JPH05316477A - Television signal processor - Google Patents

Abstract

PURPOSE:To improve the quality of down converting output and to integrate a MUSE decoder and a down converter by as few circuit blocks as possible. CONSTITUTION:An A/D converter 102 functions as the input processing part of the MUSE decoder and the down converter and analog/digital-converts a MUSE signal. A PLL circuit 104 executes synchronous reproduction by using an A/D conversion output signal. A de-emphasis circuit 107 de-emphasizing the A/D conversion output signal executes a de-emphasis processing on the A/D conversion output signal and the output signal of the de-emphasis circuit 107 is supplied to a MUSE decoding processing part 108 and a down conversion processing part 110. A synchronizing signal from the synchronous system of the MUSE decoding processing part 108 is used in the down conversion processing part 110, as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television signal processing device used in a high definition receiver.

[0002]

2. Description of the Related Art MUSE (MULTIPLE SUB-NYQUIST SAMPLING) is used as a method for compressing and transmitting high-bandwidth high-definition television signals to a practical level for transmission.
ENCODING) method has been proposed. But MUSE
Since the system that receives the standard signal and completely restores the image is expensive, the MUSE signal is a standard NTSC signal.
A simple down-converter for converting to a system has been developed. When this system is built, the video will be
It can be viewed on a C-type television receiver.

In commercializing a system capable of receiving this MUSE system signal, a television set in which a MUSE decoder, a down converter, a tuner and a monitor are housed in one housing is considered. It is thought that various sets will spread. In high-definition broadcasting, scrambling and digital transmission are expected in the future. Considering the digital interface at this time, in the present MUSE decoder, it is a generally considered system to be connected to the synchronous system, that is, the latter stage of the A / D converter. In this case, the video signal has 10 bits in FM and 8 bits in AM. FIG. 2 shows M
1 illustrates a USE signal processing system.

FIG. 2A shows a MUSE decoder, FIG.
(B) is the configuration of the down converter. The MUSE decoder will be described first. The MUSE signal is input to the A / D converter 202 via the input terminal 201 and converted into a 10-bit digital MUSE signal. The digital MUSE signal is input to the waveform equalization circuit (equalizer) 203, waveform equalized, and input to the PLL circuit 204 and the de-emphasis circuit 207. The PLL circuit 204 reproduces a clock to generate a sampling clock synchronized with the transmission data, and supplies the output sampling clock to the clock input terminal of the A / D converter 202. The de-emphasis circuit 207 expands the emphasis and outputs it as an 8-bit digital signal. This signal is input to the MUSE decoding processing unit 208, restored to a high definition television signal, and output terminal 20.
9 is derived.

FIG. 2B shows a down converter. The MUSE signal is input to the A / D converter 212 via the input terminal 211 and converted into a digital MUSE signal. In the A / D converter 212, to reduce the cost, 8
Converted to bit digital MUSE signal. This digital MUSE signal is input to the PLL circuit 214 and the de-emphasis circuit 217. PLL circuit 214
Performs clock reproduction similar to that of the MUSE decoder, generates a sampling clock synchronized with the transmission data, and supplies the sampling clock to the clock input terminal of the A / D converter 212. Further, the de-emphasis circuit 217 expands the emphasis and outputs an 8-bit digital signal. This signal is input to the down conversion processing unit 218, converted into a standard television signal, and output terminal 21.
9 is derived.

[0006]

[Problems to be Solved by the Invention] A comprehensive system for processing MUSE signals has been constructed, and M is set in one TV set.
When considering incorporating a USE decoder and a down converter, it is preferable to increase the number of sharable portions as much as possible, and it is desirable to have a configuration that allows easy addition of other functions such as a descrambler.
However, simply incorporating the MUSE decoder and the down converter shown in FIG. 2 into a television set cannot satisfy such a demand, resulting in an increase in power consumption and an increase in space. In the down converter, the digitization bit number of the A / D converter 212 is originally 8 bits for cost reduction.
The lower 2 bits are truncated as compared with the decoder, which causes a problem that the image quality is deteriorated.

In view of the above, the present invention improves the image quality of the down converter output, integrates the MUSE decoder and the down converter with as few circuit blocks as possible, and easily adds a function increasing block such as a descrambler. It is an object of the present invention to provide a television signal processing device.

[0008]

The present invention provides a MUSE decoder for receiving a MUSE signal and restoring it to a high-definition signal, and a device having a down-converter function for converting the MUSE signal into a current television system. As the input processing part of the down converter, A which converts the MUSE signal into analog digital
The A / D converter, the synchronous reproduction circuit for performing synchronous reproduction by the output signal of the A / D converter, and the de-emphasis circuit for performing de-emphasis on the output signal of the A / D converter are made common, and the de-emphasis is performed. Circuit output signal is M
It is configured to be supplied to the USE decoding processing unit and the down conversion processing unit.

[0009]

By the above means, MUSE decoding and down conversion can be realized with a small number of circuit blocks, space can be saved, and the image quality of the down converter output can be improved.

[0010]

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

FIG. 1 is a block diagram showing an embodiment of the present invention. The MUSE signal is introduced to the input terminal 101,
10-bit digital MU in A / D converter 102
Digitized into SE signal. The digital MUSE signal is waveform-equalized by the waveform equalization circuit 103, 9 bits of which are input to the PLL circuit 104 for system synchronization. The PLL circuit 104 reproduces a clock, generates a sampling clock synchronized with the transmission data, and supplies the sampling clock to the clock input terminal of the A / D converter 102. The output of the waveform equalization circuit 103 is input to the de-emphasis circuit 107, expanded, and output as an 8-bit signal.

The output of the de-emphasis circuit 107 is M
It is input to the USE decoding processing unit 108, where it is restored to a high-definition television signal and is output to the output terminal 109. The output of the de-emphasis circuit 107 is also input to the down-conversion processing unit 110, system-converted into a standard television signal (NTSC system), and led to the output terminal 111.

Here, the MUSE processing system is built in the MUSE decoding processing unit 108, but its synchronous clock and the like are also introduced and used in the down conversion processing unit 110. Further, the output terminal P of the waveform equalization circuit 103
A descrambler 120 can be inserted between the 1 and the input terminal P2 of the de-emphasis circuit 107.

According to the above-described embodiment, both the high-definition television signal obtained by decoding the MUSE signal and the signal obtained by converting the MUSE signal into the standard television signal can be obtained with a small number of circuit block configurations. If it is built into a TV set, space saving and cost reduction can be obtained. Further, the signal given from the de-emphasis circuit 107 to the down conversion processing unit 110 is originally a signal with 10-bit precision in the A / D conversion processing,
As compared with the conventional single down converter, the quality of the output image of the down converter can be improved with higher accuracy.

[0015]

As described above, according to the present invention,
It is easy to improve the image quality of the down-converted output, integrate the MUSE decoder and the down-converter with as few circuit blocks as possible, and add a function increasing block such as a descrambler.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing an embodiment of the present invention.

FIG. 2 is a block configuration diagram of a conventional MUSE decoder and a block configuration diagram of a down converter.

[Explanation of symbols]

102 ... A / D converter, 103 ... Waveform equalization circuit, 104
... PLL circuit, 107 ... De-emphasis circuit, 108
... MUSE decoding processing unit, 110 ... Down conversion processing unit, 120 ... Descrambler.

Claims (3)

[Claims] 1. A MUSE decoder for receiving a MUSE signal and restoring it to a high-definition signal, and a device having a down-converter function for converting the MUSE signal into a current television system, wherein an input processing part of the MUSE decoder and the down-converter is: A / D converter for analog-to-digital conversion of MUSE signal, synchronous reproduction circuit for synchronous reproduction by output signal of the A / D converter, and de-emphasis for de-emphasis for output signal of the A / D converter A television signal processing apparatus, characterized in that a circuit is made common and the output signal of the de-emphasis circuit is supplied to a MUSE decoding processing section and a down conversion processing section. 2. The television signal according to claim 1, wherein a signal processing circuit including a MUSE waveform equalizing circuit or a digital interface is provided between the A / D converter and the de-emphasis circuit. Processing equipment. 3. The television signal processing apparatus according to claim 1, wherein the synchronization signal in the MUSE decoding processing section is introduced into the down conversion processing section for use.