to the input terminal of the coupler the second intermediate tap 29 is in turn connected to the output tap point 16 through a resistor 33 the winding of the transformer between tap 29 and ground serve to develop a voltage sensing sample that is coupled to the output tap point 16 along with the first current sensing sample a compensation capacitor 34 is connected in parallel with resistor 33 as can be seen a portion of the autotransformer windings 28 is connected between the intermediate tap 35 and the node 23 the primary section 30 of the series transformer 26 is connected between node 23 and the output terminal 22 of the coupler as a result of this arrangement the upper portion 28 of the autotransformer is electrically placed in series with the input terminals of the coupler and the primary section of the series transformer accordingly the impedance at the input to the series transformer is raised to some value that is greater than the characteristic impedance of the line the windings of the two transformers are arranged so that the cablecast signals moving outwardly from the line amplifier toward the system load as indicated by the arrow in fig2 will cause a pair of sample signals to be applied at the output tap point 16 that are in phase accordingly the two sample signals are.