Method and apparatus for stability margin determination in a repeater

• US 20040209568A1
• Filed: 02/03/2004
• Published: 10/21/2004
• Est. Priority Date: 06/11/1999
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Allgon AB (Bure Equity AB)
• Inventors: Kerek, Daniel
• Granted Patent: US 7,398,053 B2
• Time in Patent Office: Days
• US Class Current: 455/7
• CPC Class Codes: H04B 1/60 Supervising unattended repeaters
• CPC Class Codes: H04B 17/40 of relay systems
• CPC Class Codes: H04B 7/15535 Control of relay amplifier gain amplifier gain control in general H03G3/00; gain control reducing self - or loop interference H04B7/15578
• CPC Class Codes: H04B 7/15578 by gain adjustment

Abstract

A method and device for determining the stability margin of a RF repeater. The method is carried out in two steps, viz. establishing the amplification of the repeater as a function of the frequency in a frequency band, and observing the magnitude of wave-like variations in the established frequency response, this magnitude constituting a measure of the stability margin such that an increasing magnitude corresponds to a decreasing stability margin.

Claims

1-3. -3. (canceled)

4. An apparatus for determining the stability margin, with respect to a possible self-oscillation, in a radio frequency repeater operating with a predetermined delay between an input and an output and having a feedback path between said output and said input, comprising

at least one sensing element connected to at least one of said input and said output of the repeater, and

at least one measurement receiver connected to said at least one sensing element for measuring at least an output signal from said repeater, on the basis of which the stability margin (SM) is calculated.

5. The apparatus as defined in claim 4, wherein said at least one sensing element comprises at least one directional coupler.

6. The apparatus as defined in claim 5, wherein two directional couplers are connected to a single measurement receiver via a switch for alternating measurement of the signals at the output and the input, respectively.

7. The apparatus as defined in claim 4, wherein:

said measurement receiver is connected to a control unit for controlling the gain of said repeater.

8. The apparatus as defined in claim 4, wherein:

said measurement receiver is connectable, via a modem, to a central operational monitoring unit, whereby the measurements and calculations for determining said stability margin can be made by remote control.

9. The apparatus as defined in claim 4, wherein:

a band pass filter is inserted between said sensing element and said measurement receiver.

10. A repeater system, including a radio frequency repeater of the kind having two antennas (1, 2) and the two links there between, said two links comprising an uplink (10) for amplifying signals from a mobile telephone to a base station and a downlink (20) for amplifying signals from said base station to said mobile telephone, said repeater system being provided with an apparatus as defined in claim 4.