公开(公告)号：DD292787A5

公开(公告)日：1991-08-08

申请号：DD33499989

申请日：1989-11-29

Applicant: MOTOROLA INC

Inventor： KEPLER JAMES F M ,  BORTH DAVID E ,  CERNY FRANK I JR

IPC: H03G3/20 ,  H04B3/06 ,  H04B7/005 ,  H04B7/26 ,  H04J3/00 ,  H04J3/16 ,  H04L27/18 ,  H04L27/22 ,  H04L27/38 ,  H03G3/00

Abstract: There is provided a method of digital Automatic Gain Control (AGC) in a receiver having limited dynamic range, particularly for discontinuous signals. The method is characterized by detecting the level of a received and AGC'd discontinuous signal, comparing the level of the AGC'd signal relative to the dynamic range of the receiver, and adjusting the AGC to establish a desired relationship between the AGC'd signal and the dynamic range limitation. There is also provided a method of handoff in a TDMA cellular-type transmission system utilizing this method of AGControl. The method for Automatic Gain Control (AGC) of discontinuous signals in a receiver having limited dynamic range is further characterized by: digitizing (A/D) a received and AGC'd discontinuous signal and converting the digitized samples to a power sample to sense the power of and detect the level of the signal, comparing the level of the AGC'd signal relative to the dynamic range of the receiver; and coarsely-adjusting by either progressively attenuating the signal until it falls within the dynamic range of the receiver or by progressively gain-amplifying the signal until it falls within the limited dynamic range of the receiver and finely-adjusting the AGC of the received signal until optimum use of the full (albeit limited) dynamic range of the signal processing stages is about 6-12 dB below maximum to establish a desired relationship between the AGC'd signal and the dynamic range limitation.

公开(公告)号：CA2003688A1

公开(公告)日：1990-06-16

申请号：CA2003688

申请日：1989-11-23

Applicant: MOTOROLA INC

Inventor： BORTH DAVID E ,  KEPLER JAMES F M

IPC: H03L7/095 ,  H03J7/02 ,  H03L7/08 ,  H03L7/087

Abstract: There is provided a method of and apparatus for Automatice Frequency Control (AFC) of pure sine waves (PSW). It is characterized by discriminating to detect frequency differences between a received pure sine wave and a reference frequency (20), integrating (30) the frequency differences to average the differences, and adjusting (40) the reference frequency (80) to eliminate the frequency difference. It is further characterized by digitizing, in quadrature, the received pure sine wave (70), mixing (50) the received pure sine wave with a complex sinusoid to translate the pure sine wave to baseband, quadrature filtering (60) the mixed sine wave, cross-product discrimination (20) to detect frequency differences between a received pure sine wave and a reference frequency, integration (30) the frequency differences to average the differences, selectively (100/110) calculating the mean/variance (90) between the pure sine wave and the reference frequency, and adjusting (40) the reference frequency of a Voltage Controlled Oscillator 80 to eliminate the frequency difference.