Transmitting/receiving facility and method for transmitting broadband signals as well as transmitting/receiving facility for receiving broadband signals

Abstract

Stationary interference signals from radio stations, for example, enter a transmission network (NET), e.g., a coaxial cable network with return channel, and impair the transmission of broadband signals, e.g., data, in the upstream frequency band, since they lie in the same frequency range. The transmitting/receiving unit (SE 1 ) of a terminal (END) contains a receiving unit (EMP 1 ) for receiving frequency values of stationary interference signals induced in the transmission link, a memory (MEMO 1 ) for storing the received frequency values, a generator (SG 1, NG 1 ) for generating a spreading function with spectral zeros at frequency values which are determined from the stored frequency values, and a multiplier (MUL 1 ) for multiplying the broadband signals to be transmitted by the generated spreading function with spectral zeros. The spectral zeros are so generated that, if the spreading function with the spectral zeros is multiplied by the individual interference signals, at least one of the spectral zeros is located in the frequency range of the broadband signals, so that when the broadband signals are despread at a center (ZE), the impairment caused by the interference signals is reduced.

1 . A transmitting/receiving facility (SE 1 ) for transmitting broadband signals using spread-spectrum techniques, comprising: 
 a receiving unit (EMP 1 ) for receiving frequency values of stationary interference signals which are induced in the transmission link;    a memory (MEMO 1 ) for storing the received frequency values;    a generator (SG 1 , NG 1 ) for generating a spreading function with spectral zeros at frequency values which are determined from the stored frequency values; and    a multiplier (MUL 1 ) for multiplying the broadband signals to be transmitted by the generated spreading function with spectral zeros    
     
     
         2 . A transmitting/receiving facility (SE 1 ) as claimed in  claim 1 , characterized in that the generator (SG 1 , NG 1 ) comprises a spreading-function generator (SG 1 ) for generating a spreading function for a pseudorandom 0/180° phase shift keying modulation or a pseudorandom frequency shift keying modulation and a zero generator (NG 1 ) for generating spectral zeros and inserting them into the generated spreading function, and that the spectral zeros are generated such that if the spreading function with the spectral zeros is multiplied by the individual interference signals, at least one of the spectral zeros is located in the frequency range of the broadband signals.  
     
     
         3 . A transmitting/receiving facility (SE 2 ) for receiving broadband signals modulated using spread-spectrum techniques, comprising: 
 a detection unit (DET 2 ) for detecting frequency values of stationary interference signals;    a transmitting unit (SEN 2 ) for transmitting the detected frequency values;    a memory (MEMO 2 ) for storing the detected frequency values;    a generator (SG 2 , NG 2 ) for generating a spreading function with spectral zeros at frequency values which are determined from the stored frequency values; and    a multiplier (MUL 2 ) for multiplying the received broadband signals by the generated spreading function with spectral zeros.    
     
     
         4 . A transmitting/receiving facility (SE 2 ) as claimed in  claim 3 , characterized in that the detection unit (DET 2 ) determines the amplitudes and/or intensities of the received stationary interference signals and, after comparing the amplitude and/or intensity values with a minimum value, selects the frequency values with the greatest amplitudes and/or intensities, and that only these frequency values are passed on to the memory (MEMO 2 ) and to the transmitting unit (SEN 2 ).  
     
     
         5 . A transmitting/receiving facility (SE 2 ) as claimed in  claim 3 , characterized in that the generator (SG 2 , NG 2 ) comprises a spreading-function generator (SG 2 ) for generating a spreading function for a pseudorandom 0/180° phase shift keying modulation or a pseudorandom frequency shift keying modulation and a zero generator (NG 2 ) for generating spectral zeros and inserting them into the generated spreading function, and that the spectral zeros are generated such that if the spreading function with the spectral zeros is multiplied by the individual interference signals, at least one of the spectral zeros is located in the frequency range of the broadband signals.  
     
     
         6 . A transmitting/receiving facility (SE 2 ) as claimed in  claim 3 , characterized in that the transmitting/receiving facility (SE 2 ) comprises a low-pass filter (TP) which follows the multiplier (MUL 2 ) and has a bandwidth at least equal to the bandwidth of the broadband signals.  
     
     
         7 . A method of transmitting broadband signals from a first transmitting/receiving facility (SE 1 ) to a second transmitting/receiving facility (SE 2 ), comprising the steps of: 
 detecting stationary interference signals at the second transmitting/receiving facility (SE 2 ) and transmitting them to the first transmitting/receiving facility (SE 1 );    generating in the first transmitting/receiving facility (SE 1 ) a spreading function with spectral zeros depending on the frequency values to be transmitted; and    multiplying the broadband signals to be transmitted by the spreading function with spectral zeros and transmitting the resulting signal to the second transmitting/receiving facility (SE 2 ).    
     
     
         8 . A method as claimed in  claim 7 , characterized in that in the second transmitting/receiving facility (SE 2 ), the received signals are multiplied by a spreading function having spectral zeros at the same points as the spreading function generated in the first transmitting/receiving facility (SE 1 ).  
     
     
         9 . A method as claimed in  claim 7 , characterized in that in the second transmitting/receiving facility (SE 2 ), the received signals, after being multiplied, are filtered with a low-pass filter (TP) having at least the same bandwidth as the broadband signals of the first transmitting/receiving facility (SE 1 ).  
     
     
         10 . A transmitting/receiving facility (SE 3 ) for optically transmitting broadband signals using spread-spectrum techniques, comprising: 
 a receiving unit (EMP 3 ) for receiving frequency values of stationary interference signals occurring on an optical link;    a memory (MEMO 3 ) for storing the received frequency values;    a broadband optical source (CW);    an electrooptic modulator (MOD) for modulating the optical output signals from the broadband optical source (CW) with the broadband signals to be transmitted; and    an optical filter (FIL) with variable stop frequencies which are varied, at least in part, as a function of the stored frequency values.    
     
     
         11 . A transmitting/receiving facility (SE 3 ) as claimed in  claim 10 , characterized in that the stop frequencies are identical with the stored frequency values.  
     
     
         12 . A transmitting/receiving facility (SE 4 ) for receiving broadband signals modulated using spread-spectrum techniques, comprising: 
 a detection unit (DET 4 ) for detecting frequency values of stationary interference signals;    a transmitting unit (SEN 4 ) for transmitting the detected frequency values;    a memory (MEMO 4 ) for storing the detected frequency values;    at least one optical filter (FIL 1  to FILn) with variable stop frequencies which are varied, at least in part, as a function of the stored frequency values; and    at least one optical-to-electrical transducer (OE 1  to OEn) following the at least one optical filter (FIL 1  to FILn) and serving to convert the signals passed by the at least one optical filter (FIL 1  to FILn) from optical to electrical form.