JPH0149069B2 - - Google Patents
Info
- Publication number
- JPH0149069B2 JPH0149069B2 JP58041274A JP4127483A JPH0149069B2 JP H0149069 B2 JPH0149069 B2 JP H0149069B2 JP 58041274 A JP58041274 A JP 58041274A JP 4127483 A JP4127483 A JP 4127483A JP H0149069 B2 JPH0149069 B2 JP H0149069B2
- Authority
- JP
- Japan
- Prior art keywords
- frequency
- analog signal
- modulation
- signal
- circuit
- 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
- 230000005540 biological transmission Effects 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 6
- 230000008929 regeneration Effects 0.000 description 5
- 238000011069 regeneration method Methods 0.000 description 5
- 230000006866 deterioration Effects 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000010363 phase shift Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/62—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for providing a predistortion of the signal in the transmitter and corresponding correction in the receiver, e.g. for improving the signal/noise ratio
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
- Reduction Or Emphasis Of Bandwidth Of Signals (AREA)
Description
【発明の詳細な説明】
発明の技術分野
本発明は、PSK（Phase Shift Keying）信号
に、保守用の通話信号等のアナログ信号を周波数
変調信号として重畳するサービス・チヤネル変調
方式に関するものである。DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a service channel modulation method in which an analog signal such as a maintenance call signal is superimposed on a PSK (Phase Shift Keying) signal as a frequency modulation signal.
従来技術と問題点
デイジタル無線通信方式に於ては、主信号を例
えばPSK信号とし、保守、打ち合せ等の通話信
号を周波数変調（FM）により主信号に重畳して
伝送する方式が知られている。例えば第１図に示
すように、送信変調部１の変調回路１１に送信デ
イジタル信号Ｄを入力し、搬送波発生回路１２に
通話信号等のアナログ信号OWを入力し、搬送波
発生回路１２は入力アナログ信号OWにより周波
数変調された搬送波を変調回路１１に加え、この
搬送波を入力デイジタル信号ＤによりPSK変調
してアンテナ３から送信する。受信側では、アン
テナ４で受信し、受信復調部２の復調回路２１に
搬送波再生回路２２からの搬送波を加えて位相検
波してデイジタル信号Ｄを再生し、受信搬送波と
再生搬送波との位相差（周波数差）成分を搬送波
再生回路２２に加えて、位相差が零になる方向に
搬送波再生回路２２の再生搬送波位相を制御し、
その位相差（周波数差）成分を低域フイルタ２３
を介して出力することにより、アナログ信号OW
が再生される。Prior Art and Problems In digital wireless communication systems, it is known that the main signal is, for example, a PSK signal, and a call signal for maintenance, meetings, etc. is superimposed on the main signal using frequency modulation (FM) and transmitted. . For example, as shown in FIG. 1, a transmission digital signal D is input to the modulation circuit 11 of the transmission modulation section 1, an analog signal OW such as a telephone call signal is input to the carrier wave generation circuit 12, and the carrier wave generation circuit 12 receives the input analog signal D. A carrier wave frequency-modulated by OW is applied to the modulation circuit 11, and this carrier wave is PSK-modulated by the input digital signal D and transmitted from the antenna 3. On the reception side, the antenna 4 receives the signal, and the carrier wave from the carrier regeneration circuit 22 is added to the demodulation circuit 21 of the reception demodulation unit 2 to perform phase detection and regenerate the digital signal D. adding the frequency difference) component to the carrier wave regeneration circuit 22, controlling the recovered carrier wave phase of the carrier wave regeneration circuit 22 in a direction in which the phase difference becomes zero,
The phase difference (frequency difference) component is passed through the low-pass filter 23.
Analog signal OW by outputting through
is played.
しかし、送信側のFM変調度は一定であり、最
高周波数偏移の部分のPSK信号の復調に於て、
ビツト誤り率が低下する欠点があつた。即ち
PSK信号の復調に於ける位相誤差が大きくなる
為に、ビツト認識タイミングのずれが大きくな
り、ビツト誤りが多くなる。 However, the FM modulation depth on the transmitting side is constant, and in demodulating the PSK signal at the part with the highest frequency deviation,
The disadvantage was that the bit error rate decreased. That is,
Since the phase error in demodulating the PSK signal becomes large, the deviation in bit recognition timing becomes large and the number of bit errors increases.
発明の目的
本発明は、変調周波数に応じて変調度を変化さ
せ、PSK信号の復調に対する影響を少なくして、
ビツト誤り率の劣化を防止することを目的とする
ものである。以下実施例について詳細に説明す
る。Purpose of the Invention The present invention changes the modulation degree according to the modulation frequency to reduce the influence on the demodulation of PSK signals.
The purpose is to prevent deterioration of the bit error rate. Examples will be described in detail below.
発明の実施例
第２図は本発明の実施例の要部ブロツク図であ
り、第１図と同一符号は同一部分を示し、１３は
プリエンフアシス回路、２４はデイエンフアシス
回路である。プリエンフアシス回路１３は、サー
ビス・チヤネル入力であるアナログ信号OWの周
波数が低いとき変調度が大きく、周波数が高いと
きは変調度が小さくなるような周波数特性を有す
るものであり、又デイエンフアシス回路２４は、
プリエンフアシス回路１３と逆の特性を有するも
のである。Embodiment of the Invention FIG. 2 is a block diagram of essential parts of an embodiment of the present invention, in which the same reference numerals as in FIG. 1 indicate the same parts, 13 is a pre-emphasis circuit, and 24 is a de-emphasis circuit. The pre-emphasis circuit 13 has a frequency characteristic such that the degree of modulation is large when the frequency of the analog signal OW input to the service channel is low, and the degree of modulation is small when the frequency is high, and the de-emphasis circuit 24 has the following characteristics:
It has characteristics opposite to those of the pre-emphasis circuit 13.
第３図の実線はプリエンフアシス回路１３の特
性の一例、点線はデイエンフアシス回路２４の特
性の一例を示す。従つて、送信変調部１に於て
は、搬送波発生回路１２の出力の搬送波の最大周
波数偏移が従来例に比較して小さくなる。又受信
側では、低域フイルタ２３を介したアナログ信号
に対して、送信側と逆特性のデイエンフアシス回
路２４によりアナログ信号OWが再生されること
になり、且つ最大周波数偏移が小さくなるので、
搬送波再生回路２２に於ける追従性が良くなつ
て、PSK信号の復調に於けるビツト誤り率の劣
化を防止することができる。 The solid line in FIG. 3 shows an example of the characteristics of the pre-emphasis circuit 13, and the dotted line shows an example of the characteristics of the de-emphasis circuit 24. Therefore, in the transmission modulation section 1, the maximum frequency shift of the carrier wave output from the carrier wave generation circuit 12 is smaller than in the conventional example. Furthermore, on the receiving side, the analog signal OW is regenerated by the de-emphasis circuit 24, which has characteristics opposite to those on the transmitting side, with respect to the analog signal passed through the low-pass filter 23, and the maximum frequency deviation is small.
The followability of the carrier wave regeneration circuit 22 is improved, and deterioration of the bit error rate in PSK signal demodulation can be prevented.
第４図はサービス・チヤネル入力レベルに対す
る受信側のビツト誤り率を、周波数をパラメータ
として示すものであり、曲線ａは8KHz、曲線ｂ
は1KHzの場合を示す。即ち同一の或る誤り率と
なるレベルは、周波数が8KHzのときL1、1KHzの
ときはL2となり、L1＜L2であるから、サービ
ス・チヤネル入力即ちアナログ信号の周波数が高
いときに、搬送波発生回路１２に入力するレベル
を低くすれば、受信側のビツト誤り率を改善する
ことができることが判る。即ちプリエンフアシス
回路１３の周波数特性により、アナログ信号OW
の周波数が高いときは、搬送波発生回路１２への
入力レベルを小さく、周波数が低いときは、搬送
波発生回路１２への入力レベルを大きくして、ア
ナログ信号OWにより周波数変調し、この搬送波
発生回路１２の出力の搬送波を、変調回路１１に
加えて、入力デイジタル信号ＤによりPSK変調
することにより、受信側のビツト誤り率を改善す
ることができる。 Figure 4 shows the bit error rate on the receiving side with respect to the service channel input level using frequency as a parameter, where curve a is 8KHz and curve b is 8KHz.
indicates the case of 1KHz. In other words, the level at which the same certain error rate occurs is L1 when the frequency is 8KHz, L2 when the frequency is 1KHz, and since L1<L2, when the frequency of the service channel input, that is, the analog signal is high, the carrier wave generation circuit It can be seen that by lowering the level input to 12, the bit error rate on the receiving side can be improved. That is, due to the frequency characteristics of the pre-emphasis circuit 13, the analog signal OW
When the frequency is high, the input level to the carrier wave generation circuit 12 is decreased, and when the frequency is low, the input level to the carrier wave generation circuit 12 is increased, frequency modulation is performed by the analog signal OW, and this carrier wave generation circuit 12 By adding the output carrier wave to the modulation circuit 11 and subjecting it to PSK modulation using the input digital signal D, the bit error rate on the receiving side can be improved.
前述のプリエンフアシス回路１３の構成は、入
力アナログ信号OWの周波数に対応して搬送波発
生回路１２に加える信号レベルを、第３図に示す
ように制御できる構成であれば良いので、公知の
回路構成により容易に実現することができる。又
デイエンフアシス回路２４についても同様であ
り、容易に実現できるものである。 The configuration of the pre-emphasis circuit 13 described above may be any configuration as long as it can control the signal level applied to the carrier wave generation circuit 12 in accordance with the frequency of the input analog signal OW as shown in FIG. This can be easily achieved. The same applies to the de-emphasis circuit 24, which can be easily realized.
発明の効果
以上説明したように、本発明は、周波数変調に
よるサービス・チヤネルの入力アナログ信号を、
周波数が低いときは変調度が大きく、周波数が高
いときは変調度が小さくなるような周波数特性の
プリエンフアシス回路１３を介して送信変調部１
に加えて、主信号のPSK信号にアナログ信号を
重畳して伝送し、受信側では主信号の復調を行う
と共に、復調されたアナログ信号を、プリエンフ
アシス回路１３と逆特性のデイエンフアシス回路
２４を介して出力して、送信アナログ信号を再生
するものであり、最大周波数偏移が小さくなるこ
とにより、PSK信号の復調に於けるビツト誤り
率の劣化を防止することができる利点がある。Effects of the Invention As explained above, the present invention can convert the input analog signal of a service channel by frequency modulation into
The transmission modulator 1 is transmitted through a pre-emphasis circuit 13 having a frequency characteristic such that the modulation degree is large when the frequency is low and the modulation degree is small when the frequency is high.
In addition, an analog signal is superimposed on the PSK signal of the main signal and transmitted, and the receiving side demodulates the main signal and sends the demodulated analog signal through a de-emphasis circuit 24 with characteristics opposite to that of the pre-emphasis circuit 13. This output reproduces the transmitted analog signal, and by reducing the maximum frequency deviation, there is an advantage that deterioration of the bit error rate during PSK signal demodulation can be prevented.
第１図は従来のデイジタル無線通信方式の要部
ブロツク図、第２図は本発明の実施例の要部ブロ
ツク図、第３図はプリエンフアシス回路及びデイ
エンフアシス回路の特性説明図、第４図はサービ
ス・チヤネル入力レベルと受信側のビツト誤り率
との関係を示す曲線図である。
１は送信変調部、２は受信復調部、３，４はア
ンテナ、１１は変調回路、１２は搬送波発生回
路、１３はプリエンフアシス回路、２１は復調回
路、２２は搬送波再生回路、２３は低域フイル
タ、２４はデイエンフアシス回路である。
Fig. 1 is a block diagram of the main part of a conventional digital wireless communication system, Fig. 2 is a block diagram of the main part of an embodiment of the present invention, Fig. 3 is a characteristic diagram of the pre-emphasis circuit and de-emphasis circuit, and Fig. 4 is a service diagram. - A curve diagram showing the relationship between channel input level and bit error rate on the receiving side. 1 is a transmission modulation section, 2 is a reception demodulation section, 3 and 4 are antennas, 11 is a modulation circuit, 12 is a carrier wave generation circuit, 13 is a pre-emphasis circuit, 21 is a demodulation circuit, 22 is a carrier wave regeneration circuit, and 23 is a low-pass filter. , 24 is a de-emphasis circuit.
Claims (1)
ログ信号を主信号のPSK信号に重畳して伝送す
るサービス・チヤネル変調方式に於て、前記アナ
ログ信号の周波数が高いときは変調度が小さく、
且つ周波数が低いときは変調度が大きくなるよう
な周波数特性のプリエンフアシス回路を介して前
記アナログ信号を送信変調部に加えて、前記
PSK信号に前記アナログ信号を重畳して送信し、
受信側に於ては、受信復調部で復調された前記ア
ナログ信号を前記プリエンフアシス回路と逆特性
のデイエンフアシス回路を介して再生することを
特徴とするサービス・チヤネル変調方式。1. In a service channel modulation method in which an analog signal is superimposed on the main PSK signal and transmitted through a frequency modulated service channel, when the frequency of the analog signal is high, the degree of modulation is small;
The analog signal is applied to the transmission modulation section via a pre-emphasis circuit with a frequency characteristic such that the degree of modulation becomes large when the frequency is low.
superimposing the analog signal on the PSK signal and transmitting it;
On the receiving side, the service channel modulation method is characterized in that the analog signal demodulated by the reception demodulator is reproduced through a de-emphasis circuit having characteristics opposite to those of the pre-emphasis circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58041274A JPS59167166A (en) | 1983-03-12 | 1983-03-12 | Service channel modulating system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58041274A JPS59167166A (en) | 1983-03-12 | 1983-03-12 | Service channel modulating system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59167166A JPS59167166A (en) | 1984-09-20 |
| JPH0149069B2 true JPH0149069B2 (en) | 1989-10-23 |
Family
ID=12603860
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58041274A Granted JPS59167166A (en) | 1983-03-12 | 1983-03-12 | Service channel modulating system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59167166A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4681111A (en) * | 1985-04-05 | 1987-07-21 | Siemens-Pacesetter, Inc. | Analog and digital telemetry system for an implantable device |
| JP4554800B2 (en) * | 2000-11-10 | 2010-09-29 | Ｎｅｃエンジニアリング株式会社 | Variable modulation control system |
-
1983
- 1983-03-12 JP JP58041274A patent/JPS59167166A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59167166A (en) | 1984-09-20 |
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