公开(公告)号：MY112135A

公开(公告)日：2001-04-30

申请号：MYPI19950345

申请日：1995-02-13

Applicant: QUALCOMM INC

Inventor： PAUL E PETERZELL ,  NATHANIEL B WILSON ,  PETER J BLACK

IPC: H03G3/30 ,  H03G3/20 ,  H04B1/16 ,  H04B1/18 ,  H04L27/22 ,  H04L27/38

Abstract: AN AUTOMATIC GAIN CONTROL (AGC) APPARATUS FOR A DIGITAL RECEIVER IS DISCLOSED HEREIN. THE AGC APPARATUS INCLUDES AN ADJUSTABLE GAIN AMPLIFIER HAVING AN INPUT PORT FOR RECEIVING AN INPUT SIGNAL, A CONTROL PORT FOR RECEIVING A GAIN CONTROL SIGNAL, AND AN OUTPUT PORT FOR PROVIDING AN OUTPUT SIGNAL. THE AGC APPARATUS FURTHER INCLUDES A MEASUREMENT CIRCUIT FOR GENERATING A RECEIVED POWER SIGNAL BASED ON THE POWER OF THE OUTPUT SIGNAL. A SATURATING INTEGRATOR COMPARES THE RECEIVED POWER SIGNAL TO A REFERENCE SIGNAL AND GENERATES AN GAIN CONTROL SIGNAL IN RESPONSE TO A RESULT OF THE COMPARISON. THE SATURATING INTEGRATOR INCLUDES A DECISION CIRCUIT FOR ENABLING INTEGRATION BASED ON VALUES 0' THE RECEIVED POWER SIGNAL, THE REFERENCE SIGNAL, AND THE GAIN CONTROL SIGNAL. IN A PREFERRED IMPLEMENTATION THE UTILIZATION OF AN INPUT LIMITER IN CONJUNCTION WITH AN ANALOG TO DIGITAL CONVERTER ENABLES ACCOMMODATION OF AN INCREASED INPUT SIGNAL DYNAMIC RANGE. ACCORDINGLY, THE AGC APPARATUS IS CAPABLE OF BEING USED IN DIGITAL DEMODULATION OF FM SIGNALS. THE AGC APPARATUS MAY ALSO BE EMPLOYED WITHIN A DUAL MODE RECEIVER DESIGNED TO PROCESS BOTH FM AND CODE DIVISION MULTIPLE ACCESS (CDMA) INPUT SIGNALS.FIGURE 3

公开(公告)号：MY113706A

公开(公告)日：2002-05-31

申请号：MYPI19950274

申请日：1995-02-08

Applicant: QUALCOMM INC

Inventor： PAUL E PETERZELL ,  PETER J BLACK ,  NATHANIEL B WILSON

IPC: H03G3/20 ,  H03D3/00 ,  H03D3/24 ,  H03D7/16 ,  H03G3/30 ,  H04B1/30 ,  H04L27/14 ,  H04L27/22

Abstract: AN AUTOMATIC GAIN CONTROL (AGC) AND D.C. OFFSET CORRECTION METHOD AND APPARATUS FOR CONTROLLING SIGNAL POWER OF A RECEIVED RF SIGNAL WITHIN A DUAL MODE QUADRATURE RECEIVER ARE DISCLOSED HEREIN. IN A PREFERRED IMPLEMENTATION THE AUTOMATIC GAIN CONTROL APPARATUS MAY BE ADJUSTED TO PROVIDE A DESIRED CONTROL RESPONSE TO VARIOUS FADING CHARACTERISTICS OF A RECEIVED FM, FSK, GMSK, QPSK, OR BPSK SIGNAL. THE AGC APPARATUS INCLUDES AN ADJUSTABLE GAIN AMPLIFIER (18) HAVING AN INPUT PORT FOR RECEIVING AN INPUT SIGNAL, A CONTROL PORT FOR RECEIVING A GAIN CONTROL SIGNAL, AND AN OUTPUT PORT FOR PROVIDING AN OUTPUT SIGNAL. A QUADRATURE DOWNCONVERTER (60) COUPLED TO THE OUTPUT PORT SER-VES TO TRANSLATE THE FREQUENCY OF THE OUTPUT SIGNAL TO A BASEBAND FREQUENCY,THEREBY PRODUCING BASEBAND SIGNALS. IN A PREFERRED IMPLEMENTATION THE DOWNCONVERTER (60) IS OPERATIVE TO MAP THE CARRIER FREQUENCY OF THE OUTPUT SIGNAL TO A BASEBAND FREQUENCY OFFSET BY A PREDETERMINED MARGIN FROM D.C. TWO HIGH GAIN ACTIVE LOW PASS FILTERS (76,78) PROVIDE OUT-OF-BAND SIGNAL REJECTION FOR THE BASEBAND SIGNALS. A D.C. FEEDTHROUGH SUPPRESSION LOOP (200), DISPOSED TO RECEIVE SAID BASEBAND SIGNAL, SUPPRESSES D.C. OFFSETS PRODUCED BY THE DOWN CONVERTERS (60) AND LOW PASS FILTERS (76, 78), HENCE PROVIDING A COMPENSATED BASEBAND SIGNAL. THE AGC APPARATUS IS FURTHER DISPOSED TO GENERATE A RECEIVED POWER SIGNAL BASED ON THE POWER OF THE OUTPUT SIGNAL. A SATURATING INTEGRATOR (22) COMPARES THE RECEIVED POWER SIGNAL TO A REFERENCE SIGNAL AND PRODUCES THE GAIN CONTROL SIGNAL BY INTEGRATING OR BY REFRAINING FROM INTEGRATION BASED ON VALUES OF THE REFERENCE, RECEIVED POWER SIGNAL, AND GAIN CONTROL SIGNALS, THEREBY EXTENDING THE USABLE DYNAMIC RANGE OF THE RECEIVER FOR FM MODE.FIG. 3