KR100873130B1 - Digital broadcasting receiver - Google Patents

Abstract

The present invention relates to a digital broadcast receiver performing a picture in picture function.

According to an aspect of the present invention, there is provided an apparatus for decoding a data channel by receiving a satellite DMB broadcast signal, comprising: extending an input data channel, a first bit deinterleaving, a first Viterbi decoder, a first byte deinterleaving, a first serializer, A second bit deinterleaving, a second Viterbi decoder, a second byte corresponding to an additional channel for the implementation of a Picture In Picture (PIP) function for the first RS decoder and the first data formatter Provided is a digital broadcast receiver comprising deinterleaving, a second serializer, a second RS decoder, and a second data formatter.

Accordingly, according to the present invention, a digital multimedia broadcasting (DMB) receiver can perform a picture in picture (PIP) function.

DMB receiver, PIP function

Description

Digital broadcasting receiver

1 is a block diagram of a conventional DMB broadcast receiver

2 is an input signal waveform diagram according to the present invention

3 is a data channel pass diagram in accordance with the present invention.

* Description of the symbols for the main parts of the drawings *

10: tuner 11: automatic gain control unit

12: A / D 13: searcher

14: tracker 15: despreader

16: frequency offset estimator 17: rake synthesizer

18: frame and superframe timing extraction circuit

19: pilot Viterbi decoder 20: pilot reverse interleaving

21: pilot RS decoder 22: data mode detector

23: bit reverse interleaving 24: Viterbi decoder

25 Bytes deinterleaving 26 Serializer

27: RS decoder 28: data formatter

The present invention relates to a digital broadcast receiver, and more particularly, to a digital broadcast receiver capable of implementing a picture in picture (PIP) function.

Digital multimedia broadcasting (DMB) can be divided into terrestrial DMB and satellite DMB. Terrestrial DMB provides audio and video services during the movement based on the OFDM scheme, and satellite DMB enables audio and video services during the movement using satellites and the ground gap filler that complements them based on the CDM.

1 shows a conceptual block diagram of a satellite DMB receiver.

Referring to Figure 1, the structure of the receiver, the satellite DMB receiver is tuner 10, AGC 11, A / D 12, searcher 13, tracker 14, PN despreading 15, Frequency offset estimator 16, rake synthesizer 17. Frame and superframe timing extraction circuit 18, pilot Viterbi decoder 19, pilot deinterleaving 20, pilot RS decoder 21, data mode detector 22, bit deinterleaving 23, Viterbi decoder (24), byte deinterleaving (25), serializer (26), RS decoder (27), and data formatter (28).

Referring to Figure 1 describes the operation of the receiver, the received signal input to the antenna is converted to the baseband (Baseband) via the tuner 10, the AGC 11 of the signal input to the A / D (12) In order to keep the magnitude constant, the power of the received signal is measured and multiplied by the calculated gain value, and the A / D 12 samples the signal whose magnitude is relatively constant by the AGC 11. The analog signal is converted into a digital signal. In order to demodulate a signal in the CDM transmission scheme, the acquisition of a pseudonoise sequence used for signal spreading should be a priority. This process consists of two stages of signal acquisition and tracking. The division unit of the pseudo noise sequence is called a chip, and the acquisition is a process of securing signal synchronization within +1/2 chips to -1/2 chips in the receiver, and is performed in the searcher 13. Signal tracking refers to fine synchronization of the found signal, and is performed in the trackers 141 to 14n. In this way, the synchronized signal is despread by multiplying the pseudo noise sequence generated by the receiver in (151 to 15n) of FIG. . This process is performed in all the multiple paths found by searcher 13, each of which is called a finger. The frequency offset estimator 16 estimates a frequency offset for each finger, synthesizes it, and feeds back a tuner to correct the frequency offset. The extracted symbols are synthesized by the rake synthesizer 17. In this case, a method of improving reception performance may be obtained by estimating and compensating a reception channel environment. Rake synthesis is performed for all CDM channels that want to be demodulated, and the control channel, the pilot channel, must contain demodulation because it contains information about the interleaver size and convolutional coding rate.

The present invention provides a digital broadcast receiver for implementing a picture in picture (PIP) function.

In order to achieve the above object, the present invention provides a device for decoding a data channel by receiving a satellite DMB broadcast signal, extending the input data channel, the first bit deinterleaving, the first Viterbi decoder, the first byte inverse A second bit deinterleaving corresponding to an additional channel for the implementation of Picture In Picture (PIP) function for the interleaving, the first serializer, the first RS decoder, and the first data formatter; A digital broadcast receiver comprising a Viterbi decoder, a second byte deinterleaving, a second serializer, a second RS decoder, and a second data formatter.

According to an embodiment of the present invention, the input data channel is provided with at least 8 channels.

The first bit deinterleaving, the first Viterbi decoder, the first byte deinterleaving, the first serializer, the first RS decoder, and the first data formatter are four channels, respectively, and the second bit deinterleaving. The second Viterbi decoder, the second byte deinterleaving, the second serializer, the second RS decoder, and the second data formatter each provide at least two channels.

Accordingly, according to the present invention, a digital multimedia broadcasting (DMB) receiver can perform a picture in picture (PIP) function.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can specifically realize the above object will be described.

2 illustrates an input signal waveform to a data channel of a DMB broadcast receiver, and FIG. 3 illustrates a data channel path of a DMB broadcast receiver for implementing a picture in picture (PIP) function according to the present invention.

2 and 3, a DMB broadcast receiver for implementing a Picture In Picture (PIP) function according to the present invention will be described.

First, the conventional satellite DMB system will be described. In the bit reverse interleaver used in the conventional satellite DMB system, if the soft bit is 4 bits, about 6.67 Mbits of storage space is required per channel. Supporting 4 channels requires about 26.67 Mbits. Commercially available SDRAMs typically have at least 64,128,256,512 Mbits of memory. In general, an audio channel consists of one channel and a video channel consists of two channels. However, the satellite DMB system basically needs to decode the Electronic Program Guide (EPG) and the Receiver Access System (CAS) channels in order to receive the user, so only two channels can be used as actual audio or video channels. have. In the case of audio, two different channels can be decoded, but in the case of video, only one channel can be decoded.

The Picture In Picture (PIP) function simultaneously decodes a plurality of different video channels, and displays the main picture and the sub-picture in one screen. To implement this function, it is necessary to decode several different video channels simultaneously. Therefore, the current four-channel decoding cannot decode a plurality of video channels at the same time, it is necessary to additionally decode the video channel. That is, Walsh despread and serializer, bit deinterleaving, and Viterbi decoding are additionally performed on the extra video channel.

About 6.67 Mbits is required for one channel decoding. Therefore, when considering only the memory side, if the size of the SDRAM used in the satellite DMB system is 64Mbits, up to 9 channels can be simultaneously decoded. Up to 19 channels for 128Mbits and up to 38 channels for 256Mbits can be simultaneously decoded. However, the present invention provides an embodiment for additionally decoding two channels (one channel of video) in order to implement a picture-in-picture function in consideration of gate size, power consumption, and actual user's needs.

Therefore, in order to decode the video channel for the display of the sub-screen, a Walsh despread and serializer, a bit deinterleaver, and a Viterbi decoder are additionally configured. This requires an increase in clock speed and gate size.

As shown in FIG. 2, after the Walsh spread and the serializer, a total of eight channels are decoded and input to the bit deinterleaver 100 in serialized form. Bit deinterleaving is performed on a total of eight channels. Among them, only valid channels are selected for the Viterbi decoding based on the valid signal.

3 illustrates a structure of a modified data channel path unit including a Viterbi decoder for 2-channel decoding which is added in addition to the existing Viterbi decoder for 4-channel decoding.

The selected channel comprises a first bit deinterleaving, a first Viterbi decoder, a first byte deinterleaving, a first serializer, a first RS decoder, a first data formatter, a second bit deinterleaving, A 2 Viterbi decoder, a second byte deinterleaving, a second serializer, a second RS decoder, and a second data formatter are performed. Unlike the components of the data channel path having four channels in the related art, a second channel is further added to perform the screen in-screen function.

According to a practical example according to the invention, the added channel is as a second bit deinterleaving, a second Viterbi decoder, a second byte deinterleaving, a second serializer, a second RS decoder, a second data formatter. Each consists of 2 channels.

The two channels of the above embodiment present the minimum channel for efficiently performing the picture-in-picture function, and more than two channels are possible.

The present invention is not limited to the above-described embodiments, and can be modified by those skilled in the art as can be seen from the appended claims, and such modifications are within the scope of the present invention.

The effects of the digital broadcast receiver according to the present invention described above are as follows.

According to the present invention, a digital multimedia broadcasting (DMB) receiver can perform a picture in picture (PIP) function.

Claims (5)

A digital broadcast receiver for receiving a satellite DMB broadcast signal and decoding a data channel, A Walsh despread and serializer that extends the data channel input through the Walsh despread and serialization processes; If four channels are selected from the extended data channels in the Walsh despread and serializer for the implementation of the main picture, the electronic program guide (EPG) and the receiver confinement system (CAS), the data processing of the selected four channels is performed. A 1 bit deinterleaver, a first Viterbi decoder, a first byte deinterleaver, a first serializer, a first RS decoder, and a first data formatter; And A second bit deinterleaver for processing data of the selected two channels when at least two channels are selected from the extended data channels in the Walsh spread and the serializer to implement a picture in picture (PIP), And a second Viterbi decoder, a second byte deinterleaver, a second serializer, a second RS decoder, and a second data formatter. delete delete delete delete

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