JPH0740643B2 - Demodulation distortion removal circuit - Google Patents
Demodulation distortion removal circuitInfo
- Publication number
- JPH0740643B2 JPH0740643B2 JP23644985A JP23644985A JPH0740643B2 JP H0740643 B2 JPH0740643 B2 JP H0740643B2 JP 23644985 A JP23644985 A JP 23644985A JP 23644985 A JP23644985 A JP 23644985A JP H0740643 B2 JPH0740643 B2 JP H0740643B2
- Authority
- JP
- Japan
- Prior art keywords
- output
- multiplier
- signal
- detection
- hilbert
- 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.)
- Expired - Fee Related
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- Mobile Radio Communication Systems (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、伝搬路で受けた振幅歪を除去する目的で復調
部に振幅制限器が用いられるSSB無線通信方式におい
て、復調信号に含まれる歪を除去するための回路に関す
るものである。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is included in a demodulated signal in an SSB wireless communication system in which an amplitude limiter is used in a demodulator for the purpose of removing amplitude distortion received in a propagation path. The present invention relates to a circuit for removing distortion.
（従来の技術） 送信側で情報信号でSSB変調した後、これに搬送波を付
加して送信信号となし、受信側で該信号を受信した後、
振幅制限器を用いてその振幅を一定にしてから周波数検
波により復調するように構成された無線通信系では、復
調歪を少なくするためにSSB信号に比べて搬送波のレベ
ルを大きくする必要があったため、情報伝送のための電
力効率が低くなるという欠点があった。(Prior Art) After SSB modulation with an information signal on the transmission side, a carrier wave is added to this to form a transmission signal, and after receiving the signal on the reception side,
In a wireless communication system configured to use an amplitude limiter to keep its amplitude constant and then demodulate by frequency detection, it was necessary to increase the carrier level compared to the SSB signal in order to reduce demodulation distortion. However, there is a drawback that the power efficiency for information transmission becomes low.
従来の歪除去回路として、２次歪を除去する回路が本出
願人により出願されているが（特願昭60−12618,特願昭
60−23646）、使用目的によっては更に高次の歪まで除
去しなければならない。As a conventional distortion removing circuit, a circuit for removing secondary distortion has been filed by the present applicant (Japanese Patent Application No. 60-12618, Japanese Patent Application No.
60-23646), depending on the purpose of use, higher-order distortion must be removed.
（発明が解決しようとする問題点） 本発明は、上記問題点を解決するために、復調部で発生
する歪を除去することにより、搬送波レベルを高くする
ことなく高品質な伝送を可能とする復調方式を提供する
ものである。(Problems to be Solved by the Invention) In order to solve the above problems, the present invention enables high-quality transmission without increasing the carrier level by removing the distortion generated in the demodulation unit. It provides a demodulation method.
（問題点を解決するための手段） 本発明の特徴は、送信側で情報信号でSSB変調した後、
これに搬送波を付加して送信信号となし、受信側で該信
号を受信した後、振幅制限器を用いてその振幅を一定に
してから周波数検波により復調するように構成された無
線通信系において、検波出力ｖと該出力に対しヒルベル
ト変換を行うヒルベルト変換器出力との乗算を行なう第
１の乗算器（３）、該第１の乗算器（３）の出力に対し
ヒルベルト変換を行なうヒルベルト変換器（５）の出力
と検波出力の乗算を行なう第２の乗算器（６）、検波出
力同士の乗算を行なう第３の乗算器（７）の出力と検波
出力との乗算を行なう第４の乗算器（８）、および該第
４の乗算器（８）の出力の振幅を（−1/3）倍する増幅
器を有し、前記第１の乗算器（３）および前記第２の乗
算器（６）の出力と増幅器出力および検波出力を加算合
成することにより復調出力を得る復調歪除去回路にあ
る。(Means for Solving Problems) A feature of the present invention is that after SSB modulation with an information signal on the transmission side,
In a wireless communication system configured to add a carrier wave to this to form a transmission signal, receive the signal on the receiving side, and then make the amplitude constant using an amplitude limiter and demodulate by frequency detection, A first multiplier (3) that multiplies the detection output v and an output of a Hilbert transformer that performs the Hilbert transform on the output, and a Hilbert transformer that performs the Hilbert transform on the output of the first multiplier (3) A second multiplier (6) that multiplies the output of (5) and the detection output, and a fourth multiplication that multiplies the output of the third multiplier (7) that multiplies the detection outputs by the detection output. (8) and an amplifier that multiplies the amplitude of the output of the fourth multiplier (8) by (−1/3), and the first multiplier (3) and the second multiplier ( By adding and combining the output of 6) with the amplifier output and the detection output, In the demodulation distortion elimination circuit to obtain an output.
（実施例） 第１図は本発明の実施例であって、１は信号入力端子、
２はヒルベルト変換器、３は乗算器、４は加算器、５は
ヒルベルト変換器、６は乗算器、７は乗算器、８は乗算
器、９は増幅器、10は信号出力端子である。(Embodiment) FIG. 1 shows an embodiment of the present invention, in which 1 is a signal input terminal,
2 is a Hilbert transformer, 3 is a multiplier, 4 is an adder, 5 is a Hilbert transformer, 6 is a multiplier, 7 is a multiplier, 8 is a multiplier, 9 is an amplifier, and 10 is a signal output terminal.
送信側で情報信号でSSB変調した後、これに搬送波を付
加して送信信号となし、受信側で該信号を受信した後、
振幅制限器を用いてその振幅を一定にしてから周波数検
波した信号を第１図の信号入力端子１に導く。信号入力
端子に入力された検波信号は６分され、ヒルベルト変換
器２、乗算器３、加算器４、乗算器６、乗算器７および
乗算器８にそれぞれ入力される。ヒルベルト変換器２の
出力は乗算器３に入力され検波出力信号との乗算を行な
う。乗算器３の出力は２分され、加算器４およびヒルベ
ルト変換器５に入力される。ヒルベルト変換器５の出力
は乗算器６に入力され検波出力信号と乗算される。乗算
器６の出力は加算器４に入力される。乗算器７の出力は
乗算器８に入力され別に入力された検波出力信号との間
で乗算される。乗算器８の出力は増幅器９によりゲイン
（−1/3）で増幅されその出力は加算器４に入力され
る。加算器４の出力として得られた２次および３次の高
調波成分を除去された復調信号成分は信号出力端子10に
出力される。After SSB modulation with an information signal on the transmission side, a carrier wave is added to this to form a transmission signal, and after receiving the signal on the reception side,
A signal whose frequency is detected after the amplitude is made constant by using an amplitude limiter is led to the signal input terminal 1 of FIG. The detection signal input to the signal input terminal is divided into 6 and input to the Hilbert transformer 2, the multiplier 3, the adder 4, the multiplier 6, the multiplier 7 and the multiplier 8, respectively. The output of the Hilbert transformer 2 is input to the multiplier 3 and multiplied with the detection output signal. The output of the multiplier 3 is divided into two and input to the adder 4 and the Hilbert transformer 5. The output of the Hilbert transformer 5 is input to the multiplier 6 and multiplied by the detection output signal. The output of the multiplier 6 is input to the adder 4. The output of the multiplier 7 is input to the multiplier 8 and multiplied by the separately detected detection output signal. The output of the multiplier 8 is amplified by the amplifier 9 with a gain (-1/3), and its output is input to the adder 4. The demodulated signal component obtained by removing the second and third harmonic components obtained as the output of the adder 4 is output to the signal output terminal 10.
次に、数式を用いて本発明の動作原理を詳しく説明す
る。Next, the operation principle of the present invention will be described in detail using mathematical expressions.
帯域制限された情報信号ｇ（ｔ）を以下のように解析信
号表示する。The band-limited information signal g (t) is displayed as an analytic signal as follows.
ａ（ｔ）＝ｇ（ｔ）＋ｊ（ｔ） （１） ここで、（ｔ）はｇ（ｔ）のヒルベルト変換を示す。a (t) = g (t) + j (t) (1) Here, (t) represents the Hilbert transform of g (t).
搬送波角周波数をωＣとすると、搬送波を付加したSSB
信号ｓ（ｔ）は ｓ（ｔ）＝cos ωCt＋ｍ〔ｇ（ｔ）cos ωCt ＋（ｔ）sinωCt〕 ＝Acos〔ωCt−ω（ｔ）〕 （２） ω（ｔ）＝arctan〔ｍ（ｔ）／（１＋mg（ｔ））〕
（４） と表示される。ここで、振幅制限器の使用を可能とする
ためには、１＞|mg（ｔ）｜を満たす必要がある。When the carrier frequency is ω C , SSB with carrier added
The signal s (t) is s (t) = cos ω C t + m [g (t) cos ω C t + (t) sin ω C t] = A cos [ω C t−ω (t)] (2) ω (t) = arctan [m (t) / (1 + mg (t))]
(4) is displayed. Here, in order to enable the use of the amplitude limiter, it is necessary to satisfy 1> | mg (t) |.
振幅制限器出力を周波数検波したときの検波出力ｅ
（ｔ）は ｅ（ｔ）＝d/dt（ωCt＋ω（ｔ））＝ωＣ ＋［ω（ｔ）］′∞fC＋（1/2π）［ｍ′（ｔ） −m2［′（ｔ）ｇ（ｔ）＋（ｔ）ｇ′（ｔ）］ ＋m3［′（ｔ）g2（ｔ）−′（ｔ）２（ｔ） ＋2g′（ｔ）ｇ（ｔ）（ｔ）］＋０（m4）］ （５） となる。ここで、ω（ｔ）′はω（ｔ）の時間微分を表
わす。Detection output when the amplitude limiter output is frequency detected e
(T) is e (t) = d / dt (ω C t + ω (t)) = ω C + [ω (t)] '∞f C + (1 / 2π) [m' (t) -m 2 [ '(t) g (t) + (t) g' (t)] + m 3 [ '(t) g 2 (t) -' (t) 2 (t) + 2g '(t) g (t) (t )] + 0 (m 4 )] (5). Here, ω (t) ′ represents the time derivative of ω (t).
式（５）は周波数検波の原理に基づくもので、当業者に
とって周知であるが以下のとおり、式（５）の導出過程
を示す。Expression (5) is based on the principle of frequency detection, and is well known to those skilled in the art, but the derivation process of expression (5) will be shown as follows.
式（２）のcos（ｘ）のｘを微分したものが周波数検波
器の出力として得られるから、 となる。fCは搬送波周波数である。さらに、係数を除い
て、 となるから、次式を得る。Since the derivative of x of cos (x) in equation (2) is obtained as the output of the frequency detector, Becomes f C is the carrier frequency. Furthermore, except for the coefficient, Therefore, the following equation is obtained.
（１＋ｘ）-1＝１−ｘ＋x2−x3＋０（x4） ０（x4）は４次以上の高次項を示す。 (1 + x) -1 = 1 -x + x 2 -x 3 +0 (x 4) 0 (x 4) indicates the higher-order terms of the above fourth order.
であるから、ヒルベルト変換における関係式、 を用いて、 ［１＋m2＋2mg（ｔ）］-1＝１−m2−2mg（ｔ） ＋［m2＋2mg（ｔ）］２＋［m2＋2mg（ｔ）］３＋… となる。従って、 となり、式（５）で与えられるｅ（ｔ）が得られる。Therefore, the relational expression in Hilbert transform, Is used, [1 + m 2 +2 mg (t)] −1 = 1−m 2 −2 mg (t) + [m 2 +2 mg (t)] 2 + [m 2 +2 mg (t)] 3 +. Therefore, Thus, e (t) given by equation (5) is obtained.
なお、式（２）〜（５）で g2（ｔ）＝ｇ（ｔ）2,g′（ｔ）＝ｇ（ｔ）′である。Note that in equations (2) to (5) g 2 (t) = g (t) 2 and g ′ (t) = g (t) ′.
式（５）で与えられる信号の交流成分を積分器を通して
得る検波出力は次のようになる。ただし係数（1/2π）
を無視する。The detection output for obtaining the AC component of the signal given by equation (5) through the integrator is as follows. However, coefficient (1 / 2π)
Ignore.
ｖ（ｔ）＝ｍ（ｔ）−m2（ｔ）ｇ（ｔ） ＋m3〔（ｔ）g2（ｔ）−（1/3）３（ｔ）〕＋０（m
4） （６） なる信号を得る。式（６）の第１項は基本波成分、第２
項および第３項はそれぞれ２次高調波成分および３次高
調波成分である。いま、 ＋（1/3）ｖ（ｔ）３＋０（m4） （７） とすることにより式（６）の第２項および第３項を除去
することができ、復調信号には式（８）が示すように４
次以上の高調波成分のみが含まれることになり歪率の向
上が可能となる。v (t) = m (t ) -m 2 (t) g (t) + m 3 [(t) g 2 (t) - (1/3) 3 (t) ] + 0 (m
4 ) (6) Obtain the following signal. The first term of equation (6) is the fundamental wave component, and the second term is
The term and the third term are the second harmonic component and the third harmonic component, respectively. Now + (1/3) v (t) 3 +0 (m 4 ) (7) makes it possible to remove the second term and the third term of the equation (6), and the demodulated signal is given by the equation (8). As shown by 4
Only the harmonic components of the second and higher order are included, and the distortion factor can be improved.
ｕ（ｔ）＝ｍ（ｔ）＋０（m4） （８） 情報信号が音声信号の場合にはｕ（ｔ）をもって復調信
号としてもよいが、データ信号のようにパルス信号によ
って変調が施されている場合には、パルス波形の崩れを
防ぐために、式（８）で示した信号をヒルベルト変換器
を通す必要がある。このとき、ヒルベルト変換器出力と
して ｗ（ｔ）＝mg（ｔ）＋０（m4） （９） を得る。u (t) = m (t) +0 (m 4 ) (8) When the information signal is a voice signal, u (t) may be used as the demodulated signal, but it is modulated by a pulse signal like a data signal. In this case, in order to prevent the collapse of the pulse waveform, it is necessary to pass the signal shown in equation (8) through the Hilbert transformer. At this time, w (t) = mg (t) +0 (m 4 ) (9) is obtained as the output of the Hilbert transformer.
次に、第１図に示した式（７）の第２項および第３項を
除去する回路部分の動作を説明する。ヒルベルト変換器
２の出力は（ｔ）であるから乗算器３の出力は式
（７）第２項を与える。ヒルベルト変換器５の出力は であるから乗算器６の出力は式（７）第３項を与える。
乗算器７の出力はｖ（ｔ）２であり、乗算器８の出力は
ｖ（ｔ）３となるから増幅器９の出力は式（７）第４項
を与える。従って、加算器４の出力は式（７）で与えら
れる。なお、式（７）を満足する限り実施例以外の回路
構成を採っても同様な改善効果が得られる。Next, the operation of the circuit portion for removing the second and third terms of the equation (7) shown in FIG. 1 will be described. Since the output of the Hilbert transformer 2 is (t), the output of the multiplier 3 gives the second term of equation (7). The output of the Hilbert converter 5 is Therefore, the output of the multiplier 6 gives the third term of equation (7).
Since the output of the multiplier 7 is v (t) 2 and the output of the multiplier 8 is v (t) 3 , the output of the amplifier 9 gives the fourth term of equation (7). Therefore, the output of the adder 4 is given by the equation (7). As long as Expression (7) is satisfied, the same improvement effect can be obtained even if a circuit configuration other than the embodiment is adopted.
音声信号の第１フォルマントは200−1200Hz,第２フォル
マントは1kHz−3kHz程度となっている（大泉・藤村共
著，“音声科学",東京大学出版会）。このため、３次高
調波程度まで抑圧すれば聴感上ほぼ自然な復調信号が得
られる。The first formant of the audio signal is 200-1200Hz, and the second formant is about 1kHz-3kHz (Oizumi and Fujimura, "Speech Science", The University of Tokyo Press). Therefore, if it is suppressed to about the third harmonic, a demodulated signal that is almost natural to the audible sense can be obtained.
（発明の効果） 以上説明したように、本発明の回路を用いることによっ
て検波信号に含まれる歪を除去でき、伝送品質の改善が
できる。さらに、SSB信号に付加する搬送波のレベルを
大きくする必要が無くなるため、情報伝送のための電力
効率を高められるという利点がある。(Effects of the Invention) As described above, by using the circuit of the present invention, the distortion included in the detected signal can be removed and the transmission quality can be improved. Further, since it is not necessary to increase the level of the carrier wave added to the SSB signal, there is an advantage that power efficiency for information transmission can be improved.
第１図は、本発明の一実施例のブロック図である。 １……入力信号端子、２……ヒルベルト変換器、 ３……乗算器、４……加算器、 ５……ヒルベルト変換器、６……乗算器、 ７……乗算器、８……乗算器、 ９……増幅器、10……出力信号端子。 FIG. 1 is a block diagram of an embodiment of the present invention. 1 ... Input signal terminal, 2 ... Hilbert converter, 3 ... Multiplier, 4 ... Adder, 5 ... Hilbert converter, 6 ... Multiplier, 7 ... Multiplier, 8 ... Multiplier , 9 …… Amplifier, 10 …… Output signal terminal.
Claims (1)
に搬送波を付加して送信信号となし、受信側で該信号を
受信した後、振幅制限器を用いてその振幅を一定にして
から周波数検波により復調するように構成された無線通
信系において、 検波出力ｖ（ｔ）と該出力に対しヒルベルト変換を行な
うヒルベルト変換器出力との乗算を行なう第１の乗算器
（３）、該第１の乗算器（３）の出力に対しヒルベルト
変換を行なうヒルベルト変換器（５）の出力と検波出力
の乗算を行なう第２の乗算器（６）、検波出力同士の乗
算を行なう第３の乗算器（７）の出力と検波出力との乗
算を行なう第４の乗算器（８）、および該第４の乗算器
（８）の出力の振幅を（−1/3）倍する増幅器を有し、
前記の第１の乗算器（３）および前記第２の乗算器
（６）の出力と増幅器出力および検波出力ｖ（ｔ）を加
算合成することにより復調出力を得ることを特徴とする
復調歪除去回路。1. A transmitting side performs SSB modulation with an information signal, adds a carrier wave to this to form a transmitting signal, and after the receiving side receives the signal, the amplitude is made constant by using an amplitude limiter. In a wireless communication system configured to perform demodulation by frequency detection from a first multiplier (3) that multiplies the detected output v (t) by the Hilbert transformer output that performs the Hilbert transform on the output, A second multiplier (6) that multiplies the output of the Hilbert transformer (5) that performs the Hilbert transform on the output of the first multiplier (3) and the detection output, and a third multiplier that performs the multiplication of the detection outputs. It has a fourth multiplier (8) for multiplying the output of the multiplier (7) and the detection output, and an amplifier for multiplying the amplitude of the output of the fourth multiplier (8) by (−1/3). Then
Demodulation distortion removal, characterized in that a demodulation output is obtained by adding and synthesizing the outputs of the first multiplier (3) and the second multiplier (6), the amplifier output and the detection output v (t). circuit.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23644985A JPH0740643B2 (en) | 1985-10-24 | 1985-10-24 | Demodulation distortion removal circuit |
| DE8585308784T DE3585502D1 (en) | 1984-12-10 | 1985-12-03 | SINGLE-SIDED TAPE TRANSFER SYSTEM. |
| EP85308784A EP0184923B1 (en) | 1984-12-10 | 1985-12-03 | Single-sideband communication system |
| US06/806,991 US4803739A (en) | 1984-12-10 | 1985-12-09 | SSB communication system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23644985A JPH0740643B2 (en) | 1985-10-24 | 1985-10-24 | Demodulation distortion removal circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6298808A JPS6298808A (en) | 1987-05-08 |
| JPH0740643B2 true JPH0740643B2 (en) | 1995-05-01 |
Family
ID=17000909
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23644985A Expired - Fee Related JPH0740643B2 (en) | 1984-12-10 | 1985-10-24 | Demodulation distortion removal circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0740643B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5654909A (en) * | 1993-04-15 | 1997-08-05 | Icom Incorporated | 90-degree digital phase shift network and linearizer using all-pass digital filters |
-
1985
- 1985-10-24 JP JP23644985A patent/JPH0740643B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6298808A (en) | 1987-05-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |