JPH04267695A - MUSE decoder - Google Patents

Abstract

PURPOSE:To relieve flicker of a picture and to improve the overall picture quality by discriminating the reception mode of a MUSE system High Vision satellite broadcast and a communication satellite broadcast and eliminating a dispersal (energy spread) signal at the reception of communication satellite broadcast. CONSTITUTION:Since a level of a dispersal signal differs from a difference of transmission power in the satellite broadcast and the communication satellite broadcast and the level of the communication satellite broadcast is larger, a switch circuit 4 is controlled by a discrimination signal 21 of an output of an automatic discriminating circuit 6 comparing the slope of the dispersal signals. The dispersal of the input signal is eliminated by adding a dispersal signal 18(-DISP) in opposite phase to the input MUSE signal 16 at the reception of the communication satellite broadcast.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to automatic discrimination of satellite broadcasting and communication satellite broadcasting and removal of dispersal signals in MUSE decoders of high-definition satellite broadcasting (BS) and communication satellite broadcasting (CS) receiving television receivers.

0002

[Prior Art] Currently, high-definition communication satellite broadcasting (CS) using the MUSE system has not been put into practical use. There is a problem in that the dispersal (energy diffusion) level of the MUSE signal is large, causing flicker in image reproduction and deteriorating image quality. Therefore, it is necessary to distinguish between satellite broadcasting and communication satellite broadcasting, and to remove dispersal signals when receiving communication satellite broadcasting.

0003

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned conventional example, and it is an object of the present invention to distinguish between satellite broadcasting and communication satellite broadcasting, and to remove dispersal signals when receiving communication satellite broadcasting, thereby improving overall image quality. The aim is to improve the

0004

[Means for solving the problem] The dispersal signal level differs between MUSE system high-definition satellite broadcasting (BS) and communication satellite broadcasting (CS) due to the difference in transmission power, and the dispersal signal level is higher in communication satellite broadcasting. Because of the large size, the present invention is characterized in that it automatically discriminates between satellite broadcasting and communication satellite broadcasting by comparing the magnitude of the slope of the dispersal signal.

[0005]

[Operation] As shown in FIG. 1, adder 2, analog/digital converter 3, MUSE signal 16 and AFC pulse 1
Dispersal signal of opposite phase with 7 as input (-DIS
A dispersal signal generator 5 outputting P), AFC
MUS by timing pulse based on pulse 17
Intake of E data 20 and control signal 2 from microcomputer, etc.
2 and outputs a discrimination signal 21 for satellite broadcasting (BS) and communication satellite broadcasting (CS). When receiving communications satellite broadcasting, the adder 2 adds the dispersal signal 18 (-DISP in Figure 2) output from the dispersal signal generator 5 to the analog MUSE signal 16 (MUSE in Figure 2) to generate dispersal. is canceled to produce a flat MUSE signal.

[0006]

[Example] Satellite broadcasting (BS) and communications satellite broadcasting (CS)
), when transmitting high-definition FM using the MUSE method, dispersal (energy dispersion) of triangular waves synchronized with the frame period is used to spread the energy of the radio waves so as not to concentrate them on a specific frequency, thereby preventing interference with other wireless communications. ) signal on the MUSE signal. Also, since the transmission power of satellite broadcasting and communication satellite broadcasting is different, and the transmission power of communication satellite broadcasting is small, the dispersal signal level (slope of the triangular wave) increases, and it is necessary to cancel the dispersal signal when receiving communication satellite broadcasting. There is.

2 in FIG. 1 is an analog adder of the MUSE signal 16 whose direct current is cut by the capacitor 1 and the phase-inverted dispersal signal 18 (-DISP), and 3 is the MUSE analog signal 19 output from the adder as MUSE data. 20
4 is an analog switch circuit, 5 is a MUSE signal and an AFC pulse 17
is input and the dispersal signal (-D
A dispersal signal generator 6 outputs a dispersal signal 18 that outputs a dispersal signal 18 that discriminates between satellite broadcasting and communication satellite broadcasting, and turns on the switch circuit 4 with a discrimination signal 21 when receiving the communication satellite broadcasting, and outputs a dispersal signal 18 with an inverted phase. An automatic discrimination circuit for satellite broadcasting/communication satellite broadcasting is connected to the adder 2, and 7 is a matching resistor.

FIG. 2 shows details of the automatic discrimination circuit 6 for discriminating between satellite broadcasting and communications satellite broadcasting shown in FIG. 1. 14 is AFC
Timing generator for capturing MUSE data 20 based on pulse 17, 9 and 10 are MUSE data 20
Capture register, 11 is M with dispersal
an arithmetic unit that calculates the slope of the USE signal (slope of the triangular wave);
12 is an absolute value circuit for the output data of the arithmetic unit 11, and 13 is a circuit for comparing the output of the absolute value circuit 12 with a control signal 22 from a microcomputer (not shown) or the like to discriminate between satellite broadcasting and communication satellite broadcasting. , is a comparator that connects the discrimination signal 21 to the switch circuit 4 of FIG. Figure 3 shows the field period (1V)
AFC pulse of , a dispersal-applied baseband MUSE signal, and a dispersal signal (-DISP) whose phase is inverted to cancel the dispersal (triangular wave) of the MUSE signal are shown.

In FIG. 2, the digital converter 3 output M
The USE data 20 is sent to the AFC via the switch circuit 8.
At the timing t1 shown in FIG. 3 of the timing generator 14 based on the pulse 17, the register 9 (or register 10)
Then, after a predetermined time, at timing t2 shown in FIG. 3, the MUSE data 20 is fetched into the register 10 (or register 9). The difference between the fetched data in the register 9 and the register 10 is calculated by the arithmetic unit 11, the absolute value is outputted via the absolute value circuit 12, and the absolute value is sent to the control signal 22 of a microcomputer (not shown) etc. and the comparator. At step 13, the sizes are compared and a satellite broadcast/communication satellite broadcast discrimination signal 21 is output to the analog switch circuit 4 (FIG. 1).

Although not shown, when the MUSE signal 16 is input, a signal is sent from a microcomputer or the like to determine whether it is a satellite broadcast or a communications satellite broadcast. At this time, the analog switch circuit 4 is in an off state and connects the MUSE signal 16 to the automatic discrimination circuit 6 via the analog/digital converter 3. In the case of satellite broadcast reception, the switch circuit 4 is left in the OFF state, the signal after the discrimination is returned to a microcomputer (not shown), etc., and the input MUSE signal 16 is directly sent to the adder 2.
, and output via the analog/digital converter 3. In addition, in the case of communication satellite broadcast reception, the switch circuit 4 is turned on and the phase-inverted dispersal signal 18 (-DISP in FIG. 3) of the output of the dispersal signal generator 5 is connected to the adder 2. Input MUS taken
The slope of the triangular wave of the E signal 16 (MUSE in FIG. 3) is removed, and the signal at the end of the discrimination is sent to a microcomputer (not shown), etc., thereby producing a flat MUSE signal.

[0011]

[Effects of the Invention] As described above, the present invention provides high-definition satellite broadcasting (BS) and communications satellite broadcasting (CS) using the MUSE system.
Because communication satellite broadcasting has a higher dispersal (energy diffusion) signal level than communication satellite broadcasting due to the difference in transmission power, automatic discrimination between satellite broadcasting and communication satellite broadcasting is performed by calculating and comparing the magnitude of the slope of the dispersal signal. However, by removing dispersal from the MUSE signal when receiving communication satellite broadcasting, it is possible to reduce image flicker and improve overall image quality.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a MUSE decoder that performs automatic BS/CS discrimination and CS dispersal removal.

FIG. 2 is a block diagram of the BS/CS automatic discrimination circuit of FIG. 1;

FIG. 3 is an operation waveform diagram of each part in FIG. 1;

[Explanation of symbols]

2 Adder 3 Analog/digital converter 4 Analog switch circuit 5 Dispersal signal generator 6 BS/CS automatic discrimination circuit 9 Register 11 Arithmetic unit 12 Absolute value circuit 13 Comparator 14 Timing generator 16 MUSE signal 17 AFC pulse 18 Phase inversion dispersal signal 21 BS
/CS discrimination signal

Claims (2)

[Claims] Claim 1: A dispersal signal generator for satellite broadcasting and communications satellite broadcasting receiving high-definition television receivers, etc., in which the detected output baseband MUSE signal of high-definition broadcasting is connected to an analog adder via a capacitor, and one input is an AFC pulse. The output of the analog adder is connected to the other input of the analog adder, and the output of the analog adder is connected to an analog/digital converter, and the MUSE data of the analog/digital converter output, the AFC pulse, and the control signal are transmitted to the satellite broadcast/communication satellite broadcast. A MUSE decoder which is connected to an automatic discrimination circuit, controls a switch circuit output from the dispersal signal generator by a discrimination signal output from the automatic discrimination circuit, and connects a phase-inverted dispersal signal to the analog adder. Claim 2: The automatic discrimination circuit for satellite broadcasting/communication satellite broadcasting comprises an arithmetic unit that receives and calculates the slope of the MUSE signal at a timing based on an AFC pulse, an absolute value circuit for the output of the arithmetic unit, and a comparator for discrimination. The MUSE decoder according to claim 1.