公开(公告)号：WO1981003560A1

公开(公告)日：1981-12-10

申请号：PCT/US1980000686

申请日：1980-06-02

申请人： MOSTEK CORP ,  MUELLER J ,  GILTNER M ,  FIEST R

发明人： MOSTEK CORP

IPC分类号： G06F03/04

CPC分类号： H03M7/42 ,  H04L9/0637 ,  H04L9/065 ,  H04L2209/30

摘要： In-line data compression system (10) which reduces the number of binary bits required to transmit a given text or similar message over a data network such a Telex or TWX. The unit (14) further provides an option for encrypting the compressed message. The unit (14) connected in-line between the local keyboard/printer terminal (12) and the network interface unit (16). The compression unit (14) can transmit or receive standard messages or can transmit compressed and encrypted messages to remote stations, and can receive, decrypt, and decompress messages from remote stations. The text data is compressed by identifying each word, searching for the word in a fixed library of words (38), and transmitting a first escape code plus the library address if the word is found. If the word is not found in the fixed library, a search is made for the word in a reconfiguration library (40) and a second escape code plus the reconfiguration library address is transmitted if the word is found. If the word is not found in the reconfiguration library, the word is transmitted one character at a time using variable length character codes produced by a "Huffman" type code generator. An identical unit (14) interposed at the receiving terminal but operating in the receiving mode can decrypt the message, then detect the escape codes and fetch words expressed in standard character codes from an identical fixed library (38) or an identically compiled reconfiguration library (40), or finally decodes the variable length character codes. The reconfiguration library is compiled by placing each word which is not in the library in the reconfiguration library before it is transmitted by variable length code. Then the second and each subsequent time that the same word is found in the message, the second escape code plus the address in the reconfiguration library will be transmitted in lieu of the Huffman coded characters of the word. The receiving station follows the same procedure on received messages to compile an identical reconfiguration library from which words previously in the messages can be outputted in response to a transmitted reconfiguration library escape code and address. The system is also applicable to compression of other types of data, serial or parallel, such as digital color television, for example.

摘要翻译： 在线数据压缩系统（10），其减少通过诸如电传或TWX的数据网络发送给定文本或类似消息所需的二进制位数。 单元（14）还提供用于加密压缩消息的选项。 在本地键盘/打印机终端（12）与网络接口单元（16）之间的线上连接的单元（14）。 压缩单元（14）可以发送或接收标准消息，或者可以将压缩和加密的消息发送到远程站，并且可以从远程站接收，解密和解压缩消息。 通过识别每个单词，在固定的单词库中搜索单词（38）来压缩文本数据，并且如果找到该单词，则发送第一个转义码加上库地址。 如果在固定库中没有找到该字，则在重配置库（40）中搜索该字，并且如果找到该字，则发送第二转义码加上重新配置库地址。 如果在重新配置库中没有找到该字，则使用由“霍夫曼”型代码生成器生成的可变长度字符代码，一次发送一个字符。 插入在接收终端但以接收模式操作的相同单元（14）可以对该消息进行解密，然后从相同的固定库（38）或相同编译的重新配置库（38）中检测出转义码并以标准字符代码表示的字， 40），或者最后解码可变长度字符代码。 通过将可变长度代码发送之前将不在库中的每个单词放在重新配置库中来编译重新配置库。 然后在消息中找到相同字的第二个和每个随后的时间，将发送第二转义码加上重新配置库中的地址来代替该字的霍夫曼编码字符。 接收站对接收到的消息遵循相同的过程以编译相同的重配置库，响应于所发送的重配置库转义码和地址，可以从其中输出先前在消息中的字。 该系统也适用于压缩其他类型的数据，串行或并行数据，例如数字彩色电视机。