit 10, vertical filter 12, and memory 11 perform this operation.

The luminance signal (Y) and the color difference signal (R
Each signal of -Y) and (BY) is converted into an analog signal by the D / A converter 13, and is converted into an NTSC composite video signal by the NTSC encoder 14.

By the way, except when receiving the MUSE signal, the BS tuner receives the NTSC signal. Therefore, the de-emphasized composite video signal is supplied from the external input terminal C of the MUSE / NTSC down converter, and is switched by the signal selection circuit 15 to the composite video signal processed by the MUSE / NTSC down converter. To supply.

However, in the above configuration, it is necessary to supply a de-emphasized composite video signal separately from the MUSE signal input at the time of receiving the NTSC signal, and the interconnection between the devices becomes complicated. was there.

The present invention has been made to solve the above problem, and has a MUSE signal,
It is an object of the present invention to provide a MUSE / NTSC down converter that can easily interconnect devices even when receiving both NTSC signals.

Means for Solving the Problems In order to solve the above problems, the MUSE / NTSC down converter of the present invention uses an A / D in which a MUSE signal is input from an input terminal.
A converter, a scanning speed conversion circuit for converting the output of the A / D converter to a scanning speed, a signal separation circuit for separating the output of the scanning speed conversion circuit into a luminance signal and a color difference signal, and pixel interpolation for the separated luminance signal. A time conversion and pixel interpolation process for the color signal, and a system conversion circuit for converting the MUSE signal into a luminance signal and a color difference signal of the NTSC system. A D / A converter for D / A conversion, an encoder for receiving the output of the D / A converter to form a first NTSC composite video signal, and an NTSC composite video signal from the input terminal. A de-emphasis circuit for performing and outputting, and an NTSC composite video signal which is an output of the encoder when receiving a MUSE signal, and an output of the de-emphasis circuit when receiving an NTSC signal. And a signal selection circuit for selecting and outputting the NTSC composite video signal.

Further, a second invention provides a first D / A converter for D / A converting the output of the system conversion circuit, and an encoder which receives the output of the D / A converter and forms a first NTSC composite video signal. When the NTSC composite video signal is supplied from the input terminal to the A / D converter, the second D / D to which the de-emphasized NTSC composite video signal output from the scanning speed conversion circuit is input. A signal converter for selecting an NTSC composite video signal which is an output of the encoder when receiving an A converter and a MUSE signal, and selecting and outputting an NTSC composite video signal which is an output of the second D / A converter when receiving an NTSC signal. And a circuit.

Further, in the third invention, when the MUSE signal is received, the luminance signal and the color difference signal are selected, and when the NTSC signal is received, the NTSC composite video signal input from the input terminal is converted to the A / D signal.
A signal selection circuit for selecting and outputting a signal subjected to A / D conversion and de-emphasis by a converter; a D / A converter for D / A converting the signal selected by the signal selection circuit; And an encoder for encoding the output of the / A converter.

According to the configuration of the first aspect of the invention, when receiving an NTSC signal, the NTSC composite video signal input from the input terminal is de-emphasized by the de-emphasis circuit, output through the signal selection circuit, and received when the MUSE signal is received. The NTSC composite video signal processed and converted from the MUSE signal input from the input terminal is output through the signal selection circuit.

Further, according to the configuration of the second invention, when receiving the NTSC signal, the NTSC composite video signal input from the input terminal is A / A
D-converted, de-emphasized, D / A-converted by a second D / A converter, output via a signal selection circuit, and when a MUSE signal is received, it is processed and converted from a MUSE signal input from an input terminal. The output NTSC composite video signal is output via the signal selection circuit.

Further, according to the configuration of the third aspect of the invention, the signal selection circuit selects the NTSC system luminance signal and color difference signal when receiving the MUSE signal, and converts the NTSC composite video signal input from the input terminal into the A / D signal when receiving the NTSC signal. The converted and de-emphasized signal is selected, the signal selected by the signal selection circuit is D / A converted by a D / A converter, and output as an NTSC composite video signal by an encoder.

Embodiment An embodiment of the MUSE / NTSC down converter of the present invention will be described below with reference to the drawings. The same components as those of the conventional example shown in FIG. 4 are denoted by the same reference numerals, and description thereof is omitted.

FIG. 1 is a block diagram of a MUSE / NTSC down converter showing one embodiment of the first invention.

The MUSE / NTSC downconverter shown in FIG. 1 has an input terminal A connected to a circuit for forming an NTSC composite video signal (hereinafter referred to as a first NTSC composite video signal a) from the MUSE signal shown in FIG. The NTSC composite video signal demodulated from the BS-IF signal is input and de-emphasis is performed.
A second de-emphasis circuit 16 for outputting the NTSC composite video signal b, and selecting the first NTSC composite video signal a when receiving the MUSE signal and selecting the second NTSC composite video signal b when receiving the NTSC signal. Signal selection circuit to output to terminal B
15 'is newly added.

With the above configuration, when receiving the NTSC signal in the BS tuner, the NTSC composite video signal demodulated from the BS-IF signal in the BS tuner is input to the input terminal A, and the second de-emphasis circuit 16 performs de-emphasis, The signal is output to the terminal B via the signal selection circuit 15 '. When a BS tuner receives a MUSE signal, the input terminal A
MUSE demodulated from the BS-IF signal in the BS tuner
The signal is input, processed and converted into a first NTSC composite video signal a in a circuit below the conventional A / D converter 1, and output to a terminal B via a signal selection circuit 15 '.

By adding the function of supplying the second NTSC composite video signal in this manner, the interconnection between the devices can be simplified even when receiving both the MUSE signal and the NTSC signal.

Next, an embodiment of the second invention will be described with reference to the block diagram of the MUSE / NTSC down converter shown in FIG.

The MUSE / NTSC down-converter shown in FIG. 2 receives the digital output signal of the de-emphasis circuit 2 instead of the second de-emphasis circuit 16 of the first invention, converts it into an analog signal, and When the NTSC composite video signal is input, the de-emphasized second NTSC
A second D / A converter 17 for forming a composite video signal b is provided.

With the above configuration, the first NTSC composite video signal a is selected and output by the signal selection circuit 15 'when receiving the MUSE signal, and the second NTSC composite video signal output from the second D / A converter 17 when receiving the NTSC signal. The video signal b is selected and output by the signal selection circuit 15 '.

As described above, according to the second aspect of the present invention, it is possible to simplify the interconnection between devices even when receiving both MUSE and NTSC signals.

An embodiment of the third invention will be described with reference to the configuration diagram of the MUSE / NTSC downconverter shown in FIG.

The MUSE / NTSC down-converter shown in FIG. 3 is configured such that the second D / A converter 17 of the second invention can be shared with the D / A converter 13, and instead of the signal selection circuit 15 ', the NTSC down converter is used. Selects the digital output signal of the de-emphasis circuit 2 when receiving a signal, and the vertical filter when receiving a MUSE signal.
7, 9 or the luminance signal (Y) and color difference signals (RY) and (BY) processed by the vertical compression circuit 10 are selected and D /
A signal selection circuit 18 for outputting to the A converter 13 is provided.

With the above configuration, the MUSE / NTSC
Is selected, the D / A converter 13
An NTSC composite video signal is output by the NTSC encoder 14 via the.

As described above, according to the third invention, it is possible to simplify the interconnection between devices even when receiving both MUSE and NTSC signals,
Further, it can be realized by a configuration equivalent to the conventional example.

Effects of the Invention As described above, according to the first to third inventions, the MUSE / NTSC
A new NTSC composite video signal de-emphasis in the converter and the addition of a function to obtain a second NTSC composite video signal make it easy to interconnect devices even when receiving both MUSE and NTSC signals. Can be
Further, according to the third invention, the second NTSC composite video signal can be obtained with a configuration equivalent to the configuration of the conventional example.

[Brief description of the drawings]

FIG. 1 is a block diagram of a MUSE / NTSC converter showing one embodiment of the first invention, FIG. 2 is a block diagram of a MUSE / NTSC converter showing one embodiment of the second invention, and FIG. FIG. 4 is a block diagram of a conventional MUSE / NTSC converter showing an embodiment of the invention of FIG. 1 ... A / D converter, 2,16 ... Deemphasis path,
3 Memory 4 Synchronization detection circuit 5 Memory controller 6 Signal separation circuit 7 Vertical filter for luminance signal 8 Time extension circuit for color signal 9 Color signal Vertical filter, 10 vertical compression circuit, 11 memory
12 …… Vertical filter, 13,17 …… D / A converter, 14 ……
NTSC encoder, 15, 15 ', 18 ... signal selection circuit, A ...
MUSE / NTSC composite video signal input terminal, B: NTSC composite video signal output terminal, a: first NTSC composite video signal,
b: The second NTSC composite video signal.

Claims (3)

(57) [Claims] An A / D converter to which a MUSE signal is input from an input terminal, a scanning speed conversion circuit for converting an output of the A / D converter to a scanning speed, and an output of the scanning speed conversion circuit for converting a luminance signal and a color difference signal. A signal separation circuit for separation, a pixel interpolation process is performed for the separated luminance signal, a time expansion and a pixel interpolation process are performed for the color signal, and the MUSE signal is processed.
A format conversion circuit that converts NTSC format luminance signals and color difference signals, a D / A converter that converts the output of this format conversion circuit into a digital signal, and an NTSC composite video signal that is output from the D / A converter. Having an encoder and
A de-emphasis circuit that receives an NTSC composite video signal from the input terminal, performs de-emphasis, and outputs
A signal selection circuit for selecting an NTSC composite video signal output from the encoder when receiving a MUSE signal and selecting and outputting an NTSC composite video signal output from the de-emphasis circuit when receiving an NTSC signal. To be
MUSE / NTSC down converter. 2. An A / D receiving a MUSE signal from an input terminal.
A converter, a scanning speed conversion circuit for converting the output of the A / D converter to a scanning speed, a signal separation circuit for separating the output of the scanning speed conversion circuit into a luminance signal and a color difference signal, and a pixel signal for the separated luminance signal. An interpolation process is performed, a time conversion and a pixel interpolation process are performed on the color signal, a MUSE signal is converted into an NTSC brightness signal and a color difference signal, and a D / A conversion is performed on the output of the format conversion circuit. 1 D / A converter, and an encoder which receives the output of the D / A converter as an input to form an NTSC composite video signal.
A second D / A converter to which a de-emphasized NTSC composite video signal output from the scanning speed conversion circuit when supplied to the D converter is input, and an NTSC output from the encoder when receiving a MUSE signal. A signal selecting circuit for selecting a composite video signal and selecting and outputting an NTSC composite video signal which is an output of the second D / A converter when receiving an NTSC signal.
C down converter. 3. An A / D receiving a MUSE signal from an input terminal.
A converter, a scanning speed conversion circuit for converting the output of the A / D converter to a scanning speed, a signal separation circuit for separating the output of the scanning speed conversion circuit into a luminance signal and a color difference signal, and pixel interpolation for the separated luminance signal. A time conversion and a pixel interpolation process for the color signal, and a system conversion circuit for converting the MUSE signal into a luminance signal and a color difference signal of the NTSC system, and upon receiving the MUSE signal, the luminance signal and the color difference signal are converted. Select and when receiving NTSC signal,
NTSC composite video signal input from the input terminal
A signal selection circuit for selecting and outputting a signal subjected to A / D conversion and de-emphasis by an A / D converter, a D / A converter for D / A conversion of a signal selected by the signal selection circuit, and a MUSE / NTSC downconverter equipped with an encoder that encodes the D / A converter output.