Ultra wide band radio frequency sending method and device

1 . A device for sending binary data (c i ) at radio frequency in a transmission channel comprising:

a signal generator designed to generate, for each binary data item (c i ), a pulsed signal (p i ) of duration (τ i ) shorter than the duration of said binary data item (c i ),

means for generating at least one periodic signal, the frequency (f j ) of which varies according to predetermined conditions, this variable frequency (f j ) being greater than a frequency (1/τ i ) equal to the inverse of the duration (τ i ) of said pulsed signal (p i );

means of multiplying said pulsed signal (p i ) by said periodic signal of variable frequency (f j ); and

means of sending the pulsed signal (p i .f j ) resulting from said multiplication.

2 . The device as claimed in claim 1 , wherein the variation of the frequency (f j ) of said periodic signal is such that the pulsed signal (p i ) resulting from said multiplication occupies approximately all the spectral width of the transmission channel.

3 . The sending device as claimed in claim 1 , which comprises means for generating independent periodic signals, the frequencies (f j ) of which vary according to predetermined conditions, these variable frequencies (f j ) being greater than a frequency (1/τ i ) equal to the inverse of the duration (τ i ) of said pulsed signal (p i );

wherein said multiplication means are designed to multiply said pulsed signal (p i ) respectively by said signals of variable frequencies (f j ); and which comprises means of summing the pulsed signals (p i .f j ) resulting from said multiplications;

said sending means being designed to send the pulsed signal (s i =Σp i .f j ) resulting from said summing.

4 . The sending device as claimed in claim 1 , wherein said variable frequency (f j ) is random.

5 . The sending device as claimed in claim 1 , wherein the frequency of said periodic signal of variable frequency varies during the multiplication of said pulsed signal (p i ).

6 . The sending device as claimed in claim 1 , wherein said binary data (c 1 ) is obtained by spectral spreading of information data (b i ).

7 . The sending device as claimed in claim 1 , wherein the time difference between two consecutive pulsed signals (p i , p i+1 ) is greater than the maximum depth of the delays of the multiple paths in said transmission channel.

8 . A method of sending binary data (c i ) at radio frequency in a transmission channel, which consists, for each binary data item (c i ):

in generating a pulsed signal (p i ) of duration (τ i ) shorter than the duration of said binary data (c i );

in generating at least one periodic signal, the frequency (f j ) of which varies according to predetermined conditions, this variable frequency (f j ) being greater than a frequency (1/τ i ) equal to the inverse of the duration (τ i ) of said pulsed signal (p i );

in multiplying said pulsed signal (p i ) by at least one periodic signal of variable frequency (f j ) specific to said sending method, said variable frequency (f j ) being greater than the frequency (1/τ i ) of said pulsed signal (p i ); and

in sending said pulsed signal (p i .f j ) resulting from said multiplication step.

9 . The device as claimed in claim 8 , wherein the pulsed signal (p i ) resulting from said multiplication occupies approximately all the spectral width of the transmission channel.

10 . The sending method as claimed in claim 8 , which consists

in generating independent periodic signals, the frequencies (f j ) of which vary according to predetermined conditions, these variable frequencies (f j ) being greater than a frequency (1/τ i ) equal to the inverse of the duration (τ i ) of said pulsed signal (p i );

in multiplying said pulsed signal (p i ) by respectively said signals of variable frequencies (f j ); and consists:

in summing said pulsed signals (p i .f j ) resulting from said multiplications; and

in sending the pulsed signal (s i =Σp i .f j ) resulting from said summing.

11 . The sending method as claimed in claim 8 , wherein, during said multiplication step, a periodic signal of random variable frequency (f j ) is used.

12 . The sending method as claimed in claim 8 , wherein the frequency (f j ) of the periodic signal of variable frequency is varied during the multiplication of said pulsed signal (p i ).

13 . The sending method as claimed in claim 8 , which includes a step for obtaining said binary data (c i ) by spectral spreading of information data (b i ).

14 . The sending method as claimed in claim 8 , wherein the time difference between two pulsed signal generation steps is greater than the maximum depth of the delays of the multiple paths in said transmission channel.