公开(公告)号：WO1993023963A1

公开(公告)日：1993-11-25

申请号：PCT/US1993003692

申请日：1993-04-19

Applicant: MOTOROLA INC.

Inventor： MOTOROLA INC. ,  BUSSAN, Christopher, F. ,  MARRY, Patrick, J. ,  RABE, Duane, C. ,  BINZEL, Charles, P. ,  ARORA, Arvind, S.

IPC: H04Q07/02

CPC classification number: H04W72/085 ,  H03J1/0091 ,  H04B1/26

Abstract: A circuit and method for selecting tuning of a radio receiver to a frequency channel of a set of frequency channels. The radio receiver scans selected control channels and measures the power levels of signals generated upon control channels. Only when the measured power levels (684) of the signals generated upon the respective ones of the control channels are in excess of a certain power level is a communication link attempted to be effectuated with a transmitter of such data signals (696). When a communication link cannot be effectuated, the radio receiver powers down (708) for a predetermined time period, then powers on again (710), and the power levels of signals transmitted upon the control channels are again measured (710). Effectuation of a communication link with a transmitter which transmits a signal upon one of the control channels is attempted if the measured power level on such control channel increases beyond a certain amount.

公开(公告)号：WO1993020620A1

公开(公告)日：1993-10-14

申请号：PCT/US1993002152

申请日：1993-03-11

Applicant: MOTOROLA INC.

Inventor： MOTOROLA INC. ,  GOULD, Adam, F. ,  ARORA, Arvind, S.

IPC: H03M13/12

CPC classification number: H04L1/0057 ,  H03M13/39 ,  H04L1/0054 ,  H04L1/0065 ,  H04L1/20 ,  H04L1/201 ,  H04L1/208

Abstract: An error detection system for discrete receiver. The error detection system indicates bad frames of binary information signal which contain distorted bits in excessive numbers so great as to cause a convolutional decoder to generate an incorrect, decoded signal. A signal decoded by a convolutional decoder (512) is re-encoded by an encoder (524), and the re-encoded signal (530) is compared with the signal received (506) by the receiver. When excessive numbers of re-encoded signal portions differ too greatly with corresponding portions of an actual, received signal, a bad frame indication is generated (590).

公开(公告)号：WO1992011706A1

公开(公告)日：1992-07-09

申请号：PCT/US1991009409

申请日：1991-12-11

Applicant: MOTOROLA, INC.

Inventor： MOTOROLA, INC. ,  ARORA, Arvind, S.

IPC: H04B07/00

CPC classification number: H04W56/0035 ,  H04B7/2675 ,  H04B7/2678 ,  H04B7/2681 ,  H04L2007/047

Abstract: The synchronization process of the present invention filters the received signal with an adaptive band-pass filter (101) while buffering the received signal in memory (108). The energies of the input signal and the filtered signal are estimated (103 and 104) and the gain of the filter is adapted (105) based on the difference between the energies. The pole of the filter is adapted (102) to center the frequency of the input signal in the filter's pass-band. If a tone is detected (106), the length of the tone is determined (107) to ascertain if it is a frequency correction burst (FCB). If the tone detected is an FCB, the signal in the memory is also the FCB that is then filtered in the band-pass filter (101) and the difference between the frequency of this signal and 67.5 kHz is determined (109). This difference represents the frequency offset between the base station carrier frequency and that of the mobile radiotelephone, and can be fed into the local oscillating means to compensate for the frequency offset. The boundaries of the FCB establish the time slot alignment of the TDMA structure being received from the base station.