WO1993000747A1 - Automatic frequency control by an adaptive filter - Google Patents

Automatic frequency control by an adaptive filter Download PDF

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Publication number
WO1993000747A1
WO1993000747A1 PCT/US1992/003763 US9203763W WO9300747A1 WO 1993000747 A1 WO1993000747 A1 WO 1993000747A1 US 9203763 W US9203763 W US 9203763W WO 9300747 A1 WO9300747 A1 WO 9300747A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
mean square
response
error
generating
Prior art date
Application number
PCT/US1992/003763
Other languages
English (en)
French (fr)
Inventor
Kevin L. Baum
Bruce D. Mueller
Original Assignee
Motorola, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Motorola, Inc. filed Critical Motorola, Inc.
Priority to DE4292274A priority Critical patent/DE4292274C2/de
Priority to CA002089154A priority patent/CA2089154C/en
Priority to GB9303663A priority patent/GB2263829B/en
Priority to KR1019930700393A priority patent/KR960005386B1/ko
Publication of WO1993000747A1 publication Critical patent/WO1993000747A1/en

Links

Classifications

    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03LAUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
    • H03L7/00Automatic control of frequency or phase; Synchronisation
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H21/00Adaptive networks
    • H03H21/0012Digital adaptive filters
    • H03H21/0043Adaptive algorithms
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03JTUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J7/00Automatic frequency control; Automatic scanning over a band of frequencies
    • H03J7/02Automatic frequency control
    • H03J7/04Automatic frequency control where the frequency control is accomplished by varying the electrical characteristics of a non-mechanically adjustable element or where the nature of the frequency controlling element is not significant

Definitions

  • the present invention relates generally to the field of communications and particularly to automatic frequency con ⁇ trol.
  • U.S. digital cellular (USDC) communications uses digi ⁇ tized voice and data signals for communication between a mo ⁇ bile telephone and a base station.
  • the mobiles and bases em- ploy time division multiple access (TDMA) modulation for the transmission of these signals.
  • TDMA time division multiple access
  • FIG. 5 A typical format for the TDMA data bursts is illustrated in FIG. 5. This data burst, as well as USDC in general, is discussed in more detail in the USDC specification EIA/TIA IS-54 available from Electronic Industries Association, Engineering Department, 2001 Eye
  • FIG. 1 A typical adaptive filter is illustrated in FIG. 1.
  • the in ⁇ put signal (106) is processed by the adaptive filter (101), pro ⁇ ducing the adaptive filter output signal (102).
  • the output of the filter is then subtracted (105) from a reference signal (103), typically the unfiltered input signal (106), to produce an error signal (104).
  • This error signal (104) is used by an adaptive al- gorithm with an update coefficient, ⁇ , in the adaptive filter to update the filter coefficients.
  • the update coefficient is also re ⁇ ferred to as a tracking coefficient or memory coefficient.
  • the memory of the adaptive algorithm increases as the value of ⁇ increases.
  • the adaptive algorith may be a Kal an, Recursive Least Square, or Least Mean Square (LMS) algorithm.
  • LMS Least Mean Square
  • the typical goal of the adaptive algorithm is to minimize the mean square value of the error signal (104), fixed update coefficient. This value is typically designated mean square error (MSE).
  • MSE mean square error
  • a detrimental characteristic of adaptive channel equal ⁇ izers is that they can experience degraded performance in the presence of a frequency offset of more than approximately 10 Hz (in a system with a 24 kHz symbol rate). While the spe ⁇ fi- cation for a transmission system requires a certain frequency variation limit, the adaptive channel equalizer may require a stricter limit.
  • An example is the USDC system. USDC re ⁇ quires the receiver operating frequency to be locked within 200 Hz of the transmitter.
  • a coarse automatic frequency control is typically used to remove most of the offset. Any remaining offset, however, can detrimentally af ⁇ fect a detection algorithm and increase the detected bit error rate. There is a resulting need for an AFC that can reduce the frequency offset to an acceptably small level and track any variation of the offset as the environment changes when the mobile moves.
  • the process of the present invention generates an opti ⁇ mum automatic frequency control signal in an apparatus that has a plurality of adaptive algorithms, each adaptive algo ⁇ rithm having a reference signal with an associated frequency dither.
  • the process starts by comparing the performance of each of the plurality of adaptive algorithms then modifying the automatic frequency control signal in response to a difference in the performances.
  • FIG. 3 shows a graph of mean square error versus residual frequency offset in accordance with the process of the present invention.
  • the difference in performance of the adaptive filters is used to modify the AFC signal, thereby reducing the frequency offset.
  • This signal is then operated on by a detection algorithm (10) that is driven by the ACE 2 output.
  • the resulting symbol decision signal, ⁇ is input to the three ACE's (1 - 3).

Landscapes

  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
  • Channel Selection Circuits, Automatic Tuning Circuits (AREA)
  • Circuits Of Receivers In General (AREA)
  • Radio Relay Systems (AREA)
  • Feedback Control In General (AREA)
PCT/US1992/003763 1991-06-28 1992-05-08 Automatic frequency control by an adaptive filter WO1993000747A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
DE4292274A DE4292274C2 (de) 1991-06-28 1992-05-08 Automatische Frequenzsteuerung durch ein adaptives Filter
CA002089154A CA2089154C (en) 1991-06-28 1992-05-08 Automatic frequency control by an adaptive filter
GB9303663A GB2263829B (en) 1991-06-28 1992-05-08 Automatic frequency control by an adaptive filter
KR1019930700393A KR960005386B1 (ko) 1991-06-28 1992-05-08 적응형 필터에 의한 자동 주파수 제어방법 및 장치

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US72282891A 1991-06-28 1991-06-28
US722,828 1991-06-28

Publications (1)

Publication Number Publication Date
WO1993000747A1 true WO1993000747A1 (en) 1993-01-07

Family

ID=24903558

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1992/003763 WO1993000747A1 (en) 1991-06-28 1992-05-08 Automatic frequency control by an adaptive filter

Country Status (7)

Country Link
JP (1) JP2830471B2 (bg)
KR (1) KR960005386B1 (bg)
CA (1) CA2089154C (bg)
DE (2) DE4292274C2 (bg)
GB (1) GB2263829B (bg)
MX (1) MX9203307A (bg)
WO (1) WO1993000747A1 (bg)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0685082A1 (en) * 1993-02-19 1995-12-06 Mts Systems Corporation Control network with on-line iteration and adaptive filtering
DE19705055A1 (de) * 1996-02-09 1997-08-21 Mitsubishi Electric Corp Digitaler Rundfunkempfänger und Verfahren zur Abstimmsteuerung
DE19721864A1 (de) * 1996-05-22 1997-11-27 Mitsubishi Electric Corp Digitaler Rundsendeempfänger
GB2334392A (en) * 1998-02-13 1999-08-18 Daewoo Electronics Co Ltd Tracking a centre frequency

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3846546B2 (ja) 2000-08-29 2006-11-15 日本電気株式会社 周波数オフセット推定器

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4466108A (en) * 1981-10-06 1984-08-14 Communications Satellite Corporation TDMA/PSK Carrier synchronization without preamble
US4835790A (en) * 1987-06-23 1989-05-30 Nec Corporation Carrier-to-noise detector for digital transmission systems
US4852090A (en) * 1987-02-02 1989-07-25 Motorola, Inc. TDMA communications system with adaptive equalization
US4896336A (en) * 1988-08-29 1990-01-23 Rockwell International Corporation Differential phase-shift keying demodulator

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4691176A (en) * 1986-03-17 1987-09-01 General Electric Company Adaptive carrier tracking circuit
US5230007A (en) * 1991-06-28 1993-07-20 Motorola, Inc. Method for optimizing an adaptive filter update coefficient

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4466108A (en) * 1981-10-06 1984-08-14 Communications Satellite Corporation TDMA/PSK Carrier synchronization without preamble
US4852090A (en) * 1987-02-02 1989-07-25 Motorola, Inc. TDMA communications system with adaptive equalization
US4835790A (en) * 1987-06-23 1989-05-30 Nec Corporation Carrier-to-noise detector for digital transmission systems
US4896336A (en) * 1988-08-29 1990-01-23 Rockwell International Corporation Differential phase-shift keying demodulator

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0685082A1 (en) * 1993-02-19 1995-12-06 Mts Systems Corporation Control network with on-line iteration and adaptive filtering
EP0685082A4 (en) * 1993-02-19 1996-07-03 Mts System Corp CONTROL NETWORK WITH ON-LINE ITERATION AND ADAPTIVE FILTERING.
DE19705055A1 (de) * 1996-02-09 1997-08-21 Mitsubishi Electric Corp Digitaler Rundfunkempfänger und Verfahren zur Abstimmsteuerung
US6021165A (en) * 1996-02-09 2000-02-01 Mitsubishi Denki Kabushiki Kaisha Digital Broadcast receiver and method of tuning control
DE19705055C2 (de) * 1996-02-09 2001-02-22 Mitsubishi Electric Corp Verfahren zur Frequenzsteuerung eines Oszillators sowie digitaler Rundfunkempfänger
DE19721864A1 (de) * 1996-05-22 1997-11-27 Mitsubishi Electric Corp Digitaler Rundsendeempfänger
US6028900A (en) * 1996-05-22 2000-02-22 Mitsubishi Denki Kabushiki Kaisha Digital broadcast receiver
US6148045A (en) * 1996-05-22 2000-11-14 Mitsubishi Denki Kabushiki Kaisha Digital broadcast receiver
DE19721864C2 (de) * 1996-05-22 2001-05-17 Mitsubishi Electric Corp Verfahren zum Abstimmen eines digitalen Rundfunkempfängers sowie digitaler Rundfunkempfänger
GB2334392A (en) * 1998-02-13 1999-08-18 Daewoo Electronics Co Ltd Tracking a centre frequency

Also Published As

Publication number Publication date
GB2263829A (en) 1993-08-04
KR930701869A (ko) 1993-06-12
DE4292274T1 (bg) 1993-07-15
GB2263829B (en) 1995-07-26
DE4292274C2 (de) 1999-05-27
JPH05508989A (ja) 1993-12-09
JP2830471B2 (ja) 1998-12-02
GB9303663D0 (en) 1993-05-05
CA2089154C (en) 1999-08-03
MX9203307A (es) 1992-12-01
CA2089154A1 (en) 1992-12-29
KR960005386B1 (ko) 1996-04-24

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