Patent ID: 7398053
Filing Date: 2008-07-08
Classification: H04B

Abstract:
1. An apparatus for determining a stability margin (SM) with respect to a possible self-oscillation in a radio frequency repeater receiving, amplifying and retransmitting radio frequency signals between an input and an output, and operating with a predetermined delay between the input and the output, and having a feedback path between said output and said input, said apparatus comprising at least one sensing element connected to at least said output of the repeater, 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 is calculated, said sensing element establishing an amplification of the repeater as a function of the radio frequency in a frequency band, and means for producing a magnitude (MA) of harmonic variations in a signal level for various frequencies measured by the at least one measurement receiver constituting a measure of the stability margin in that an increase of the magnitude of the harmonic variations corresponds to a decrease of the stability margin and vice versa.