BRUEL & KJAER 1617 User manual

Instruction Manual
Band Pass Filter Type 1617
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033-0143
1617
The Type 161 7 has 50 third -octave filter
bands with centre frequencies 2 Hz to
160 kHz, 41 overlapping octave filter bands
from 2 Hz to 20 kHz, A, 6 , C, D- weighting
networks , and a Linear pass band 1 Hz to
200 kHz. The filter pass bands fulfil the
most severe standards, IEC 225 - 1966 , DIN
45651 (1 / 1-oct) and 45652 (1 / 3-oct).
and ANSI 51 . 11 - 1966 Class II (1 /1-oct)
and Class III
(1 / 3-oct) .
In addition to facilities for filter scanning
controlled by 6 & K Level Recorders, there
is a built-in interface to the proposed IEC
standard via which full control can be exer-
cised.
An internal control system is able to
programme the averaging times of the mea-
suring i nstrument that is connected to the
Type 161 7 so that the optimum 6T product
is maintained during a frequency scan.
~ Bruel & Kjcer

BAND PASS FILTER
TYPE 1617
September 1977

CONTENTS
1. INTRODUCTION AND SPECIFICATIONS (PRODUCT DATA) .......... ............ ........ .... ................. 1
2. CONTROlS ............. .......... ....... .. ........... .. .... .. ................................... ............... ..................... .. 9
2.1 . FRONT PANEL .................. ....... .......... ..................... ....... .. ... ........ ........ .. .... 9
2.2. REAR PANEL
...... .... .. .... .. .. ... ............................. ..... .. .. .... ....... ...... .............. 10
3. OPERATION ..................... .. ...................... ........... ................... ............... ........... .. ......... .. ........ 13
3.1. PRELIMINARY ADJUSTMENTS ..... ........ ..... ............. .. ... .. . ........ .. .... .. .. .. ........ 13
Selection of Line Voltage ............................................................... :............ 13
Fuse Rating
...... . .......................... . .................................... ...... .... ............ .. 13
Line Connections ........ .. ...... ...... .... .. ........... ... .. ......... .. ....... .. ....... ............ ... 13
Grounding Considerations ................... . .......................... .. .... ........... ........... 14
3.2. OPERATION WITH MEASURING AMPLIFIERS ALONE ................... .. ............... 14
Measuring Procedure .... .................. .. .. ............. ...... .. .. ............ .. ........ .. .. . .. ... 15
Calibration .. .... .. .......... ...................................... ................ . ................... .... 16
3. 3. OPERATION WITH MEASURING AMPLIFIER AND LEVEL RECORDER .......... .... 16
Fixed averaging time analysis with
Level Recorder Type 2306 .. .......... ........ .... .................... ........... .. .......... .... .. 16
Analysis with variable averaging time using
the Level Recorder Type 2306 ........ ...... .. .......... ...... ....... . ............................ 20
Fixed averaging time analysis with the
Level Recorder Type 2307 ............................................................ ............. 22
Analysis with variable averaging time using
the Level Recorder 2307 ................................ .... ........ .......... . ....... ... .. ........ 25
Analysis with variable averaging time using an X-Y Recorder .............. . .. .. .. .. .. 27
3.4 . OPERATION WITH OTHER Bruel & Kjrer INSTRUMENTS ........ ...... .. ...... .. ........ 28
Operation with Sound Level Meter Type 2203
and Type 2209 ..... .. . .. . .. . ...................... ... .. ........ .. ....... .. . .. ........ .... ........ ...... 28
Operation with Vibration Meter Type 2511 ......................... ............ ........... .. 29
3.5. DIGITAL DATA TRANSFER AND REMOTE CONTROL
VIA THE IEC INTERFACE BUS ................ .. .. .. ........... .. ...... ....... ...... ........... .. .. 30
IEC Functions Implemented ......... ....... .. ...................... ........ ........................ 31
Selection of Listener Address ........ . ...... .. .. ..... .. ......... .. .. ......... ....... .. ............ 31
Programming Sequence .................... . .. ......... .. ......... .... ........ .... .. ....... ... .. .... 31
Parallel Poll .... ...... ......... ..... .......... .. ..... ..... ....... .. ......... ...... .... .. ........ ......... .. 33
Indication of busy ..... ......... ........... ......... .. ....... ........ ..... .. ........ .......... .. .. .. .. .. 33
Interruption of readout ................. ....... ......... .. . .......... ....... ........... .. . ............ 34
3.6. DIGITAL PROGRAMMING EXAMPLES ......... .. .................. .. ...... . ................... 34
General Programming .............. .... ......... . ........... ......... ........ ..... .. .......... ....... 34
Programming for operation with the Hewlett -Packard 9825A .... ............ ......... 35
Programming for operation with the Tektronix 4051 ........ ...... .. ............ ......... 36

4. SPECIAL CONSIDERATIONS IN FREQUENCY ANALYSIS .... ................ .. .................... .. ........ .. 38
4.1. FILTER DEFINITIONS ................ ........ ... ...... . .. .. .. .... .. .. .. .. ....... .. .................... 38
The Ideal Filter .. . .............. ....... .. .. .. ........ ...... ................. ................ .. ..... .. ... 38
Bandwidth ....... .. .. .. .. ............ .......... .. .. .. . .. ........ . .. ................. .. .... ................ 38
Octaves and Third Octave ...... .. . .. .. . .. .. .... .. ...... .:........... .. . .. .. ............... .. .... .. .. 39
Specified Filter Frequencies .. .. .... .. ....... . .. ......... .. . .. . .. .... .. ......... .. .. .... .. .. .. .. .. .. 39
4.2 . RMS MEASUREMENT AND STATISTICAL ACCURACY ... .................... ...... .. ... .40
4.3. PRACTICAL ANALYSIS OF STATIONARY SIGNALS .. .. .............. .. ......... .. .. .......41
Averaging Time . .. .. .. ...... .. .. ........ ............. .. ........ .. .. .. .... .. . ............ .. .... .. .. .. ....41
DC or AC Recording ... .. .. .. . ...... . .. .. .... .............. ................. ...... ................. .. . .42
Writing Speed ..... .. ........ .. .. .. ...... ............ .. .. .. .................. ..... ................. .. .. .. 42
Paper Speed . .. . .. . .. . ........... ...... .. ........ .............. ......... ......... .. .... .. .. .. ........... .42
4.4 . USE OF VARIABLE AVERAGING TIME PROGRAMS ... .. ....... ........ ..... .... .. ....... 44

GENERAL FEATURES:
• .41 third-octave filter
bands, centre frequencies
2 Hz to 20 kHz
• 41 overlapping octave
filter bands, centre
frequencies 2 Hz to 20 kHz
• Third -octave and octave
filters in accordance with
IEC 225 - 1966 , DIN
45651 and 45652, and
ANSI S1. 11-1966
• Digital display of selected
centre frequency and
bandwidth
• Built-in A-weighting
network
• Electronic control of filter
switching
• Manual or Level Recorder
controlled filter scanning
• Selectable scan start
position to save time,
eliminates low frequencies
when required
• Input overload warning
circuit
• Floating or grounded
Signal input
17 - 094
types 161 7 and 161 8
Third-Octave and
Octave Band Pass Filters
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1618
ADDITIONAL FEATURES
TYPE 1617 :
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• 9 third-octave filter bands,
centre frequencies 25 kHz
to 160 kHz
• Built-in B, C, D-weighting
networks
• Comprehensive connection
facilities for use with other
instruments
• Operation of front panel
controls via built-in IEC
Interface
• Selection and control of
averaging time program for
the measuring instrument
USES:
_-.....e-no __
---
' .... , ...
(With suitable Measuring
Amplif iers)
•
Third-octave and octave
frequency analysis of
sound and vibration
• Measurement of frequency
response
• Measurement of sound
transmission loss
•
Measurement bf vibration
isolation
• Testing acoustic materials
• Recording of spectrograms
with constant confidence
level (1 61 7)

The Third-Octave and Octave
Band Pass Filters Type 1617 and
Type
1618 are key links in any in-
strumentation chain for measure-
ment and recording of the fre-
quency spectra of sound, vibration,
and electro-acoustic signals . Sev-
eral novel
features have been in-
corporated, including electronic fil-
ter switching and digital indication
of the selected filter . The Band Pass
Filter Type 1618 is the basic instru-
ment, while the Type 1617 com-
bines an extended frequency range
with comprehensive control and syn-
chronisation facilities for use with
other instruments.
The Type 161 8 has fiIter band
centre frequencies from 2 Hz to
20 kHz that can be divided into 41
third-octave bands, or 41 overlap-
ping octave bands covering the 14
octave frequency range. It has a
built-in A-weighting network, and
there is indication given when the
level of the signal being analyzed
overloads
the input section. The
Band Pass Filter has provision for fil-
ter scanning controlled by B & K Le-
vel Recorders.
The Type
1617 has filter band
centre frequencies from 2 Hz to
160 kHz that can be divided into 50
third-octave bands. It has 41 over-
lapping octave bands covering 14
octaves from 2 Hz to 20 kHz. In addi-
tion to the A-weighting, it includes
B, C, and D-weighting networks,
and there is also an input overload
indicator lamp. Filter scanning can
be controlled by a Level Recorder,
and
there is a built-in interface to
the proposed IEC Digital Bus Stand-
ard to permit direct control by other
instruments and systems using this
standard. A DC ramp output can
control the X-axis of an X-V Recor-
der, and a control circuit is included
to select averaging time programs
for use by the measuring instru-
ment.
Both Band Pass Filters will gener-
ally be used with one of the Measur-
ing Amplifiers Type 2606, Type
2607, or Type 2608, but other in-
struments such as the Frequency
Analyzers Type 2120 and Type
2121 , or the Heterodyne Analyzer
Type 2010 can be employed . Con-
nected to a B & K Condenser M icro-
phone, these measuring instru-
ments all form a sound measure-
2
ment system that satisfies IEC 179
for precision sound level meters,
while Type 2606, Type 2607, and
Type
2120 satisfy IEC 179 A for Im-
pulse measurement .
sic
system of Type 1618 and Type
2608 is for RMS measurement in
the audio frequency range, with fil-
ter selection by Level Recorder. Opti-
mum utilisation of all measuring
modes and control possibilities is ob-
tained with a combination of Type
1617 and Type 2607, which gives
the ability to measure and analyze
in the frequency range from 2 Hz to
160 kHz, obtaining RMS and Peak
values from all commonly encoun-
tered random, quasi-random, peri-
odic, and complex waveforms . This
combination can be used together
with an X-V Recorder.
All three Measuring Amplifiers
can be employed with either Band
Pass Filter , so that selection of
which Measuring Amplifier to use
will largely depend on the particular
measurement application. Table 1
shows the various combinations
available, together with brief specifi-
cations, and the type of measure-
ment and analysis possible. The ba-
Measuring Amplifiers
Band Pass Filter Type 1618
Band Pass Filter Type 1617
General :
General: General:
Freq. Range: 2 Hz - 200 kHz Freq. Rang e: 1.4 Hz - 22 kHz Freq. Range: 1.4 Hz - 180 kHz
Dyn . Range: 1 OIN - 300V
41 third-oct. bands 50 third-oct. bands
Fast and Slow averaging 41
overlapping octave bands 41 overlapping octave bands
Input overload warning
A-weighting filter
-A, B, C, D-weighting filters
Averaging time programs
Control via built-in IEC interface
• DC ramp for X-V Recorder control
Type 2608 and 2121
RMS measurement
RMS measurement
Crest factors up to 5
20Hz - 22 kHz
20 Hz - 180 kHz
AC output to Level Recorders
(Audio frequencies)
A-weighting network
Manual or remote control of filter scanning
Digital bus control of filter
scanning
Measurements can be made at lower frequen cies if th e
averaging
ability of a Level Recorder 2307 is used
Type 2606 Comprehensive RMS measurement at high crest factors
RMS and Peak
measurement
Impulse and Hold modes
20Hz - 22 kHz 20Hz- 180kHz
Crest factors up to 40 (Audio frequencies)
AC or DC outputs to Recorders
A, B, C, D-weighting networks
Manual or remote control of filter scanning
Range settings shown on
Digital bus control of filt er
meter scale
scanning
Measurement in Peak or Impulse Modes
1.4 Hz - 22 kHz 1.4 Hz - 1 80 kHz
RMS measu
rement s ca n be made at l ower fre quencies if th e
averaging ability of a Level Recorder 2307 is used
Type 2010 (RMS only) ,
Measurement of RMS and Peak values of all commonly encount- I
2607, & 2120
ered random . quasi- random . periodic. and complex waveforms
RMS and Peak measurement
Impulse and Hold modes
1.4 Hz -'22 kHz 1
.4 Hz - 1 80 kHz
Crest factors up to 5
Manual or remote control of filter scanning
AC or DC outputs to Recorders
50 dB logarithmic DC output
Manual control of avo
time fur 2607 , 2120 , m2010
proportional to RMS Level
A, B, C,
D-weighting networks
Digital bus control of filter
Range settings shown on meter
scanning and averaging times
scale
for 2607 and 2120
This combination gives optimum
use of all meas urem e nt and
control facilities , including
X-V recordin!'l (not 2010)
Table 1. Band Pass Filter and Measuring Amplifier Combinations

Description
Both Band Pass Filters are de-
signed to operate on the signals ob-
tained from the External Filter termi-
nals of the Measuring Amplifiers ,
but any input signal of approxi-
mately 1 V RMS with a crest factor
less than 5 can be accepted (the
higher crest factor capability of the
Type 2606 can be used at lower sig-
nal levels). Input and output are via
coaxial B & K sockets
on the front
panel, paralled by BNC terminals on
the rear.
Filter I Filter
II
11 3 Octave
Centre Centre
Bandwidth
Frequency Frequency
at 3.7 dB
Hz Hz Hz
Approx .
2
0,46
2.5 0 .
50
3. 15
0 . 73
4
0.92
5 1.
16
6.3
1,45
B 1.
83
10 2. 30
12.5
2. 90
16
3. 70
20
4.60
25
5.8
31 .5 7
.3
40
9.2
50
11 .6
63
14 .5
80
18 .3
100 23
125
29
160 37
200
46
250 58
315
73
400 92
500
116
630
145
800
183
1000
230
1250
290
1600 370
2000
460
2500
580
3150
730
4000 920
5000
1160
6300
1450
8000
1830
10000 2300
12500
2900
16000 3700
20000
4600
25000
5800
31500
7300
40000
Additional
9200
50000
1/ 3-octav e
11600
63000
filters
14500
80000
in 1617
18300
100000
23000
125000
29000
160000
37000
Table 2. Filter centre frequencies in pre-
ferred series . Heavy type denotes
preferred series for full-octaves
Input
Warning
Front
P anel'
Controls
Amplifier
Low Pass
F ilter
Output
Amplifi er
Digital . t::=+.;;
Controller t-
Ou tput
761039
Fig.l . Block diagram of the Band Pass Filters Type 1617 and Type 1618
Fig.1 is a block diagram valid for
both versions of Band Pass Filter,
where shaded areas represent fea-
tures found only in the Type 1617 .
Third-Octave Band Pass Filters
The active Filter sections consist
of a matched pair of variable fre-
quency six-pole Butterworth filters
which can be electronically
switched to yield third-octave or full -
octave bandwidths . Between them
the two Filters cover the frequency
range from 2 Hz to 20 kHz centre
frequencies , with each Filter being
switched to alternate third-octave
centre frequencies in the preferred
series (see Table 2).
In the Band Pass Filter Type
1617 there is an additional set of
third-octave Filters with centre fre-
quencies between 25 kHz and
160 kHz, to extend the high fre-
quency range of the instrument.
The filter characteristics of the in-
dividual third-octave Filters used in
these instruments fulfil the require-
ments of IEC 225 - 1966 , DIN
45652, and ANSI S1. 11-1966
Class III, which are the most rigor-
o
I,
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/
I
/
0.2 0,5
00
~ 60
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~ 70
< 75
2
\ ........
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Typical B & K
1/3 Octave Filter
'. ANSI Class III
.lOIN 45652)
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4
Frequency relative
to centre frequency fl fm
110103
Fig.2 . Typical third - octave filter response
3

ous standards applying to third-
octave filters .The response curve for
a typical third-octave filter is shown
in Fig.2, and the top of the curve in
the enlarged view in Fig .3. The IEC,
DIN, and ANSI
limitations are also
indicated in both Figures. Peak-to-
valley ripple in
the pass band is less
than 0,5 dB with attenuation within
± 0,5 dB . Attenuation of frequencies
outside 5 x and 1/ 5 of the band
centre
frequency is better than
75dB .
Octave Band Pass Filters
Octave Filters are formed in both
Band Pass
Filters by electronically
altering the components and charac-
t~stics of the Filter circuits. This ar-
rangement gives a flat crest to the
characteristic curve, and low peak-
to-valley
ripple . The octave Filters
cover
the frequency range from
2 Hz to 20 kHz centre frequencies,
selectable at third-octaves in the
preferred series. There is no provi-
sion for connection of full-octave fil-
ters at higher frequencies in either
Filter Set.
All octave Filters contained in the
Type 161 7 and Type 161 8 conform
to IEC 225 - 1966, DIN 45651 ,
and ANSI S1. 11-1966 Class II,
which are the strictest standards for
octave filters. Fig.4 shows the top
of a typical octave filter characteris-
tic, attenuation outside 8 x and 1/ 8
of the band centre frequency is bet-
ter than 60 dB. Peak-to-valley ripple
is less
than 0,5 dB, while attenua-
tion in the pass band is within
± 0,5 dB .
The
total integrated random
(white) noise power passed by the
practical octave and third-octave Fil-
+5
a Linear 1
Hz to 200 kHz
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6
8
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16
18
20
22
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0,4 0,6 0,8 1,0 1,4 1,8 2,5
0,5 0,7 0,9 1,2 1,6 2,0
Frequency relative to centre frequency flfm
170124/1
Fig.3. Top of a third-octave filter characteris-
tic
ters in the Type 1617 and Type
1618 is equal to that which would
be passed by an ideal octave or
third-octave filter.
Weighting Networks
In addition to the Linear re-
sponse, and A-weighting network in-
cluded in the Type 1618, the Type
1617 contains B- and C-weighting
networks, plus the D-weighting net-
work specified in IEC 537 for meas-
urement of aircraft noise. The fre-
quency responses of the four
weighting networks are shown in
Fig.5 . The Figure also indicates the
Linear range 1 Hz to 200 kHz obtain-
able from the Type 1617, and the
Linear range 1 Hz to 40 kHz from
the Type 1618.
Filter Selection and
Scanning Ranges
Filter switching is accomplished
electronically by FET switches in
the Filter Selectors that are regu-
~~
~i!all Fre~Ue~cy Char~ctJri ! ti~sl
V
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~ ./
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/"
V
0
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-20
-2 5
-30
0,2 V a,s
V V
10
,/
V
/20 50 100 200 500 1 k 2 k
:-
Fig.5 . Weighting networks and linear functions
4
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a; 3
::: .
« 5
0.5 0.6 0.7 Q.8 0.9 1. 0 1.2 1.-4 1.6 1 .8 2 .0 2.5
Frequency relative to centre frequency flfm
170125/2
Fig.4. Top of a typical octave filter charac-
teristic
lated by the Digital Controller acting
on instructions from internal or re-
mote control settings . Bandwidth of
the Filter in use is selected by the
three position Selectivity switch, giv-
ing a choice
of third-octave band-
width scanning in third -octave
steps, octave bandwidth scanning
in third-octave steps (with adjacent
bands partially overlapping). or oc-
tave
bandwidth scanning in full-
octave steps.
Manual selection of any particular
Filter band is made by turning the
Manual Filter Selector control to the
required position . On the Band Pass
Filter Type
1618 the Manual Filter
Selector has a scale graduated in
third-octave centre frequencies
from 2 Hz to 20 kHz, plus the two
positions "A-weighting" and "lin-
ear" . There are two measuring
ranges on the Band Pass Filter Type
161
7, selected by the Ra nge
switch , and hence two frequency
0
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~
B+C
r\
5 k 10 k 20 k
Linear 1 Hz to 200 kHz
1'.
~
1'\
\
1161
1
S1
I'"
1\
'"
\ \
~l\
"-
~
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i
~
1\
50 k lOa k 200 k 500 k
770105

scales. One covers the full fre-
quency range with graduations in
third-octaves with centre frequen-
cies from 2 Hz to 160 kHz. The
other range covers third-octave cen-
tre frequencies between 2 Hz and
40 kHz, and includes A- , B- , C-, D-
weighting, and a Linear position .
Both models have a "Linear" mode
available on the Range switch,
which permits a Linear output to be
obtained at any point in a scan,
without moving the Manual Filter
Selector .
The centre frequency of the se-
lected Filter band is indicated on a
half -i nch digital display that also
shows whether the Filter is function -
ing as a
third-octave or as an oc-
tave
filter , or whether a weighting
network has been selected.
Filter Scanning
In addition to its control of the Fil-
ter switching as directed by the
Manual Filter Selector , the Digital
Controller can operate the Filter
scan on the command s of an exter -
nal source . Control by a Level Recor-
der Type 2306 or Type 2307 is pos-
sible with both Band Pass Filters .
On the Type 1617 control can also
be exercised via the built -in IEC In-
terface , or an X-V Recorder can be
operated in synchronism with Filter
scanning (possible with Type 2607
Measuring Amplifier or equivalent).
Selection of manual or recorder
control is made by the Filter Control
Mode Manual /Recorder switch,
while the Stop/Run switch enables
the Recorder in use to be controlled
from the Band Pass Filter. This con-
trol facility is blocked when "Man-
ual" is selected, or when the Type
1617 is being controlled via the In-
terface .
When operating in any remote
control mode , the progress of the
scan can be followed on the Digital
Display , as the Manual Filter Selec-
tor does not rotate during an auto-
matic scan. The Filter frequency
sweep always starts from the band
in
which the Manual Filter Selector
is standing, it sweeps through the
selected range, and being internally
actuated, it returns instantly to its
starting point. This saves analysis
time when low frequencies (with
correspondingly long averaging
times) will not be required while
operating the Type 1617 with an X-
Y Recorder, or under digital control
via the Interface bus. Similarly,
when recording sound on a Level
Recorder, unwanted low frequency
bands can be excluded from the
trace to yield a clear audio fre -
quency spectrogram .
Connections for synchronisation
with a Level Recorder Type 2307 is
made via a
7-pin DIN socket on the
rear panel (see Fig.6). Connection
to a Level Recorder Type
2306 is
achieved via an 8-pin DIN socket.
which with the Type 1617 is also
used for X-V recording.
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-,-
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• •
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11111111111111111111111111111111111111
Fig . 6. Rear panels of the Band Pass Filters
CO(/)'f'ighI AGF 2005
Fig .7 . Conditions where longer averaging times are required for high frequency signals . The
lower curve was made with too short averaging time. while for the upper curve . averag-
ing was correct
5

Averaging Time Control
This ability, allows the Type 1617
to vary the averaging time of the
Measuring Amplifier Type 2607 or
the Narrow Band Analyzer Type
2120 during the course of the fre-
quency scan. The advantage is that
the averaging time can be kept as
short as possible to maintain an ac-
ceptable analysis time , while being
long enough at lower frequencies to
achieve optimum measuring accu-
racy, i.e. to maintain a good confi-
dence level. The best analysis condi-
tions are obtained when the product
of bandwidth B (in Hz) and averag-
ing
time T (in s) is held constant
throughout the scan. Therefore the
Type 1617 is equipped with averag-
ing
time programs which can be se-
lected according to test conditions
to maintain the BT product as near
constant as possible and give a con-
stant confidence level.
At higher frequencies, if a con-
stant BT product is to be main-
tained , the averaging time becomes
so
short that the writing speed of
the Recorder will be the practical li-
mitation on the speed of the analy-
sis. Therefore the shortest averag-
ing
time that can be selected by the
programs in the Type 1617 is
0,1 s. However , some high fre-
quency signals like the noise or vi-
bration
from a slowly rotating ma-
chine may have a low repetition fre -
quency
that causes low frequency
modulation as shown in Fig.7,
where 0,1 s averaging time is too
short . To allow satisfactory averag-
ing
times to be selected for this
type of signal, a choice of three min -
imum times (0 ,1 s, 1,0 s, and 10 s)
is provided on the Type 1617 . Fig.8
is a
chart indicating the averaging
times and change-over frequencies
in the nine programs available, to-
gether with the minimum and maxi-
mum averaging times.
When operating with variable av-
eraging
times , selection of the re-
quired program is made with the
two Averaging Control switches on
the front panel, and the Recorder
Averaging Time switch on the rear
panel must also be set to "Variable
Averaging Time". Table 3 shows
how the programs can be selected
by suitable combination of the Pro-
gram and Minimum Time switch po-
sitions. The
programs are obtained
6
A ve raging Time
(S)
100 C,F.J Slow Random
30 10 S
G,H,J
10
3
0,3
0,1
L-----~- ___ D __ -,~,-----------·.------------'B=~--=~F~~~-,~~~~~~~~--C--D~;~:~.:
A,B,C
, ! , ! , , I ! ,
2 5 10 20
50 100 200 500 lk 2k 5 k 10 k 20 k
Sw itchover Frequency (Hz)
Fig .S. Averaging times and changeover frequencies
Minimum Av . Ti me(s) 0,1 1,0 10
Slow Rand om
C F J
Fa st Ra nd om
B E H
Sin e A 0 (G)
Table 3. Selection of the required averaging
time program
via the 15 lead AVERAGING TIME
CONTROL socket on
the rear panel.
With a Level Recorder, automatic
averaging time control functions as
follows . The scan starts with the Re-
corder being held
for a period of
five times the programmed averag-
ing
time for the band, during which
time the pen comes up to the cor-
rectly averaged level. Then a long
averaging time is selected that
keeps the output constant while the
Recorder draws the trace by advan-
cing
the paper at high speed to the
next frequency band. The Filter
steps to the next band in the se-
quence , and the programmed aver-
aging
time is selected, after which
the Recorder hold period begins
again.
Using an X-V Recorder,
where
the X-axis is controlled by the DC
ramp output from the Type 161 7,
the Recorder pauses for five times
the averaging time, and then takes
eight steps through each third-
octave band.
Figs.9 , 10 , and 11 show analysis
of the same input signal recorded
using
three different methods to il-
lustrate their relative merits .
Built - in IEC Interface
The Type 1617 is fully program -
mable via a built - in interface that sat-
isfies
the requirements of the pro-
posed
IEC Standard Digital Interface
for Programmable Instrumentation .
This permits the filter frequency
bandwidths, and averaging time to
be varied in an arbitary sequence,
and recording
initiated to suit any
particular measuring program. It
also
permits on- line changes to be
made to accomodate
new events as
they occur .
- Br uel & Kj ae r Br uet & Kjm r Sru et & Kje r
DO OOOOO DOaOOQOoaOOOOODOOOOOODDOOOOODOODDOOOODDODD
~ - ruel & Kjmr P otentiomet er R a n ge : ~ dB R ec t i f ier : ~ l ower lim . Freq .: ~ Hz Wr. Speed :~ mm / 5ec. Pap e r ~ e d :-L mm / .e c
C open hag en 50 2 1075
dBdS
40 2050
~ eas u'ing Ob j.:
Fi xed ---
~~;~ag;ng - 3 rs 40
1/3 octave-
Time used 250 s
20 f, 0 30
~~ ~.' B ~ ~~ ~~f"
--- 1 20
~
Date -==
5 ign .: __ _
10 20 ' 'tt z 50 1 00 200
OP 1124
Multipl v Fre qu ency Scal e by Ze ro l eve l: 1612 / 2 112
Fig.9 . Frequency analysis with Level Recorder and fixed averaging time
d dB
60
3C
15
ABC 76 1042

The following interface functions
are available on the Type 1617:
Acceptor Handshake (AH 1)
Listener Function (L2)
Remote Local Function (RL2)
Parallel Poll Function (PP2)
Busy is indicated via NRFD (not
ready
for data) hold method when
the Band Pass Filter is feeding a Re-
corder.
A
Listen Address switch on the
rear panel allows the instrument
Listener address to be set for use
with remote digital control. There is
a
PPR Selector for setting the Paral-
lel Poll Response, used
here to re-
port whether there has been an
overload in the Input Amplifier
si nce the previous interrogation .
This is used to assess the validity of
the levels measured in the filter
bands.
Connection to the digital bus is
made via
the 25-lead plug on the
rear panel of the instrument .
Operation with other
instruments
Fig.12 shows the connection pos-
sibilities with other Bruel & Kjcer in-
struments, including the cables re-
quired.
The Band Pass Filters can also be
employed as external filters for
B & K Sound Level Meters Type
2203 and Type 2209 , and for Vibra -
tion Meters Type 2510 and Type
2511 .
,-
.,1
~I
~I~
o ~
~Io
81~
.,1
~I
", I
' ~ I
~I
~I
Input I
Input
Input
Band Pass Filter 1618
Measuring Amplifier 2608
Measuring Amplifier 2606
Mea suring Amplifier 2607
Br ue l & Kj le r Bru el & Kj se r Bt uel & Kj e ,
000000000000000000000000 000 0000000000000000000000
rue I& Kjrer Potent iome te: R ange '~ dB R ec tifier· DC l ow er li m Fr eq ' 200 Hz Wr Sp eed" 800 mm/ sec Pap er Speed· .!Q.. mm / sec
.- -
.. -.
--
10 7
Co penhagen 50 2 5
dBd B
40 2
aas ur ing Obj .:
Variable -
Averaging -
Time --
3 1
1/3 octave-
Fast Random/D,1
Time used 90 ~
--- 21
0 50
540
s.
0 30
~~ ~~ ; ~~ ~ ~ ~f' :
R ae . No .:
0 8 18 __
Sign .: __ 00
20
10 20
H,
50 100
QP 1124
Mul t ipl y Fre qu enc y Scale by
200
d d
6
4
3
1
50 0 1000 2000
5000 1 0000 200 00 40 0000 A 8 e li
Zero l eve l: 161 2 / 211 2
AB C 161043
Fig. 10 . Frequency analysis with level Recorder and variable averaging times
Ab l(iue 4 dekader I 62 ,S mm. Copyright
AG F 1008
Fig.11 . Frequency analysis with X-V Recorder and variable averaging times
Control Cable AQ 0034
------------- -l~
Digital Conn ec tion I 18
to IEC I nterf ac e bus I I ~
AO 0129 I <{
I 1 :3
~~~-~~-~~~~~~~~~~~~~~~~-J~
2306 with 8 - pin Control I I ~
Socket: AQ 0034 Level Recorder 2306 1 0
2306 with 7 - pin Control + ~
Socket:. AQ 0182 I ~
Signal Output, B & K to BNC Connection Cable AO 0064
Signal Output , B & K Connection Cable
AO 0014
Level Recorder 2307
1£
I.;,
I . ~
1'=
__ ...I
x- Y Recorder
AO 0064
Tape Re corder 7003 or 7004
76 1040
Fig.12. Connection possibilities with other B & K instrumentation
7

Specifications l61 7 and 1 61 8
Band Pass Filters :
In accordance with IEC 225 1966 , DIN
45651 and 45652 , and ANSI Sl . ll-
1966 best classes
The total integrated r
andom white noise
power passed by
the filters in these in -
struments is e qual to that which would
be passed by an ideal filter
Centre Frequencies 1617 :
1/ 3
oct: 2 Hz to 160 kHz (50 bands)
1/ 1
oct : 2 Hz to 20 kHz (41 overlapping
bands at 1/ 3 octave interv als covering
14 octaves)
Centre Frequencies 1618 :
1/ 3
oct: 2 Hz to 20kHz (41 bands)
1/ 1
oct : 2 Hz to 20 kHz (41 overlapping
bands at 1/ 3 octave intervals covering
14 octave s)
Attenuation Outside Pass Band :
1/ 3
oct : > 75 dB at 5 x and 115 ce n-
tre
fr e quency
1/ 1 oct: > 60 dB at Sx and l / S centre
frequency
Attenuation at Centre Frequency (fm) :
1/ 3 oct and 1/ 1 oct : OdB ±O , 5dB
Maximum Peak-to-Valley Ripple :
1/ 3 oct: O, 5dB
1/ 1 oct : O, 5dB
Overall Selective Frequency Range :
1617 : l.4Hz to lS0kH z
1618 : l.4H z to 22kH z
Linear Pass Band (Available from Range
switch or Ma nual Filter Selector):
1617:
l,6Hz to 160kHz attenuati on is OdS
± 0,3 dB
1
Hz to 200 kHz att e nuation is 0 dB
±0,5 dB
1618:
1,6 Hz to 31 ,5 kHz a tt e nuati on is 0 dB
±0,3 dB
1
Hz to 40 kHz atte nuati on is 0 dB
±0,5 dB
Filter Selection :
Type 1617 :
2
Hz to 1 60 kHz
2
Hz to 40 kHz, D, A, B, C, Linear
Type 1618 :
2
Hz to 20 kHz, A, Linear
Switching control :
Manual : from " Manual Filter Se lector"
Automatic : from a Level Recorder
Automatic : to control an X-V Recor der
(1617 only)
(When sc anning octave filters, e ither full -
octave or third -octave stepping can be se-
lected)
Automatic : via th e IEC interface bus
(1617 only)
Weighting Networks:
Curves A, B, and C are in accordance
with IEC 179 for pr ecision sound level
meters (1 61 S has A-w e ighting only)
Curve D is in a cc ordance with IEC 537
Averaging Time Programmes (1617 only):
Used with Measuring Amplifi ers that fea-
ture remote controlled averaging tim es
(Type
2607)
Programmes Available :
See Table 3 and Fig.S
Input:
Via B & K coaxial socket on front panel,
paralleled by
BNC socket on rear
Impedance :
1 MOl l l00pF
Voltage :
1V RMS nominal
5 Vpeak maximum
5, 6V (± O, 3V) overload warning lamp
lights
Distortion :
Band Pass Filters :
< 0,1% with 1V signal level
< 0,3% with 3,6 V signal level
Linear Range:
< 0,1% with 1V signal level
< 0,3 % with 3,6 V signal level
Noise :
< 150j1V (typ. 100) Band Pass Filters
< 11 Oj1V (typ. SO) A, B, and C-w eighting
network s
< 250j1V (typ. lS0) D-weig hting net-
work
< 1 OOj1V (typ. SO) Linear range
Output :
Via B & K coaxial socket on front panel,
paralleled by
BNC socket on rear
Impedance :
< 500
Minimum Load Impedance :
5 kO 11 1 nF for less than ± 0,2% reading
error
DC Ramp Output (1617 only):
Used for controlling the X-axis of an X-V
Recorder
oV at the starting fr e quency
O, 20S V per 1/ 3 octave increase rate
10.4 V maximum output
Load impedance > 10 kO
Digital Bus Interface (1617 only):
Conforms with the proposed IEC Stand-
ard Digital Interface for Progra mmable In-
strum e ntation
Contains the following function s:
Acceptor Handshake (AH1) .
Listener
Function (L2)
Remote Local Function (RL2)
Parallel Poll Function (PP2)
Environmental Conditions :
Operating Temperature Range :
5°C to 40 °C (41 °F to 104 ° F) giv e no ef -
fect
Storage Temperature :
-25 °C to + 70 °C (- 13 °F to + 15S 0 F)
Permitted Humidity Range :
The
outputs from the i nstruments are ac-
curate between 0 and 90 % relative hu-
mid i ty , provided there is no condensation
Power Requirements :
100 , 115 , 127 , 200 , 220 , 240 V AC
±1 0%
50 to 400Hz
1617 : appro x. 30VA
1618 : approx. 2SVA
Comply with IEC 34S Class I
Cabinet :
Suppli ed as model A (light - weight metal
cabinet), B (model A in a mahogany cab-
inet), or C (as A
but with flanges for
standard
19 " ra ck mounting)
Dimensions :
Height : 133 mm (5, 25 in)
Width : 430 mm (16 ,9 in)
Depth : 200mm (7, 9in)
Weight:
1617 : 6, 5kg(14,3Ib)
1618 : 6,3 kg (13 , 9Ib)
Accessories Included :
1 AN 0010 Power cable
2 JB 0002 Banana plug
2 JP 0035 BNC plug
2 JP 0101 B & K coaxial plug
1 JP 0703 7-pin DIN plug
1 JP OS02 S- pin DIN plug
2 VF 0012 Fu se
Accessories Available :
See Fig.
12 .

2. 1. FRONT PANEL
Se lected Fi lt er -~ -
r r 'H
,I-' ,.
_ L,~ . •_
.....
.-
2. CONTROLS
Ma n ua l Filter Se lector Averaging Control
. -- ~ - Power On
r _ ._c.. .... ... _ -,
In pu t Se l ectivity Ra n ge
Filter Co n tro l Mode Ou tp ut
770353
Fig .2.1. Front panel controls of the Type 1617
POWER ON:
AVERAGING CONTROL:
MANUAL FILTER SELECTOR:
SELECTED FILTER:
INPUT:
Power is on with the switch in the up position . Warm -up time is ap-
proximately five seconds.
Two switches used to select averaging time programs , when the
Band Pass Filter is connected to a Measuring Amplif i er such as the
Type 2607, which has provision for remote control of its averaging
time .
Program: Selects an averaging time program suitable for " Sine ",
"Fast Random", or "Slow Random" signals .
Minimum Time: Selects minimum averaging times for the averaging
time programs.
A rotary switch that selects the filters and we i ghting networks when
operating in the "Manual" control mode . The two frequency scales
cover the measuring ranges that can be chosen by the "Range" sw i tch
and indicate the selected frequency band.
A
digital display that shows the centre frequency of the selected filter .
The display also indicates the bandwidth chosen, and whether a linear
or weighted response has been selected.
Standard B & K coaxial socket, fitting JP 0101 Plugs, paralleled by a
BNC socket
on the rear panel. There is an i nput " Overload" lamp , and
9

SELECTIVITY:
RANGE:
FILTER CONTROL MODE :
OUTPUT:
2.2. REAR PANEL
CHASSIS-SIGNAL GROUND :
10
a separate ground terminal. The maximum input voltage is 5 V, and
the impedance is 1 MO in parallel with 100 pF.
A
three-position switch that selects the bandwidth of the filters , and
the centre frequency step length for full-octave scanning . Functions
are as follows:
Upper
position:
third-octave bandwidth with
scanning
in third-octave
steps.
Middle
position: full-octave
bandwidth with scanning
in third-octave
steps, with overlapping .
Lower
position: full-octave bandwidth with scanning in
full-octave
steps.
A
three-position switch to select the narrow band ranges, or "Linear",
for both manual and recorder controlled operation . Functions are as fol-
lows :
Upper position: "Linear" range from 1 Hz to 1 80 kHz, independent of
the position of the MANUAL FILTER SELECTOR.
Middle position: "2 Hz to 160 kHz" , filters are selected automatically ,
or by the MANUAL FILTER SELECTOR from the inner scale on the
MANUAL FILTER SELECTOR.
Lower position: "2 Hz to 40 kHz-D-A-B-C-Lin .", filters are selected au-
tomatically, or by the MANUAL FILTER SELECTOR from the outer scale
on the MANUAL FILTER SELECTOR.
Two switches that control how the filters are selected, plus two LED in-
dicators , one to show whether the instrument is in operation under
manual control, and the other indicating that all front panel controls
are inactive while the i nstrument is being controlled via the Digital In-
terface .
The left-hand switch can select "Manual " so that the filters are
chosen by the MANUAL FILTER SELECTOR and start of Recorder read-
out is impossible, or it can select "Recorder" mode allowing filter selec-
tion to be made by extern aI control .
The right - hand switch enables the Recorder in use to be controlled
from the Band Pass Filter . This facility is blocked when "Manual" has
been selected, or when control is being exercised via the Digital Inter-
face. Two LEOs light to indicate whether "Stop" or "Run" is selected .
Standard B & K coaxial socket, fitting JP 0101 Plugs, paralleled by a
BNC socket on the rear panel. There is a separate ground terminal. Im-
pedance less than 200, minimum load impedance 50 in parallel with
1 nF.
A
pair of clamping terminals with a shorting strap permits the signal
ground to be connected to the instrument chassis .

Line Voltage
Se lector
Ch assis
Sign al Gr ound
A
ve raging Tim e
F
uses
PPR Se l ec t or L is ten Add ress
Output
r;
III
Mains Input
Di g it al Bu s (I EC I A
v. Tim e Control
Fig.2.2 . Rear panel connections on the Type 1617
I nput
R eco rder
Control II
LINE VOLTAGE SELECTOR: Allows the Filter to be operated on mains voltages of 100 , 115, 127,
150 , 220 , and 240V (± 10%), selected by turg the selector with a
small coin or a w ide-bladed screwdriver to indicate the available vol-
tage value . Any mains frequency from 50 to 400 Hz may be used.
LINE INPUT:
[
FUSES:
DIGITAL BUS (IEC):
LISTEN ADDRESS:
PPR SELECTOR:
A three - pin socket for connecting line and ground to the i nstrument .
The
Line connection lead AN 0010 (supplied) is delivered without a
plug to permit fitting an appropriate plug suiting local standards
Note,
the colour code is given in Fig .2.3. Before connecting a supply
the line voltage setting and fuse checks given in section 3.1.1 and
3.1 .2
should be carried out .
Blue Neutral
AC Power
"oJ
Brown Supply
Liv
I J
Gr een and Ye llow Ground
172246
Fig.2.3. Line input connections
Two 0,2 A line fuses . With line voltages 100, 115, and 127 V, both
fuses are used, while with 200, 220 , and 240 V only one fuse is
used, see section 3.1 .2.
25 -pole D-socket for connecting to the IEC Interface Bus.
5-pole switch for selecting the listening address of the instrument
when under remote control via the IEC Interface Bus .
8-pole switch for selecting the Parallel Pole Response (only one pole
may be set to 1).
11

AVERAGING TIME
FIXED VARIABLE: A two-pOSition
sliding switch to select one of two operation modes
with a Level Recorder, as further explained in sections 3.3.3/ 24 and
3.3.4/ 9 .
AVERAGING TIME CONTROL: A
15-pin outlet for the averaging time control program signals from
the Band Pass Filter to the Measuring Amplifier. The socket fits the 15 -
pin Plug JP 1501 . For connections see section 3.3.2.
OUTPUT:
INPUT:
RECORDER CONTROL I:
RECORDER CONTROL
II :
BNC socket in parallel
with front panel output socket.
BNC socket in parallel with front panel input socket.
7-pin DIN socket
for remote switching of the filters by a Level Recorder
Type
2307, and for remote control of the Level Recorder by the Type
1617 . For connections see Fig.2. 4.
8-pin DIN socket for remote switching of the filters by a Level Recorder
Type
2306, and for remote start and stop of the Recorder by the Type
1617 . X-ramp and pen- down signals for an X-V Recorder are also sup-
plied via this socket. For connections see Fig .2.5.
Input for fil te r
shi ft pu lses n + 32
J Lov
+ 32 V
to se lect --t-t-
Au tomatic Stop
Not u sed
+ 32 V DC from
Record er lindi ca t es)
Recor de r on)
+ 32 V to
-,:-t--- stop Recorder
immediately
+ 32 V to
se lect pe n I itt 77 0 774
Fig.2.4. RECORDER CONTROL I viewed from outside the socket
12
X ra mp ou tp ut wh en no L eve l
Recorder is connected. W it h
L evel Recorder + 6 V to se lect
1/3 oct . interval between pul se s
Fi
lte r sh i ft
pu lses
oV to se lect
Au to matic Stop
oV to stop
Recorder imm ediately
Not used
+ 6 V from
Level Recorder
(in dicat es recorder
on)
oV f or
pen d ow n
770 3 55
Fig. 2.5. RECORDER CONTROL /I viewed from outside the socket

3. OPERATION
3.1. PRELIMINARY ADJUSTMENTS
Before connecting a mains supply the following checks and adjustments should be car-
ried
out to ensure safe operation of the apparatus.
3. 1.1. Selection of Line Voltage
The instrument can be operated on single phase AC line voltage from 100 V to 240 V,
with a tolerance of ± 10% , at frequencies between 50 and 400 Hz.
Set the LINE VOLTAGE SELECTOR to the voltage to be used by turning it with a small
coin or a broad-bladed screwdriver .
3.1.2. Fuse Rating
For operation on 100, 115 and 127 V, two 0,2 A fuses (VF 0012) are required, one in
each
holder . Operation with 200, 220 and 240 V requires only one 0,2 A fuse, and
when these voltages are selected as described in 3.1. 1, the left-hand fuse is electrically
by-passed.
Make sure that only fuses with the required rated current and of the specified type are
used
for replacement. The use of mended fuses and the short-circuiting of fuse holders
shall be avoided.
3.1.3 . Line Connections
Blue Neutral
AC Power '"
B row n Supply
Li ve
[ •
I~ I J
Gr ee n and Yell ow
Gr ound
172246
Fig.3. T. Line input connections
13

Once the line voltage setting and fuse have been checked, the line supply may be con-
nected
to the LINE input socket using the Power Cable AN 0010 supplied. To fit a suit-
able mains plug to the cable see Fig.3 .1.
For
maximum operating safety it is recommended that the protective (green and yellow)
conductor of the cable be connected to a suitable ground, such as the protective ground
contact of a line socket outlet. The use of an extension cable without a protective ground
conductor should be avoided.
3.1.4. Grounding Considerations
When several instruments are used together, ground loops and their resulting problems
can easily be formed . Therefore, the following procedure is necessary to ensure that the
system is free from ground loops, by connecting each instrument in the arrangement to
ground via the same path.
1.
Connect the signal grounds of all the instruments together (this automatically occurs
through the screens of the signal cables). However, if two instruments are con-
nected in parallel, it may be necessary to disconnect one of the screens in the signal
cables to prevent formation of a loop.
2.
Connect the signal ground to the chassis, and the chassis to the mains ground of
one instrument only , preferably the one closest to the measuring point.
3. Check each of the other instru ments in the system to verify that its chassis is con-
nected to one and only one of the following : mains ground, si gnal ground , or the
chassis of another instrument .
The signal
ground and chassis of the Type 1617 are normally connected by the metal
strap between the ground terminals on the rear panel. The strap must be removed to iso-
late
the signal ground from chassis ground .
3.2. OPERATION WITH MEASURING AMPLIFIERS ALONE
14
The Measuring Amplifiers Type 2606, Type 2607, and Type 2608 are amplifiers cover-
ing
the frequency range 2 Hz to 200 kHz. They are designed for sound and vibration
measurement. accepting inputs from a wide range of transducers and preamplifiers .
They can supply 12 volts DC for preamplifier power supplies, or the 200 volt polarization
voltage
and 150 volt anode supply for B & K condenser microphones. They contain selec-
table
frequency - weighted networks for sound level measurement. and high and low pass
filters to limit the frequency range for audio frequency measurements .
An external filter such as the Type 1617 can be connected in series with, or in place
of, the internal weighting networks and filters to permit frequency analysis. Such an ar-
rangement is shown in Fig.3.2. Indication of the signal level can be obtained either from
the built-in meter , or from a permanent record obtained on a Level or X-V Recorder con-
nected to the measuring amplifier 's output. see section 3.3 .
For
further information on measur ing amplifiers to help in deciding the best for a particu-
lar application , a more comprehensive review of the capabilities of the Measuring Ampli-
fier is gi ~ en in section 1. See also the relevant Product Data sheets .

3. 2.1. Measuring Procedures
Input
Signal
Measuring Ampl if ie r 2606,
2607, 2608 Band
Pa ss Filter 1617
770356
Fig.3,2. Basic instrumentation arrangement
1. Connect the instrumentation as shown in Fig.3.2.
2. Perform
the preliminary adjustments for the Measuring Amplifier as described in the
relevant Instruction Manual .
3. Set the Measuring Amplifier controls as follows :
INPUT
"Direct" when the B & K coaxial input is used, or
" Preamplifier Input" when the 7-pin B &K socket
is used
METER FUNCTION
As appropriate: for further information see the
Measuring Amplifier Instruction Manual
GAIN CONTROL "Calibrated"
INPUT ATIENUATOR "300 V"
OUTPUT ATIENUATOR "x 1"
FILTERS " External", plus any weighted network required; if
only audio frequencies are to be measured, the
high pass 22.4 Hz filter and the low pass
22.4 kHz fil!er (not on 2608) can be used to limit
the frequency range of the Filter output signal.
REMOTE/ MANUAL Averaging .
Time
Switch (rear panel
of 2607 only) "Manual"
POWER "On"
4. Perform the preliminary adjustments for the Band Pass Filter as described in section
3.1.
5. Set
the Band Pass Filter controls as follows:
SELECTIVITY
RANGE
AVERAGING CONTROL
FILTER CONTROL MODE
Bandwidth (and stepping) as required
As appropriate
Switch positions immaterial
Left-hand switch "Manual"
Right- hand switch in neutral position
15