Omicron Lab CP AL1 User manual

CP AL1
User Manual
FFT VOLTMETER FOR STEP AND TOUCH
VOLTAGE MEASUREMENTS

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CP AL1 User Manual
Manual Version: CPAL1.AE.1
© OMICRON electronics 2007. All rights reserved.
This User Manual is a publication of OMICRON electronics GmbH.
All rights including translation reserved. Reproduction of any kind, e.g., photocopying, microfilming or
storage in electronic data processing systems, requires the explicit consent of OMICRON electronics.
Reprinting, wholly or in part, is not permitted.
This User Manual represents the technical status at the time of printing. The product information,
specifications, and all technical data contained within this User Manual are not contractually binding.
OMICRON electronics reserves the right to make changes at any time to the technology and/or
configuration without announcement. OMICRON electronics is not to be held liable for statements and
declarations given in this User Manual. The user is responsible for every application described in this
User Manual and its results. OMICRON electronics explicitly exonerates itself from all liability for
mistakes in this manual.
OMICRON electronics translates this manual from its source language English into a number of other
languages. Any translation of this manual is done for local requirements, and in the event of a dispute
between the English and any non-English versions, the English version of this manual shall govern.

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Contents
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
1.1 Delivery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3 Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4 Battery Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.5 CE Declaration of Conformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.6 Test & Calibration Certificates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.7 International Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
2.1 Menu Bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.2 Measurement Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.2.1 FFT Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.2.2 RMS/THD Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.3 Input Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.4 Setup Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.5 Memory Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.6 Battery State Indication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3 Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Contact Information / Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . .29
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

CP AL1 User Manual
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5
Introduction
1 Introduction
Congratulations and thank you for buying NTI's FFT voltmeter CP AL1, a
product which is primarily designed for professional acoustical test applications.
For step and touch voltage measurements, the CP AL1 is delivered with an
OMICRON electronics software which allows measuring the frequency selective
voltage level by using a real-time Zoom FFT. This User Manual describes in
detail the OMICRON electronics software specific CP AL1 functions and
measurements. The CP AL1 makes understanding and handling the step and
touch voltage measurements simple. However, fundamental working knowledge
of the step and touch voltage measurement techniques is a prerequisite for
using the CP AL1.
1.1 Delivery
The CP AL1 delivery includes:
• FFT voltmeter CP AL1
• Adapter ML 1 –20 dB (1:10)
• Adapter XLR to BNC with 1 kΩ
• 3 × 1.5 V LR6/AA battery
• CP AL1 User Manual
1.2 Warnings
For a proper operation of the CP AL1, observe the following rules:
• Read this manual thoroughly before putting the CP AL1 into operation.
• Use the CP AL1 for the intended purpose only.
• Never connect the CP AL1 to a high-voltage output such as a power
amplifier, mains power plug, etc.
• Do not disassemble the CP AL1.
• Never use the CP AL1 in a damp environment.
• Remove the batteries as soon as they are flat or if the CP AL1 is not intended
to be used for a longer period of time.

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1.3 Connectors
The CP AL1 provides the following connectors on the rear:
• XLR input for feeding a signal to the CP AL1
• RCA input for feeding a signal to the CP AL1
• 3.5 mm (1/18") jack designed for internal use only
Never connect any electrical signal to this connector.
Note: Never connect electrical signals simultaneously to both the XLR and the
RCA connector.
Figure 1-1:
Connectors
XLR connector
RCA connector
For internal use only

7
Introduction
1.4 Battery Replacement
To insert or replace batteries, remove the rear cover, and then insert three 1.5 V
alkaline batteries, type AA/LR6 into the CP AL1 battery compartment as shown
below. The typical life-time for a set of alkaline batteries is 16 hours.
Figure 1-2:
Inserting batteries
When replacing the batteries:
• Do not use rechargeable NiCd or NiMH batteries.
• Do not use batteries of different types.
• Observe the correct battery polarity.
• Remove the batteries as soon as they are flat and replace all batteries at the
same time.

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1.5 CE Declaration of Conformity
We, the manufacturer
NTI AG
Im alten Riet 102
9494 Schaan
Liechtenstein, Europe
hereby declare that the product Acoustilyzer CP AL1, released in 2004,
conforms to the following standards or other normative documents:
EMC-Directives: 89/336, 92/31, 93/68
Harmonized Standards:EN 61326-1
This declaration becomes void in case of any changes on the product without
written authorization by NTI.
Date: 1. September 2004
Signature:
Position of signatory: Technical Director
1.6 Test & Calibration Certificates
This is to certify the Acoustilyzer CP AL1 is fully tested to the manufacturer’s
specifications. NTI recommends to calibrate this test instrument one (1) year
after purchase. Thereafter the calibration and adjustment interval is
subsequently one (1) year.

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Introduction
1.7 International Warranty
NTI guarantees the functionality of the Acoustilyzer CP AL1 against defects in
material or workmanship for a period of one year from the date of original
purchase, and agrees to repair or to replace at its discretion any defective unit
at no cost for either parts or labor during this period.
Restrictions
This warranty does not cover damages caused through accidents, misuse, lack
of care, the attachment or installation of any components that were not provided
with the product, loss of parts, connecting the instrument to a power supply,
input signal voltage or connector type other than specified or wrongly polarized
batteries. In particular, no responsibility is granted for special, incidental or
consequential damages.
This warranty becomes void if servicing or repairs of the product are performed
by any party other than an authorized NTI service center or if the instrument has
been opened in a manner other than specified in this manual.
No other warranty, written or verbal, is authorized by NTI. Except as otherwise
stated in this warranty, NTI makes no representation or warranty of any kind,
expressed or implied in law or in fact, including, without limitation,
merchandising or fitting for any particular purpose and assumes no liability,
either in tort, strict liability, contract or warranty for products.

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11
Operation
2 Operation
In spite of the wide range of available measurement functions and optional
setups, the operation of the CP AL1 is almost self-explanatory.
Figure 2-1:
Operating controls
To switch the CP AL1 on/off, press the power on/off button for at least 2 sec.
The LCD displays the menu bar on the top and the measurement results
beneath. The cursor keys and the ESC button allow straightforward navigation
through the current screen displaying:
• Measurement settings (measurement function, filters)
• Measurement results (numerical or graphical display)
The base element is the cursor (inverted area) which may be navigated through
the various functions by using the cursor keys. All selectable settings may be
simply set by pressing the ENTER key. Alternatively, at longer selection lists the
selected field is flashing. In this case select the value you want to enter using the
cursor keys, and then confirm the setting by pressing the ENTER key again.
Menu bar
ESC button
ENTER/cursor keys
Measurement result
Power on/off button

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2.1 Menu Bar
The menu bar allows configuring the CP AL1 for the measurement.
Figure 2-2:
Menu bar
Measurement function
Input filter
Setup screen
Memory menu & battery
state indication

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Operation
2.2 Measurement Functions
Figure 2-3:
Measurement function
menu
The CP AL1 features two major measurement functions accessible via the menu bar:
• FFT: real-time Zoom FFT
• RMS/THD: level and distortion measurements
To set the measurement function, select FFT or RMS/THD on the measurement
function menu.
2.2.1 FFT Analysis
The CP AL1 implements an extremely fast, real-time Zoom FFT analysis with
resolutions up to 0.7 Hz over the entire frequency range. The FFT analysis
results are displayed by 93 bins.
Figure 2-4:
FFT analysis display
Set menu
Pause Cursor readout
Displayed start frequency
Displayed frequency range
Displayed end frequency
Y-axis
FFT spectrum
X-axis

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The screen elements in the FFT measurement mode are described below.
Pause
Figure 2-5:
Pause
The command stops measurements temporarily. To pause a measurement:
1. Select the symbol, and then press the ENTER key.
The symbol is flashing.
2. Select the symbol, and then press the ENTER key to continue the
measurement.

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Operation
Cursor Readout
Figure 2-6:
Cursor readout
The cursor readout displays the frequency and level of the bin marked by the
cursor. Initially, the cursor automatically marks the bin with the highest level. To
control the cursor readout:
1. Select the cursor readout field, and then press the ENTER key.
A frame around the field is flashing.
2. Move the cursor using the left/right arrow keys.
The cursor readout field displays the measurement values corresponding to
the bin marked by the cursor.

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X-Axis
Figure 2-7:
X-axis
The X-axis displays from left to right the start frequency, the frequency range
and the stop frequency. To set the displayed frequency range:
1. Select the frequency range field, and then press the ENTER key.
2. Set the displayed frequency range using the up/down arrow keys.
3. Move the displayed frequency range using the left/right arrow keys.
Y-Axis
Figure 2-8:
Y-axis
The Y-axis displays the signal level in dB. The signal level in volts is given by
(Eq. 2-1)
where
…signal level in volts
…signal level in dB
U10
x134–
20
-----------------
=
U
x

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Operation
By the default setting, the Y-axis range is 80…150 dB. This corresponds to the
following range in volts:
:
(Eq. 2-2)
:
(Eq. 2-3)
Note: The signal level is displayed in logarithmic scale.
To scale the Y-axis:
1. Select the Y-axis maximum value field, and then press the ENTER key.
2. Move the displayed Y-axis range using the up/down arrow keys.
3. Set the Y-axis resolution using the left/right arrow keys.
2.2.2 RMS/THD Measurement
In the RMS/THD mode, the CP AL1 implements the following measurement
functions:
• Level RMS: level of the measured signal
• THD+N: total harmonic distortion plus noise
Figure 2-9:
RMS/THD
measurement display
x80dB=
U10
80 134–
20
---------------------
210
3–
⋅≈ 0.002 V==
x150dB=
U10
150 134–
20
------------------------
100.8 6.3V===
Signal frequency
Signal balance
Distortion THD+N
Level RMS

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Level RMS
The units dBµ, dBV, dBSPL and V are selectable.
Distortion THD+N
The distortion measurement is carried out within the bandwidth 10 Hz…20 kHz.
The results are given in dB or in %.
Signal Balance
The signal balance field shows the matching deviation of the incoming signal
between pin 2 and pin 3 in %. The signal balance field indicates the following:
• Arrow in center: the input signal is balanced.
• Arrow out of center: linear indication of a balancing problem.
E.g. the arrow shifted to the left shows the signal level on pin 2 is higher than
on pin 3.
• Arrow at the left or right end: the signal balance error is 33% or higher.
33% corresponds to a difference of the signal level of 6 dB.
• 2UBAL-: indicates a signal only on pin 2 of the symmetrical XLR cable, no
signal at pin 3.
• -UBAL3: indicates a signal only on pin 3 of the symmetrical XLR cable, no
signal at pin 2.
Note: Use the adapter –20 dB for balanced input levels higher than 3.8 V
(unbalanced).

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Operation
2.3 Input Filters
Figure 2-10:
Input filter menu
In the RMS/THD measurement mode, filters are available on the input filter menu. For
the filter characteristics and applications, see Table 3-2: "Input filters" on page 27.
2.4 Setup Screen
Figure 2-11:
Setup screen
The setup screen allows customizing the CP AL1 basic settings. To customize
the settings:
1. Select the setup screen menu (SET) on the menu bar.
The setup screen opens.
2. Move the cursor to the entry field corresponding to the setting you want to
change, and then press the ENTER key.
3. Select the required value by using the arrow keys.
4. Press the ENTER key.

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The available settings are described below.
Table 2-1:
Setup screen settings
Note: To load the default settings after switching the CP AL1 off, press and hold
the ESC button, and then press the power on/off key for at least 2 sec.
Setting Description
AUTO POWER OFF Defines the time the CP AL1 is switched off
automatically after the last key press. The available
values are: 3 MIN, 10 MIN, 30 MIN, 60 MIN and
DISABLE. If DISABLE is selected, the CP AL1 is
turned on until it is switched off by pressing the power
on/off button.
AUTO LIGHT OFF Defines how long the backlight stays on after any key
press. The available values are: 3 SEC, 10 SEC,
60 SEC and DISABLE. If DISABLE is selected, the
backlight stay on until the CP AL1 is switched off.
Note: Lighting of the backlight shortens the battery life.
LCD CONTRAST Adjusts the contrast of the display.
Note: Alternatively, you can adjust the contrast if a
measurement result is displayed by holding the ESC
button down and pressing the up/down arrow key.
MULTIPLE SETUP Allows storing up to four individual settings.
To enable the MULTIPLE SETUP mode, set the
corresponding value to ENABLE. The next time the
CP AL1 is switched on, select the setting ID (1, 2, 3 or
4) on the start screen. After the CP AL1 is switched off,
the setting values are stored under this ID.