JPH0225306B2 - - Google Patents
Info
- Publication number
- JPH0225306B2 JPH0225306B2 JP1055585A JP1055585A JPH0225306B2 JP H0225306 B2 JPH0225306 B2 JP H0225306B2 JP 1055585 A JP1055585 A JP 1055585A JP 1055585 A JP1055585 A JP 1055585A JP H0225306 B2 JPH0225306 B2 JP H0225306B2
- Authority
- JP
- Japan
- Prior art keywords
- radians
- signal
- phase
- time slot
- binary information
- 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
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/18—Phase-modulated carrier systems, i.e. using phase-shift keying
- H04L27/22—Demodulator circuits; Receiver circuits
- H04L27/233—Demodulator circuits; Receiver circuits using non-coherent demodulation
- H04L27/2331—Demodulator circuits; Receiver circuits using non-coherent demodulation wherein the received signal is demodulated using one or more delayed versions of itself
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/18—Phase-modulated carrier systems, i.e. using phase-shift keying
- H04L27/20—Modulator circuits; Transmitter circuits
- H04L27/2032—Modulator circuits; Transmitter circuits for discrete phase modulation, e.g. in which the phase of the carrier is modulated in a nominally instantaneous manner
- H04L27/2053—Modulator circuits; Transmitter circuits for discrete phase modulation, e.g. in which the phase of the carrier is modulated in a nominally instantaneous manner using more than one carrier, e.g. carriers with different phases
- H04L27/206—Modulator circuits; Transmitter circuits for discrete phase modulation, e.g. in which the phase of the carrier is modulated in a nominally instantaneous manner using more than one carrier, e.g. carriers with different phases using a pair of orthogonal carriers, e.g. quadrature carriers
- H04L27/2067—Modulator circuits; Transmitter circuits for discrete phase modulation, e.g. in which the phase of the carrier is modulated in a nominally instantaneous manner using more than one carrier, e.g. carriers with different phases using a pair of orthogonal carriers, e.g. quadrature carriers with more than two phase states
- H04L27/2085—Modulator circuits; Transmitter circuits for discrete phase modulation, e.g. in which the phase of the carrier is modulated in a nominally instantaneous manner using more than one carrier, e.g. carriers with different phases using a pair of orthogonal carriers, e.g. quadrature carriers with more than two phase states with more than one phase shift per symbol period
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Description
この発明は、多重波干渉に強いデイジタル通信
方式に関するものである。
〔従来の技術〕
従来のデイジタル通信方式は、例えば移動無線
のように一つのデイジタル情報によつて変調され
た一つのデイジタル信号が異なる伝送路を経て多
重波として受信される場合の多い通信系ではこれ
ら多重波による相互干渉のため、符号誤り率が非
常に劣化するという問題があつた。
この符号誤り率の劣化を解決するためには符号
誤り率の程度に応じ各種誤り訂正符号を構成する
方法がとられる。
〔発明が解決しようとする問題点〕
しかしながら、例えば移動通信においてみられ
るように誤りがバースト的に生ずる通信路ではか
かる誤り訂正符号の構成は一般に伝送しようとす
る符号に比べ非常に大きなものになり、また復号
化のため一旦メモリに蓄えて処理するため総合の
伝送時間が長くなり装置も複雑になるという問題
があつた。
この発明は上記のような問題を解消するために
なされたもので、これら誤り訂正符号の構成を行
うことなく符号誤り率の劣下の問題を解消して総
合の伝送時間の短縮化及び装置の簡単化をはかる
デイジタル通信方式を得ることを目的とする。
〔問題点を解決するための手段〕
この発明に係るデイジタル通信方式の変調方式
は、シンボル送出間隔を１タイムスロツトとする
と「０」あるいは「１」の２進情報シンボルに対
応して、搬送波の位相を1/2タイムスロツト毎に
２回続けて＋π／２ラジアンあるいは−π／２ラジアン
ずつ変化させ１タイムスロツト当り＋πラジアン
又は−πラジアン位相を変化させるようにしたも
のである。また復調方式は、遅延量を1/2タイム
スロツトに選んだ遅延検波を用いるものである。
なお、上記変調方式は２進情報シンボルの１つ
に対し２回位相シフトを行うので、Double
phase Shift Keying方式（以下DSK方式）と呼
ぶ。
〔作 用〕
この発明に係るデイジタル通信方式は、その変
調方式がDSK方式であるので多重波干渉があつ
ても２進情報シンボルに対応した正しい復調出力
が常に大きくとれ符号誤り率の大幅な改善が得ら
れる。
〔発明の実施例〕
以下、この発明を図について説明する。
第１図Ａは、この発明に係る変調方式における
２値情報シンボルの「０」、「１」に対応する搬送
波の位相遷移の一例を説明する図、第１図Ｂはか
かる位相遷移を行う変調器において、２値情報信
号「１、０、１」により変調を行つた場合の搬送
波の位相変化を示す図である。
第１図Ａにおいて、矢印はその矢印上に示す２
値情報シンボルに対応した位相遷移の方向を示
す。また第１図Ｂにおいて、(イ)は２値情報信号を
示す２値情報シンボルの並び、(ロ)は対応する搬送
波の位相変化をうけた信号（以下DSK信号とい
う）、を示す。また、Ｔはタイムスロツトの長さ
で、これは単位２値情報シンボルにおけるシンボ
ル送出間隔に相当する。
まず、DSK信号の生成の仕方を第１図に基づ
いて説明する。２値情報信号を構成する第１番目
の２値情報シンボル「１」に対しては、まず＋
π／２ラジアンシフトし、1/2タイムスロツト経過後
さらに＋π／２ラジアンシフトして合計＋πラジア
ン位相シフトする。次に、第２番目の２値情報シ
ンボル「０」に対しては前記第１番目のシンボル
対応の最終位相＋πラジアンからスタートして、
まず−π／２ラジアンシフトし、1/2タイムスロツト
経過後さらに−π／２ラジアンシフトして合計−π
ラジアンシフトするので初期位相０ラジアンの位
置へ戻つている。
さらに、第３番目の２値情報シンボル「１」に
対しては前記第２番目のシンボル対応の最終位相
０ラジアンからスタートして、まず＋π／２ラジア
ンシフトし、1/2タイムスロツト経過後さらに＋
π／２ラジアンシフトして合計πラジアンシフトし
初期位相０ラジアンに対し＋πラジアンの位相に
なる。
このようにこの発明に係るデイジタル通信方式
のDSK信号は、１つの２値情報シンボルを1/2タ
イムスロツト毎にシンボルの符号に応じ＋π／２ラ
ジアン又は−π／２ラジアンずつ２回シフトさせ＋
πラジアン又は−πラジアンシフトさせる所に特
徴がある。
次に、１つのDSK信号が遅延時間の異なる通
信路を経て受信された場合における２値情報信号
の再生について説明すると共に、このように干渉
がある場合にDSK信号だと従来の２相PSK信号
（以下BPSK信号という）に比べどうして符号誤
り率がよくなるかにつき説明する。
第２図Ａは２値情報信号「１、０、１」に対応
して到着するDSK信目のうち、最初に到着する
信号（以下Ｄ波という）と遅れて到着する信号
（以下Ｕ波という）の位相関係を示す。この図で
は説明の都合上Ｄ波に対してτだけ遅れて到着す
る１つのＵ波を示している。
第２図ＢはDSK信号の復調回路の系統図を示
す。復調回路は遅延時間を1/2タイムスロツトに
設定した遅延検波回路で構成する。
受信側においてはＤ波の他にτだけ遅れてＵ波
が到着しＤ波とＵ波は合成されて復調器へ導びか
れる。この合成波を調べると第２図Ａの各々の１
タイムスロツトＴの間の区間ａを除くｂ、ｃ、ｄ
の区間では、Ｄ波とＵ波の干渉状態の如何にかか
わらず常に２値情報信号（この場合「１、０、
１」）を構成する個々の２値情報シンボルに対応
した正しい情報となつている。すなわちＤ波とＵ
波は区間ｂ、ｄでは同相部分、区間ｃではπ／２位
相がシフトした部分、という関係にあり実際に起
き得る条件の下では区間ａ、ｂ、ｃ、ｄにおける
復調出力は次のようになる。
The present invention relates to a digital communication system that is resistant to multiple wave interference. [Prior Art] Conventional digital communication systems are used in communication systems such as mobile radio, where one digital signal modulated by one piece of digital information is often received as multiple waves via different transmission paths. Mutual interference caused by these multiple waves has caused a problem in that the code error rate is significantly degraded. In order to solve this deterioration of the code error rate, methods are used to construct various error correction codes depending on the degree of the code error rate. [Problems to be Solved by the Invention] However, in a communication channel where errors occur in bursts, such as in mobile communications, the structure of such an error correction code is generally much larger than the code to be transmitted. Furthermore, since the information is stored in memory and then processed for decoding, there is a problem that the total transmission time becomes long and the device becomes complicated. This invention was made in order to solve the above-mentioned problems, and it solves the problem of deterioration of the code error rate without configuring these error correction codes, thereby shortening the overall transmission time and reducing the equipment cost. The purpose is to obtain a digital communication method that is simple. [Means for Solving the Problems] The modulation method of the digital communication system according to the present invention has a modulation method of a carrier wave corresponding to a binary information symbol of "0" or "1" when the symbol transmission interval is one time slot. The phase is changed twice in succession by +π/2 radians or -π/2 radians every 1/2 time slot, and the phase is changed by +π radians or -π radians per time slot. The demodulation method uses delayed detection with a delay amount of 1/2 time slot. Note that the above modulation method performs phase shift twice for one binary information symbol, so Double
This is called the phase shift keying method (hereinafter referred to as the DSK method). [Function] Since the digital communication method according to the present invention uses the DSK method as its modulation method, even if there is multiple wave interference, the correct demodulated output corresponding to the binary information symbol can always be large, and the code error rate can be significantly improved. is obtained. [Embodiments of the Invention] The present invention will be explained below with reference to the drawings. FIG. 1A is a diagram illustrating an example of phase transition of a carrier wave corresponding to "0" and "1" of a binary information symbol in the modulation method according to the present invention, and FIG. 1B is a diagram illustrating modulation that performs such a phase transition. FIG. 3 is a diagram showing a phase change of a carrier wave when modulation is performed using a binary information signal “1, 0, 1” in the device. In Figure 1A, the arrow indicates 2
Indicates the direction of phase transition corresponding to the value information symbol. Further, in FIG. 1B, (a) shows a sequence of binary information symbols representing a binary information signal, and (b) shows a signal (hereinafter referred to as a DSK signal) that has undergone a phase change of the corresponding carrier wave. Further, T is the length of the time slot, which corresponds to the symbol transmission interval in a unit binary information symbol. First, how to generate a DSK signal will be explained based on FIG. For the first binary information symbol "1" constituting the binary information signal, first +
It is shifted by π/2 radians, and after 1/2 time slot has elapsed, it is further shifted by +π/2 radians, resulting in a total phase shift of +π radians. Next, for the second binary information symbol "0", start from the final phase +π radians corresponding to the first symbol,
First, it is shifted by -π/2 radians, and after 1/2 time slot has elapsed, it is further shifted by -π/2 radians, resulting in a total shift of -π radians, so that the initial phase returns to the position of 0 radians. Furthermore, for the third binary information symbol "1", the final phase corresponding to the second symbol starts from 0 radians, is first shifted by +π/2 radians, and then further shifted after 1/2 time slot has elapsed. +
The phase is shifted by π/2 radians, resulting in a total shift of π radians, resulting in a phase of +π radians relative to the initial phase of 0 radians. As described above, the DSK signal of the digital communication system according to the present invention is produced by shifting one binary information symbol twice by +π/2 radians or −π/2 radians every 1/2 time slot depending on the sign of the symbol. It is characterized by a shift of π radians or -π radians. Next, we will explain the reproduction of a binary information signal when a single DSK signal is received through communication channels with different delay times, and also explain how the DSK signal is different from the conventional 2-phase PSK signal when there is interference in this way. (hereinafter referred to as BPSK signal), we will explain why the bit error rate is better than that of BPSK signal. Figure 2A shows the signal that arrives first (hereinafter referred to as D wave) and the signal that arrives later (hereinafter referred to as U wave) among the DSK signals that arrive corresponding to the binary information signal "1, 0, 1". ) shows the phase relationship. For convenience of explanation, this figure shows one U wave that arrives after the D wave by τ. FIG. 2B shows a system diagram of a DSK signal demodulation circuit. The demodulation circuit consists of a delay detection circuit whose delay time is set to 1/2 time slot. On the receiving side, in addition to the D wave, the U wave arrives with a delay of τ, and the D wave and U wave are combined and guided to the demodulator. Examining this composite wave, each 1 in Figure 2A is
b, c, d excluding section a between time slots T
In this section, the binary information signal (in this case, "1, 0,
This is correct information corresponding to the individual binary information symbols that make up ``1''). That is, D wave and U
The wave has an in-phase part in sections b and d, and a π/2 phase shifted part in section c. Under conditions that can actually occur, the demodulated output in sections a, b, c, and d is as follows. Become.
以上のように、この発明によれば２値情報シン
ボルに対応して搬送波の位相を1/2タイムスロツ
ト毎に２度続けて＋π／２ラジアンあるいは−π／２ラ
ジアンシフトし、１タイムスロツト当り合計＋π
ラジアン又は−πラジアンの位相シフトを与える
DSK信号を用いるようにしたので、遅延時間の
大きい多重波伝播の条件下でも符号誤り率を著し
く改善させることができる効果がある。
As described above, according to the present invention, the phase of the carrier wave is shifted by +π/2 radians or −π/2 radians twice every 1/2 time slot in correspondence with the binary information symbol, and Total + π
gives a phase shift of radians or -π radians
Since a DSK signal is used, the code error rate can be significantly improved even under conditions of multi-wave propagation with a large delay time.
第１図Ａはこの発明に係るデジタル通信方式の
DSK方式における２値情報シンボルに対応する
搬送波の位相遷移の一例を説明する図、第１図Ｂ
は同じく２値情報信号とDSK信号の関係を説明
する図である。第２図Ａは、２つのDSK信号、
Ｕ波とＤ波の関係を説明する図、第２図Ｂは
DSK信号の復調回路の系統図を示す図である。
第３図はDSK方式及びBPSK方式の符号誤り特
性の一例を示す図、第４図はDSK方式の変調回
路の一構成例を示す図、第５図はDSK方式にお
ける復調回路の一構成例を示す図、第６図は
DSK−ENC１がもつべき動作内容を説明する図、
第７図はDSK−ENC１の構成例を示す図、第８
図はDSK信号の復調回路の動作を説明する図で
ある。
図において、１はDSK−ENC、２はDBM、３
はDBM、４はPC、５はPD、６はDL、７は
DBM、８はLPFである。なお、図中、同一符号
は同一又は相当部分を示す。
Figure 1A shows the digital communication system according to the present invention.
A diagram illustrating an example of the phase transition of a carrier wave corresponding to a binary information symbol in the DSK system, Figure 1B
2 is a diagram similarly explaining the relationship between a binary information signal and a DSK signal. Figure 2A shows two DSK signals,
Figure 2B is a diagram explaining the relationship between U waves and D waves.
FIG. 3 is a diagram showing a system diagram of a demodulation circuit for a DSK signal.
Figure 3 is a diagram showing an example of the code error characteristics of the DSK system and BPSK system, Figure 4 is a diagram showing an example of the configuration of a modulation circuit in the DSK system, and Figure 5 is a diagram showing an example of the configuration of a demodulation circuit in the DSK system. The diagram shown in Figure 6 is
A diagram explaining the operation contents that DSK-ENC1 should have,
Figure 7 is a diagram showing an example of the configuration of DSK-ENC1, Figure 8
The figure is a diagram illustrating the operation of a DSK signal demodulation circuit. In the figure, 1 is DSK-ENC, 2 is DBM, 3
is DBM, 4 is PC, 5 is PD, 6 is DL, 7 is
DBM, 8 is LPF. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.
Claims (1)
シンボルに対応して、その第１の情報シンボルは
1/2タイムスロツト毎に２度続けて＋π／２ラジアン ずつ位相シフトを行い、その第２の情報シンボル
は1/2タイムスロツト毎に２度続けて−π／２ラジア ンずつ位相シフトを行つて位相シフトキーイング
変調を行う変調方式と、この変調方式により変調
された信号を受信し、その出力を２分割して得た
一方の信号を1/2タイムスロツト遅延させて他方
の信号と乗算積分して元の２値情報シンボルを得
るようにした復調方式とを備えたことを特徴とす
るデイジタル通信方式。[Claims] 1. Corresponding to a binary information symbol transmitted in a predetermined time slot, the first information symbol is
The second information symbol is phase-shifted by +π/2 radians twice in every 1/2 time slot, and the second information symbol is phase-shifted by −π/2 radians twice in every 1/2 time slot. A modulation method that performs phase shift keying modulation, a signal modulated by this modulation method is received, the output is divided into two, one signal is delayed by 1/2 time slot, and the other signal is multiplied and integrated. 1. A digital communication system comprising: a demodulation method for obtaining original binary information symbols using a demodulation method.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1055585A JPS61169049A (en) | 1985-01-22 | 1985-01-22 | Digital communication system |
| US06/768,551 US4726038A (en) | 1985-01-22 | 1985-08-22 | Digital communication system |
| CA000489287A CA1254622A (en) | 1985-01-22 | 1985-08-23 | Digital communication system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1055585A JPS61169049A (en) | 1985-01-22 | 1985-01-22 | Digital communication system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61169049A JPS61169049A (en) | 1986-07-30 |
| JPH0225306B2 true JPH0225306B2 (en) | 1990-06-01 |
Family
ID=11753497
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1055585A Granted JPS61169049A (en) | 1985-01-22 | 1985-01-22 | Digital communication system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61169049A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0746799B2 (en) * | 1986-03-14 | 1995-05-17 | 松下電器産業株式会社 | Digital signal transmission method |
| JPH0746797B2 (en) * | 1986-02-20 | 1995-05-17 | 松下電器産業株式会社 | Digital signal transmission method |
| JPH0746798B2 (en) * | 1986-02-20 | 1995-05-17 | 松下電器産業株式会社 | Digital signal transmission method |
| JPH0746796B2 (en) * | 1986-02-20 | 1995-05-17 | 松下電器産業株式会社 | Digital signal transmission method |
| FR2884373B1 (en) * | 2005-04-12 | 2009-07-10 | Commissariat Energie Atomique | CONTACTLESS COMMUNICATION METHOD BASED ON ASYNCHRONOUS MODULATIONS AND DEMODULATIONS |
-
1985
- 1985-01-22 JP JP1055585A patent/JPS61169049A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61169049A (en) | 1986-07-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |