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BrUel
&
ll:)au
.5025
s.o.l
a.
Kpr
s.o.l
a.
Kpr
c...-..
Measuring
Object:
_ _ _
dB dB
Ba Ti
03c~linder
40
20
30
15
I'.
20 10
Roc. No.:
Dote:
Sign"
Rec:t"
......
z...,L
... :
10 5
L
lim.
F"
80
Pot.:
50
Wr.Sp.:
200
Popor Sp.:
3
Multiply Freq. Scale
b y " - -
0 0
1000
2000
5000
10000
20000
50000
QP
1123
1000
10000
Hz
(6(771.
Fig. 5.5. The impedance of a piezo-electric transducer as a function of
frequency obtained with the set-up illustrated in
Fig. 5.4.
Frequency Range of High Quality Amplifiers.
The Beat Frequency Oscillator Type 1013 which covers the frequency range
20o--200ooo Hz and the Beat Frequency Oscillator Type 1017 which covers
the frequency
range 2'--2ooo
Hz will
when combined cover
the frequency
range from
2'
Hz to 200ooo Hz. This is done in the Automatic in the Auto-
matic Frequency Response Recorder Type 3328,
which consists
of
a
BFO
Type 1017,
a
BFO
Type
1013 and a Level Recorder Type 2305 mounted in
a
Rack and with manual as well as
automatically switching
between the
BFO 1013 and 1017. Using the automatically
switching
and the recording
paper QP 1141 the whole frequency range 2-200ooo
Hz
can be recorded
automatically and
Fig.
5.6 shows
the
set
up for
measurements
on
a
high
quality amplifier. The operation of the 3328 is described under section
4
(Combined
Units). The cross-over frequency in this case
was
300 Hz.
(As
mentioned in
section 4
it is from the factory
adjusted
to be 2ooo Hz)
and
Fig.
5.7 shows
the frequency response of the
amplifier.
When properly
adjusted there will be no change in level when the
"eros-over"
frequency
is passed.
31
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