公开(公告)号：CA2399543A1

公开(公告)日：2001-08-09

申请号：CA2399543

申请日：2001-02-01

Applicant: MOTOROLA INC ,  3COM CORP

Inventor： LIU JACK ,  AHMED S ARIF ,  PARIZHSKY VLADIMIR ,  KIM DAE-YOUNG ,  PILOZZI JOHN ,  MEHRABANZAD SEPEHR

IPC: H04L7/00 ,  H04L25/49

Abstract: A system and method for adjusting the phase of the analog signal produced by an analog modem connected to a digital modem over a telephone network. The digital portion of the telephone network is locked to the network clock, and the modems have no control over the sampling timing or rate as the analog signal is sampled and quantized by a codec. If the analog signal is shifted in phase relative to the network clock, then the codec may be sampling at unresolvable points on the analog signal, thereby causing errors and a decrease in the usable bandwidth for transmitting data. The analog modem symbol frequency is locked to the clock of the digital network using loop-back timing. A phase estimate is computed using the quantized samples of a known reference signal. Next, a "phase offset" is calculated by comparing the phase estimate to an optimum phase value. Then the digital modem sends the calculated phase offset information to the analog modem. The analog modem then delays its transmitted signal by the phase offset. After the phase of the analog modem's transmitter is adjusted, the analog signal reaches the codec at the phase desired by the digital modem.

公开(公告)号：CA2399513C

公开(公告)日：2005-04-19

申请号：CA2399513

申请日：2001-02-01

Applicant: MOTOROLA INC ,  3COM CORP

Inventor： MAURER PATRICK ,  MEHRABANZAD SEPEHR ,  LIU JACK ,  AHMED S ARIF ,  PARIZHSKY VLADIMIR ,  KIM DAE-YOUNG ,  PILOZZI JOHN

IPC: H04J3/00 ,  H04B14/04 ,  H04J3/12 ,  H04L25/49 ,  H04M7/06 ,  H04L23/02 ,  H03M13/25

Abstract: A system and method for shifting the relative phases of a PCM data frame and a network RBS frame by one or more symbols is disclosed. The method includes determining whether or not RBS is present (100). If RBS is present, the slots affected by RBS are identifed. Next it is determined what data slots, if any, are affected by encoding (102). The PCM data frame is shifted to the RBS constraint and the encoding constraint do not coincide at any particular data slot (104). For one particular PCM upstream modulation scheme, the digital modem adjusts the relative phases of the data-mode frame and network RBS frame such that a minimum number of trellis-modified symbols fall on network RBS affected slots. This information is transmitted to an analog modem (106). The amount of shift can be conveyed to an analog modem in the same data sequence used to send upstream constellation sets and mapping parameters during an initial training sequence. The present invention improves the performance of any PCM modem that employs a data frame structure in which not all symbols are subject to the same constraints, for example, due to trellis coding.

公开(公告)号：CA2399543C

公开(公告)日：2004-08-17

申请号：CA2399543

申请日：2001-02-01

Applicant: 3COM CORP ,  MOTOROLA INC

Inventor： PARIZHSKY VLADIMIR ,  AHMED S ARIF ,  MEHRABANZAD SEPEHR ,  LIU JACK ,  PILOZZI JOHN ,  KIM DAE-YOUNG

IPC: H04L7/00 ,  H04L25/49

Abstract: A system and method for adjusting the phase of the analog signal produced by an analog modem (26) connected to a digital modem (20) over a telephone network (22). The digital portion of the telephone network is locked to the network clock, and the modems (20 and 26) have no control over the sampling timing or rate as the analog signal is sampled and quantized by a codec (23). If the analog signal is shifted in phase relative to the network clock.the codec (23) may be sampling at unresolvable points on the analog signal, thereby causing errors and a decrease in the usable bandwidth for transmitting data. The analog modem (26) symbol frequency is locked (101) to the clock of the digital network (22) using loop-back timing. A phase estimate (103) is computed using the quantized samples of a known reference signal. Next, a phase offset (105) is calculated by comparing the phase estimate to an optimum phase value. Then the digital modem (20) sends the calculated phase offset information ( 107) to the analog modem (26). The analog modem (26) then delays its transmitted signal by the phase offset (109). After the phase of the analog modem's transmitter is adjusted, the analog signal reaches the codec (23) at the phase desired by the digital modem (20).

公开(公告)号：AU3473701A

公开(公告)日：2001-08-14

申请号：AU3473701

申请日：2001-02-01

Applicant: MOTOROLA INC

Inventor： PILOZZI JOHN ,  KIM DAE-YOUNG ,  MEHRABANZAD SEPEHR ,  LIU JACK ,  AHMED S ARIF ,  PARIZHSKY VLADIMIR

IPC: H04L7/00 ,  H04L25/49

Abstract: A system and method for adjusting the phase of the analog signal produced by an analog modem connected to a digital modem over a telephone network. The digital portion of the telephone network is locked to the network clock, and the modems have no control over the sampling timing or rate as the analog signal is sampled and quantized by a codec. If the analog signal is shifted in phase relative to the network clock, then the codec may be sampling at unresolvable points on the analog signal, thereby causing errors and a decrease in the usable bandwidth for transmitting data. The analog modem symbol frequency is locked to the clock of the digital network using loop-back timing. A phase estimate is computed using the quantized samples of a known reference signal. Next, a "phase offset" is calculated by comparing the phase estimate to an optimum phase value. Then the digital modem sends the calculated phase offset information to the analog modem. The analog modem then delays its transmitted signal by the phase offset. After the phase of the analog modem's transmitter is adjusted, the analog signal reaches the codec at the phase desired by the digital modem.

公开(公告)号：AU3322401A

公开(公告)日：2001-08-14

申请号：AU3322401

申请日：2001-02-01

Applicant: MOTOROLA INC

Inventor： PILOZZI JOHN ,  KIM DAE-YOUNG ,  MEHRABANZAD SEPEHR ,  MAURER PATRICK ,  LIU JACK ,  AHMED S ARIF ,  PARIZHSKY VLADIMIR

IPC: H04J3/00 ,  H04B14/04 ,  H04J3/12 ,  H04L25/49 ,  H04M7/06 ,  H03M13/25 ,  H04L23/02

Abstract: A system and method for shifting the relative phases of a PCM data frame and a network RBS frame by one or more symbols is disclosed. The method includes determining whether or not RBS is present. If RBS is present, the slots affected by RBS are identified. Next it is determined what data slots, if any, are affected by encoding. The PCM data frame is shifted so the RBS constraint and the encoding constraint do not coincide at any particular data slot. For one particular PCM upstream modulation scheme, the digital modem adjusts the relative phases of the data-mode frame and network RBS frame such that a minimum number of trellis-modified symbols fall on network RBS affected slots. This information is transmitted to an analog modem. The amount of shift can be conveyed to an analog modem in the same data sequence used to send upstream constellation sets and mapping parameters during an initial training sequence. The present invention improves the performance of any PCM modem that employs a data frame structure in which not all symbols are subject to the same constraints, for example, due to trellis coding.

公开(公告)号：CA2399513A1

公开(公告)日：2001-08-09

申请号：CA2399513

申请日：2001-02-01

Applicant: MOTOROLA INC ,  3COM CORP

Inventor： PILOZZI JOHN ,  PARIZHSKY VLADIMIR ,  MEHRABANZAD SEPEHR ,  KIM DAE-YOUNG ,  MAURER PATRICK ,  LIU JACK ,  AHMED S ARIF

IPC: H04J3/00 ,  H04B14/04 ,  H04J3/12 ,  H04L25/49 ,  H04M7/06 ,  H04L23/02 ,  H03M13/25

Abstract: A system and method for shifting the relative phases of a PCM data frame and a network RBS frame by one or more symbols is disclosed. The method includes determining whether or not RBS is present. If RBS is present, the slots affected by RBS are identified. Next it is determined what data slots, if any, are affected by encoding. The PCM data frame is shifted so the RBS constraint and the encoding constraint do not coincide at any particular data slot. For one particular PCM upstream modulation scheme, the digital modem adjusts the relative phases of the data-mode frame and network RBS frame such that a minimum number of trellis-modified symbols fall on network RBS affected slots. This information is transmitted to an analog modem. The amount of shift can be conveyed to an analog modem in the same data sequence used to send upstream constellation sets and mapping parameters during an initial training sequence. The present invention improves the performance of any PCM modem that employs a data frame structure in which not all symbols are subject to the same constraints, for example, due to trellis coding.

公开(公告)号：WO0158173A2

公开(公告)日：2001-08-09

申请号：PCT/US0103340

申请日：2001-02-01

Applicant: MOTOROLA INC

Inventor： PILOZZI JOHN ,  KIM DAE-YOUNG ,  MEHRABANZAD SEPEHR ,  LIU JACK ,  AHMED S ARIF ,  PARIZHSKY VLADIMIR

IPC: H04L7/00 ,  H04L25/49 ,  H04Q

CPC classification number: H04L25/4927

Abstract: A system and method for adjusting the phase of the analog signal produced by an analog modem (26) connected to a digital modem (20) over a telephone network (22). The digital portion of the telephone network is locked to the network clock, and the modems (20 and 26) have no control over the sampling timing or rate as the analog signal is sampled and quantized by a codec (23). If the analog signal is shifted in phase relative to the network clock, the codec (23) may be sampling at unresolvable points on the analog signal, thereby causing errors and a decrease in the usable bandwidth for transmitting data. The analog modem (26) symbol frequency is locked (101) to the clock of the digital network (22) using loop-back timing. A phase estimate (103) is computed using the quantized samples of a known reference signal. Next, a phase offset (105) is calculated by comparing the phase estimate to an optimum phase value. Then the digital modem (20) sends the calculated phase offset information (107) to the analog modem (26). The analog modem (26) then delays its transmitted signal by the phase offset (109). After the phase of the analog modem's transmitter is adjusted, the analog signal reaches the codec (23) at the phase desired by the digital modem (20).

Abstract translation: 一种用于调节通过电话网络（22）连接到数字调制解调器（20）的模拟调制解调器（26）产生的模拟信号的相位的系统和方法。 电话网络的数字部分被锁定到网络时钟，并且当模拟信号被编解码器（23）采样和量化时，调制解调器（20和26）不能控制采样定时或速率。 如果模拟信号相对于网络时钟相位移位，则编解码器（23）可以在模拟信号上的不可解析点进行采样，从而导致发送数据的可用带宽的错误和降低。 使用环回定时将模拟调制解调器（26）符号频率锁定（101）到数字网络（22）的时钟。 使用已知参考信号的量化采样来计算相位估计（103）。 接下来，通过将相位估计与最佳相位值进行比较来计算相位偏移（105）。 然后数字调制解调器（20）将计算的相位偏移信息（107）发送到模拟调制解调器（26）。 模拟调制解调器（26）然后将其发送的信号延迟相位偏移（109）。 在模拟调制解调器的发射机的相位被调整之后，模拟信号以数字调制解调器（20）所期望的相位达到编解码器（23）。