JP2000134168A - Data output system after receipt of digital broadcast - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the data output system for a digital broadcast receiver that outputs hierarchical information and a demodulation pilot signal modulated by a binary phase shift modulation BPSK method or the like to a post-stage MPEG decoder or the like. SOLUTION: A demodulation section 1 receives a digital broadcast reception section (a). An error correction section 3 processes the output of the demodulation section 1 and provides an output to a data demultiplexer section 5. The data demultiplexer section 5 selects desired information from hierarchical information and outputs the selected information to a multiplexer section 7. Furthermore, the demodulation section 1 gives a demodulation auxiliary signal (b), the error correction section 3 gives a correction auxiliary signal (c), and the data demultiplexer section 5 gives hierarchical information (d) to the multiplexer section 6 respectively. The multiplexer section 6 applies time division multiplex processings to the information sets b, c, d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a data output system after receiving a digital broadcast.

[0002]

2. Description of the Related Art In digital broadcasting, MPEG TS (Transport Stream) data is often transmitted, and is transmitted with an error correction code added. MP
From the EG TS data, 188 bytes of valid data and 16 bytes of parity for correction are used to convert RS (Reed-Sol
omon: Reed-Solomon) packet is formed, but is output with a 204-byte clock and indicates a data valid period for the operation of the descrambler IC.
Signals are used. Then, the data of the invalid period of 16 bytes is ignored.

[0003]

In a conventional digital broadcast receiver, hierarchical information, BPSK (binaryp
A demodulation pilot signal or the like modulated by a phase shift keying (hase shift keying) has not been output to an MPEG decoder or the like at a subsequent stage.

Accordingly, an object of the present invention is to provide a data output method in a digital broadcast receiver for outputting hierarchical information, a demodulation pilot signal modulated by BPSK, and the like to a subsequent MPEG decoder or the like.

[0005]

After receiving a digital broadcast, during a parity period of a transport stream,
At least one of hierarchical information, TS-ID, pilot signal modulated by PBSK, demodulation pilot signal, C / N, and reception quality level is time-division multiplexed and output.

[0006]

FIG. 1 shows the configuration of a digital broadcast receiver employing the data output system of the present invention.

The received signal a of the digital broadcast is input to the demodulation unit 1. The output of the demodulation unit 1 is processed in the error correction unit 3 and sent to the data separation unit 5. Data separation unit 5
Selects the desired information from the hierarchical information,
Send to

Further, the demodulation unit 1 uses the demodulation auxiliary signal b, the error correction unit 3 uses the correction auxiliary signal c, and the data separation unit 5
Sends the layer information d to the multiplexing unit 6, respectively. Multiplexer 6
Performs time division multiplexing of the pieces of information b, c, and d.

The demodulation auxiliary signal b is a demodulation pilot signal modulated by BPSK, a reception quality signal, or the like. The correction auxiliary signal c is a non-correctable flag and a correctable required reception quality level. The hierarchy information 9 is the ISDB (Int
Egrated Services Digital
Broadcasting (TMC) information in an integrated digital broadcasting service) system.

A satellite BS digital broadcast will be described as an example. In BS digital broadcasting, a signal with stronger transmission characteristics against changes in transmission line quality such as rainfall,
Alternatively, hierarchical information (such as a signal having a weak transmission characteristic but capable of transmitting a larger amount of data) can be transmitted in a time-division multiplexed manner with a plurality of different modulation schemes and coding rates according to a service mode. TMCC) and transmit them. FIG. 2 shows the TS packet structure. FIG. 3 shows a transmission frame structure.

[0011] As shown in FIG.
In digital broadcasting, in addition to the main signal, a demodulation pilot signal (burst BPSK) modulated by BPSK is transmitted by T
Only four symbols are inserted after 203 symbols of S data. When transmitting data with a pilot signal for demodulation carried thereon, the burst BPSK symbol per frame is 4 × 4 × 48 = 768 symbols, whereas the output TS is 48 slots = 48TS in one frame. The packet is transmitted. Since the parity period has 16 bytes per TS, the total is 48 ×
There are 16 = 768 bytes.

Therefore, if one byte is replaced per symbol, all burst BPSK can be output in all parity periods. For one symbol, the burst BSPK
If only 4 bits of the I signal are multiplexed, only half of the entire parity period is required, and 768/8 = 96 bytes is required for 1-bit hard decision per symbol.

Since the encoding method and the like are undecided, the parity period of the TS is used so that the soft decision output is output without using an extra pin.

Since the hierarchical information (TMCC) has 48 bytes per 8 frames, it can be similarly output.

In the latter stage of the MPEG decoder 9, when a large number of packet errors occur, mute processing (operation stop) is performed in order to prevent the operation due to the error from becoming abnormal. Due to the multiplexing, there are cases where audio packets can be used even though video packets cannot actually be processed. In this case, instead of checking the number of errors, by multiplexing a flag indicating that there is a surviving packet and transmitting the multiplexed flag to the subsequent MPEG decoder 9, it is possible to output only audio, for example.

If data is selected based on the TS-ID of hierarchical information (TMCC) from a main signal in which a plurality of data are time-division multiplexed, only one data can be processed at a time. In addition, when all data is output, the hierarchical information (TMCC) is output in real time and the hierarchical information processing is performed.

Therefore, when the TS-ID of the corresponding packet is output simultaneously or several times during the parity period for each TS packet, the multiplexing unit 7 determines whether or not they match in the processing of only a single TS. Then, only the matched one is output to the MPEG decoder 9. When processing a plurality of TSs in the multiplexing unit 7,
The main signal of the corresponding TS-ID is output to the MPEG decoder 9.

These demodulation auxiliary signal b, correction auxiliary signal c,
FIG. 4 shows an example of a packet structure when hierarchical information (TMCC) d is time-division multiplexed and output in a parity period of a TS packet.

In addition, the transmission path C / N (Carrier
Since the instantaneous value of “to noise ratio (carrier-to-noise ratio)” does not always appear, it is necessary to output only once per frame, for example.
If the demodulation auxiliary signal b, the correction auxiliary signal c, and the hierarchical information (TMCC) d are output over a unit such as a frame, more information can be output, which is efficient. Of course, a synchronization code or the like may be inserted at a cycle independent of the frame.

As an example, as a breakdown of 16 bytes, burst BPSK [15th to 14th bytes], TS
-ID [13th to 10th bytes], modulation scheme and coding rate [9th to 7th bytes], reception quality [6th to 5th bytes], emergency information [4th byte], C / N [0 from the third byte].

Example of definition of reception quality level (QEF: error-free state) (0: all errors cannot be corrected, 1: error occurrence level (correctable packet exists), 2: QEF limit, 3: QEF) Performing data output is the purpose of the present invention, and is not limited to the type and format of data.

Next, as an example, OFDM (Ortho)
gonal FrequencyDivision M
(multiplex: orthogonal frequency division multiplexing) Terrestrial digital broadcasting will be described.

In terrestrial broadcasting, a signal having a stronger transmission characteristic with respect to a change in the quality of a transmission path such as rainfall,
Alternatively, hierarchical information (TM) is further provided so that a signal or the like having a weak transmission characteristic but capable of transmitting a larger amount of data can be multiplexed and transmitted using a plurality of different modulation schemes and coding rates.
CC) are multiplexed and transmitted. In OFDM, several types of pilot signals are multiplexed to demodulate a received signal due to transmission interference such as multipath and fading. Therefore, similarly, as shown in FIGS. 4 and 5, the demodulation auxiliary signal b, the correction auxiliary information c, and the hierarchical information d can be output.

[0024]

As described above, according to the present invention, in a digital broadcasting receiver, hierarchical information, a pilot signal for demodulation modulated by BPSK, and the like are transmitted simultaneously with TS data to a subsequent MPE.
It can be output to a G decoder or the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a digital broadcast receiver employing a data output system of the present invention.

FIG. 2 is a diagram showing a TS packet structure.

FIG. 3 is a diagram showing a transmission frame structure.

FIG. 4 is a diagram illustrating an example of a format of a TS packet in which TS data, hierarchical information (TMCC), and the like are time-division multiplexed.

FIG. 5 is a diagram illustrating an example of a format of a TS packet in which TS data, hierarchical information (TMCC), and the like are time-division multiplexed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Decoding part, 3 ... Error correction part, 5 ... Data separation part, 7 ... Multiplexing part, 9 ... MPEG decoder, a ... Digital broadcast reception signal, b. .. Demodulation auxiliary signal, c: correction auxiliary signal, d: hierarchical information.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 7/00 H04N 7/00 Z 5K028 7/24 7/13 A 5K030 F term (reference) 5C025 BA14 BA25 BA28 DA01 DA04 5C059 KK40 MA00 PP04 RB01 RB05 RC12 RC32 RD03 RD09 RF04 RF07 SS02 TA19 TA39 TC22 UA05 5C063 AB03 AB06 AB07 AB20 AC01 AC05 AC10 CA12 CA20 CA31 CA40 DA05 DA07 DA13 DA20 DB10 5K004 AA05 FA03 FA09 FB00 DD03 DD DD00 EE03 EE09 FF13 KK01 KK18 MM10 MM14 PP23 RR04 SS05 SS15 5K030 HB01 HB02 HB11 HB12 HB28 JA01 JA05 JL01 JT04 KA19 LA07

Claims (5)

[Claims] 1. After receiving a digital broadcast, during a parity period of a transport stream, hierarchical information, TS
-A data output method after digital broadcast reception characterized in that at least one of a demodulation pilot signal modulated by ID, BPSK, C / N, and reception quality level is multiplexed and output. 2. A digital broadcast system comprising: first determining means for determining a reception state when a digital broadcast is multiplexed hierarchically according to a plurality of different modulation schemes and coding rates; and the hierarchy can be received. Second determining means for determining whether the data is possible or impossible, and output means for outputting a flag indicating that possible data is present when possible and impossible data are mixed. And outputting the flag during a parity period of a transport stream. 3. The data output method after receiving a digital broadcast according to claim 1, wherein the digital broadcast is a digital satellite broadcast. 4. The data output method after receiving a digital broadcast according to claim 1, wherein the digital broadcast is an OFDM terrestrial digital broadcast. 5. A data output method after receiving a digital broadcast, wherein a signal other than a transport stream obtained from a demodulator is time-division multiplexed with the transport stream and output after receiving the digital broadcast. .