M. P. Foach 113 
2 SS aaa: c 
E = S 
5 E # @ 
5 5 
2 
2 = = 
£ 5 
= 5 
3 8 
5 BE 
2) $ 
2 zs PEE ERIE 33 
ga arr eg BE e = Sas 
He i AS a SESE teat tnt SBE 
je SSS 
= HEE EEE ETERS es 
z te 
HE: fst Hf 
oF Hes sate re HE 
3 Eat 
Hf = HEHE SESH 
= +t 
He H iii f 
SEH HEHE: HE fait Si jessie 
eS aE if = be meee ea ED) 
ea eats ai E TEE F sa: fee 
b sirieriete ae st HEE sastasel eee teee - 
= sigzs nesses Ses stones tescsesesiscs SSesress z 
=e | 
ettssttt 
¢ = i i oa 
pe SE2E HEEEEEESEES 
= | eats pakes pespestests est ae 
] is : t= Seif {2S SSE sspetss pest as 
z : tee —— : = = sSyass pesssssse| 
$ SS = 
ae 355 ft {ESE + Sy fot +: 33 feast 
SHEE Resissansisnnnsses este ais 
Hn isis: nae 33355 tats # fal | 
i # 
fat i a5 =: is f 
HE SE Sass sists Bets = 
# =f a3 sete 3: aH i pitiists: te 
+ 
# sf He Siiasitstes sto eeSEE i = 
+ si523 SEE: + Seessiti 
ees — 
: Bees eet pet f Sas 
Hines nantes fea eee i 
aes = : : = f BE 
: SSSfE peasee BEE ETH nna fee : 
1 2 3 4 Denm 
Fig. 6.10. Basic diagram plotted for measuring tank, 
by 7.5m. As a matter of fact, a new tank is to be installed at the Laboratory, 
measuring 16 by 8 by 8m. 
6.2.2.5. Instrumentation 
The electronic equipment, shown in Fig. 6.12, consists of an ac generator 
and a broad-band power amplifier delivering a driving power of 1 kw for pulses 
and 500 w for continuous waves. The frequency range covered is 7 to 27 kcps. 
A tuned circuit provides the possibility of driving either magnetostrictive or 
piezoelectric transducers. The power driving the transducer is measured by 
a voltage divider for very high potentials. Pulses with a length from 2 msec to 
1.5 sec are delivered by the generator. 
The receiver—amplifier is gated to measure only the part of the signal cor- 
responding to steady state. A B.K. Level Recorder is also provided for plotting 
signals received as a function of varying elements. 
In normal or routine measurements, the receiver response is obtained by us- 
ing two standard projectors, the PP25 and the P30P, their response curve, de- 
termined by the reciprocity method, being flat enough in the frequency band 
explored. The receiving standards are the omnidirectional hydrophones BRUSH 
BM 101 and MASSA M 115 B, the response of which is nearly flat between 1 and 
100 kcps. 
