System and method for amplifying a signal

Abstract

An amplification system, connected to a modem delivering a signal to be amplified, includes at least one amplification device, at least one first determination device for determination of a first difference and at least one second determination device for determination of a variable gain. Moreover, the system is characterized in that the second determination device is capable of the determination of said variable gain on the basis of said signal to be amplified, said amplified signal and said first difference.

The invention claimed is: 
     
       1. An amplification system, connected to a modem delivering a signal to be amplified, comprising:
 at least one amplification device in which an amplification gain is variable, 
 at least one first determination device for determination of a first difference between an amplified signal and said signal to be amplified, 
 at least one second determination device for determination of said variable gain, 
 wherein said second determination device is capable of the determination of said variable gain on the basis of said signal to be amplified, said amplified signal and said first difference; 
 said second device having: 
 at least one third determination device for determination of a model, comprising a delay and a gain, of a perturbation of the first difference by the amplification device by means of a correlation between said signal to be amplified and said amplified signal, 
 at least one fourth determination device for determination of perturbations of the first difference that are caused by said amplification device, on the basis of said model and said signal to be amplified, 
 at least one fifth determination device for determination of a second difference between said first difference and said perturbations, and 
 a controller that is capable of determining said variable gain on the basis of said second difference. 
 
     
     
       2. The amplification system of  claim 1 , having at least one extraction device, for extraction of said amplified signal to said first determination device, wherein said extraction device comprises:
 a directional coupler that is used to recover a signal transmitted on a wire connecting said amplification device and an antenna, 
 at least one device for regulating the gain of the recovered signal, 
 a mixer for mixing the recovered signal that has had its gain regulated with a sinusoidal signal, and 
 a plurality of filters for filtering the mixed signal, said filters comprising at least one fixed-bandwidth analogue filter that is used for anti-aliasing and/or anti-jamming and at least one switchable digital filter for the bandwidth that varies as a function of a bandwidth of said signal to be amplified and/or of a disparity between a frequency of said signal to be amplified and a frequency of said perturbations, and 
 said third device is suited further to the determination of a model of the perturbation of the first difference by said amplification device and said extraction device. 
 
     
     
       3. The amplification system of  claim 1 , wherein said first determination device is connected directly to said modem. 
     
     
       4. The amplification system of  claim 1 , wherein said controller is a PID controller. 
     
     
       5. The amplification system of  claim 1 , wherein said second determination device has a conversion table relating a power of a signal to be transmitted to said amplification gain. 
     
     
       6. A method for using the amplification system of  claim 1 , wherein the method comprises the successive steps of:
 a step of configuration of the gain of said amplification device, said step of configuration being carried out when said signal to be amplified has zero power, 
 a step of increase of the amplification gain of the amplification device, in an initialization phase, during which said signal to be amplified does not have any useful data, 
 a step of deactivation of regulation of the gain, said step of deactivation being carried out when the signal to be amplified has useful data. 
 
     
     
       7. The method of  claim 6 , further comprising
 a step of regulation of the amplification gain of the amplification device, said step) of regulation of the amplification gain being carried out after said step of increase of the amplification gain, moreover said step of regulation being carried out on the basis of a setpoint. 
 
     
     
       8. The method of  claim 6 , in which said step of configuration is suited to the implementation of the relationship:
     P out_max= P out_mean_MODEM_setpoint+Modulation_crest_factor 
 
       where
 Pout_max represents the maximum output power in dB, 
 Pout_mean_MODEM_setpoint represents the mean power in dB of the signal that said modem will transmit, and 
 Modulation_crest_factor represents the modulation crest factor in dB of the signal that will be transmitted by said modem, 
 
       and in which the step of configuration is suited to configuring said amplification device so as to be able to transmit a maximum output power of Pout_max. 
     
     
       9. The method of  claim 6 , wherein said step of increase of the amplification gain is implemented:
 by means of a conversion table relating a power of a signal to be transmitted to said amplification gain when the power of said signal to be amplified is lower than a threshold; and 
 by means of said controller when the power of said signal to be amplified is higher than said threshold.