All drawings appearing in this Recommendation have been done in Autocad.
                                                    ANNEX A
                                      (to Recommendation Q.552)
                 Example of a longitudinal interference coupling network
                The component should be chosen with small  absolute  tolerances  (at  least
          resistors and capacitors with 1% and  the  inductance  with  less  than  5%)  and
          matched to pairs where relevant to achieve a longitudinal conversion loss  better
          than 60 dB at 1000 Hz. For this LCL measurement a terminating resistance  of  600
          Ohms symetrically applied to each port should be used.
                                        Figure A-1/Q.552 - T1105730-87

                                                TABLE A-1/Q.552
                                                Components list
                  Quantity                Type
                                  Metallized resistors
            1        10      R1  . . . R10:   ohm 1%, 1.1 W
                             100              
            2         4     R11 . . . R14:   ohm 1%, 1.1 W
                             49.9             
            3        12     R15 . . . R26:   ohm 1%, 0.35 
                             133              W
            4        12     R27 . . . R38:   ohm 1%, 0.35 
                             32.4             W
            5         2      R39 . . . R40:   ohm 1%, 0.35 
                             24.9             W
            6         4      R41 . . . R44:   







































                                                         Fascicle VI.5 - Rec. Q.552   PAGE1

                             200              kohm 1%, 0.35 
                                              W
                               Styroflex foil capacitors
            1         4     C1  . . . C4:    nF 1%, 160 V
                             15               
            2         8     C5  . . . C12:   nF 1%, 160 V
                             7.5              
            3         4     C13 . . . C16:   nF 1%, 160 V
                             28               
            4         2     C17 . . . C18:   nF 1%, 160 V
                             24.3             
            5         2     C19 . . . C20:   nF 1%, 160 V
                             20               
            6         2     C21 . . . C22:   pF 1%, 160 V
                             499              
            7        12      C23 . . . C34:   nF 1%,  63 V
                             60.4             




















































          PAGE2   Fascicle VI.5 - Rec. Q.552




                                           

                                HF-chokes, ferrite rod
           1         2     L1 . . . L2: 47 mH 5%, Ro 1.1 
                            ohm






























































                                                        Fascicle VI.5 - Rec. Q.552   PAGE1






































































         PAGE2   Fascicle VI.5 - Rec. Q.552