JPH0766793A - Receiver for encoded orthogonal frequency-divided multiplex signal - Google Patents
Receiver for encoded orthogonal frequency-divided multiplex signalInfo
- Publication number
- JPH0766793A JPH0766793A JP5212576A JP21257693A JPH0766793A JP H0766793 A JPH0766793 A JP H0766793A JP 5212576 A JP5212576 A JP 5212576A JP 21257693 A JP21257693 A JP 21257693A JP H0766793 A JPH0766793 A JP H0766793A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- voltage
- offset
- orthogonal frequency
- baseband
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/06—Dc level restoring means; Bias distortion correction ; Decision circuits providing symbol by symbol detection
- H04L25/061—Dc level restoring means; Bias distortion correction ; Decision circuits providing symbol by symbol detection providing hard decisions only; arrangements for tracking or suppressing unwanted low frequency components, e.g. removal of dc offset
- H04L25/063—Setting decision thresholds using feedback techniques only
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は符号化直交周波数分割
多重（Ｃｏｄｅｄ ＯｒｔｈｏｇｏｎａｌＦｒｅｑｕｅ
ｎｃｙ Ｄｉｖｉｓｉｏｎ Ｍｕｌｔｉｐｌｅｘｉｎ
ｇ：以下、ＣＯＦＤＭ信号と称する）受信機に関し、特
に、変調されたデータを時系列的に送信するときの単位
であるフレーム内に無信号状態のシンボルであるヌルシ
ンボルを有するＣＯＦＤＭ信号を受信し、その受信信号
をベースバンド帯域に変換し、そのベースバンド信号を
高速フーリエ変換（Ｆａｓｔ Ｆｏｕｒｉｅｒ Ｔｒａ
ｎｓｆｏｒｍ：以下、ＦＦＴと称する）して変調データ
を復調するようなＣＯＦＤＭ信号受信機に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to coded orthogonal frequency division multiplexing (Coded Orthogonal Frequency Division Multiplexing).
ncy Division Multiplexin
g: hereinafter referred to as COFDM signal), in particular, a COFDM signal having a null symbol that is a non-signal state symbol in a frame that is a unit when transmitting modulated data in time series is received. , The received signal is converted to a baseband band, and the baseband signal is converted to a fast Fourier transform (Fast Fourier Transform).
nsform: hereinafter referred to as FFT) to demodulate modulated data and to a COFDM signal receiver.
【０００２】[0002]
【従来の技術】図３は従来のＣＯＦＤＭ信号受信機の概
略ブロック図である。図３において、ＲＦ帯域のＣＯＦ
ＤＭ信号はＲＦ−ＩＦ周波数変換部１に入力されてＩＦ
帯域の周波数信号に変換され、ディバイダ２によって２
つの経路に分割され、ミキサ５，６に送られる。一方、
局部発振器３で発生された局部発振信号は位相変換器４
によって位相が互いに９０°異なる局部発振信号に変換
され、それぞれがミキサ５，６に与えられる。ミキサ５
は、ディバイダ２から入力された中間周波信号と位相変
換器４からの位相が０°の局部発振信号とを混合し、第
１のベースバンド信号に変換する。他方のミキサ６は、
ディバイダ２から入力されてきた中間周波信号と位相変
換器４からの位相が９０°の局部発振信号と混合し、第
２のベースバンド信号に変換する。2. Description of the Related Art FIG. 3 is a schematic block diagram of a conventional COFDM signal receiver. In FIG. 3, the COF in the RF band
The DM signal is input to the RF-IF frequency conversion unit 1 and IF
Converted to a frequency signal in the band and divided by divider 2 to 2
It is divided into two paths and sent to mixers 5 and 6. on the other hand,
The local oscillator signal generated by the local oscillator 3 is supplied to the phase converter 4
Are converted into local oscillation signals whose phases are different from each other by 90 ° and are supplied to mixers 5 and 6, respectively. Mixer 5
Mixes the intermediate frequency signal input from the divider 2 and the local oscillation signal from the phase converter 4 having a phase of 0 °, and converts the mixed signal into a first baseband signal. The other mixer 6 is
The intermediate frequency signal input from the divider 2 and the local oscillation signal having a phase of 90 ° from the phase converter 4 are mixed and converted into a second baseband signal.
【０００３】第１および第２のベースバンド信号はそれ
ぞれローパスフィルタ７，８によって高周波成分が除去
され、アナログ／ディジタル（以下、Ａ／Ｄと称する）
変換器９，１０に与えられる。そして、Ａ／Ｄ変換器
９，１０によってディジタルベースバンド信号Ｓ1 ，Ｓ
2 に変換され、ＦＦＴ演算部１１に入力される。このデ
ィジタル化されたベースバンド信号Ｓ1 ，Ｓ2 をそれぞ
れ図４の（ａ），（ｂ）に示す。ＦＦＴ演算部１１にお
いては、入力されてきた２つのベースバンド信号を高速
フーリエ変換し、ＣＯＦＤＭ信号の各キャリアに重畳さ
れている変調データを復調し、データ処理部１２に出力
する。High-frequency components are removed from the first and second baseband signals by low-pass filters 7 and 8, respectively, and analog / digital (hereinafter referred to as A / D).
It is provided to the converters 9, 10. Then, the A / D converters 9 and 10 cause the digital baseband signals S 1 and S
It is converted to 2 and input to the FFT calculation unit 11. The digitized baseband signals S 1 and S 2 are shown in FIGS. 4A and 4B, respectively. The FFT calculation unit 11 performs fast Fourier transform on the two input baseband signals, demodulates the modulated data superimposed on each carrier of the COFDM signal, and outputs the demodulated data to the data processing unit 12.
【０００４】[0004]
【発明が解決しようとする課題】一例として、図４に示
したディジタル化されたベースバンド信号Ｓ1 ，Ｓ
2 は、各キャリアにＱＰＳＫ（直交位相変調）を施した
ＣＯＦＤＭ信号のベースバンド帯域における変調波形で
ある。一般に、ＣＯＦＤＭ信号を構成している各変調波
はすべて等しい振幅を有する信号であり、それらを合成
したＣＯＦＤＭ信号においては、図４に示すように直流
成分を変調した変調データによるＣＯＦＤＭ信号のＤＣ
レベルの変化はＣＯＦＤＭ信号の振幅に比べると非常に
小さいものである。As an example, the digitized baseband signals S 1 and S shown in FIG. 4 are used.
Reference numeral 2 is a modulation waveform in the baseband of a COFDM signal in which each carrier is QPSK (quadrature phase modulation). In general, all the modulated waves forming the COFDM signal are signals having the same amplitude, and in the COFDM signal obtained by combining them, as shown in FIG.
The change in level is very small compared to the amplitude of the COFDM signal.
【０００５】一方、このような送受信システムでは、送
信側および受信側の回路においてＤＣオフセットが生じ
ることがある。このＤＣオフセットはＦＦＴによる演算
結果のＤＣ成分に影響を与え、誤りの原因となる。On the other hand, in such a transmitting / receiving system, DC offset may occur in the circuits on the transmitting side and the receiving side. This DC offset affects the DC component of the calculation result by the FFT and causes an error.
【０００６】たとえば、各キャリアがＱＰＳＫ変調され
たＣＯＦＤＭ波の場合、本来変調データに対応してＤＣ
成分が＋になったり−になったりするものである。しか
し、ＤＣオフセットが生じていると、ＤＣ成分が＋の
み、あるいは−のみとなる。この結果として、ＤＣ成分
に対応する変調データが正しく復調されないことにな
る。また、ＤＣオフセットによりＣＯＦＤＭ信号がＡ／
Ｄ変換器９，１０の入力電圧範囲を超えるような場合に
は、他の復調データにも誤りが生じることがある。各キ
ャリアの変調法は、他の位相変調あるいはＱＡＭ（直交
振幅変調：Ｑｕａｄｒａｔｕｒｅ Ａｍｐｌｉｔｕｄｅ
Ｍｏｄｕｌａｔｉｏｎ）の場合にも同様の悪影響を及
ぼす。For example, in the case of a QPSK-modulated COFDM wave for each carrier, DC is originally associated with the modulated data.
A component becomes + or-. However, when the DC offset is generated, the DC component is only + or −. As a result, the modulated data corresponding to the DC component will not be demodulated correctly. Also, due to the DC offset, the COFDM signal is A /
When the input voltage range of the D converters 9 and 10 is exceeded, an error may occur in other demodulated data. The modulation method of each carrier is other phase modulation or QAM (Quadrature Amplitude Modulation).
Modulation) also has the same adverse effect.
【０００７】それゆえに、この発明の主たる目的は、Ｄ
Ｃオフセットによる悪影響を取り除き、変調データを正
しく復調できるような符号化直交周波数分割多重信号受
信機を提供することである。Therefore, the main object of the present invention is to
An object of the present invention is to provide a coded orthogonal frequency division multiplex signal receiver capable of removing the adverse effect of C offset and demodulating modulated data correctly.
【０００８】[0008]
【課題を解決するための手段】請求項１に係る発明は、
フレーム内に無信号状態のシンボルを有する符号化直交
周波数分割多重信号を受信し、その受信信号をベースバ
ンド帯域に変換し、そのベースバンド信号を高速フーリ
エ変換して変調データを復調する符号化直交周波数分割
多重信号受信機において、ベースバンドに付加されてい
る直流電圧無信号状態での平均電圧に基づいて直流オフ
セット電圧を補正する補正手段を備えて構成される。The invention according to claim 1 is
Coded orthogonal that receives a coded orthogonal frequency division multiplexed signal that has a signalless symbol in a frame, converts the received signal to a baseband band, and fast Fourier transforms the baseband signal to demodulate modulated data. The frequency division multiplex signal receiver is configured to include a correction unit that corrects the DC offset voltage based on the average voltage in the no DC signal state added to the baseband.
【０００９】請求項２に係る発明は、請求項１の補正手
段が、ベースバンド信号から無信号状態での平均電圧を
検出するための検出手段と、検出手段の検出出力に応じ
てベースバンド信号に付加されている直流オフセット電
圧を減殺するための制御手段とを備えて構成される。According to a second aspect of the present invention, the correcting means of the first aspect detects the average voltage in the no-signal state from the baseband signal, and the baseband signal according to the detection output of the detecting means. Control means for reducing the DC offset voltage added to the.
【００１０】[0010]
【作用】この発明に係る符号化直交周波数分割多重信号
受信機は、ベースバンド信号に付加されている直流電圧
を無信号状態での平均電圧に基づいて減殺されるよう
に、変調データの復調の際に補正を与える補正手段を設
けることにより、直流オフセット電圧による悪影響を取
り除くことができる。The coded orthogonal frequency division multiplex signal receiver according to the present invention demodulates the modulated data so that the DC voltage added to the baseband signal is reduced based on the average voltage in the no signal state. By providing a correction means for providing correction at that time, the adverse effect of the DC offset voltage can be eliminated.
【００１１】[0011]
【実施例】図１はこの発明の一実施例のＣＯＦＤＭ信号
受信機の概略ブロック図である。図１において、ＲＦ−
ＩＦ周波数変換器１とディバイダ２と局部発振器３と位
相変換器４とミキサ５，６とＡ／Ｄ変換器９，１０とＦ
ＦＴ演算部１１とデータ処理部１２は前述の図３と同じ
であり、以下の点が異なっている。すなわち、Ａ／Ｄ変
換器９，１０の出力とＦＦＴ演算部１１との間にヌルシ
ンボル平均電圧測定回路１３と１４が接続される。ヌル
シンボル平均電圧測定回路１３，１４はＡ／Ｄ変換器
９，１０の出力であるディジタルのベースバンド信号Ｓ
1 ，Ｓ2 に含まれるヌルシンボル（無信号状態のシンボ
ル）での平均電圧を測定するものであり、測定された電
圧はオフセット調整回路１５，１６に与えられ、オフセ
ット電圧が調整されて電圧制御回路１７，１８に与えら
れる。電圧制御回路１７はＡ／Ｄ変換器９の基準電圧を
調整し、電圧制御回路１８はＡ／Ｄ変換器１０の基準電
圧を調整し、それぞれベースバンド信号に付加されるＤ
Ｃオフセットを減殺する。このように、ヌルシンボル平
均電圧測定回路１３，１４とオフセット調整回路１５，
１６と電圧制御回路１７，１８とを設けることにより、
ＤＣオフセットによる影響を除去でき、変調データを正
しく復調することができる。1 is a schematic block diagram of a COFDM signal receiver according to an embodiment of the present invention. In FIG. 1, RF-
IF frequency converter 1, divider 2, local oscillator 3, phase converter 4, mixers 5, 6, A / D converters 9, 10 and F
The FT calculation unit 11 and the data processing unit 12 are the same as those in FIG. 3 described above, and are different in the following points. That is, the null symbol average voltage measuring circuits 13 and 14 are connected between the outputs of the A / D converters 9 and 10 and the FFT calculator 11. The null symbol average voltage measuring circuits 13 and 14 output digital baseband signals S output from the A / D converters 9 and 10.
The average voltage of the null symbols (symbols in no signal state) included in 1 and S 2 is measured, and the measured voltage is given to the offset adjusting circuits 15 and 16, and the offset voltage is adjusted to control the voltage. It is provided to the circuits 17 and 18. The voltage control circuit 17 adjusts the reference voltage of the A / D converter 9, the voltage control circuit 18 adjusts the reference voltage of the A / D converter 10, and D added to the baseband signal, respectively.
C offset is reduced. In this way, the null symbol average voltage measuring circuits 13 and 14 and the offset adjusting circuit 15,
By providing 16 and voltage control circuits 17 and 18,
The influence of the DC offset can be removed, and the modulated data can be demodulated correctly.
【００１２】図２はこの発明の第２実施例のＣＯＦＤＭ
信号受信機のブロック図である。前述の図１に示した実
施例では、オフセット調整回路１５，１６の出力を電圧
制御回路１７，１８に与え、それぞれＡ／Ｄ変換器９，
１０の基準電圧を調整するようにしたが、この図２に示
した実施例では、ローパスフィルタ７，８とＡ／Ｄ変換
器９，１０の間にオペアンプ２１，２２を挿入し、オフ
セット調整回路１５，１６によって制御されるＤＣ制御
部１９，２０を設け、ＤＣ制御部１９，２０の出力によ
りオペアンプ２１，２２の出力電圧を調整するようにし
たものである。このように、オフセット調整回路１５，
１６によって制御されるＤＣ制御部１９，２０を制御
し、このＤＣ制御部１９，２０からオペアンプ２１，２
２に出力される電圧を調整することにより、ＤＣオフセ
ットを減殺し、変調データを正しく復調することができ
る。FIG. 2 shows a COFDM according to a second embodiment of the present invention.
It is a block diagram of a signal receiver. In the embodiment shown in FIG. 1 described above, the outputs of the offset adjusting circuits 15 and 16 are given to the voltage control circuits 17 and 18, and the A / D converter 9 and
Although the reference voltage of 10 is adjusted, in the embodiment shown in FIG. 2, the operational amplifiers 21 and 22 are inserted between the low pass filters 7 and 8 and the A / D converters 9 and 10 to adjust the offset adjustment circuit. DC control units 19 and 20 controlled by 15 and 16 are provided, and the output voltages of the operational amplifiers 21 and 22 are adjusted by the outputs of the DC control units 19 and 20. In this way, the offset adjustment circuit 15,
The DC control units 19 and 20 controlled by 16 are controlled by the DC control units 19 and 20.
By adjusting the voltage output to 2, the DC offset can be canceled and the modulated data can be demodulated correctly.
【００１３】[0013]
【発明の効果】以上のように、この発明によれば、ヌル
シンボルにおける平均電圧の結果により、変調データ復
調の際にＤＣオフセットを減殺できるので、ＤＣオフセ
ットの影響を受けることなく、変調データを正しく復調
することができる。As described above, according to the present invention, the DC offset can be canceled during the demodulation of the modulation data by the result of the average voltage in the null symbol, so that the modulation data is not affected by the DC offset. Can be demodulated correctly.
【図１】図１はこの発明の一実施例のＣＯＦＤＭ信号受
信機のブロック図である。FIG. 1 is a block diagram of a COFDM signal receiver according to an embodiment of the present invention.
【図２】この発明の第２実施例のＣＯＦＤＭ信号受信機
のブロック図である。FIG. 2 is a block diagram of a COFDM signal receiver according to a second embodiment of the present invention.
【図３】従来のＣＯＦＤＭ信号受信機のブロック図であ
る。FIG. 3 is a block diagram of a conventional COFDM signal receiver.
【図４】図３に示したＣＯＦＤＭ信号受信機におけるベ
ースバンド信号を示す図である。FIG. 4 is a diagram showing a baseband signal in the COFDM signal receiver shown in FIG.
１ ＲＦ−ＩＦ周波数変換部 ２ ディバイダ ３ 局部発振器 ４ 位相変換器 ５，６ ミキサ ７，８ ローパスフィルタ ９，１０ Ａ／Ｄ変換器 １１ ＦＦＴ演算部 １２ データ処理部 １３，１４ ヌルシンボル平均電圧測定回路 １５，１６ オフセット調整回路 １７，１８ 電圧制御回路 １９，２０ ＤＣ制御部 ２１，２２ オペアンプ 1 RF-IF Frequency Converter 2 Divider 3 Local Oscillator 4 Phase Converter 5,6 Mixer 7,8 Low Pass Filter 9,10 A / D Converter 11 FFT Calculator 12 Data Processor 13,14 Null Symbol Average Voltage Measuring Circuit 15, 16 Offset adjustment circuit 17, 18 Voltage control circuit 19, 20 DC control unit 21, 22 Operational amplifier
Claims (2)
する符号化直交周波数分割多重信号を受信し、その受信
信号をベースバンド帯域に変換し、そのベースバンド信
号を高速フーリエ変換して変調データを復調する符号化
直交周波数分割多重信号受信機において、 前記ベースバンドに付加されている直流電圧無信号状態
での平均電圧に基づいて直流オフセット電圧を補正する
補正手段を備えた、符号化直交周波数分割多重信号受信
機。1. A coded orthogonal frequency division multiplexed signal having a signalless symbol in a frame is received, the received signal is converted into a baseband band, and the baseband signal is subjected to fast Fourier transform to obtain modulated data. In the coded orthogonal frequency division multiplex signal receiver for demodulation, the coded orthogonal frequency division is provided with a correction means for correcting the DC offset voltage based on the average voltage in the no DC voltage signal state added to the baseband. Multiple signal receiver.
を検出するための検出手段と、 前記検出手段の検出出力に応じて、前記ベースバンド信
号に付加されている直流オフセット電圧を減殺するため
の制御手段を含む、請求項１の符号化直交周波数分割多
重信号受信機。2. The correcting means detects the average voltage in the no-signal state from the baseband signal, and is added to the baseband signal according to the detection output of the detecting means. 2. The coded orthogonal frequency division multiplex signal receiver of claim 1 including control means for canceling the DC offset voltage present.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5212576A JPH0766793A (en) | 1993-08-27 | 1993-08-27 | Receiver for encoded orthogonal frequency-divided multiplex signal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5212576A JPH0766793A (en) | 1993-08-27 | 1993-08-27 | Receiver for encoded orthogonal frequency-divided multiplex signal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0766793A true JPH0766793A (en) | 1995-03-10 |
Family
ID=16624993
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5212576A Withdrawn JPH0766793A (en) | 1993-08-27 | 1993-08-27 | Receiver for encoded orthogonal frequency-divided multiplex signal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0766793A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2735636A1 (en) * | 1995-06-16 | 1996-12-20 | Thomson Csf | METHOD AND DEVICE FOR OVER-SAMPLING AND FREQUENCY TRANSPOSITION OF A DIGITAL RADIO SIGNAL |
| WO1998001981A1 (en) * | 1996-07-08 | 1998-01-15 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and apparatus for compensating for a varying d.c. offset in a sampled signal |
| JP2000228638A (en) * | 1999-02-08 | 2000-08-15 | Sharp Corp | Ss radio receiver |
| JP2006254289A (en) * | 2005-03-14 | 2006-09-21 | Nec Corp | Dc offset removal control method, and transmitting and receiving apparatus |
| JP2007088983A (en) * | 2005-09-26 | 2007-04-05 | Sharp Corp | Ofdm reception circuit, communication apparatus, and broadcast receiver |
-
1993
- 1993-08-27 JP JP5212576A patent/JPH0766793A/en not_active Withdrawn
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2735636A1 (en) * | 1995-06-16 | 1996-12-20 | Thomson Csf | METHOD AND DEVICE FOR OVER-SAMPLING AND FREQUENCY TRANSPOSITION OF A DIGITAL RADIO SIGNAL |
| WO1997000566A2 (en) * | 1995-06-16 | 1997-01-03 | Thomson-Csf | Digital radio signal frequency translation and oversampling device and method |
| WO1997000566A3 (en) * | 1995-06-16 | 1997-01-23 | Thomson Csf | Digital radio signal frequency translation and oversampling device and method |
| WO1998001981A1 (en) * | 1996-07-08 | 1998-01-15 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and apparatus for compensating for a varying d.c. offset in a sampled signal |
| AU723089B2 (en) * | 1996-07-08 | 2000-08-17 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and apparatus for compensating for a varying D.C. offset in a sampled signal |
| JP2000514965A (en) * | 1996-07-08 | 2000-11-07 | テレフオンアクチーボラゲツト エル エム エリクソン（パブル） | Variable of sampled signal C. Method and apparatus for compensating offset |
| JP2000228638A (en) * | 1999-02-08 | 2000-08-15 | Sharp Corp | Ss radio receiver |
| JP2006254289A (en) * | 2005-03-14 | 2006-09-21 | Nec Corp | Dc offset removal control method, and transmitting and receiving apparatus |
| JP4661281B2 (en) * | 2005-03-14 | 2011-03-30 | 日本電気株式会社 | DC offset removal control method and transmitter / receiver |
| JP2007088983A (en) * | 2005-09-26 | 2007-04-05 | Sharp Corp | Ofdm reception circuit, communication apparatus, and broadcast receiver |
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