JPH05336187A - Demodulator - Google Patents
DemodulatorInfo
- Publication number
- JPH05336187A JPH05336187A JP16347292A JP16347292A JPH05336187A JP H05336187 A JPH05336187 A JP H05336187A JP 16347292 A JP16347292 A JP 16347292A JP 16347292 A JP16347292 A JP 16347292A JP H05336187 A JPH05336187 A JP H05336187A
- Authority
- JP
- Japan
- Prior art keywords
- band
- interference wave
- adjacent interference
- digital
- pass filters
- 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.)
- Granted
Links
Landscapes
- Noise Elimination (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、ＰＳＫ（Ｐｈａｓｅ
Ｓｈｉｆｔ Ｋｅｙｉｎｇ）変調方式衛星通信で使用さ
れる復調装置に関し、特に隣接干渉波による符号誤り率
を改善した復調装置に関する。BACKGROUND OF THE INVENTION The present invention relates to PSK (Phase).
TECHNICAL FIELD The present invention relates to a demodulation device used in Shift Keying) satellite communication, and more particularly to a demodulation device with an improved code error rate due to adjacent interference waves.
【０００２】[0002]
【従来の技術】従来のこの種の復調装置の構成を図４に
示す。2. Description of the Related Art The structure of a conventional demodulator of this type is shown in FIG.
【０００３】図４において、受信信号Ｓ１は、自動利得
増幅器１を通り、分配器２で２分され、それぞれミキサ
３，４へ入力される。そしてこのミキサ３，４におい
て、局部発振器５からの受信信号Ｓ１とほぼ同一の中間
周波数（ＩＦ）により準同期検波される。但し、局部発
振器５からのミキサ４への入力信号は、ミキサ３への入
力信号に対して９０°位相偏移器６により９０°位相が
偏移している。In FIG. 4, the received signal S1 passes through the automatic gain amplifier 1, is divided into two by the distributor 2, and is input to the mixers 3 and 4, respectively. Then, in the mixers 3 and 4, the quasi-coherent detection is performed with an intermediate frequency (IF) substantially the same as the received signal S1 from the local oscillator 5. However, the input signal from the local oscillator 5 to the mixer 4 is 90 ° out of phase with the input signal to the mixer 3 by the 90 ° phase shifter 6.
【０００４】ミキサ３，４の各出力信号は、それぞれ準
同期検波後のベースバンド信号の干渉波雑音除去用の低
域通過ろ波器７，８を介してアナログ−デジタル変換器
９，１０へ入力され、任意ビットのデジタル信号とな
り、次のデジタル復調器１３へ供給される。デジタル復
調器１３内では、デジタル信号処理により波形整形およ
び同期検波等が行われる。このようにして、復調された
ＰＣＭ，ＱＣＨ信号とクロックが次段の誤り訂正器１５
へ送られ、ここで、必要に応じて誤りが訂正されて受信
復調データＳ２と受信クロックＳ３が出力される。The output signals of the mixers 3 and 4 are passed to the analog-digital converters 9 and 10 via the low-pass filters 7 and 8 for removing the interference wave noise of the baseband signal after the quasi-coherent detection. It is input, becomes a digital signal of an arbitrary bit, and is supplied to the next digital demodulator 13. In the digital demodulator 13, waveform shaping and synchronous detection are performed by digital signal processing. In this way, the demodulated PCM and QCH signals and the clock are the error corrector 15 in the next stage.
Then, the received demodulated data S2 and the received clock S3 are output after error correction, if necessary.
【０００５】なお、デジタル復調器１３から、アナログ
−デジタル変換器９，１０のサンプリングクロック用の
デジタル信号をデジタル−アナログ変換器１１へ送り、
次段の電圧制御発振器１２によりアナログ−デジタル変
換器９，１０のサンプリングクロックを生成している。The digital signal for the sampling clock of the analog-digital converters 9 and 10 is sent from the digital demodulator 13 to the digital-analog converter 11,
The voltage controlled oscillator 12 in the next stage generates the sampling clock for the analog-digital converters 9 and 10.
【０００６】更に、デジタル復調器１３からデジタル−
アナログ変換器１４へデジタル信号を供給して、このデ
ジタル−アナログ変換器１４の出力信号により、自動利
得増幅器１の利得を制御している。Further, the digital demodulator 13 outputs a digital signal.
A digital signal is supplied to the analog converter 14, and the output signal of the digital-analog converter 14 controls the gain of the automatic gain amplifier 1.
【０００７】[0007]
【発明が解決しようとする課題】従来の復調装置は上述
したような構成を有しており、限られた条件の下では充
分に機能するものであったが、希望受信波に隣接して干
渉波が存在し、その干渉波のレベルが高いと、低域通過
ろ波器７，８で充分に干渉波を抑圧しきれず、符号誤り
率が大きくなるという問題点があった。The conventional demodulation device has the above-mentioned structure and is fully functional under the limited conditions, but it interferes with the desired received wave. If a wave exists and the level of the interference wave is high, there is a problem that the low-pass filters 7 and 8 cannot sufficiently suppress the interference wave and the code error rate increases.
【０００８】そこで本発明の目的は、隣接干渉波による
符号誤り率の劣化を改善することができる復調装置を提
供することにある。Therefore, an object of the present invention is to provide a demodulator which can improve the deterioration of the code error rate due to adjacent interference waves.
【０００９】[0009]
【課題を解決するための手段】本発明は上記の目的を達
成するために、準同期検波復調回路と誤り訂正器と自動
利得増幅器等を有する復調装置において、準同期検波後
のベースバンド信号の干渉波雑音除去用に帯域可変低域
通過ろ波器等の帯域可変ろ波器を備え、且つ、この帯域
可変ろ波器の入力端の隣接干渉波レベルを監視するため
に、帯域通過ろ波器，検波器，アナログ−デジタル変換
器等の手段を備え、更に、この手段によって監視された
隣接干渉波レベルに応じて例えばデジタル−アナログ変
換器を介して前記帯域可変ろ波器の帯域幅を制御する制
御手段を備えている。In order to achieve the above object, the present invention provides a demodulator having a quasi-coherent detection demodulation circuit, an error corrector, an automatic gain amplifier, etc. A band-variable low-pass filter such as a band-variable low-pass filter is provided to remove interference noise, and the band-pass filter is used to monitor the level of adjacent interference at the input end of this band-variable filter. Means such as a detector, a detector, an analog-digital converter, etc., and further, according to the level of the adjacent interference wave monitored by this means, the bandwidth of the band variable filter is changed, for example, via the digital-analog converter. The control means for controlling is provided.
【００１０】[0010]
【作用】本発明の復調装置においては、帯域通過ろ波
器，検波器，アナログ−デジタル変換器等の手段が、準
同期検波後のベースバンド信号から干渉波雑音を除去す
る帯域可変低域通過ろ波器等の帯域可変ろ波器に入力さ
れる隣接干渉波レベルを監視し、制御手段が、この手段
によって監視された隣接干渉波レベルに応じて例えばデ
ジタル−アナログ変換器を介して前記帯域可変ろ波器の
帯域幅を制御して隣接干渉波が帯域可変ろ波器で充分に
抑圧されるようにする。In the demodulator of the present invention, means such as a bandpass filter, a detector, and an analog-digital converter removes interference noise from the baseband signal after the quasi-coherent detection. The adjacent interference wave level input to the band variable filter such as a filter is monitored, and the control means responds to the adjacent interference wave level monitored by this means by, for example, a digital-analog converter to change the band. The bandwidth of the variable filter is controlled so that adjacent interference waves are sufficiently suppressed by the variable filter.
【００１１】[0011]
【実施例】次に本発明の実施例について図面を参照して
詳細に説明する。Embodiments of the present invention will now be described in detail with reference to the drawings.
【００１２】図１は本発明の復調装置の一実施例のブロ
ック図であり、既に参照した図４と同一符号は同一部分
を示し、１０１，１０２は帯域可変低域通過ろ波器、１
０３，１０４は帯域通過ろ波器、１０５，１０６は検波
器、１０７，１０８はアナログ−デジタル変換器、１０
９は制御器、１１０はデジタル−アナログ変換器、Ｓ４
は同期信号である。FIG. 1 is a block diagram of an embodiment of a demodulation device of the present invention. The same reference numerals as those in FIG. 4 referred to above indicate the same parts, and 101 and 102 are band variable low-pass filters and 1
Reference numerals 03 and 104 are band pass filters, reference numerals 105 and 106 are detectors, reference numerals 107 and 108 are analog-digital converters, and 10
9 is a controller, 110 is a digital-analog converter, S4
Is a synchronization signal.
【００１３】本実施例の復調装置が図４に示した従来の
復調装置と相違するところは、図４の低域通過ろ波器
７，８に代えて帯域可変低域通過ろ波器１０１，１０２
を備え、その入力端の隣接干渉波レベルを監視するため
に、帯域通過ろ波器１０３，１０４と、その出力を検波
する検波器１０５，１０６と、その出力をデジタル信号
に変換するアナログ−デジタル変換器１０７，１０８と
を備え、更に、このアナログ−デジタル変換器１０７，
１０８から出力される隣接干渉波のレベルに応じてデジ
タル−アナログ変換器１１０を介して帯域可変低域通過
ろ波器１０１，１０２の帯域幅を制御する制御器１０９
を備えた点にある。The demodulator of this embodiment is different from the conventional demodulator shown in FIG. 4 in that instead of the low pass filters 7 and 8 shown in FIG. 4, a variable band low pass filter 101, 102
And bandpass filters 103 and 104, detectors 105 and 106 that detect the outputs of the bandpass filters 103 and 104, and analog-digital converters that convert the outputs to digital signals in order to monitor the level of the adjacent interference wave at the input end. Converters 107 and 108, and the analog-digital converter 107,
A controller 109 that controls the bandwidth of the band variable low-pass filters 101 and 102 via a digital-analog converter 110 according to the level of the adjacent interference wave output from 108.
Is equipped with.
【００１４】図２に、帯域可変低域通過ろ波器１０１，
１０２の入力端、即ちベースバンド帯での希望波と隣接
干渉波との関係および低域通過ろ波器の帯域特性例を、
縦軸にレベルを、横軸に周波数をとって示す。この図２
に示されるように、希望波の中心からΔｆだけ離れたと
ころに希望波より高いレベルの干渉波が存在する場合、
帯域可変低域通過ろ波器１０１，１０２の代わりに図４
の従来の復調装置のように例えば図２の破線で示すよう
な固定の帯域特性を持つ低域通過ろ波器７，８を使用す
ると、それによって隣接干渉波の電力は或る程度軽減さ
れるものの、隣接干渉波のレベルが非常に高くなると、
固定の帯域特性を持つ低域通過ろ波器７，８では充分に
軽減されずにアナログ−デジタル変換器９，１０の入力
に供給され、このアナログ−デジタル変換器９，１０を
飽和させてしまう。そのため、復調データの符号誤り率
が劣化する。FIG. 2 shows a band variable low pass filter 101,
The relationship between the desired wave and the adjacent interference wave at the input end of 102, that is, the baseband, and the band characteristic example of the low-pass filter,
The vertical axis represents level and the horizontal axis represents frequency. This Figure 2
As shown in, when there is an interference wave at a level higher than the desired wave at a distance Δf from the center of the desired wave,
Instead of the band-variable low-pass filters 101 and 102, FIG.
When the low pass filters 7 and 8 having fixed band characteristics as shown by the broken line in FIG. 2 are used as in the conventional demodulator of FIG. 2, the power of the adjacent interference wave is reduced to some extent. However, when the level of the adjacent interference wave becomes very high,
The low-pass filters 7 and 8 having a fixed band characteristic are not sufficiently reduced and are supplied to the inputs of the analog-digital converters 9 and 10 to saturate the analog-digital converters 9 and 10. . Therefore, the code error rate of the demodulated data deteriorates.
【００１５】図３に、低域通過ろ波器の帯域幅と符号誤
り率の劣化との関係を示す。この図３において、破線
は、低域通過ろ波器の帯域幅と隣接干渉波による符号誤
り率との関係を示しており、低域通過ろ波器の帯域幅を
小さくすればするほど隣接干渉波の影響が小さくなるこ
とを表している。一方、図３の実線は、低域通過ろ波器
の帯域幅と希望波の波形歪による符号誤り率との関係を
示しており、低域通過ろ波器の帯域幅を小さくすると、
希望波の波形に歪が生じて希望波信号自体の符号誤り率
が劣化することを表している。FIG. 3 shows the relationship between the bandwidth of the low-pass filter and the deterioration of the code error rate. In FIG. 3, the broken line shows the relationship between the bandwidth of the low-pass filter and the code error rate due to the adjacent interference wave. The smaller the bandwidth of the low-pass filter, the closer the interference. It shows that the influence of the wave becomes small. On the other hand, the solid line in FIG. 3 shows the relationship between the bandwidth of the low-pass filter and the code error rate due to the waveform distortion of the desired wave. When the bandwidth of the low-pass filter is reduced,
This indicates that the waveform of the desired wave is distorted and the code error rate of the desired wave signal itself is deteriorated.
【００１６】そこで、本実施例では、図１に示すよう
に、隣接干渉波を帯域通過ろ波器１０３，１０４で抽出
し、それを検波器１０５，１０６で検波後、アナログ−
デジタル変換器１０７，１０８に通すことによって、隣
接干渉波のレベルをデジタル信号とし、これを制御器１
０９に入力して隣接干渉波のレベルを監視し、隣接干渉
波のレベルに応じて、デジタル−アナログ変換器１１０
を介して帯域可変低域通過ろ波器１０１，１０２の帯域
幅を総合的な符号誤り率が最小となる最適値に設定す
る。Therefore, in the present embodiment, as shown in FIG. 1, the adjacent interference waves are extracted by the bandpass filters 103 and 104, detected by the wave detectors 105 and 106, and then analog-
By passing the signals through the digital converters 107 and 108, the level of the adjacent interference wave is converted into a digital signal, and the digital signal is supplied to the controller 1
09 to monitor the level of the adjacent interference wave, and according to the level of the adjacent interference wave, the digital-analog converter 110
The bandwidth of the band-variable low-pass filters 101 and 102 is set to the optimum value with which the overall code error rate is minimized.
【００１７】その最適値は、実線で示される劣化の程度
と破線で示される劣化の程度とを加え合わせた劣化の程
度が最小となるときの帯域幅である。制御器１０９に
は、隣接干渉波の幾つかのレベル毎にその帯域幅の最適
値が記憶されており、検出した隣接干渉波のレベルに対
応する最適値の帯域幅となるように帯域幅可変低域通過
ろ波器１０１，１０２を制御する。The optimum value is the bandwidth when the degree of deterioration obtained by adding the degree of deterioration shown by the solid line and the degree of deterioration shown by the broken line is minimum. The controller 109 stores the optimum value of the bandwidth for each of several levels of the adjacent interference waves, and the bandwidth is changed so that the optimum value of the bandwidth corresponds to the detected level of the adjacent interference waves. It controls the low pass filters 101 and 102.
【００１８】但し、この帯域幅の設定は、誤り訂正器１
５が同期した状態で行われなくてはならないため、その
同期信号Ｓ４を制御器１０９が常に監視している。ま
た、この同期している状態では、自動利得増幅器１の制
御も正常に行われているため、検波器１０５，１０６で
の検波信号も正しい値となっている。However, the bandwidth is set by the error corrector 1
5 must be performed in a synchronized state, the controller 109 constantly monitors the synchronization signal S4. Further, in this synchronized state, the control of the automatic gain amplifier 1 is also normally performed, so that the detection signals of the detectors 105 and 106 have correct values.
【００１９】[0019]
【発明の効果】以上説明したように、本発明の復調装置
は、準同期検波後のベースバンド信号の干渉波雑音除去
用に帯域可変低域通過ろ波器等の帯域可変ろ波器を使用
し、隣接干渉波のレベルを常に監視してそのレベルに応
じて帯域可変ろ波器の帯域幅を制御することにより隣接
干渉波を充分に抑圧するようにしたので、隣接干渉波に
よる復調データの符号誤り率の劣化を防止できる効果が
ある。As described above, the demodulator of the present invention uses the band variable filter such as the band variable low pass filter for removing the interference noise of the baseband signal after the quasi-coherent detection. However, the level of the adjacent interference wave is constantly monitored and the adjacent interference wave is sufficiently suppressed by controlling the bandwidth of the variable band filter according to the level. There is an effect that the deterioration of the code error rate can be prevented.
【図１】本発明の一実施例の復調装置のブロック図であ
る。FIG. 1 is a block diagram of a demodulation device according to an embodiment of the present invention.
【図２】ベースバンド帯での希望波と隣接干渉波の関係
と低域通過ろ波器の帯域特性例を示す図である。FIG. 2 is a diagram showing a relationship between a desired wave and an adjacent interference wave in a baseband band and an example of band characteristics of a low-pass filter.
【図３】低域通過ろ波器の帯域幅と符号誤り率の劣化と
の関係を示す図である。FIG. 3 is a diagram showing a relationship between a bandwidth of a low pass filter and deterioration of a code error rate.
【図４】従来の復調装置のブロック図である。FIG. 4 is a block diagram of a conventional demodulation device.
１…自動利得増幅器 ２…分配器 ３，４…ミキサ ５…局部発振器 ６…９０°位相偏移器 ７，８…低域通過ろ波器 ９，１０…アナログ−デジタル変換器 １１…デジタル−アナログ変換器 １２…電圧制御発振器 １３…デジタル復調器 １４…デジタル−アナログ変換器 １５…誤り訂正器 １０１，１０２…帯域可変低域通過ろ波器 １０３，１０４…帯域通過ろ波器 １０５，１０６…検波器 １０７，１０８…アナログ−デジタル変換器 １０９…制御器 １１０…デジタル−アナログ変換器 Ｓ１…受信信号 Ｓ２…受信復調データ Ｓ３…受信クロック Ｓ４…同期信号 1 ... Automatic gain amplifier 2 ... Distributor 3,4 ... Mixer 5 ... Local oscillator 6 ... 90 ° phase shifter 7,8 ... Low pass filter 9,10 ... Analog-digital converter 11 ... Digital-analog Converter 12 ... Voltage controlled oscillator 13 ... Digital demodulator 14 ... Digital-analog converter 15 ... Error corrector 101, 102 ... Band variable low-pass filter 103, 104 ... Band pass filter 105, 106 ... Detection Units 107, 108 ... Analog-digital converter 109 ... Controller 110 ... Digital-analog converter S1 ... Received signal S2 ... Received demodulation data S3 ... Received clock S4 ... Synchronous signal
Claims (1)
波雑音除去用に帯域可変ろ波器を備え、且つ、 該帯域可変ろ波器の入力端の隣接干渉波レベルを監視す
る手段と、 該手段によって監視された隣接干渉波レベルに応じて前
記帯域可変ろ波器の帯域幅を制御する制御手段とを備え
たことを特徴とする復調装置。1. A band-variable filter for removing interference wave noise of a baseband signal after quasi-coherent detection, and means for monitoring an adjacent interference wave level at an input end of the band-variable filter, A demodulation device comprising: a control unit that controls the bandwidth of the variable band filter according to the adjacent interference wave level monitored by the unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16347292A JP2874457B2 (en) | 1992-05-29 | 1992-05-29 | Demodulator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16347292A JP2874457B2 (en) | 1992-05-29 | 1992-05-29 | Demodulator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05336187A true JPH05336187A (en) | 1993-12-17 |
| JP2874457B2 JP2874457B2 (en) | 1999-03-24 |
Family
ID=15774524
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16347292A Expired - Fee Related JP2874457B2 (en) | 1992-05-29 | 1992-05-29 | Demodulator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2874457B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008035413A (en) * | 2006-07-31 | 2008-02-14 | Fujitsu Ltd | Receiver and receiving method |
| JP2008521357A (en) * | 2004-11-19 | 2008-06-19 | クゥアルコム・インコーポレイテッド | Filter and adjustable delay unit for narrowband noise reduction |
| JP2010505359A (en) * | 2006-09-29 | 2010-02-18 | センサーマティック・エレクトロニクス・コーポレーション | Adaptive filter and method for filtering radio frequency identification signals |
| CN102077473A (en) * | 2008-07-01 | 2011-05-25 | 高通股份有限公司 | Dynamic filtering for adjacent channel interference suppression |
-
1992
- 1992-05-29 JP JP16347292A patent/JP2874457B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008521357A (en) * | 2004-11-19 | 2008-06-19 | クゥアルコム・インコーポレイテッド | Filter and adjustable delay unit for narrowband noise reduction |
| JP2011250427A (en) * | 2004-11-19 | 2011-12-08 | Qualcomm Incorporated | Filter for narrowband noise reduction and adjustable delay unit |
| US8243864B2 (en) | 2004-11-19 | 2012-08-14 | Qualcomm, Incorporated | Noise reduction filtering in a wireless communication system |
| JP2008035413A (en) * | 2006-07-31 | 2008-02-14 | Fujitsu Ltd | Receiver and receiving method |
| JP2010505359A (en) * | 2006-09-29 | 2010-02-18 | センサーマティック・エレクトロニクス・コーポレーション | Adaptive filter and method for filtering radio frequency identification signals |
| CN102077473A (en) * | 2008-07-01 | 2011-05-25 | 高通股份有限公司 | Dynamic filtering for adjacent channel interference suppression |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2874457B2 (en) | 1999-03-24 |
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