Patent ID: 7668245

Claim:
A method for monitoring stability of a carrier frequency (ω i ) of identical transmitted signals (s i (t)) of several transmitters (S 1 , . . . , S i , . . . , S n ) of a single-frequency network comprising: receiving, by a receiver device (E) positioned within the transmission range of the single-frequency network, a signal (e i (t)) associated with a transmitted signal (s i (t)) of a transmitter (S i ) and a reference signal (e 0 (t)) of a reference transmitter (S 0 ); evaluating a phase position of the received signal (e i (t)) associated with the transmitted signal (s i (t)) of the transmitter (S i ) with reference to the received signal (e 0 (t)) of the reference transmitter (S 0 ); and calculating a carrier-frequency displacement (Δω i ) of a carrier frequency (ω i ) of a transmitter (S i ) relative to a reference carrier frequency (ω 0 ) of the reference transmitter (S 0 ) from a phase-displacement difference (ΔΔθ i (t B2 −t B1 )) caused by the carrier-frequency displacement (Δω i ) of this transmitter between a phase displacement (Δθ i (t B2 )) at least at one second observation time (t B2 ) and a phase displacement (Δθ i (t B1 )) at a first observation time of a received signal (e i (t)) of this transmitter (S i ) associated with the transmitted signal (s i (t)) relative to a received signal (e 0 (t)) of the reference transmitter (S 0 ) associated with the transmitted signal (s 0 (t)).