JP4035671B2 - Digital broadcasting receiver and receiving method thereof - Google Patents

Description

となる。
【００１５】
そして、ノイズＮs(k,i)、Ｎs(k,i-1)は定常的なものであるから、それらの差は０であり、したがって、上式は、
ΔＰ(k) ＝Ｓ(k,i) −Ｓ(k,i-1) ＋Ｎr(k,i)−Ｎr(k,i-1)
となる。
【００１６】
さらに、識別情報TIIは１フレームおきに送信されるので、信号Ｓ(k,i)、Ｓ(k,i-1)のどちらかのレベルは０である。したがって、識別情報TIIが第ｉ番目のフレームに含まれている場合、上式における値（Ｓ(k,i)−Ｓ(k,i-1)）は、キャリア信号の存在するキャリア番号ｋでは、正となり、キャリア信号の存在しないキャリア番号ｋでは、負となる。
【００１７】
したがって、384 個の値ΔＰ(k) のうち、正となった値ΔＰ(k) の平均値の絶対値と、負となった値ΔＰ(k) の平均値の絶対値とを比較したとき、正となった値ΔＰ(k) の平均値の絶対値が、負となった値ΔＰ(k) の平均値の絶対値よりも大きければ、第ｉ番目のフレームに識別情報TII が含まれていると判断できる。
また、このとき、負となった値ΔＰ(k) の平均値は、上式における値（Ｎr(k,i)−Ｎr(k,i-1)）のうちの負となった値の平均値であり、これはランダム性のノイズの振幅の平均を表している。したがって、負となった値ΔＰ(k) の平均値の絶対値を、識別情報TII を検出するときの基準値（スレッショールドレベル）として使用することができる。
【００１８】
例えば、負の値ΔＰ(k) の平均値の絶対値を数倍した結果の値をスレッショールドレベルとし、値ΔＰ(k) のうち、そのスレッショールドレベルよりも大きい部分を取り出せば、それは、例えば図９に示すキャリア番号ｋのキャリア信号であり、したがって、識別情報TII を得ることができる。
【００１９】
図２および図３は、データＰ(k,i) の周波数スペクトルの観測例を示すもので、図２は、ヌルシンボルNULLが識別情報TII を含んでいる場合、図３は識別情報TII を含んでいない場合である。そして、図２におけるレベルの大きい線スペクトル成分は、識別情報TII にしたがって分布するキャリア信号である。また、図２および図３において、ほぼ一様に分布する低いレベルの成分はノイズ成分である。さらに、×印を付けた線スペクトル成分は、受信機内部で定常的に発生しているノイズである。
【００２０】
そして、図４および図５は、図２および図３のデータの差分ΔＰ(k) を正負に分けて示すもので、図４は、差分ΔＰ(k) のうちの符号が正になる成分を示し、図５は、差分ΔＰ(k) のうちの符号が負になる成分の絶対値を示す。
【００２１】
したがって、上記のように、図５に示すデータの平均値をスレッショールドレベルとして図４に示すデータのピーク検出を行えば、図４におけるキャリア信号を適切に取り出すことができ、その結果、識別情報TII を知ることができる。
【００２２】
この発明は、以上のような考えに基づいて識別情報TII を得るようにしたものである。以下、この発明の一形態について説明する。
【００２３】
図１において、ＤＡＢの放送波信号がアンテナ１１により受信され、この受信信号が、スーパーヘテロダイン形式に構成されたフロントエンド回路１２に供給されて中間周波信号に変換され、この中間周波信号がＡ／Ｄコンバータ回路１３に供給されてデジタル信号とされる。
【００２４】
そして、このデジタル信号が直交復調回路１４に供給されて同相成分および直交成分が復調され、これらがＦＦＴ回路１５に供給されてＯＦＤＭ復調され、そのＯＦＤＭ復調されたデータがビタビデコーダ回路１６に供給されてデインターリーブおよびエラー訂正が行われるとともに、番組（チャンネル）の選択が行われて目的とする番組のデジタルオーディオデータが選択される。
【００２５】
続いて、この選択されたデータがデータ伸長回路１７に供給されてＭＰＥＧデータ伸長が行われ、データ伸長回路１７からは、目的とする番組のデジタルオーディオデータがもとのデータ長のデータにデータ伸長されて取り出され、この取り出されたデジタルオーディオデータがＤ／Ａコンバータ回路１８に供給されてアナログオーディオ信号にＤ／Ａ変換され、この信号が端子１９に取り出される。
【００２６】
さらに、ビタビデコーダ回路１６からデータの一部がＲＤＩ回路２１に供給されて所定の転送フォーマットのデータとされ、このデータが端子２９に出力される。また、例えばＤＳＰにより同期回路２２が構成されてフロントエンド回路１２のＡＦＣが行われるとともに、ＦＦＴ回路１５における同期などの処理が実行される。
【００２７】
さらに、ＦＦＴ回路１５からのデータがパワー算出回路３１に供給され、そのデータの実部をＩ、虚部をＱとするとき、各周波数成分（各キャリア信号）ごとに、
Ｐ(k,i) ＝Ｉ**２＋Ｑ**２
（Ｉ**２、Ｑ**２は、それぞれ値Ｉ、Ｑの２乗を示す）
で示されるデータＰ(k,i) が求められる。ただし、このとき、同期回路２２から算出回路３１にヌルシンボルNULLの期間を示す信号が供給され、算出回路３１においては、各フレームの先頭のヌルシンボルNULLの期間のみ、データＰ(k,i) の演算が実行されるとともに、その演算結果であるデータＰ(k,i) が取り出される。なお、このデータＰ(k,i) の平方根をグラフ化したものが、図２および図３である。
【００２８】
そして、このように算出回路３１から取り出されたデータＰ(k,i) が、メモリ３２に供給されるとともに、同期回路２２から所定の制御信号が供給されてデータＰ(k,i) がメモリ３２において１フレーム期間だけ遅延され、メモリ３２からは１フレーム期間前のデータＰ(k,i-1) が、データＰ(k,i) に同時化されて取り出される。そして、この１フレーム期間前のデータＰ(k,i-1) と、算出回路３１からの現在のデータＰ(k,i) とが差分回路３３に供給されて両データＰ(k,i-1) 、Ｐ(k,i) の差分のデータΔＰ(k) が取り出される。
【００２９】
さらに、このデータΔＰ(k) が演算回路３６に供給されてキャリア信号ごとに和が計算されるとともに、その負符号の値の平均値が算出され、この平均値の符号を反転して絶対値が算出される。そして、この絶対値が、検出回路３５にスレッショールドレベルを示す信号として供給される。
【００３０】
また、差分回路３３からのデータΔＰ(k) が、メモリ３４に供給されて演算回路３６の出力と同時化されてからピーク値検出回路３５に供給される。こうして、検出回路３５においては、データΔＰ(k) は、演算回路３６からの信号の示すスレッショールドレベルに基づいてピーク値が検出される。
【００３１】
そして、この検出出力が判別回路３７に供給され、データΔＰ(k) のピークの存在する周波数から送信所の識別情報TII が解析され、この解析結果の識別情報TII が端子３９に取り出される。
【００３２】
こうして、このＤＡＢ受信機によれば、送信所の識別情報TII を得ることができるが、この場合、特に上述の受信機によれば、識別情報TII の含まれるフレームであるかどうかの判別に高速情報ブロックFIB をデコードする必要がなく、したがって、そのためのデコーダ回路が不要となるので、回路規模を小さくすることができる。
【００３３】
また、差分回路３３において、１フレーム期間前のデータＰ(k,i-1) と現在のフレーム期間のデータＰ(k,i) との差分のデータΔＰ(k) を得ると、このデータΔＰ(k) においては、定常的なノイズ成分が相殺され、例えば図４に示すように、図２の場合に比べて、ノイズ成分が低減される。特に受信機の内部で定常的に発生しているノイズ（×印で示す）が大幅に低減される。そして、そのようなデータΔＰ(k) から識別情報TII を得るようにしているので、ノイズの影響を受けにくい。
【００３４】
さらに、データΔＰ(k) に含まれるノイズ成分のレベルを基準にしてデータΔＰ(k) をピーク検出してキャリア番号ｋとなるデータを得ているので、ノイズ成分のレベルが変動しても、そのデータを正しく得ることができる。
【００３５】
また、回路３１〜３７の処理は、マイクロコンピュータやＤＳＰによっても実行することができるとともに、その実行が容易である。さらに、マイクロコンピュータやＤＳＰを使用する場合、そのマイクロコンピュータやＤＳＰにより識別情報TII を得ることができ、外部の回路により判別する必要がないので、その外部の回路とのインターフェイスを持つ必要がなく、ハードウエアを簡略化することができる。
【００３６】
なお、上述において、フロントエンド回路１２からの中間周波信号を直交復調してＩ成分およびＱ成分を得、これらをＡ／Ｄ変換してからＦＦＴ回路１５に供給することもできる。
【００３７】
【発明の効果】
この発明によれば、ＤＡＢ受信機において、送信所の識別情報を得ることができるとともに、回路規模を小さくすることができる。また、受信したデータ中の定常的なノイズ成分が低減され、特に受信機の内部で定常的に発生しているノイズが大幅に低減され、ノイズの影響を受けにくい。
【００３８】
さらに、ノイズ成分のレベルが変動しても、識別情報のデータを正しく得ることができる。また、処理を、マイクロコンピュータやＤＳＰなどによっても容易に実行することができるとともに、ハードウエアを簡略化することができる。
【図面の簡単な説明】
【図１】この発明の一形態を示す系統図である。
【図２】この発明を説明するための周波数スペクトル図である。
【図３】この発明を説明するための周波数スペクトル図である。
【図４】この発明を説明するための周波数スペクトル図である。
【図５】この発明を説明するための周波数スペクトル図である。
【図６】この発明を説明するための図である。
【図７】この発明を説明するためのフォーマット図である。
【図８】この発明を説明するための周波数スペクトル図である。
【図９】この発明を説明するための図である。
【符号の説明】
１１…アンテナ、１２…フロントエンド回路、１３…Ａ／Ｄコンバータ回路、１４…直交復調回路、１５…ＦＦＴ回路、１６…ビタビデコーダ回路、１７…データ伸長回路、１８…Ｄ／Ａコンバータ回路、２１…ＲＤＩ回路、２２…同期回路、３１…パワー算出回路、３２…メモリ、３３…差分回路、３４…メモリ、３５…ピーク検出回路、３６…演算回路、３７…判別回路[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a digital broadcast receiver suitable for application to a digital audio broadcast receiver.
[0002]
[Prior art]
In Europe, DAB (digital audio broadcasting) according to the EUREKA 147 standard is implemented, and signal processing on the transmission side is as follows.
(1) Digital audio data of up to 64 channels is compressed by MPEG audio layer II for each channel.
(2) The error correction encoding process is performed on the data of each channel as a result of (1) by convolutional coding and time-axis interleaving.
(3) The result of (2) is multiplexed into one channel. At this time, auxiliary data such as PAD is also added.
(4) The result of (3) is interleaved on the frequency axis and a synchronization symbol is added.
(5) The result of (4) is subjected to OFDM processing (orthogonal frequency division multiplexing), and further D / A converted.
(6) QPSK modulation (orthogonal modulation) is performed on the main carrier signal according to the result of item (5), and this QPSK signal is transmitted.
In this case, generally, even if there is only one provider (a radio wave provider), the QPSK signal is transmitted or broadcast to the service area SA by a plurality of transmitting stations # 1 to #N as shown in FIG. 6, for example. The
[0003]
FIG. 7 shows the frame structure of the OFDM processed data of item (5), that is, baseband data. In this case, there are four operation modes in DAB. FIG. 7 is mainly in the case of mode II for terrestrial broadcasting. One frame of this data has a time length of 24 ms and is divided into a synchronization channel SC, a high-speed information channel FIC, and a main service channel MSC in order from the top.
[0004]
The synchronization channel SC is used for processing such as frame synchronization and AFC, and is composed of two symbols. The first symbol is a null symbol NULL and the second symbol is a phase reference symbol PRS. ing. In this case, the null symbol NULL in every other frame includes the identification information TII for identifying the transmitting stations # 1 to #N, and nothing is transmitted during the remaining null symbol null period. Not.
[0005]
The high-speed information channel FIC is used to provide data related to the main service channel MSC, and is divided into three high-speed information blocks FIB. The high-speed information block FIB includes time, date, type, data arrangement, traffic・ Data such as message control is arranged. Furthermore, data called a CIF counter is prepared in the high-speed information block FIB.
The remainder of 8 of the CIF counter value is 0, 1, 2, 3 (in mode I)
The remainder of 2 of the CIF counter value is 0 (in modes II and III)
The remainder of 4 of the CIF counter value is 0, 1 (in the case of mode IV)
At this time, the frame for which the CIF counter is prepared is the above-mentioned every other frame and includes the identification information TII.
[0006]
Further, the main service channel MSC is divided into a number of CI frames CIF determined by the mode, and digital audio data and various data as main data are arranged. The value of the CIF counter is the count result of this CI frame CIF.
[0007]
Further, in the case of mode II, the QPSK signal in item (6) has 384 carrier signals distributed every 4 kHz, so the power spectrum thereof is as shown in FIG. The identification information TII is also expressed by transmitting only the carrier signal of the carrier number k corresponding to the transmitting station among the 384 carrier signals. For example, in the case of mode II, when a transmitting station with a main identification value of 16 and a sub identification value of 4 performs transmission, a carrier signal of carrier number k as shown in FIG. 9 is transmitted.
[0008]
[Problems to be solved by the invention]
By the way, in order to obtain the transmitter identification information TII from the received signal in the DAB receiver, it is necessary to determine and process the null symbol NULL including the identification information TII. However, for that purpose, it is necessary to decode the high-speed information block FIB and determine whether or not the identification information TII is included in the null symbol NULL of the corresponding frame from the remainder of the CIF counter. Since a decoder circuit for decoding the FIB is required, the circuit scale becomes large.
[0009]
It is also conceivable to obtain the identification information TII by extracting the null symbol NULL as it is from the synchronization channel SC and determining the presence or absence of the identification information TII. However, since noise due to a clock or the like is constantly generated inside the receiver, the noise may affect the extraction of correct identification information TII.
[0010]
The present invention solves the above problems and makes it possible to extract the identification information TII more reliably.
[0011]
[Means for Solving the Problems]
For this reason, in the present invention,
As the digital data is framed, auxiliary data is included in a part of every other frame, and the auxiliary data is not included in a part corresponding to the part of the remaining frames. In a digital broadcast receiver broadcast on
A difference circuit that extracts a difference between the signal of the partial section of the previous frame of the received frame and the signal of the partial section of the current frame;
An arithmetic circuit for calculating an absolute value of an average value of negative values of outputs of the difference circuit;
A synchronization circuit that synchronizes the output of the partial section of the output of the difference circuit with the output of the arithmetic circuit;
A peak detection circuit for detecting a positive peak with reference to the output of the arithmetic circuit, the output of the synchronization circuit;
A discrimination circuit for discriminating a frame including the auxiliary data from the output of the peak detection circuit;
The digital broadcast receiver is characterized in that information is obtained from the auxiliary data based on a discrimination result of the discrimination circuit.
Therefore, auxiliary data is detected based on the level of the noise component.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Consider baseband data (FIG. 7) received and processed by a DAB receiver. And in this data, for the null symbol NULL period,
S (k, i): level Ns (k, i) of identification information TII: stationary noise level Nr (k, i): random noise level k: carrier number. k = -192 ~ 192
i: Assuming the frame number, the data level or power P (k, i) in the null symbol NULL period of the i-th frame is
P (k, i) = S (k, i) + Ns (k, i) + Nr (k, i)
It is represented by
[0013]
The power P (k, i-1) of data in the null symbol NULL period of the previous (i-1) th frame is
P (k, i-1) = S (k, i-1) + Ns (k, i-1) + Nr (k, i-1)
It is represented by
[0014]
Accordingly, when the difference in data power between the null symbols NULL of two consecutive frames is taken, the difference ΔP (k) is

It becomes.
[0015]
Since the noises Ns (k, i) and Ns (k, i-1) are stationary, the difference between them is zero.
ΔP (k) = S (k, i) −S (k, i−1) + Nr (k, i) −Nr (k, i−1)
It becomes.
[0016]
Further, since the identification information TII is transmitted every other frame, the level of one of the signals S (k, i) and S (k, i-1) is zero. Therefore, when the identification information TII is included in the i-th frame, the value (S (k, i) −S (k, i−1)) in the above equation is the carrier number k in which the carrier signal exists. , Is positive, and is negative at carrier number k where no carrier signal exists.
[0017]
Therefore, among the 384 values ΔP (k), the absolute value of the average value of the positive values ΔP (k) is compared with the absolute value of the average value of the negative values ΔP (k). If the absolute value of the average value of the positive values ΔP (k) is larger than the absolute value of the average value of the negative values ΔP (k), the identification information TII is included in the i-th frame. Can be judged.
At this time, the average value of the negative value ΔP (k) is the average of the negative values among the values (Nr (k, i) −Nr (k, i−1)) in the above equation. Value, which represents the average of the random noise amplitude. Therefore, the absolute value of the average value of the negative values ΔP (k) can be used as a reference value (threshold level) when detecting the identification information TII.
[0018]
For example, if the value obtained by multiplying the absolute value of the average value of the negative values ΔP (k) by several times is used as a threshold level, and a portion larger than the threshold level is extracted from the value ΔP (k), For example, it is a carrier signal of carrier number k shown in FIG. 9, and thus identification information TII can be obtained.
[0019]
2 and 3 show examples of observation of the frequency spectrum of the data P (k, i). FIG. 2 shows the case where the null symbol NULL includes the identification information TII, and FIG. 3 includes the identification information TII. This is the case. The line spectrum component having a large level in FIG. 2 is a carrier signal distributed according to the identification information TII. In FIG. 2 and FIG. 3, the low level component distributed substantially uniformly is a noise component. Furthermore, the line spectral components marked with “x” are noises that are constantly generated inside the receiver.
[0020]
4 and 5 show the difference ΔP (k) of the data in FIGS. 2 and 3 divided into positive and negative, and FIG. 4 shows the component of the difference ΔP (k) whose sign is positive. FIG. 5 shows the absolute value of the component of which the sign of the difference ΔP (k) is negative.
[0021]
Therefore, as described above, if the peak detection of the data shown in FIG. 4 is performed using the average value of the data shown in FIG. 5 as the threshold level, the carrier signal in FIG. You can know information TII.
[0022]
According to the present invention, identification information TII is obtained based on the above-described idea. Hereinafter, an embodiment of the present invention will be described.
[0023]
In FIG. 1, a DAB broadcast wave signal is received by an antenna 11, and this received signal is supplied to a front-end circuit 12 configured in a superheterodyne format to be converted into an intermediate frequency signal. The digital signal is supplied to the D converter circuit 13.
[0024]
Then, this digital signal is supplied to the quadrature demodulation circuit 14 to demodulate the in-phase component and the quadrature component, and these are supplied to the FFT circuit 15 for OFDM demodulation, and the OFDM demodulated data is supplied to the Viterbi decoder circuit 16. In addition to deinterleaving and error correction, a program (channel) is selected and digital audio data of the target program is selected.
[0025]
Subsequently, the selected data is supplied to the data decompression circuit 17 to perform MPEG data decompression, and the data decompression circuit 17 decompresses the digital audio data of the target program to the original data length data. The extracted digital audio data is supplied to the D / A converter circuit 18 and D / A converted into an analog audio signal, and this signal is extracted to the terminal 19.
[0026]
Further, a part of the data is supplied from the Viterbi decoder circuit 16 to the RDI circuit 21 to be data of a predetermined transfer format, and this data is output to the terminal 29. Further, for example, the synchronization circuit 22 is configured by a DSP to perform AFC of the front end circuit 12, and processing such as synchronization in the FFT circuit 15 is executed.
[0027]
Further, when the data from the FFT circuit 15 is supplied to the power calculation circuit 31, and the real part of the data is I and the imaginary part is Q, for each frequency component (each carrier signal),
P (k, i) = I ** 2 + Q ** 2
(I ** 2 and Q ** 2 indicate the squares of the values I and Q, respectively)
The data P (k, i) indicated by However, at this time, a signal indicating the null symbol NULL period is supplied from the synchronization circuit 22 to the calculation circuit 31, and in the calculation circuit 31, the data P (k, i) is only in the null symbol NULL period at the head of each frame. And the data P (k, i), which is the result of the calculation, is extracted. FIG. 2 and FIG. 3 are graphs showing the square root of the data P (k, i).
[0028]
The data P (k, i) thus extracted from the calculation circuit 31 is supplied to the memory 32, and a predetermined control signal is supplied from the synchronization circuit 22 to store the data P (k, i) in the memory. 32, the data P (k, i-1) one frame before is synchronized with the data P (k, i) and taken out from the memory 32. Then, the data P (k, i-1) before this one frame period and the current data P (k, i) from the calculation circuit 31 are supplied to the difference circuit 33 and both data P (k, i- 1) The difference data ΔP (k) of P (k, i) is extracted.
[0029]
Further, this data ΔP (k) is supplied to the arithmetic circuit 36 and the sum is calculated for each carrier signal, the average value of the negative sign value is calculated, the sign of the average value is inverted, and the absolute value is obtained. Is calculated. This absolute value is supplied to the detection circuit 35 as a signal indicating the threshold level.
[0030]
The data ΔP (k) from the difference circuit 33 is supplied to the memory 34 and synchronized with the output of the arithmetic circuit 36 before being supplied to the peak value detection circuit 35. Thus, the detection circuit 35 detects the peak value of the data ΔP (k) based on the threshold level indicated by the signal from the arithmetic circuit 36.
[0031]
Then, this detection output is supplied to the discrimination circuit 37, the transmitting station identification information TII is analyzed from the frequency at which the peak of the data ΔP (k) exists, and the analysis result identification information TII is taken out to the terminal 39.
[0032]
Thus, according to the DAB receiver, the transmitting station identification information TII can be obtained. In this case, in particular, according to the above-described receiver, it is possible to quickly determine whether the frame includes the identification information TII. It is not necessary to decode the information block FIB, and therefore a decoder circuit for that purpose is not required, so that the circuit scale can be reduced.
[0033]
Further, when the difference circuit 33 obtains the difference data ΔP (k) between the data P (k, i−1) one frame before and the data P (k, i) of the current frame period, the data ΔP In (k), the stationary noise component is canceled out, and for example, as shown in FIG. 4, the noise component is reduced compared to the case of FIG. In particular, noise (indicated by x) that is constantly generated inside the receiver is greatly reduced. Since the identification information TII is obtained from such data ΔP (k), it is less susceptible to noise.
[0034]
Furthermore, since data ΔP (k) is peak-detected based on the level of the noise component included in the data ΔP (k) to obtain data corresponding to the carrier number k, even if the level of the noise component fluctuates, The data can be obtained correctly.
[0035]
Further, the processes of the circuits 31 to 37 can be executed by a microcomputer or a DSP and are easy to execute. Furthermore, when a microcomputer or DSP is used, the identification information TII can be obtained by the microcomputer or DSP, and it is not necessary to discriminate by an external circuit, so there is no need to have an interface with the external circuit. Hardware can be simplified.
[0036]
In the above description, the intermediate frequency signal from the front end circuit 12 can be orthogonally demodulated to obtain the I component and the Q component, and these can be A / D converted before being supplied to the FFT circuit 15.
[0037]
【The invention's effect】
According to the present invention, in the DAB receiver, identification information of the transmitting station can be obtained and the circuit scale can be reduced. In addition, stationary noise components in the received data are reduced, particularly noise that is steadily generated inside the receiver is greatly reduced, and is less susceptible to noise.
[0038]
Furthermore, even if the level of the noise component varies, the identification information data can be obtained correctly. Further, the processing can be easily executed by a microcomputer or a DSP, and the hardware can be simplified.
[Brief description of the drawings]
FIG. 1 is a system diagram showing an embodiment of the present invention.
FIG. 2 is a frequency spectrum diagram for explaining the present invention.
FIG. 3 is a frequency spectrum diagram for explaining the present invention.
FIG. 4 is a frequency spectrum diagram for explaining the present invention.
FIG. 5 is a frequency spectrum diagram for explaining the present invention.
FIG. 6 is a diagram for explaining the present invention.
FIG. 7 is a format diagram for explaining the present invention;
FIG. 8 is a frequency spectrum diagram for explaining the present invention.
FIG. 9 is a diagram for explaining the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Antenna, 12 ... Front end circuit, 13 ... A / D converter circuit, 14 ... Orthogonal demodulation circuit, 15 ... FFT circuit, 16 ... Viterbi decoder circuit, 17 ... Data decompression circuit, 18 ... D / A converter circuit, 21 ... RDI circuit, 22 ... Synchronous circuit, 31 ... Power calculation circuit, 32 ... Memory, 33 ... Difference circuit, 34 ... Memory, 35 ... Peak detection circuit, 36 ... Calculation circuit, 37 ... Discrimination circuit

Claims (4)

As the digital data is framed, auxiliary data is included in a part of every other frame, and the auxiliary data is not included in a part corresponding to the part of the remaining frames. In a digital broadcast receiver broadcast on
A difference circuit that extracts a difference between the signal of the partial section of the previous frame of the received frame and the signal of the partial section of the current frame;
An arithmetic circuit for calculating an absolute value of an average value of negative values of outputs of the difference circuit;
A synchronization circuit that synchronizes the output of the partial section of the output of the difference circuit with the output of the arithmetic circuit;
A peak detection circuit for detecting a positive peak with reference to the output of the arithmetic circuit, the output of the synchronization circuit;
A discrimination circuit for discriminating a frame including the auxiliary data from the output of the peak detection circuit;
A digital broadcast receiver characterized in that information is obtained from the auxiliary data based on a discrimination result of the discrimination circuit. The digital broadcast receiver according to claim 1,
Receiver characteristics and to Lud digital broadcast that data of the auxiliary is an identification information of the transmitting station. The digital broadcast receiver according to claim 1,
The digital broadcast receiver characteristics and to Lud digital broadcast that is broadcast according EUREKA147 standards. As the digital data is framed, auxiliary data is included in a part of every other frame, and the auxiliary data is not included in a part corresponding to the part of the remaining frames. In a digital broadcast receiving method for receiving a digital broadcast broadcast on
In the received frame, the difference between the signal of the partial section of the previous frame and the signal of the partial section of the current frame is extracted,
Calculate the absolute value of the average of the negative values of the above differences,
Synchronizing the difference of the part of the difference with the signal indicating the absolute value of the average value of the negative values,
The synchronization is difference, to detect the positive peak based on the signal indicating the absolute value of the average value of the negative value,
Determine the frame containing the auxiliary data from the peak detection output,
A method for receiving a digital broadcast, wherein information is obtained from the auxiliary data based on the determination result.

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