Tucker-Davis Technologies TDT PA5 Application guide

PA5 Programmable Attenuator
Hardware Reference
Updated 2021-04-19

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Phone: [phone]
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Notices
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without notice. TDT shall not be liable for errors or damages in connection with the furnishing, use, or
performance of this document or of any information contained herein.
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PA5 Programmable Attenuator | 2

Table of Contents
PA5 Programmable Attenuator
4Overview
5Power and Interface
5Features
5Display
5(ESC) Button
5SELECT (ENTER) Knob
6INPUT BNC
6OUTPUT BNC
6PA5 Manual Operation
7Operation in Atten Mode
7Operation in UserAtt Mode
8About UserAtten Mode Parameters
9PA5 Manual Operation Menus
10PA5 Top Level Menu
12Setting Base Attenuation
13Setting a Reference Value
13Using Preset Congurations
14Saving Preset Congurations
14Loading Preset Congurations
15PA5 Display Icons
15Menu Level Icons
15Attenuation Mode Icons
16PA5 Technical Specications
16PA5 Frequency Response
17PA5 Frequency Response with 50 dB Attenuation
17PA5 Total Harmonic Distortion
Table of Contents | 3

PA5 Programmable Attenuator
Overview
The PA5 Programmable Attenuator is a precision device for controlling signal levels over a
wide dynamic range, providing 0 to 120 dB of attenuation for signals up to 100 kHz in
frequency. The device is fully programmable; however, simple manual operation is also
available using front panel controls.
When used programmatically, the module may be controlled via TDT's ActiveX Controls in any
programming environment that supports ActiveX controls, such as Matlab, Python, or
LabVIEW. For information about how to control the module programmatically, see the ActiveX
Reference Manual.
When used in manual operation, the attenuation level is adjusted in two modes of operation:
In Atten mode, the attenuation level of the signal can be adjusted from 0 to 120 dB in
increments of 0.1 dB.
UserAtt mode applies user-programmed parameters to adjust the attenuation level.
Before using the UserAtt mode, attenuation parameters must be set up using the UserOps
menu.
•
•
PA5 Programmable Attenuator | 4

Power and Interface
The PA5 Programmable Attenuator is powered via the System 3 zBus (ZB1PS). and requires an
interface to the PC (Gigabit, Optibit, or USB). Ensure that the ZB1PS chassis housing the PA5 is
connected in the interface loop according to the installation instructions for the interface in
use.
Features
Display
Displays the current level of attenuation being applied to the signal or displays the manual
operations menu. During manual operation it is used to set up user-dened attenuation
parameters and to obtain descriptions for menu items. See PA5 Display Icons for more
information.
(ESC) Button
Exits the manual operations menu items without accepting changes.
SELECT (ENTER) Knob
During manual operation, allows the user to adjust the attenuation applied to the signal. In
addition, it allows the user to scroll through the manual operation menus, set up user-dened
attenuation parameters, and access descriptions of menu item.
Turn the Select knob to adjust attenuation or view menus. Press and release the knob to make
a selection. The module must be in Atten or UserAtt mode to manually adjust attenuation. See
PA5 Manual Operation for more information.
The
chassis
housing
the
PA5
must
be
powered
and
connected
to
a
PC
via
the
PC
interface
for
BOTH
manual
and
programmed operation.
Important
PA5 Programmable Attenuator | 5

INPUT BNC
Source signal input. The maximum input voltage is ± 10 V peak.
OUTPUT BNC
Attenuated signal output.
PA5 Manual Operation
In manual operation, the PA5 is operated using front panel controls. The menu options are
viewed by turning the Select knob and entered by pressing and releasing the knob. The module
must rst be set to Attn or UserAtt mode to manually adjust attenuation.
To access a menu:
Turn the knob until the name of the desired menu appears on the display, then press and
release the knob. The module has two levels of menus.
Top-level menu items are indicated by a single lled box in the upper left corner of the
menu display, and sub-menus are indicated with an additional indicator box for each level.
Only the UserOps menu item has sub-menu items. See PA5 Display Icons for more
information.
For a denition of each menu item:
Turn the Select knob until the name of the menu appears on the display, then press and
hold down the Select knob. A description of the menu function will scroll across the
display.
To exit a menu without changing settings:
Press and release the ESC button.
The
PA5
is
powered
via
the
zBus
and
must
be
connected
to
the
PC
via
an
interface
module
during
manual
operation.
Important
•
•
•
PA5 Programmable Attenuator | 6

Operation in Atten Mode
In Atten mode, the user sets the desired level of attenuation with the Select knob. When the
unit is powered on, it defaults to the Atten mode with 0.0 dB of attenuation.
To use Atten mode:
Turn the Select knob until Atten appears on the display, then press and release the Select
knob.
A small letter "A" appears in the upper left corner of the display, indicating the unit is in Atten
mode, and a decibel reading appears on the right side of the display. See PA5 Display Icons
for more information.
Turn the Select knob to adjust attenuation in 0.1 dB increments.
Operation in UserAtt Mode
In UserAtt mode, the user can adjust the attenuation level of the signal using user-programmed
parameters available in the UserOps menu. Users can also save common parameter
congurations in the PA5's nonvolatile memory. See Using Preset Congurations for more
information.
To use UserAtt mode:
Turn the Select knob until UserAtt appears on the display, then press and release the Select
knob.
A small letter "U" appears in the upper left corner of the display, indicating the unit is in
UserAtten mode, and a decibel reading appears on the right side of the display. See PA5
Display Icons for more information.
Turn the Select knob to adjust attenuation according the current user programmable
parameters (available in the UserOps menu). The default settings include a step size of 3.0
dB and dynamic update mode.
1.
2.
1.
2.
When
the
Update
attenuation
parameter
is
set
to
Manual
,
the
intensity
of
the
display
will
dim
as
the
user
turns
the
knob.
This
indicates
that
the
changes
have
not
been
applied
to
the
output
signal.
The
user
must
press
and
release the
Select
knob to apply attenuation changes to the output signal.
Note
PA5 Programmable Attenuator | 7

To access the UserOps menu:
Turn the Select knob until UserOps appears on the display.
Press and release the Select knob.
Set the UserOps parameters as desired.
To set parameters such as step size ( StpSize ), update mode ( Update ), minimum
attenuation ( AbsMin ), base attenuation ( BaseAtt ), and reference value ( Refrnce ); turn the
Select knob to the desired value and then press and release to save changes.
To exit any menu without saving parameter changes, press and release the ESC button
before the settings are saved.
About UserAtten Mode Parameters
In UserAtten Mode, the user may set parameters such as step size (StpSize), update mode
(Update), and minimum attenuation (AbsMin). The scale can be adjusted using the base
attenuation (BaseAtt) and reference value (Refrnce) parameters. Both base attenuation and
reference can be used simultaneously, producing an actual attenuation equal to (Refrnce +
BaseAtt - {dial setting}). See PA5 Manual Operation for more information.
BaseAtt - Base Attenuation
Adds a xed attenuation value, shifting the scale down and allowing attenuation to be
displayed relative to this base level (useful for calibrating signals played over varying
transducers). See Setting Base Attenuation, for more information.
StpSize - Step Size
Sets the increments in which attenuation is applied to the signal when using the Select knob.
Refrnce - Reference
Sets a reference value used to "ip" the scale of the display (useful for displaying actual signal
level on the front panel of the PA5). May be used only when the intensity of the input signal is
known. See Setting a Reference Value for more information.
1.
2.
3.
4.
PA5 Programmable Attenuator | 8

Update - Update
Determines whether attenuation changes dynamically as the selector knob is turned or only
after pressing enter to select the current value.
AbsMin - Minimum Attenuation
Sets the minimum level of attenuation the user can apply to the signal (to avoid accidentally
presenting excessively loud signals).
PA5 Manual Operation Menus
To access a menu:
Turn the knob until the name of the desired menu appears on the display, then press and
release the knob. The module has two levels of menus.
Top-level menu items are indicated by a single lled box in the upper left corner of the
menu display, and sub-menus are indicated with an additional indicator box for each level.
Only the UserOps menu item has sub-menu items.
For a denition of each menu item:
Turn the Select knob until the name of the menu appears on the display, then press and
hold down the Select knob. A description of the menu function will scroll across the
display.
To exit a menu without changing settings:
Press and release the ESC button.
•
•
•
PA5 Programmable Attenuator | 9

PA5 Top Level Menu
Atten
Sets attenuation from 0.0 to 120.0 dB in 0.1 dB increments. The default setting is 0.0 dB. When
Atten is in use, the letter "A" appears on the left side of the display, while the attenuation level
appears on the right side of the display.
UserAtt
Sets attenuation based on UserOps settings. Before use, attenuation parameters must be set
up via the UserOps sub-menus (see below). The default setting is 0.0 dB. When UserAtt is in
use, the letter "U" appears on the left side of the display, while the attenuation level appears on
the right side of the display.
UserOps
Access UserOps submenu:
BaseAtt
Sets a xed level of attenuation as a reference. The default setting is 0.0 dB and the range is 0
to 100.0 dB. When BaseAtt is set, a "+" symbol appears on the left side of the display.
When used, the attenuation level displayed is relative to BaseAtt. For example, with BaseAtt set
to 60.0 dB, the attenuation level will be display from -60.0 dB to 60.0 dB.
StpSize
Sets the increments of attenuation. The default setting is 3.0 dB, and the range is 0.1 to 60.0
dB.
Refrnce
Changes the display so it shows the output signal intensity rather than the attenuation level.
This function may be used only when the input signal strength is known. When Refrnce is set,
the letter "R" appears on the left side of the display. The default setting is 0.0, and the range is
± 300.0.
For example, when Refrnce is set to 136 and the attenuation level set to 0.0 dB, the display
shows 136.0. When the attenuation level is adjusted to 30.0 the display shows 106.
PA5 Programmable Attenuator | 10

Update
Determines when attenuation is applied to the signal. When set to Dynamic, attenuation is
applied as the Select knob is turned. When set to Manual, attenuation is applied after the
Select knob is pressed and released. The default setting is Dynamic.
Note that when Update is set to Manual, the attenuation level on the display changes as the
Select knob is turned, but the attenuation is not applied to the signal until the Select knob is
pressed and released. In this mode, the intensity of the display dims to indicate that the
attenuation has not been applied to the signal.
MinAttn
Sets the minimum attenuation level for the UserAtt mode. This is used to avoid signals that are
too loud for the subject or equipment. The default value is 0.0 dB and its range is 0.0 to 100.0
dB.
Note that setting this parameter limits the range of possible attenuation levels. For example,
when it is set to 30.0 dB, the range of attenuation is 30 db to 120 dB. Access UserOps
submenu.
Load PS
Loads one of four preset UserAtt congurations from non-volatile memory. See Save PS
(Below). The default is 1 and its range is 1 to 4.
Save PS
Saves the current UserAtt conguration in one of four non-volatile memory buffers. This
permits the user to save commonly used UserAtt congurations. The default is 1 and its range
is 1 to 4.
To save a conguration, rst ensure that all UserAtt parameters are set as desired then turn the
Select knob until the desired memory location is displayed, and press the Select knob. Saving
appears on the display. The preset is ready of use.
PA5 Programmable Attenuator | 11

Reset
Resets all menu items, including presets, to their default conditions.
Conrm
The user must conrm the reset by pressing and releasing the Select knob. While the module is
resetting, Reseting appears on the display.
To exit without resetting, turn the Select knob until Cancel appears on the display and then
press and release the Select knob, or press the Esc button.
Cancel
Cancels the reset.
Setting Base Attenuation
When operating the PA5 manually in User Attenuation (UserAtt) mode, the Base Attenuation
(BaseAtt) parameter can be used to apply a xed attenuation level to the signal. Any additional
attenuation to the signal is displayed relative to this base level within a range of 0 to 120 dB.
For example: if the BaseAtt is set to 6 dB, when the user sets the attenuation to 3 dB the actual
attenuation applied is 9 dB. This feature can be used to calibrate a number of different
experimental setups, attenuating each by a different base attenuation so as to provide identical
signal levels when each is set to 0.0 dB UserAtt.
When this feature is in use, a "+" symbol is displayed on the left side of the display. Note that
the Base Attenuation and Reference parameters can be used simultaneously. When both of
these features are in use, the letter "R" and a "+" symbol are displayed on the left side of the
display. See PA5 Display Icons for more information.
To set the base attenuation:
Access the UserAtt mode, by turning the Select knob until UserAtt appears on the display,
then pressing and releasing the knob.
Access the UserOps menu, and turn the Select knob until BaseAtt appears on the display.
Press and release the Select knob. 0.0 dB appears on the display.
Turn the Select knob until the display shows the desired level of attenuation.
Press and release the Select knob. The level is saved and BaseAtt appears on the display.
1.
2.
3.
4.
5.
PA5 Programmable Attenuator | 12

To exit the UserOps menu, press and release the ESC button again.
Setting a Reference Value
The Reference parameter is used to display the intensity of the output signal. This parameter
can be used only when the strength of the input signal is known. This serves to "ip" the scale,
displaying larger numbers for smaller attenuation values.
When in use, a letter "R" is displayed on the left side of the display. Note that the Base
Attenuation and Reference parameters can be used simultaneously. When both of these
features are in use, the letter "R" and a "+" symbol are displayed on the left side of the display.
See PA5 Display Icons for more information.
To set the Reference parameter:
Access the UserOps menu, and turn the Select knob until Refrnce appears on the display.
Press and release the Select knob. 0.0 dB appears on the display.
Turn the Select knob until the display shows the desired level.
Press and release the Select knob. The reference is saved.
To exit the UserOps menu, press and release the ESC button.
Using Preset Congurations
The PA5 Programmable Attenuator allows users to save four unique User Operation
congurations that may be used in UserAttn mode. These congurations may include any of
the UserOps parameters (such as step size, base attenuation, and minimum attenuation).
Before a conguration can be loaded, it must be set up via the UserOps menu and saved via
the SavePS menu.
6.
1.
2.
3.
4.
5.
PA5 Programmable Attenuator | 13

Saving Preset Congurations
Before a conguration can be saved, it must be set up via the UserOps menu. Once the
conguration is set up as desired, save the conguration by performing the following:
At any top-level menu, turn the Select knob until SavePS appears on the display.
Press and release the Select knob. Preset-1 appears on the display.
Turn the Select knob until the desired preset location is displayed and then press and
release the Select knob.
Saving appears on the display and then Atten appears on the display.
The conguration is saved.
Loading Preset Congurations
When a conguration has been set up via the UserOps menu and saved via the SavePS menu,
load the conguration by performing the following:
Turn the Select knob until LoadPS appears on the display.
Press and release the Select knob. Preset-1 appears on the display.
Turn the Select knob until the desired preset location is displayed, and then press and
release the Select knob.
Loading appears on the display and then Atten appears on the display.
The conguration is loaded.
This
procedure
overwrites
the
contents
of
the
selected
preset
location.
Be
certain
that
the
existing
conguration
is not needed before continuing.
Warning
1.
2.
3.
1.
2.
3.
PA5 Programmable Attenuator | 14

PA5 Display Icons
Menu Level Icons
Attenuation Mode Icons
Display Description
Single Box: indicates a top-level menu.
Double Box: indicates a second-level menu.
Display Description
A: Normal Attenuation Mode
U: User Attenuation Mode
U+: User Attenuation Mode. Base attenuation value set.
R: User Attenuation Mode. Reference level set.
R+: User Attenuation Mode. Base attenuation value and reference level set.
PA5 Programmable Attenuator | 15

PA5 Technical Specications
PA5 Frequency Response
Input Signal Range ±10 V peak
Frequency Range DC - 200 kHz
Attenuation Range 0.0 to 120.0 dB
Attenuation Resolution 0.1 dB
Attenuation Accuracy 0.05 dB
Spectral Variation < 0.04 dB (20Hz to 80 kHz)
Offset < 10 mV
Signal/Noise 113 dB (20 Hz to 80 kHz at 9.9 V)
Noise Floor 16 uV rms (20 Hz to 80 kHz)
THD < 0.003% (1kHz tone ± 7V peak, 0 dB attenuation)
Attenuation Settling Time 5 ms
Switching Transient < 8 mV (0 Hz to 80 kHz)
Input Impedance 10 kOhm
Output Impedance 10 Ohm
PA5 Programmable Attenuator | 16

PA5 Frequency Response with 50 dB Attenuation
PA5 Total Harmonic Distortion
PA5 Programmable Attenuator | 17