JPH05137162A - Muse decoder - Google Patents

Abstract

PURPOSE:To decrease a high speed operating part, and to stabilize an operation by executing time division multiplex of a color difference signal alternately by a selector at every one clock, and outputting it to an output part. CONSTITUTION:A selector 5 switches alternately color difference signals R-Y, B-Y sent from interpolation filters 1, 2 by a select signal SEL, and executes its time division multiplexing. A multiplexed color difference signal C is outputted from a time base converting circuit 4 together with a luminance signal Y. This luminance signal is applied to a matrix and a gamma correcting circuit 3, and the color difference signal C is applied to an interpolation filter 6. The filter 6 shifts successively the color difference signals R-Y, B-Y by synchronizing with a clock CLK in order to return them to the original signals. In this case the selector is switched and interpolated at a prescribed timing. As a result, the number of necessary bits decreases, the circuit 4 is constituted at a low cost, and also, since a time base conversion is executed by the luminance signal Y and the color difference signal C, the signal processing can be executed by the same clock. In such a way, an operation of an MUSE decoder can be stabilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a MUSE (Multip) used for receiving terminals for high-definition (high-definition television) broadcasting.
le Sub-Nyquist Sampling Encoding)
In particular, it relates to improvement of the color difference signal processing circuit in the MUSE decoder.

Hi-vision broadcasting has been developed as a next-generation television broadcasting, and scheduled experimental broadcasting by satellite broadcasting is being carried out. To transmit high definition signals,
A wide transmission band (about 5 times the current television broadcasting system) is required. Such a broadband signal is transmitted by one of the broadcasting satellites.
A technique for compressing the band of the transmission signal is required to transmit in the band of the channel. The MUSE transmission method is widely known as such a band compression method (Paper "Hi-Vision satellite transmission method-MUSE-", Television Society Magazine, Vol. 42, No. 5 (1988)).

The MUSE signal includes a color signal C and a luminance signal Y, and the MUSE decoder demodulates the luminance signal Y and the color difference signals RY and BY signals to obtain R, G and B signals.
A signal is generated. In this MUSE decoder, complication of the circuit due to the difference in signal clock rate becomes a problem.

[0004]

2. Description of the Related Art FIG. 6 shows a structure of an output section of a conventional MUSE decoder. In FIG. 6, the matrix & γ correction circuit 3 has a luminance signal Y (8
bit) is input. The color difference signal RY (10 bits) having a 16.2 MHz clock rate is converted to a 48.6 MHz clock rate by the interpolation filter 1, and 1
Color difference signal BY (10b with 6.2 MHz clock rate)
It) is also converted into a 48.6 MHz clock rate by the interpolation filter 2 and is respectively converted into the matrix & γ correction circuit 3
Entered in.

The matrix & γ correction circuit 3 generates R, G, B signals from the input luminance signal Y, color difference signal RY and color difference signal B-Y, and CRTs the R, G, B signals. The R, G, and B signals are output to the time axis conversion circuit 4 in 10 bits (30 bits in total) after γ correction based on the property of The clock rate of these R, G, B signals is 4
It is 8.6 MHz.

The time axis conversion circuit 4 receives the input 48.6M
The R, G, and B signals (30 bits) of Hz are subjected to 12/11 time axis conversion processing, expanded to 12/11 in the time axis direction, and output as R, G, and B signals of 44.55 MHz clock rate. These R, G, B signals are not shown in D / A.
It is converted into an analog signal through the converter and sent to the CRT monitor.

[0007]

In the prior art, RGB is used.
After performing the inverse matrix processing and the CRT-γ correction processing, the 12/11 time axis conversion was performed.
The number of signal bits required for time-axis conversion was 30 and many circuit blocks operated at a high speed with a 48.6 MHz clock. In such a situation, there has been a strong demand to reduce the high-speed operation part of the MUSE decoder as much as possible to stabilize the operation and to reduce the number of signal bits required for the 12/11 time base conversion.

An object of the present invention is to solve the above two problems and provide a low-cost MUSE decoder with stable operation.

[0009]

In order to solve the above problems, the present invention is constructed using the following principles. MUSE
Since the band of the color difference signal in the signal is about 8 MHz,
If the data is sampled with a clock having a frequency twice as high as that, that is, a clock having a frequency of 16 MHz or higher, the data is guaranteed. Therefore, it is possible to resample the color difference signal currently sampled at the 48.6 MHz clock at the 24.3 MHz clock and thin the data amount to half.

The present invention utilizes the above principle to reduce the data amount of a color difference signal by half and reduce the number of bits required for 12/11 time base conversion of the color difference signal. That is,
The present invention, as shown in FIG. 1, uses luminance signals (Y) and 2
In a MUSE decoder equipped with an output section for generating R, G, B signals from system color difference signals (RY, BY),
The color difference signals (R-Y, B-Y) are alternately time-division-multiplexed for each clock, and a selector (5) for outputting to the output unit is provided.

[0011]

In the present invention, as shown in FIG. 1 and FIG.
8.6 MHz clock rate RY color difference signal, BY
The color difference signal is input to the selector, and the select signal corresponding to the 24.3 MHz clock alternates every RY,
BY is selected and output. As a result, the RY color difference signal and the BY color difference signal are apparently 24.3 MH, respectively.
This means that the data is sampled again with the z clock, multiplexed, and converted into one data string (48.6 MHz clock rate, 10-bit signal).

By adding this circuit, the conventional 20
It is possible to reduce the color difference signal that required bits to 10 bits, and because the clock rate is the same as that of the luminance signal (48.6MHz clock rate, 8-bit signal), the 12/11 time axis following the latter stage Easy conversion circuit,
In addition, it is possible to configure at low cost.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 3 shows an embodiment of the present invention. In FIG. 3, the same parts as those in FIG. 6 (conventional example) are designated by the same reference numerals and described below.

3 is different from that of FIG. 6 in that the time axis conversion circuit 4 is placed in the preceding stage, and the matrix & γ correction circuit 3 is provided.
In the latter stage, the interpolation filter 1 and the interpolation filter 2
The selector 5 is interposed between the time axis conversion circuit 4 and the time axis conversion circuit 4, and the interpolation filter 6 is provided between the time axis conversion circuit 4 and the matrix & γ correction circuit 3.

In the above configuration, the selector 5 alternately switches the color difference signal R-Y and the color difference signal B-Y of 48.6 MHz sent from the interpolation filter 1 and the interpolation filter 2 by the select signal SEL to perform time division multiplexing. 10bi
The time-axis conversion circuit 4 converts the multiplexed color difference signal C of t
Output to. Therefore, the time axis conversion circuit 4 has a luminance signal Y.
8 bits of the multiplexed color difference signal C of 10 bits
At t, a signal of 48.6 MHz clock rate is input with a total of 18 bits. By the way, in this point, in the past, a total of 30
The bit signal is input to the time axis conversion circuit 4.

The time-axis conversion circuit 4 converts the input 8-bit luminance signal Y and 10-bit multiplexed color difference signal C into a 12/11 time-axis signal to obtain a 10-bit luminance signal Y and 22.275 at a 44.55 MHz clock rate.
A 10-bit multiplexed color difference signal C having an MHz clock rate is output. Luminance signal Y is matrix & γ
It is given to the correction circuit 3. The multiplexed color difference signal C is given to the interpolation filter 6.

The interpolation filter 6 outputs the color difference signal R-Y and the color difference signal B-Y having a clock rate of 22.275 MHz to four.
It is a circuit for returning to a signal of 5.55 MHz clock rate. Here, FIG. 4 shows a circuit configuration example of the interpolation filter 6. The interpolation filter 6 is composed of a D flip-flop 61, a D flip-flop 62, an addition element 63, a selector 64 and a selector 65, and is a multiplexed color difference signal C.
Are sequentially shifted in synchronism with the 44.55 MHz clock CLK, and at the timing shown in FIG.
Interpolation is performed by switching the selector 64 and the selector 65 based on EL.

As described above, since the color difference signal RY and the color difference signal BY are time-division multiplexed by the selector 5, the conventional RGB signal has been subjected to the 12/11 time base conversion process. Was 30 bits, but now it can be processed with 18 bits,
It is possible to inexpensively configure the one-time axis conversion circuit.

Further, since the 12/11 time axis conversion processing is performed with the luminance signal and the color difference signal, the signal processing circuit (RGB
Inverse matrix, CRT-γ correction) can be operated with a clock of 44.55 MHz, which contributes to stable operation of the MUSE decoder, reduction of power consumption, and cost reduction.

[0020]

As described above, according to the present invention, the MUS is constructed by providing the output section with the selector for time-division multiplexing the color difference signals (RY, BY) every clock.
The high-speed operation part of the E decoder can be reduced as much as possible to stabilize the operation, and the number of signal bits required for the 12/11 time axis conversion can be reduced. Can be provided.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a timing chart showing the operation of FIG.

FIG. 3 is a block diagram showing a configuration of a MUSE decoder output unit according to the present invention.

FIG. 4 is a circuit diagram showing a circuit configuration example of a color difference signal interpolation filter.

FIG. 5 is a timing chart of a color difference signal interpolation filter.

FIG. 6 is a block diagram showing a configuration of a conventional MUSE decoder output unit.

[Explanation of symbols]

1 ... Interpolation filter 2 ... Interpolation filter 3 ... Matrix & γ correction circuit 4 ... Time axis conversion circuit 5 ... Selector 6 ... Interpolation filter 61 ... D flip-flop 62 ... D flip-flop 63 ... Addition element 64 ... Selector 65 ... Selector CLK ... clock C ... multiplex the color difference signals C ₁ ... chrominance signal C ₂ ... color difference signals C ₃ ... color difference signals C ₄ ... interpolating the interpolated signal SEL ... select signal R-Y ... color difference signal B-Y ... color difference signal Y ... Luminance signal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor ▲ Yoshi ▼ Masahiro Tada 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Kiyoyuki Obiyama 1015, Kamedotachu, Nakahara-ku, Kawasaki, Kanagawa Prefecture Fujitsu Incorporated (72) Inventor Yuichi Ninomiya 1-10-11 Kinuta, Setagaya-ku, Tokyo Within the Japan Broadcasting Corporation Broadcasting Technology Laboratory (72) Inventor Izumi ▲ Yoshi ▼ Nori 1-10-11 Kinuta, Setagaya-ku, Tokyo Broadcasting Technology Institute of Japan Broadcasting Corporation (72) Seiichi Koshi 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside Broadcasting Technology Laboratory of Japan Broadcasting Corporation (72) Inventor Koichi Yamaguchi 1-10 Kinuta, Setagaya-ku, Tokyo No. 11 Inside the Japan Broadcasting Corporation Broadcasting Technology Laboratory

Claims (1)

[Claims] 1. A MUSE decoder having an output section for generating R, G, B signals from a luminance signal (Y) and two color difference signals (RY, BY), wherein the color difference signal (R- A MUSE decoder comprising a selector (5) for alternately time-division-multiplexing (Y, BY) every one clock and outputting to the output section.