公开(公告)号：DE3789260D1

公开(公告)日：1994-04-14

申请号：DE3789260

申请日：1987-07-31

Applicant: IBM

Inventor： PEARCE HAROLD BRENT ,  WEST LYNN PARKER

IPC: H03G3/20 ,  H03G7/00

Abstract: Automatic gain control in a digital signal processor is described. An incoming electrical signal is sampled and multiplied by a gain factor with the resulting product compared to a constantly changing maximum value. If the magnitude of the changing maximum value lies outside a predetermined range of values, then the gain factor is adjusted proportionally to the error calculated by the amount the maximum value is outside the threshold range. In an alternative embodiment, the gain is adjusted according to whether or not one of the resulting products lies outside such upper and lower threshold range. The running maximum value decays with time in order to allow the automatic gain control to track a signal which slowly weakens in strength. A time dependent factor enables the gain to be adjusted much more radically when a signal is first received.

公开(公告)号：DE3789260T2

公开(公告)日：1994-09-22

申请号：DE3789260

申请日：1987-07-31

Applicant: IBM

Inventor： PEARCE HAROLD BRENT ,  WEST LYNN PARKER

IPC: H03G3/20 ,  H03G7/00

Abstract: Automatic gain control in a digital signal processor is described. An incoming electrical signal is sampled and multiplied by a gain factor with the resulting product compared to a constantly changing maximum value. If the magnitude of the changing maximum value lies outside a predetermined range of values, then the gain factor is adjusted proportionally to the error calculated by the amount the maximum value is outside the threshold range. In an alternative embodiment, the gain is adjusted according to whether or not one of the resulting products lies outside such upper and lower threshold range. The running maximum value decays with time in order to allow the automatic gain control to track a signal which slowly weakens in strength. A time dependent factor enables the gain to be adjusted much more radically when a signal is first received.

公开(公告)号：DE3783837T2

公开(公告)日：1993-08-19

申请号：DE3783837

申请日：1987-07-31

Applicant: IBM

Inventor： PEARCE HAROLD BRENT ,  WEST LYNN PARKER

IPC: H04L27/38 ,  H04L27/00 ,  H04L27/227

Abstract: A method and apparatus are described for phase and frequency locking a reference oscillator to an incoming modulated signal. The method and apparatus enable the carrier recovery of the incoming modulated signal. Phase and frequency locking devices are connected in feedback loops (20, 30) with a coherent detector (10) that determine the amount of phase and frequency error between the reference oscillator of the coherent detector and the incoming modulated signal. The feedback loops correct such frequency and phase error so as to enable the reference oscillator to be in phase and frequency step with the modulated signal.

公开(公告)号：DE3783837D1

公开(公告)日：1993-03-11

申请号：DE3783837

申请日：1987-07-31

Applicant: IBM

Inventor： PEARCE HAROLD BRENT ,  WEST LYNN PARKER

IPC: H04L27/38 ,  H04L27/00 ,  H04L27/227

Abstract: A method and apparatus are described for phase and frequency locking a reference oscillator to an incoming modulated signal. The method and apparatus enable the carrier recovery of the incoming modulated signal. Phase and frequency locking devices are connected in feedback loops (20, 30) with a coherent detector (10) that determine the amount of phase and frequency error between the reference oscillator of the coherent detector and the incoming modulated signal. The feedback loops correct such frequency and phase error so as to enable the reference oscillator to be in phase and frequency step with the modulated signal.