Table of Contents
Advertisement
DATE
8/2/79
DATE
3/2/79
Monitor
Microphone
Bone
V ibrator
J
. R.H.
J
. R.H.
..
dB
1
,,
.
?
~
1
40
1
1
130
f7o-
I
I
I
~
120
:
:
r-ro
INPUT SPL 110
r---es
I
C
AL
I
BRATE
r--eo
100
I
I
-
i4dB
r---;;--
L C .
MODE
00
I
I
I
~
I
~
~
80
,..,.-
v
I
I
'-'
f-'\J'v
I
I
---
~
70
I
I
HARMONIC
{
I
_./f
I
1
"
3•d
f---
8
0
~
I
I
I
I
INTERMODULATION
{
~
50
I
'--------;""
I
~
..
1
'I"
2f
~
1
40
130
I
I
~
~
I
I
~
120
I
I
~
I
NPUT SPL 110
I
I
CALIBRATE
-
100
I
I
~
. . . . . . . v
----;...
-94dB
~
LC,
MOOE
I
~
00
v . . . . . . . .
v
~
\.
~
80
v v.......-v
~
_\."\
HARMONI
C
{
~
70
/
v
:
\_"\
'--./
......
eo
-
/
I
1"\
' - J - ......
INTERMODU
L
ATION
{
-;;-
~
I
I
w
0 ,125
0
,250
0
,1
25
0 ,250
0
0
DO
+
0
0
DO
+
790047
790045
Fig.6. Typical frequency response of a monitor microphone at con-
stant sound pressure level
Fig .7. Constant voltage frequency response of a bone vibrator using
Artificial Mastoid Type 4930
Measurements on Telephone ear-
pieces
Fig .8 shows a simple measuring
arrangement which enables the fre
-
quency response and distortion of
telephone earpieces to be recorded
automatically. The Generator sec-
Generator Output
•
/.:
Audio Test Station
Type 2116
Test Object
Microphone
Preamp! ifier
L
-..-----1=111
Type 2642
Artificial Ear
Type 4153
790057
Fig .8. Use of the Audio Test Station with
Ar-
tificial Ear Type 4153 to record the
frequency response of telephone
ear-
pieces
pATE
3/
2/79
Telep hone
earp
iece
J
. R.H.
INTERMODULATION
{
0
0
tion of the Type 211 6 supplies a
constant voltage signal to the ear-
piece
to
be
tested,
which
is
mounted on the Artificial Ear Type
41 52 or 41 53. The output from the
microphone of the Artificial Ear is
fed to the Analyzer section of the
Type 211 6 and the response curve
recorded automatically on the chart.
A 1
/
2 inch microphone Type 41 34
is used with the Artificial Ear Type
41 53 which is in accordance with
IEC R31 8. A Type 4144 one inch
Microphone is used in conjunction
with the Artificial Ear Type 41 52,
for which a variety of couplers are
available
.
An
adaptor
Type
DB
0962 is required to fit the preampli-
fier to this artificial ear
.
Typical re-
sponse curves for a range of input
levels
at
constant
voltage
are
shown in Fig .9
.
General Quality Control Applica
-
tions
The 211 6 can also be used advan-
tageously in situations which nor-
mally only require the frequency an-
alyzer and recorder functions of the
instrument, e .g
.
for noise control
checks on items such as sma II elec-
tric motors and fans, where the fre-
quency range of interest lies in the
region above 500Hz
.
(The BT pro-
duct below 500Hz is too small to
obtain reliable results.) The result-
ing frequency spectrum is compared
with a predetermined spectrum of li-
mit levels against which the perfor-
mance of the item is judged. The
chart
may
be
included
with
the
tested item as an assurance of qual-
ity, or used as an aid to fault diagno-
sis
in the event of a failure to
achieve the stated specifications
.
A
typical
analysis
is
reproduced
in
Fig
.
1 0
.
H
mE~
A m B I W N G
L
9
~
~ ~ ~ :
L
: Y ~ P ~
E
--~S~
m
~ a
l l
~
f a ~ n
________
~---------~-----~~-
J
.
R.
H
-~--
I
DO
+
790048
CALIB RAT
E
-
9
4
d
8
~
~
~
~
~~.-------------~-+
' ·r
·
--~
~
·
----~
~
-
INPUT SPL
llOt----- - - - - - - - - - - - - - - - = - - - - =
~
7o
II
~
,..
,.~·'
""-~---
...I
\.
.1"1
-
~
I
L •
HARM
O
N
IC
-
-
,..
1
~
r~~
~
~
oo
~I
-------+---~--4
1-r--=~"
t :------l
INT
ERM
ODULATION
-
-
50
J-------------------------~
-
ltd
~
0
,125
0
,25
0
0
0
DO
+
790272/2
Fig .9. Constant voltage frequency response of a telephone earpiece
for a range of input levels, recorded using the Artificial Ear
Type 4153
Fig.1 0.
Noise output of a small fan recorded using the Audio Test
Station
5
Advertisement
Table of Contents
