JPS6316939B2 - - Google Patents
Info
- Publication number
- JPS6316939B2 JPS6316939B2 JP54146670A JP14667079A JPS6316939B2 JP S6316939 B2 JPS6316939 B2 JP S6316939B2 JP 54146670 A JP54146670 A JP 54146670A JP 14667079 A JP14667079 A JP 14667079A JP S6316939 B2 JPS6316939 B2 JP S6316939B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- frequency
- side transmission
- shifted
- transmission signal
- 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
- 230000001360 synchronised effect Effects 0.000 claims description 9
- 230000005540 biological transmission Effects 0.000 claims description 7
- 238000001514 detection method Methods 0.000 claims description 6
- 238000000034 method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 1
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
- H04L27/227—Demodulator circuits; Receiver circuits using coherent demodulation
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Description
【発明の詳細な説明】
本発明はオフセツト直交振幅変調等の同相側送
信信号と直交側送信信号を１信号間隔の半分ずら
して送信する変調方式の受信機に関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a receiver using a modulation method such as offset quadrature amplitude modulation, which transmits an in-phase side transmission signal and a quadrature side transmission signal with a shift of half of one signal interval.
オフセツト直交振幅変調においては従来２軸同
期検波による復調が行なわれていたが、これだと
復調後２つの信号波形を並列に処理せねばなら
ず、自動等化器等を適用する際装置が複雑になる
欠点があつた。本発明では復調周波数を変える事
により１系列の信号処理にて復調後の処理を可能
とした。以下に本発明の原理を述べる。 Conventionally, in offset quadrature amplitude modulation, demodulation was performed using two-axis synchronous detection, but with this method, two signal waveforms had to be processed in parallel after demodulation, making the equipment complicated when applying an automatic equalizer etc. It had some drawbacks. In the present invention, by changing the demodulation frequency, it is possible to perform post-demodulation processing using one series of signal processing. The principle of the present invention will be described below.
オフセツト直交振幅変調の送出信号ｓ（ｔ）は、
搬送波周波数をfc、送信同相側信号をao、直交側
信号をbo、送信フイルタのインパルス応答をｐ
（ｔ）、１信号間隔をＴとすると、
と表わされる。この信号を搬送波周波数fcから1/
2Ｔだけ正方向にずれた周波数（fc＋１／2T）で同
期検波すると、復調信号ｒ（ｔ）は
となる。ここで復調信号ｒ（ｔ）のT/2おきのサ
ンプル値をriとし、pR′はｐ（ｔ）のＴおきのサン
プルpiにより、p2K′＝piおよびp2K+I′＝ｏできめら
れ、またデータaoおよびboは以下の規則にてan′
に変換する。 The offset quadrature amplitude modulation transmission signal s(t) is:
The carrier frequency is f c , the transmitting in-phase signal is a o , the quadrature side signal is b o , and the impulse response of the transmitting filter is p
(t), and if one signal interval is T, then It is expressed as This signal is converted from carrier frequency f c to 1/
When performing synchronous detection at a frequency (f c + 1/2T) shifted in the positive direction by 2T, the demodulated signal r(t) is becomes. Here, let r i be the sample value of the demodulated signal r(t) every T/2, and p R ′ is the sample value p i of p(t) every T, so that p 2K ′=p i and p 2K+I ′ = o, and the data a o and b o are a n ′ according to the following rules.
Convert to
a4n′＝a2o、a4n+1′＝b2o、a4n+2′＝a2o+1、
a4n+3＝b2o+1
従つてサンプル値riは
ri＝１／２〓
ｍan′pi-n
と表わされ通常のPAM伝送と同じ形態となり、
したがつて、装置を複雑にすることなく自動等化
を行なうことが出来、かつ片側の情報のみでも送
信の両側信号の情報を得られる。実際の受信信号
はan′に変換した規則の逆交換によつて得られ
る。尚、同期検波のため発振器出力周波数fcに対
し1/2Ｔだけ正方向のみでなく負方向であつても
同様に実施できる。 a 4n ′=a 2o , a 4n+1 ′=b 2o , a 4n+2 ′=a 2o+1 ,
a 4n+3 = b 2o+1 Therefore, the sample value r i is expressed as r i = 1/2〓 ma n ′p in , which is the same form as normal PAM transmission,
Therefore, automatic equalization can be performed without complicating the device, and information on signals on both sides of the transmission can be obtained even with only information on one side. The actual received signal is obtained by inverse exchange of the rules converted to a n '. Incidentally, for synchronous detection, the same operation can be performed not only in the positive direction but also in the negative direction by 1/2T with respect to the oscillator output frequency f c .
以上述べた如く本発明は周波数をずらした同期
検波によつて復調器を簡単化できる。 As described above, the present invention can simplify the demodulator by performing frequency-shifted synchronous detection.
以下に図を用いて本発明の実施例を述べる。 Examples of the present invention will be described below using figures.
図は本発明の実施例である。端子１より入来し
た受信信号は同期検波器２に入力される。同期検
波器においては、搬送波周波数を1/2Ｔずらした
周波数をもつ発振器３から発生された正弦波によ
つて検波が行なわれ、端子４に復調信号が出力さ
れる。 The figure shows an embodiment of the invention. A received signal coming from terminal 1 is input to synchronous detector 2 . In the synchronous detector, detection is performed using a sine wave generated from an oscillator 3 having a frequency shifted by 1/2T from the carrier frequency, and a demodulated signal is outputted to a terminal 4.
図は本発明の一実施例を示すブロツク図であ
る。図において、２は同期検波器、３は発振器で
ある。
The figure is a block diagram showing one embodiment of the present invention. In the figure, 2 is a synchronous detector and 3 is an oscillator.
Claims (1)
隔の半分ずらして送信する直交振幅変調の受信機
において、受信信号を搬送波周波数から２信号間
隔の逆数分だけ正方向または負方向にずらした周
波数をもつた発振器で同期検波する同期検波器を
用いることを特徴とする復調器。1 In a quadrature amplitude modulation receiver that transmits the in-phase side transmission signal and the orthogonal side transmission signal with a shift of half of one signal interval, the frequency at which the received signal is shifted from the carrier frequency by the reciprocal of the two signal intervals in the positive or negative direction. A demodulator characterized in that it uses a synchronous detector that performs synchronous detection with an oscillator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14667079A JPS5669958A (en) | 1979-11-13 | 1979-11-13 | Demodulator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14667079A JPS5669958A (en) | 1979-11-13 | 1979-11-13 | Demodulator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5669958A JPS5669958A (en) | 1981-06-11 |
| JPS6316939B2 true JPS6316939B2 (en) | 1988-04-12 |
Family
ID=15412947
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14667079A Granted JPS5669958A (en) | 1979-11-13 | 1979-11-13 | Demodulator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5669958A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4759039A (en) * | 1986-10-20 | 1988-07-19 | American Telephone & Telegraph Company | Simplified recovery of data signals from quadrature-related carrier signals |
-
1979
- 1979-11-13 JP JP14667079A patent/JPS5669958A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5669958A (en) | 1981-06-11 |
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