US 2003/0190891 A1 · Initial frequency synchronization mechanism

Abstract

Method for acquiring frequency of a desired channel having a carrier frequency FMAIN, for a dynamic receiver frequency FMOBILE, from a starting frequency FSTART, in the presence of high power adjacent interfering channels, wherein the starting frequency FSTART is shifted from FMAIN by not more than a predetermined frequency gap ΔF, the method includes the steps of determining a first frequency boundary and a second frequency boundary, detecting channels within a filtering bandwidth, selecting a dominant channel from the detected channels, progressing the dynamic receiver frequency FMOBILE towards the carrier frequency of the dominant channel, detecting when the step of progressing has exceeded one of the first frequency boundary and the second frequency boundary, restarting the step of detecting channels, from the other of the one of the first frequency boundary and the second frequency boundary, and repeating from the step of detecting channels.

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Claims13

Dependent claims

A method for acquiring frequency of a desired channel having a carrier frequency FMAIN, for a dynamic receiver frequency FMOBILE, from a starting frequency FSTART, in the presence of high power adjacent interfering channels, wherein FSTART is shifted from FMAIN by not more than a predetermined frequency gap ΔF, the method comprising the steps of:

determining a first frequency boundary and a second frequency boundary;
detecting channels within a filtering bandwidth;
selecting a dominant channel from said detected channels;
progressing said dynamic receiver frequency FMOBILE towards the carrier frequency of said dominant channel;
detecting when said step of progressing has exceeded one of said first frequency boundary and said second frequency boundary;
restarting said step of detecting channels, from the other of said one of said first frequency boundary and said second frequency boundary;
and
repeating from said step of detecting channels.

5 more elements

A device for acquiring frequency of a desired channel having a carrier frequency FMAIN, for a dynamic receiver frequency FMOBILE, from a starting frequency FSTART, in the presence of high power adjacent interfering channels, wherein FSTART is shifted from FMAIN by not more than a predetermined frequency gap ΔF, the device being connected to an antenna via a receiver and to a reference frequency FREFERENCE source, the device comprising:

controllable frequency generating means for generating an internal frequency FINTERNAL;
frequency shift means connected to said controllable frequency generating means, and to said receiver, for shifting received frequency FRECEIVED, of a received channel, according to said internal frequency FINTERNAL;
a frequency shift detector, connected to said frequency shift means, for detecting a frequency difference between said internal frequency FINTERNAL and said received frequency FRECEIVED, with respect to said reference frequency FREFERENCE, thereby producing a frequency shift value FSHIFT;
loop filtering means, connected to said frequency shift detector, for filtering said frequency shift value FSHIFT, thereby producing a filtered frequency shift value FSHIFT-FILTERED;
and
controlling means, connected to said controllable frequency generating means and to said loop filtering means, for determining a frequency step FSTEP from said filtered frequency shift value FSHIFT-FILTERED,
wherein said controlling means provide said frequency shift value FSHIFT to said controllable frequency generating means,
wherein said controllable frequency generating means adjust said internal frequency FINTERNAL according to said frequency shift value FSHIFT, and
wherein said controlling means control said controllable frequency generating means to generate frequency in a range from a first frequency boundary FFIRST and a second frequency boundary FSECOND.

6 more elements

Dependencies are inferred from the claim text.

Description4,396 words

Summary1,154 words

#The present invention relates to frequency acquisition in general and to frequency acquisition in the presence of high power adjacent channels, in particular.

#Reference is now made to FIGS. 1A and 1B. FIG. 1A is a schematic illustration of frequency versus power, describing the initial stage of a initial frequency synchronization procedure, known in the art. The present example describes a closed loop automatic frequency control (AFC) mechanism.

#FIG. 1B is a schematic illustration of frequency versus power, describing the final stage of the initial frequency synchronization procedure of FIG. 1A.

Brief description of the drawings12 figures

#The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which:

#FIG. 1A is a schematic illustration of frequency versus power, describing the initial stage of a conventional initial frequency synchronization procedure;

#FIG. 1B is a schematic illustration of frequency power, describing the final stage of the initial frequency synchronization procedure of FIG. 1A;

Detailed description2,920 words

#The present invention overcomes the disadvantages of the prior art by providing a frequency detect and fold mechanism. Accordingly, when the frequency shift exceeds a boundary value, then a predetermined frequency shift is enforced.

#Reference is now made to FIGS. 2A, 2B, 2C and 2D. FIG. 2A is a schematic illustration of frequency versus power, describing the initial stage of a frequency synchronization procedure, operative in accordance with the present invention. FIG. 2B is a schematic illustration of frequency versus power, describing the secondary stage of a frequency synchronization procedure, operative in accordance with the present invention. FIG. 2C is a schematic illustration of frequency versus power, describing the third stage of a frequency synchronization procedure, operative in accordance with the present invention. FIG. 2D is a schematic illustration of frequency versus power, describing the final stage of a frequency synchronization procedure, operative in accordance with the present invention.

#The schematic illustration provided by FIG. 2A describes the frequency 100 of a base station, having a value FBASE, a frequency 104 of a mobile unit, having an initial value F0MOBILE and a frequency 102 of a neighbor transmitter, having the value of FNEIGHBOR, wherein

Facts

Application

09/731,821Filed 8 Dec 2000

Priority

23 Jan 1998

Published

9 Oct 2003

Term ends

Not estimatedThe source records don’t support an estimate.

Classification2 codes

H03J 7/045
Where the frequency control is accomplished by varying the electrical characteristics of a non-mechanically adjustable element or where the…
H03J
Tuning resonant circuits

Initial frequency synchronization mechanism

Life of this patent

Initial frequency synchronization mechanism

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims13

Description4,396 words

Drawings

Classification2 codes

Life of this patent

Description4,396 words