Method and apparatus for stability margin determination in a repeater

• US 6,745,007 B1
• Filed: 04/04/2000
• Issued: 06/01/2004
• Est. Priority Date: 06/11/1999
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: Allgon AB (Bure Equity AB)
• Inventors: Kerek, Daniel
• Primary Examiner(s): Appiah, Charles
• Assistant Examiner(s): Iqbal, Khawar
• Application Number:
  US09/542,951
• Time in Patent Office: 1,519 Days
• Field of Search: 455/20, 455/11.1, 455/13.1, 455/9, 455/7, 455/22, 455/16, 455/67.1, 455/71, 455/75, 455/19, 455/24, 455/18, 455/15, 455/423, 370/232, 370/315, 370/226, 370/343
• US Class Current: 455/20
• 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. A method of 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 the steps of

establishing the amplification of the repeater as a function of the frequency in a frequency band, and

observing the magnitude (MA) of wave-like variations in said amplification as a function of the frequency, said magnitude constituting a measure of the stability margin, whereby an increasing magnitude corresponds to a decreasing stability margin.

2. The method defined in claim 1, wherein the spectral properties of an input signal are known and wherein:

the step of establishing the amplification as a function of the frequency comprises measuring an output signal (P) as a function of the frequency (f) in said frequency band, and

calculating said magnitude (MA) of said wave-like variations and said stability margin (SM) on the basis of the result of the first step.

3. A method of controlling 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, including the steps of:

determining the stability margin in the repeater in accordance with claim 1, and

controlling the gain of the repeater in response to the determining stability margin.