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公开(公告)号：AU6938000A
公开(公告)日：2001-04-10
申请号：AU6938000
申请日：2000-08-25
Applicant: MOTOROLA INC
Inventor： MEHRABANZAD SEPEHR , KIM DAE-YOUNG , PILOZZI JOHN
Abstract: In order to achieve reliable and efficient communication over public switched telephone networks (PSTN), voice-band modems utilize sophisticated start-up procedures. This invention involves a start-up procedure that allows an analog modem and a digital modem to establish a dial-up connection that utilizes PCM modulation in both upstream and downstream directions for data transmission.
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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
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.
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公开(公告)号：CA2398487C
公开(公告)日：2010-04-20
申请号：CA2398487
申请日：2001-02-01
Applicant: MOTOROLA INC
Inventor： KIM DAE-YOUNG , MEHRABANZAD SEPEHR , PILOZZI JOHN
IPC: H04B1/38 , H04L25/03 , H04B1/00 , H04B1/10 , H04B3/04 , H04B3/06 , H04B7/005 , H04B14/04 , H04L25/49
Abstract: A method and apparatus is provided for controlling the transmit power of an analog modem (12) when the transmit power does not match the desired transmit power level, thus conforming to FCC regulations on transmit power and/or eliminating non-linearities associated with higher than required power levels and loss of signal-to-noise ratio and concomitant at loss of data rate if the transmit power levels are less than that desired. The power level (26) at the analog modem (12) is sensed to ascertain if it is not at the desired transmit power level (28), with adjustment being provided by transmitting the desired change (30) in the transmit power level to the digital modem (18), whereupon mapping parameters (34, 36) are redefined by adjusting the number of equivalence classes, thus to adjust transmit power at analog modem (12).
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4.发明专利
公开(公告)号：AU4963501A
公开(公告)日：2001-12-11
申请号：AU4963501
申请日：2001-03-30
Applicant: MOTOROLA INC
Inventor： KIM DAE-YOUNG , MEHRABANZAD SEPEHR , PILOZZI JOHN
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公开(公告)号：AU3322101A
公开(公告)日：2001-08-14
申请号：AU3322101
申请日：2001-02-01
Applicant: MOTOROLA INC
Inventor： PILOZZI JOHN , MEHRABANZAD SEPEHR , KIM DAE-YOUNG , BROWN WILLIAM LESLIE
Abstract: In a PCM modem system, a method and apparatus for optimizing the fractional sampling phase offset in the upstream direction to maximize the upstream data rate utilizes a probing signal from the analog modem generated during startup and having at least two distinct phases of a pure tone, with the probing signal being detected at the digital modem where an optimum sampling phase value is calculated. From this calculated value, a signal representing the appropriate amount to delay the input data stream is transmitted back to the analog modem for adjustment of the fractional sampling phase so that the fractional sampling phase offset at the central office quantizer is optimized.
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Patent Agency Ranking
公开(公告)号：CA2397971A1
公开(公告)日：2001-08-09
申请号：CA2397971
申请日：2001-02-01
Applicant: MOTOROLA INC
Inventor： PILOZZI JOHN , KIM DAE-YOUNG , MEHRABANZAD SEPEHR
Abstract: In a full duplex PCM modem system (10) having an analog (12) and digital (18 ) modem, a method and apparatus is provided for on-the-fly reconfiguring of analog (12) or digital (18) modem transmitter parameters without switching back to a retrain or startup mode. In one embodiment, the transmitter parameters for the analog modem (12) are modified to take into account chann el impairments, in which modified precompensation parameters are sent from the digital modem (18) to the analog modem (12) without switching out of the dat a mode. In another embodiment, transmit power levels sensed at the analog mode m (12) which are non-optimal are adjusted by new parameters sent from the digital modem (18) without having to switch back to the startup mode. In a further embodiment, transmitter parameters in the digital modem (18) are reconfigured to provide more an increased downstream data rate from the digital modem (18) upon sensing improvement in the quality of the downstream channel without switching back to the startup mode.
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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
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.
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公开(公告)号：AU3324901A
公开(公告)日：2001-08-14
申请号：AU3324901
申请日：2001-02-01
Applicant: MOTOROLA INC
Inventor： KIM DAE-YOUNG , MEHRABANZAD SEPEHR , PILOZZI JOHN
IPC: H04L25/03 , H04B3/04 , H04B3/06 , H04B7/005 , H04L25/49 , H04B1/38 , H04B14/04 , H04B1/10 , H04B1/00
Abstract: A method and apparatus is provided for controlling the transmit power of an analog modem when the transmit power level does not match the desired transmit power level, thus conforming to FCC regulations on transmit power and/or eliminating non-linearities associated with higher than required power levels and loss of signal-to-noise ratio and concomitant at loss of data rate if the transmit power levels are less than that desired. In one embodiment, the power level at the analog modem is sensed to ascertain if it is not at the desired transmit power level, with adjustment being provided by transmitting the desired change in the transmit power level to the digital modem, whereupon mapping parameters are redefined by adjusting the number of equivalence classes, thus to adjust transmit power at analog modem.
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9.发明专利
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
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.
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10.发明专利
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
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.
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