IVIE IE-10A User manual

Our new address
lvie Technologies, Inc.
1605 NW State St.
Lclli UT 84043
Ph: 801 - 766 - 7600
Fax: 80 1 - 766 - 8282
Audio Spectrum Analyzer
Owners and Operators Manual
January 1977
Printed in U.S.A.

TABLE OF CONTENTS
Warranty .................................................. Page 1
Introduction ..............................................
page 2
Operation ------------------------------------------------- Page 3
Octave Filter Characteristics ----------------------- page 3
IE-1OA Front Panel and Controls ..................... Page 5
Selecting The Detector Response ..................... page 8
Battery and Line Operation ------------------- ------- Page
9
Pink Noise Testing ........................................ page' 10
Calibrating the IE-20A/IE-10A ----------- ------------ page 10
Gain and Loss Testing
............................... page 11
Room Response Testing ............................... page 15
Sound Level Testing
....................................... page 19
Introduction To Sound Level ~eiisurements -- -- -- - - - -- - page 19
Body Effects On Sound Measurements
-- -- -------- - - ---- page 23
Correcting For Background Noise
..................... page 23
Adding Sound Levels ................................. page 23
Measuring dB
- SPL With The IE-1OA .................... page 25
Making DBM Measurements ----------------------------------- page 29
Identifying the Levels
of Unknown Signals - - - - ---- - - -
J
page 31
Measuring Volta es With the IE-1OA
- - -- - --- - - - - - -- --- page 34
Impedance ~onvdrters/Attenuators .................... page 36
Using ~xternaiAttenuators
--- ---------- ------------- Page 37
Measuring Output Power .............................. page 39
Measuring Gain/Loss in Audio Systems - -- ---- - - - ---- - - page 41
Operating The Precision Preamplifier ...................... page 45
IE-1OA Specifications ..................................... page 47
Architect's and Engineers Specifications ------------------ page 49
Service -- - - - - - - - - ---- -- - - - - - --- - ---- - --- --- - - - - -- - -- - -- - - - page 50
Notes --------------------------------------- page 51

I E-1OA WARRANTY
The IE-1OA is warranted against defects in
materials and workmanship for one
(1) year
from the date of purchase. During the
warranty period Ivie Electronics will
repair, or at its option, replace components
which prove to be defective provided the
analyzer is returned shipping prepaid to
an authorized Ivie Electronics service
faci
1ity. Defects caused by modifications,
misuse or accidents are not covered
by
this warranty. No other warranties are
wctronicsis
expressed or
i mpl ied.
not liable for consequenti amages.
All
requests for repairs and information
should include the instrument serial
number to assure rapid service.

I NTRODUCT I ON
In the past, real - time analysis of the audio spectrum has been an expensive
process requiring a substantial investment in test equipment. The
benefits of such analysis have long been appreciated, but the process
has been so costly that only those with sufficiently large operating
budgets have been able to afford
it.
The IE-1OA Spectrum Analyzer is a versatile piece of test equipment that
is capable of making both relative and absolute measurements in the
audio spectrum. Frequency response, amp1
i fier gain, insertion loss,
sound pressure levels, dBm and voltage testing represent a few of the
IE-1OA measurement applications. Unlike a typical voltmeter, the IE-1OA
simultaneously displays the octave frequencies of the signals being
measured. The user can select a detector response for pink noise
averaging or a fast response for real time signal monitoring. Many
valuable uses can also be made of the built
- in precision preamplifier.
Every IE-1OA is built to last. The case is aluminum, fusion bonded with
nylon, and internal construction is 100% modular. Every IE-1OA is
thoroughly and painstakingly tested to assure complete perfo~ance.
Each unit is then heat tested in an oven for 72 hours at 125 F to assure
reliability. Any unit that doesn't measure up doesn't leave the factory.
The following pages in this manual explain the many features and uses of
the IE-1OA. We suggest that
it be read thoroughly.
With your IE-1OA you should have received the fol1owing standard accessories
pictured below:
IE-1OA Audio Spectrum Analyzer.
" Fast Charge " nickel cadmium batteries
(mounted inside the IE-1OA.)
AC adaptor/charger that provides
continuous 1ine operation.
Vinyl carrying case with be1
t loop.
Standard phono plug patch cord. (Not
pictured
)
Operator's Manual with i 1lustrations
and examples
.
Figure 1
It is recommended that your IE-1OA be charged for two to three hours
after
it is unpackaged. This
will assure a full two hours of operating
time before recharging is again necessary.
Make sure the voltage selection switch on the IE
- 165A Charger/Adaptor is
in the correct position for the line voltage being used (either 115v. or
230 v. AC at 50
- 60 Hz).

OPEEAT1 ON
OCTAVE FILTER CHARACTERISTICS
The ten octave filters in the IE-1OA Spectrum Analyzer meet the requirements
of the
ANSI S1.ll - 1966 (R 1975) Class I filter standards.
A plot comparing
the second order Chebychev filters in the IE-1OA with the
ANSI standard
curves can be seen in Figure
2.
FREQUENCY RATIO - f/f,
Figure 2
In the above plot of an octave width bandpass
fi 1ter, the frequency
scale (horizontal axis) has been normalized (f/fm) so that the same plot
can be used to represent any one of the IE-1OA octave filters. For
example, the number
1 on the horizontal axis represents the filter
center frequency fm, 2 is a frequency that is twice
fm (the second
harmonic) and 0.4 is a frequency that is four tenths that of the filter
center frequency.
.
A well designed bandpass filter should a1low passband information to be
transniitted through it without significant energy loss while a11 frequencies
outside the passband should be rejected or attenuated to some degree.
Transmission loss (vertical axis of Fig. 2) is simply a measurement of
the
" attenuation " of energy (usually expressed in dB) as it passes
through a device or circuit.
If we inject a pure 1 KHz tone into an octave filter having a center
frequency of
1 KHz, the " transmission loss " would be minimal, or close
to 0 dB. However, an out
- of - band 2 KHz tone into the 1 KHz octave
fi 1ter of the IE-1OA would have a " transmission loss " of approximately
15 dB as can be seen by studying
Fig. 2.
page 3

If all ten TE-1OA filters are aligned in parallel they will have a
frequency response similar to that shown in Fig.
3 .
FREQUENCY IN HERTZ
Figure 3
An interesting question might be:
What kind of display would we expect to see on a real
- time
analyzer if we inject a pure sine wave signal at
a frequency
equal
to one of the filter centers (ie.
1 KHz)?
Many peopiewould assume that
a 1 Mz frequency tone would cause energy
to be displayed only at the
1 KHz filter position on the analyzer, but
this is not true. Remember
that bandpass filters can attenuate out of
band energy but they cannot eliminate it completely. Fi1ters that are
close in frequency to
1
KHz also detect a small part of the incoming
energy and they will display that energy on the analyzer at an attenuated
1eve1 . Depending upon the display range selected, several fi1ters could
respond to a signal, even though the energy is at one single frequency.
A 1 KHz signal fed into the filters of Fig.
3 will be displayed at the
highest amp1itude in fi1ter number
6, which, of course, is the
1 KHz
fi1ter. Fi 1ters
3 through 9 a1so respond, in varying degrees, to the 1
KHz signal at a level where the individual filter skirts intercept the
signal. Injecting a sine wave into the center frequency of one of the
IE-1OA filters results in a display of the shape of that exact sanie
filter. This property is not unique to the IE-lOA,
but of all spectrum
analyzers whether
" real - time " or " swept tuned. "
We can view the filter
shapes of every spectrum analyzer by injecting sine waves that are
wi thin the frequency range of the analyzer.

IE-1OA FRONT PANEL AND CONTROLS
Figure 4
Page 5

I E - 1OA FRONT PANEL CONTROLS
Referring to the picture of FIG. 4, the following number codes describe
the various functions and controls of the IE-1OA Real Time Analyzer.
@ POWER ONIOFF Placing the power switch in the " ON " position applies
power to all IE-1OA circuits. Leaving this switch in the
" OFF " position
between measurements
wi 11 extend the battery 1
i fe between charges.
9 DISPLAY GRATICULE. The left hand scale is calibrated to e used
wi h the 1 dB/step setting of the display resolution switch 6 .
Measurement range is +3 dB to - 12 dB.
@ DISPLAY GRATICULE. The center scale is calibrated be used with
the 2 dB/step setting of the display resolution switch
. Measurement
range is
+6 dB to - 24 dB;
@ MICROPHONE.. The omnidirectional condenser microphone is a professional
qua1 i ty Sound Level Meter type 2. The microphone becomes fu tional as
the signal source for the IE-1OA only when the INPUT switch is set
to internal (INT).
Q DISPLAY GRATICULE. The right hand scale is calibrated
wi h the 3 dB/step setting of the display resolution switch
Measurement range is
+9 dB to - 36 dB.
@ DISPLAY RESOLUTION. Display resolution can be selected in steps of
1, 2 or 3dB providing the operator with display ranges of 15, 30, and
45dB respectively. Note that the correct display graticule must be used
with the appropriate dB/step resolution setting. or exa~nple ldB/step
n should be used wi display graticule 2 and likewise 2dB/step
and 3dB/steb with 6
9 INPUT SELECTOR SWITCH. When the inpu is set to internal
(I T) the analyzer's built
- in microphone the signal source
for the IE-1OA. Setting the input switch (EXT) allows the
to inject other signals into the analyzer through the phono
at^ marked " IN " .

@ SENSITIVITY SWITCHES. The sensitivity switches add gain in lOdB
steps (to a total of 80dB) to the analyzer front end which changes the
measurement range. To determine analyzer gain,add the absolute values
of the two sensitivity switch settings as shown in the table below.
SENSITIVITY
Table 1
@ PREAMP OUTPUT. The IE-1OA has a bui 1 t in,low - noise preamp circuit
with gain adjustable in
lOdB teps to a maximum of 80 dB. ut to the
preamplifier is phono jack
@) , the output is phono jack
details and applications refer to the manual section about
@) BATTERY STATUS INDICATOR. This LED indicator has two important
functions.
It lights when the IE-1OA is being charged, thus providing
indication of a properly working battery charger.
Its second function
is providing indication of battery level.
It illuminates when the Ni -
Cad batteries are low and require charging.
BATTERY CHARGER JACK. This jack is provided to recharge the
Ni -
Ca batteries in the IE-1OA using the model IE - 165A adaptor/charger.
9 SIGNAL INPUT JACK. The pho jack marked " IN " is the signal port
to e used with the input switch set to "EXT". Having an input
impedance of 100 K ohms, this external input
will accept most of the
microphones and signal generators avai
1able in the market today.
@ MODE SELECTOR. Positions " A " and "C" select filters for Sound
Level Meter applications, and
" OCT " selects the ten octave bandwidth
filters for Spectrum Analyzer operation. In the
" OCT " mode the IE-1OA
has two selectable detector responses, one for pink noise measurements
and the other for monitoring. Pink noise averaging is activated by
switching the mode first to " C "
and then to " OCT. " The monitoring
response is activated by switching the mode to
" A " and then to "OCT."
The monitoring detector response is activated when the power is first
turned on. page
7

SELECTING THE DETECTOR RESPONSE
There are three different detector response modes used in the
IE-1OA
filter circuits, two for the OCT filters and one for the A and C filters.
For sound level meter applications using the
A and C weighted filters,
the detectors satisfy
ANSI S1.4 1971, SZA, S2C and IEC 123 (1961) for
the
" slow " response. For the OCT mode of the IE-lOA, you may select
either the signal monitor mode, or the pink noise averaging mode. The
signal monitor detectors have a very fast rise
- time and fall - time response
to enable the operator to view signal transients, impulses
, osci11ations ,
music signatures and other rapidly changing phenomenon. The pink noise
averaging mode was designed mainly for tests using pink noise and other
types of random signals
.
The mode switch has only three toggle positions, but it is used to
select A, OCT or
C filters and also the detector responses. To select
the signal monitor detectors,the mode switch is moved to the A filter
and then returned to OCT. If the mode switch is moved to the C filter
and then returned to the OCT position, the pink noise averaging detectors
will be activated.
SELECTABLE DETECTOR RESPOtiSES
PINK NOISE MODE
MOHITOR MODE
Figure 5

BATTERY AND LINE OPERATION
An IE
- 165A AC Adaptor/Charger has been supplied with your IE-1OA Audio
Spectrum Ana-lyzer that will recharge the batteries in about
3 hours.
The IE-1OA will operate approximately 2 hours between charges, depending
upon the ambient light level. The battery current drain varies because
of the automatic, display intensifier circuits in the IE-1OA. Normal
room lighting will provide about 2+\ hours of operating time with less
than
2 hours available under bright stage lights or sunlight.
When the
" CHARGE " LED lights indicating low batteries, recharging is
immediately necessary. The IE-1OA specifications cease to be accurate
shortly after this LED illuminates.
CAUTION: Use of an AC adaptor/charger other than the IE
- 165A may cause
damage to your IE-1OA.
The IE - 165A AC Adaptor/Charger is selectable for voltages of 115v. or
230v. AC at 50 to 60 Hz. Make sure the voltage switch on the IE-165A is
in the correct position for the AC power line being used. Using the
ZE-
165A with - AC power other than 115v. or 230v. at 50 - 60 Hz. may cause
damage to your
I E - 1OA.
The IE-1OA may also be operated directly from the AC power 1ine using
the IE
- 165A as an adaptor if the batteries have some charge in them.
The ZE-165A will not operate an IE-1OA directly from the power line
if
the batteries in the IE-1OA are discharged.
The Ni.-Cad batteries in the IE-1OA are of the highest quality and are
capable of withstanding extended overcharging.
It is recommended that
they be com letely discharged (until the
" Charge " LED on the IE-1OA
illuminates ! from time time to minimize the possibility of " memory
effect
" on the batteries. Ni
- Cad batteries can lose their ability to
give up 100%of their charge if they are only partially discharged on a
frequent basis
.
If permanent power line operation of the IE-1OA is desired, it is
recomnded that the Ni - Cad batteries be removed and that a line operated
DC power supply of 6v. and 250ma be provided in their place. The external
power
SUD ly can be conveniently provided to the IE-1OA through the charge
jack
( &igure 4) (center pin is positive).

PINK NOISE TESTING AND THE IE-1OA
There are a few fundamentals that the reader should be made aware of
before doing pink noise testing. Pink noise is random noise that
appears flat only after being time averaged by special detectors on a
real
- time analyzer. When used with pink noise, the detectors in the IE-
10A should always be in the pink noise averaging mode. The rms voltage
output of a pink noise generator must be measured by special means using
sampling techniques and a true rms voltmeter. To an oscilloscope, pink
noise appears to be a mass of random voltage spikes.
The output of the IE-20A Pink Noise Generator has been calibrated in
volts rms.
A very important specification on a pink noise generator is
its " crest factor. " Crest factor is simply the ratio of the peak
voltage to the rms output voltage of the generator. For example,
if we
select an output level from the IE-20A equal to 30 mv rms, a crest
factor of 3.75 predicts that there could be instantaneous voltage peaks
in the output that are 3.75 times the magnitude of the rms output
voltage. In this particular case, a 30 mv rms output will produce
voltage peaks as large as 113 mv. Pink noise is one of the best signal
sources available for doing rigorous testing of amplifier durability,
and transient signal hand1ing capabi1 i ties. Pink noise also approximates
actual audio signals better than any other type of signal source.
The IE-1OA is calibrated to measure voltage and dBm for sine wave
inputs using the external jack. With a pink noise input the IE-1OA is
only calibrated in dB for relative measurements like gain, loss and
frequency response. For sound 1eve1 measurements, using the IE-1OA
microphone, the analyzer is always calibrated in absolute dB - SPL whether
the sound in the room is pink noise or another type.
CALIBRATING THE IE-20A TO THE IE-1OA
The IE-IOA filters are very flat electrically, to within a small fraction
of a dB,as can be verified with a swept sine wave input signal. Likewise,
the IE-20A is designed to provide very flat pink noise output into a
real
- time spectrum analyzer. Being designed flat
" independently " , any
IE-20A will work with any IE-1OA produced, and visa versa.
Many analyzer/pink noise combinations availab1e in the audio marketplace
use non
- flat pink noise that is compensated for by adjusting the analyzer
fi 1ters to be inversely non - flat so that the analyzer/pink noise combination
wi 11 appear flat. This type of system is accurate only for relative
measurements and cannot be used for accurate testing of absolute levels
of voltage, dBm or dB
- SPL. A further limitation is that the pink noise
source and the analyzer cannot be interchanged with other units unless a
complete recal
i bration is performed on the instruments.
To check proper operation of the IE-1OA and the IE-20A, set the output
attenuator on the IE-20A to zero and set the controls on the
TE-1OA as
shown in Fig.
6 .
Next feed the IE-20A output into the IE-1OA using one
of the patch cords supplied. The signal should appear flat and at the 0
dB line on the IE-1OA display as shown. If the pink noise is flat but
does not appear at the 0 dB line on the
IE-1OA consult the IE-20A manual
on adjusting the output reference level. page 10

-r0i;;4++;'& - CALIBRATION LINE
-1 - - - - -2 - - - - -3
I111111111
2---- 4 ----
I I I I111111
3 - -- - dm --- .
I1l1111111
4 - - - - 8 - - - - 11
II11111111
~ -
5 ---- w ---- 8,
IIIIl11111
6 - - - - n - - - -
*Note settings of SENSITIVITY
III1111111
I - - - - Y - - - - 3s switches .
-.
IIII111111
p - - - - 18 - - - - 27
I III111111
1o----X)----X)
IE-1OA detectors should be
IIII111111
)I - - - - n - - - - J.I
in pink noise averaging mode.
Figure 6
Increase the IE-1OA DISPLAY switch resolution to 2 dB per step, and then
to
1 dB per step. The pink noise should remain at the 0 dB line, but if
it does not, readjust the reference on the IE-20A. Now you are calibrated,
and the output voltage on the IE-20A is equal to 940 mv rms.
Now try another experiment with the IE-lOA/IE-20A. - Set the dial attenuator
on the IE-20A to 12 dB. As you switch the display resolution on the IE-
10A between 1, 2, and 3 dB, note that the signal is 12 dB down from the
.
calibration line (0 dB) on all three display scales. The resolution
settings on the analyzer always expand around the 0 dB reference line.
As analyzer resolution reaches
1 dB per step it can be observed that
pink noise in the low frequency filters appears less stable in amplitude
when viewed on the IE-1OA. This is a normal occurence with any pink
noise source and analyzer, and is due to the random nature of pink noise
and the fact that the low frequency filters have narrower bandwidths.
If pink noise is averaged over a long period of time it wi11 appear very
flat with little variation in amplitude. Using a long detector time
constant,we would be forced to wait for an excessively long time period
for the analyzer to respond to a change in frequency response and we
would have something' less than a
" real-timeu analyzer. The IE-1OA
detectors are optimized for best stability versus fast response time of
the displayed signal. High resolution measurements need not be less
accurate
if we simply observe the level at which the LEDs spend most of
the time.
PINK NOISE GAIN/LOSS TESTING
Using pink noise as a signal source with the
IE-1OA will enable a measurement
of frequency response and gain (or loss) simultaneously. The simplest
way to describe the procedure is through the use of a few examples.
page
11

1st EXAMPLE
Measure the gain' and the frequency response of a preamp1 i fier with 10 mv
input signal
.
Procedure ;
1.
Using the table on page 9 of the IE-20A operator's manual, set the
output level of the IE-20A to 10 mv. An attenuator setting of 40
dB
will provide a 9.4 mv signal.
2. Initially set the switches on the
IE-1OA as shown. Display resolution
is set to
2 dB per step for this example.
Figure
7
3. Set the ZE-1OA detectors in the pink noise averaging mode. This is
accomplished by moving the MODE switch to the
C filter position and
then back to OCT.
4. Using the patch cable provided, connect the IE-20A output to the
IE-1OA input as shown. The signal from the IE-20A should appear at
the -20dB line on the IE-1OA (2 dB per step scale). Notice that
the signal was purposely displayed near the bottom of the screen
because the signal gain from the amp1ifier
wi 11 cause the display
to rise.
CALIBRATION STEP
- 20 dB Calibration
Line
Note:
2 dB/s tep ~esoluti0n
Figure 8
page 12

5. Connect the test amplifier between the IE-20A and the IE-1OA as
shown be1ow.
MEASURE AMPLIFIER
f
'r
.era
g
L /
\ J
U
IE-2OA IE-1OA
TEST
AMPLIFIER
+2 dB Test Level
Note:
2 dB/step Resolution
Figure 9
6.
Gain of the test amplifier is determined by calculating the dB difference
between the two display readings on the IE-1OA. The dB range
between
- 20 dB and + 2 dB represents a test amplifier gain of 22
dB.
7.
Any deviation from amplitude flatness on the display is caused by
the test amplifier's frequency response.
If desired, display
resolution can be increased for improved measurement accuracy of
the frequency response.
2nd EXAMPLE
A manufacturer specifies his audio device to, have less than 10 dB
insertion loss at any frequency from
60 Hz to 4 KHz.
Acceptable input
levels are 10 rnv to 100 rnv rms. Verify his claim.
Procedure:
1.
Set attenuator on IE-20A for an acceptable signal output level.
Referring to the table on page
9 of the IE - 20A manual, 30 dB of
attenuation will provide a 30 mv rms signal output.
2. Initially set the switches on the IE-1OA to the positions shown
below. Always begin a measurement with both analyzer sensitivity
switches set to 0 dB.
page 13

Figure 10
3.
Feed the IE-20A signal into the IE-1OA as shown below and add
sufficient gain to the IE-1OA to bring the calibration signal high
on the display.
It does not have to be at the 0 dB line as shown.
CALIBRATION STEP
0 dB calibration
Line
Figure 11
4. Insert the audio test device between the IE-20A and the IE-IOA.
Record the signal levels at each frequency because the insertion
lcss may be different at each frequency.
page 14