公开(公告)号：US3828346A

公开(公告)日：1974-08-06

申请号：US34122173

申请日：1973-03-14

Applicant: INT STANDARD ELECTRIC CORP

Inventor： FORSTER D ,  PERRAULT J

IPC: H03M5/16 ,  H04J3/06 ,  H04L7/06 ,  H04L25/48 ,  H04L25/49 ,  H04L15/00 ,  G06F5/00

CPC classification number: H04L7/06 ,  H04J3/0614 ,  H04L25/4925

Abstract: This relates to a PCM transmission system employing alternate polarity (bipolar) transmission having a reduction of disparity. This is accomplished by employing the techniques of U.S. Pat. No. 3,300,774 and copending application Ser. No. 252,112, filed May 10, 1972, now U.S. Pat. No. 3,783,383, issued Jan. 1, 1974. In U.S. Pat. No. 3,300,774 the disparity is reduced by complementing a normal bipolar PCM word if the number of binary 1 bits in a word are less than n/2, where n is equal to the number of bits per PCM word. An extra bit is added to the complemented word to indicate to the receiver that the word has been complemented. This extra digit reduced the amount of information bits, or required an increase in transmission rate to maintain the same amount of information bits. This disadvantage was overcome by the above cited copending application by providing two adjacent pulses of the same polarity to indicate a complemented PCM word which is a violation of the alternate polarity rule as found in bipolar PCM. This latter arrangement has the disadvantage that a D.C. component greater than zero is introduced. The present invention overcomes this disadvantage by providing adjacent polarity violations with opposite polarity, for instance, one polarity violation is positive and the next adjacent polarity violation is negative.

Abstract translation: 这涉及采用具有差异减小的交替极性（双极性）传输的PCM传输系统。 这是通过采用美国专利No. 第3300,774号和共同未决申请 1972年5月10日提交的第252,112号，现为美国专利 1974年1月1日授权的第3,783,383号。 如果一个字中的二进制1位的数目小于n / 2，其中n等于每个PCM字的位数，则通过补充正常的双极PCM字来减小视差。 补充的字添加一个额外的位，以向接收者指示该字被补充。 这个额外的数字减少了信息位的数量，或者需要增加传输速率来保持相同的信息位数量。 通过提供相同极性的两个相邻脉冲来指示补充的PCM字，这是上述引用的共同未决申请中克服的这个缺点，这是在双极PCM中发现的违反交替极性规则的补充PCM字。 后一种布置具有引入大于零的直流分量的缺点。 本发明通过提供相反极性的相邻极性冲突来克服这个缺点，例如，一个极性违反是正的，而下一个相邻的极性违反是负的。

公开(公告)号：US3783383A

公开(公告)日：1974-01-01

申请号：US3783383D

申请日：1972-05-10

Applicant: INT STANDARD ELECTRIC CORP

Inventor： FORSTER D ,  PERRAULT J

IPC: H04L7/02 ,  H04L7/06 ,  H04L25/49 ,  H04B1/00

CPC classification number: H04L25/4925 ,  H04L7/02 ,  H04L7/06

Abstract: There is disclosed herein a signalling process for a PCM transmission system having reduced disparity, that is, a substantially equal number of binary ''''1'''' digits for the pulse stream. This is accomplished by complementing normal PCM words if the number of binary ''''1''''s in a word are less than n/2, where n is equal to the number of digits per word, and using alternatepolarity bipolar code PCM transmission. In accordance with the present invention the complementing of PCM words is indicated by a polarity violation of the bipolar code of the first digit of the complemented words. This results in two pulses of the same polarity being adjacent each other rather than alternate polarity as is usual in alternate-polarity bipolar PCM. Transmission and reception circuits are also disclosed to implement the PCM signalling process of this invention.

Abstract translation: 这里公开了一种具有减小的差异的PCM传输系统的信令过程，即脉冲流的基本相等数量的二进制“1”数字。 如果一个字中的二进制“1”的数目小于n / 2，其中n等于每个字的位数，并使用交替极性双极码PCM传输，则通过补充正常的PCM字来实现。 根据本发明，通过对补码字的第一数字的双极性代码的极性违反来指示PCM字的补码。 这导致相同极性的两个脉冲彼此相邻，而不是像交替极性双极PCM中通常的交替极性。 还公开了发送和接收电路以实现本发明的PCM信令过程。