JPH0216070B2 - - Google Patents
Info
- Publication number
- JPH0216070B2 JPH0216070B2 JP14055879A JP14055879A JPH0216070B2 JP H0216070 B2 JPH0216070 B2 JP H0216070B2 JP 14055879 A JP14055879 A JP 14055879A JP 14055879 A JP14055879 A JP 14055879A JP H0216070 B2 JPH0216070 B2 JP H0216070B2
- Authority
- JP
- Japan
- Prior art keywords
- image signal
- data
- signal
- radiometer
- bits
- 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 12
- 238000000034 method Methods 0.000 claims description 9
- 230000001976 improved effect Effects 0.000 description 3
- 230000005855 radiation Effects 0.000 description 3
- 240000001082 Bambusa multiplex Species 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/16—Time-division multiplex systems in which the time allocation to individual channels within a transmission cycle is variable, e.g. to accommodate varying complexity of signals, to vary number of channels transmitted
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Time-Division Multiplex Systems (AREA)
Description
【発明の詳細な説明】
本発明はデータレートの異なる２種類の画像信
号の多重伝送方式に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multiplex transmission system for two types of image signals having different data rates.
一般に、データレートがｎ対１（ｎ：整数）の
関係にある様な２種類の画像信号Ａ，Ｂを符号化
し、ｎフレームの信号Ａに対し１フレームの信号
Ｂを時分割的に並べた符号系列で多重伝送してい
る。この符号系列においてS/Nが劣化して回線マ
ージンの確保が非常に難しくなり低データレート
の画像信号Ｂのみを伝送する場合に、回線のS/N
を改善する方法として次の２つの方法が考えられ
る。その１つは伝送する画像信号の符号列に伝送
しない画像信号Ａの符号列の個所に冗長符号を付
加して誤り訂正を計る方法である。この誤り訂正
符号としてはBCH符号等が一般に用いられてい
る。しかし、この場合は複雑な符号化器を構成し
なくてはならず、コスト、信頼性の点から問題が
ある。 Generally, two types of image signals A and B whose data rates have a relationship of n to 1 (n: an integer) are encoded, and one frame of signal B is time-divisionally arranged for n frames of signal A. Multiplex transmission is performed using code sequences. In this code sequence, the S/N deteriorates and it becomes very difficult to secure a line margin, so when transmitting only image signal B at a low data rate, the line S/N
The following two methods can be considered to improve this. One of them is a method of correcting errors by adding redundant codes to the code strings of the image signal A to be transmitted, where the code strings of the image signal A are not transmitted. A BCH code or the like is generally used as this error correction code. However, in this case, a complicated encoder must be constructed, which poses problems in terms of cost and reliability.
また、もう一つの方法はビツトレートを下げる
ことである。この方法によると単純な比較計算で
はビツトレートの比程度のマージンが増加とな
る。 Another method is to lower the bit rate. According to this method, the margin increases by a bit rate ratio in a simple comparison calculation.
しかし、変調系及び符号系列等の変更が必要で
あり、地上局復調系も伝送の場合に応じて２台も
しくはそれと等価な方法を考えねばならず、シス
テムが複雑化しコストも高くなる。 However, it is necessary to change the modulation system, code sequence, etc., and it is necessary to consider two ground station demodulation systems or an equivalent method depending on the case of transmission, which complicates the system and increases costs.
本発明の目的は、データレートの異なる２種類
の画像信号の多重伝送において、低データレート
の画像信号のみを伝送する場合に現在のフレーム
フオーマツトおよびビツトレートを変えずにS/N
改善効果が得られる多重伝送方式を提供すること
である。 An object of the present invention is to improve the S/N ratio without changing the current frame format and bit rate when transmitting only a low data rate image signal in multiplex transmission of two types of image signals with different data rates.
It is an object of the present invention to provide a multiplex transmission method that provides improved effects.
以下図面により本発明を詳細に説明する。 The present invention will be explained in detail below with reference to the drawings.
第１図は本発明に用いられる画像信号Ａ，Ｂの
符号系列を示すタイムチヤートである。すなわ
ち、データは８ビツトの周期パターン１と、信号
Ｂ(1)のデータ２と、信号Ａ（１〜４）の４個のデ
ータ３，４，５，６とからなるサブフレームを周
期として送出し、次の周期にも同様に同期パター
ン７と、信号Ｂ(2)のデータ８と、信号（５〜８）
のデータ７，１０，１１，１２をサブフレームを
繰返してデータを送出している。このようなデー
タとしては、例えば人工衛星に搭載される赤外線
および可視光の２種類の放射計において、可視光
の放射計Ａの画像信号４バンド（各６ビツト）と
データレートの異なる赤外線の放射計Ｂの画像信
号３バンド（各８ビツト）を多重伝送する場合が
ある。 FIG. 1 is a time chart showing the code sequences of image signals A and B used in the present invention. In other words, data is sent out periodically in subframes consisting of an 8-bit periodic pattern 1, data 2 of signal B (1), and four pieces of data 3, 4, 5, and 6 of signal A (1 to 4). Then, in the next cycle, synchronization pattern 7, data 8 of signal B(2), and signals (5 to 8)
Data 7, 10, 11, and 12 are sent out repeatedly in subframes. Such data includes, for example, two types of infrared and visible radiation radiometers mounted on an artificial satellite, the image signal of 4 bands (6 bits each) of visible radiation radiometer A and the infrared radiation with different data rates. In some cases, a total of B three bands of image signals (8 bits each) are multiplexed and transmitted.
通常の伝送回線においては回線マージンは十分
に確保できるが、放射計の性質上等から回線マー
ジンの確保が極めて難しい状態となると、例えば
放射計Ｂの画像信号だけを伝送する必要性があ
る。この場合、第２図のままではデータレートが
異なるので伝送することは非常に難しく、又放射
計Ａの画像信号は必要でないことから情報に多大
の無駄を生じる。このため回線マージンを確保す
る為の前述のBCH符号化では、放射計Ｂの24ビ
ツトに３ビツトを符加することによつて約2.5dB
改善され、又、低ビツトレート化により約10dB
改善される。しかし、これらの方法は前述の様に
システムが複雑化され、衛星搭載用として問題が
ある。 In a normal transmission line, a sufficient line margin can be secured, but if it becomes extremely difficult to secure a line margin due to the nature of the radiometer, it becomes necessary to transmit only the image signal of radiometer B, for example. In this case, it is very difficult to transmit the signals as shown in FIG. 2 because the data rates are different, and since the image signal of the radiometer A is not required, a large amount of information is wasted. For this reason, in the BCH encoding described above to ensure line margin, by adding 3 bits to the 24 bits of radiometer B, approximately 2.5 dB is added.
This has been improved and the bit rate has been lowered by approximately 10dB.
Improved. However, as mentioned above, these methods complicate the system and are problematic for use onboard a satellite.
第２図は本発明の実施例のフレームフオーマツ
トのタイムチヤートである。これは第２図のフレ
ームフオーマツトにおいて放射計Ａの画像信号に
割り当てられたタイムスロツトを放射計Ｂの画像
信号に割り当て、同一データを５回繰り返して伝
送することによつて回線マージンを増加させよう
とするものである。 FIG. 2 is a time chart of a frame format according to an embodiment of the present invention. This increases the line margin by assigning the time slot assigned to the image signal of radiometer A to the image signal of radiometer B in the frame format shown in Figure 2, and transmitting the same data five times. This is what we are trying to do.
この場合、回線状態を仮に10-6の誤り率の回線
からS/Nで4dB低下した10-3にした場合地上で復
調後の５回繰り返された同一データを比較し、誤
り訂正を行うとする。伝送回線の誤りはランダム
であるから24ビツト中の１ビツトに注目して、そ
のビツトが５回の内２回まで誤ることを許す確率
は2
〓i=0
（５
ｉ）（１−１×10-3）5-i（１×10-3）i
＝0.99999999900
となる。 In this case, if the line condition is changed from a line with an error rate of 10 -6 to 10 -3 , which is a 4 dB drop in S/N, the same data repeated five times after demodulation on the ground are compared and error correction is performed. do. Since errors in transmission lines are random, focusing on 1 bit out of 24 bits, the probability of allowing that bit to be erroneous 2 out of 5 times is 2 〓 i=0 (5 i) (1-1× 10 -3 ) 5-i (1×10 -3 ) i =0.99999999900.
したがつて、地上で放射計Ｂの画像信号24ビツ
トの各々のビツトに対して、多数決論理によつ
て、５個の「１」又は「０」のうち、３個以上の
方をデータとするだけで１×10-9のビツト誤り率
が得られる。この単純なフオーマツト変更だけで
7dB以上のS/N改善が可能であり、合計11dB改
善されることになる。 Therefore, for each bit of the 24-bit image signal from radiometer B on the ground, 3 or more of the 5 1's or 0's are determined as data using majority logic. A bit error rate of 1×10 −9 can be obtained by using only Just this simple format change
S/N improvement of 7dB or more is possible, resulting in a total improvement of 11dB.
このような繰返しデータの送出の具体回路とし
ては、１タイムスロツトのデータを記憶回路に入
れておき、これを必要回数だけ繰返して送り出せ
ばよいので任意の記憶回路を用いることができ
る。 As a specific circuit for sending out such repeated data, any storage circuit can be used since data for one time slot is stored in a storage circuit and the data is sent out repeatedly as many times as necessary.
以上説明した様に性質の異つた画像信号の多重
伝送において、一方の画像信号のみを伝送する必
要性に基づいて、使用されない画像信号のタイム
スロツトを伝送すべき画像信号のタイムスロツト
にを置き換えて、同一データを何度か繰返して伝
送するだけで、搭載機器及び地上局に大きな変更
を与えることなく回線マージンを増加させること
ができる。 As explained above, in multiplex transmission of image signals with different properties, based on the need to transmit only one image signal, the time slot of the unused image signal is replaced with the time slot of the image signal to be transmitted. By simply transmitting the same data several times, the line margin can be increased without making any major changes to the onboard equipment or ground station.
第１図は本発明に用いられる通常の多重伝送フ
オーマツトのタイムチヤート、第２図は本発明の
実施例の伝送フオーマツトのタイムチヤートであ
る。図において、１，７…同期パターン（８ビツ
ト）、２，８…信号Ｂの３バンド（各８ビツト）
データ、３，４，５，６，９，１０，１１，１２
…信号Ａの４バンド（各６ビツト）データであ
る。
FIG. 1 is a time chart of a normal multiplex transmission format used in the present invention, and FIG. 2 is a time chart of a transmission format according to an embodiment of the present invention. In the figure, 1, 7...synchronization pattern (8 bits), 2, 8...3 bands of signal B (8 bits each)
Data, 3, 4, 5, 6, 9, 10, 11, 12
...This is 4 band (6 bits each) data of signal A.
Claims (1)
ある画像信号Ａ，Ｂの符号列を時分割的に多重伝
送する伝送方式において、前記画像信号Ｂのみの
伝送要求に基づき、前記画像信号Ａに割り当てら
れたｎ回のタイムスロツトを前記画像信号Ｂに置
き換えて（ｎ＋１）回繰り返して前記画像信号Ｂ
を伝送することを特徴とする画像信号の多重伝送
方式。1 In a transmission method in which code strings of image signals A and B whose data rates are in a relationship of n to 1 (n: an integer) are time-division multiplexed, the image signal The n time slots assigned to A are replaced with the image signal B, and the image signal B is repeated (n+1) times.
An image signal multiplex transmission method characterized by transmitting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14055879A JPS5664532A (en) | 1979-10-31 | 1979-10-31 | Multiplex transmission system for picture signal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14055879A JPS5664532A (en) | 1979-10-31 | 1979-10-31 | Multiplex transmission system for picture signal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5664532A JPS5664532A (en) | 1981-06-01 |
| JPH0216070B2 true JPH0216070B2 (en) | 1990-04-16 |
Family
ID=15271466
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14055879A Granted JPS5664532A (en) | 1979-10-31 | 1979-10-31 | Multiplex transmission system for picture signal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5664532A (en) |
-
1979
- 1979-10-31 JP JP14055879A patent/JPS5664532A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5664532A (en) | 1981-06-01 |
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