RECEIVING RESPONSE 



139 



3 4 5 6 7 8 9 10 20 30 



KILOCYCLES PER SECOND 



40 



60 



Figure 2. Receiving response chart, 3A89 hydrophone vs AX70 projector. Reference run No. I on log sheet (Figure 1). 



from the pier to the receiving amplifier is included in aid and the transducer under test. These circuits are 

 the calibration of the system, the voltage at the line reproduced in Figures 5 and 6. It may be seen that the 

 terminals may be substituted for the voltage at the transducer was connected through a balanced coup- 

 input to the receiving amplifier. ling amplifier to the 1 35-ohm receiving line. To eval- 

 Referring to the example, the log sheet in Figure 4 uate the coupling loss of this amplifier, two measure- 

 contains a reference to the circuits used for the stand- merits were made, as shown in Figure 7. First, a volt- 



4 5 6 7 8 9 tO 20 30 



KILOCYCLES PER SECOND 



50 



Figure 3. Receiving response chart. QB No. Ill vs AX70 projector. Reference rim No. 2 on log sheet (Figure 4). 



