BHI NEDSP1062 KBD User manual

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual Page 1
bhibhi
bhibhi
bhi
NEDSP1062 KBD
Amplified Noise Eliminating DSP Module
Installation and Operating Manual
Sound Engineering Solutions from bhi
1062-107D
Issue E
Page 40
bhi Ltd
22 Woolven Close
Burgess Hill
West Sussex
RH159RR
tel: [phone]
fax: [phone]
[email protected]
www.bhi-ltd.co.uk
bhibhi
bhibhi
bhi
Sound Engineering Solutions
DSP Noise Cancellation

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual
Page 2
Copyright
This publication, including all photographs and
illustrations is protected under international
copyright laws, with all rights reserved. Neither
this manual, nor any of the material within, may
be copied or reproduced without the written
consent of bhi Ltd.
Disclaimer
The information in this document is subject to
change without notice. bhi Ltd. makes no
representations or warranties with respect to the
contents hereof and specifically disclaims any
impliedwarrantiesofmerchantabilityorfitnessfor
any particular purpose. Furthermore, bhi Ltd.
reserves the right to revise this publication and to
make changes from time to time in the content
hereof without obligation of bhi Ltd. to notify any
person of such revision or changes.
Important Information
Page 39
8.3 NEIM1031 In-line module.
Then NEIM1031 provides a flexible solution to noise reduction. It
features both amplified inputs and outputs, along with line level sig-
nal processing. The unit also features an audio bypass when the
unit is switched off, so there is no need to disconnect when not in
use.
Features:
•Fully adaptive noise cancellation 9 -35dB
•8 user selectable noise cancellation levels
•Mono earpiece socket
•Input sensitivity control
•Noise cancellation On/Off switch
•Line level in/out
•Input overload indication
•Power on/off with audio bypass.
8.4 NEIM1031 accessories.
8.5 DSP modules.
LSPKR
20 Watt extension speaker
for use with the NEIM1031.
Fitted with a 3.5mm mono
jack plug.
1031-STA
MountingstandfortheNEIM1031.
Allows the NEIM1031 to be ad-
justed for the most comfortable
operatingpostion.
8. Other bhi products.
DSP module range.
NEDSP1061: Low signal level module
NEDSP1062 - KBD: Low signal level module
controlled by single button
keyboard.
NEDSP1062 - KBD: Amplified DSP module
controlled by a 2 button
keyboard.
1030-UKPA UK DC power adapter
1030-EUPA European DC power adapter

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual Page 3
1. Introduction
1.1 NEDSP1062-KBD features 5
1.2 Limitations 5
1.3 Module connection and mounting 6
1.4 Keyboardmounting 7
1.5 Sounder mounting 8
1.6 DSP noise cancellation 9
2. Module description
2.1 Block diagram 10
2.2 Modulelayout 11
2.3 Pin functions 11
2.4 Controls 12
2.4.1 PCB controls 12
2.4.2Keyboard 12
2.5 Electrical characteristics 12
3. Installation
3.1 Installationoverview 16
3.2 Module setup 17
3.2.1 Overview 17
3.2.2 Suggested set up procedure 17
3.2.3 Changes to output load 18
3.2.4 Other signal considerations 18
3.3 Driving the module from a low level signal 19
4. Functions
4.1 Keyboard 20
4.1.1 Power button 20
4.1.2 DSP level button 20
4.2 Set up 21
4.3 Demonstration modes 23
4.4 Noise cancellation levels 24
5. Application notes
5.1 Yaesu SP8 25
5.2 KenwoodSP31 28
5.3 bhi label 31
Contents
Page 38
8. Other bhi products
Other noise cancellation products from bhi. Visit www.bhi-ltd.co.uk
for more information.
DSP noise cancellation built into a compact
speaker unit. the unit provides an easy to
install solution to noise reduction
Features:
•Fully adaptive noise cancellation 9 -35dB
•8 user selectable noise cancellation levels
•Mono earpiece socket
•Input sensitivity control
•Noise cancellation On/Off switch
•LED indication of power and noise cancellation
•12-24VDCoperation
•On/Off audio bypass switch.
•Greatly improved signal to noise ratio
•Easy to install with adjustable mounting bracket
•2m audio lead
•Optional extras avaiable.
8.1 NES10-2 MKII Noise Eliminating speaker.
Basic plug and go noise cancelling
speaker preset to 20dB of noise
reduction.
Features:
•Fully adaptive noise cancellation 20dB
•12-24VDCoperation
•Compact robust speaker unit.
•Greatly improved signal to noise ratio
•Easy to install with adjustable mounting bracket
•2m audio lead
8.2 NES5 Noise Eliminating speaker.
8. Other bhi products.

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual
Page 4
6. Physical dimensions
6.1 Physical dimensions 32
6.2 Keyboardholedrillingdetail 35
7. Troubleshooting
Troubleshooting 37
8. Other bhi products
Other bhi products 38
Page 37
Start
Increase input
level
Over load LED
illuminates? No
Yes
Reduce input
so LED goes
out
Increase output
level P1
Sufficient
output volume? Supply voltage
<13.8 Vdc
Input level
too low
Increase
supply
voltage
Finish
Yes
Disconnect
R6
(see section 3.3)
Over load LED
illuminates?
Add additional
amplification
NoYes
No No
Yes
7.2 Insuffucient output volume
7. Troubleshooting
Input
signal
Overload
LED on Reduce input
level
Increase
output level
P1
Apply
audio signal
Increase input
signal
P2
No
Yes
No
Yes
Audio
out?
Finish
Start
Yes
No
7.1 No audio out
7. Troubleshooting.

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual Page 5
1. Introduction.
The NEDSP1061-KBD is a modular solution for noise
reduction.ItincorporatesDigitalSignalProcessing(DSP)
technology to provide up to 35dB of noise cancellation
and 65dB of tone reduction. The module features an on
boardpoweramplifiertoallowittobeeasilyincorporated
in to existing equipment by installing the module in line
with the loudspeaker. All functions of the module are
controlled by an easy to use keyboard.
1.1 NEDSP1062-KBD module features:
Fully adaptive noise cancellation up to 35dB
Input and output level controls
Input level over load indication
Virtually no distortion to speech signal
Easy to install
4/8 levels of noise reduction (selectable)
Frequency response 50Hz - 4.3KHz
3 Watts output (4W)
Single button operation of DSP mode with LED and
audible indication
12 - 18V supply range
27dB on board gain
Power on/off - bypass pushbutton
Small size 37 x 50mm (DSP pcb)
Audio bypassed when power disconnected
Supplied with fixing and wiring kit and all labels
1.2 Limitations.
This module is designed to pass speech. Other signals
suchasdata,music and morse (CW) will to some degree
pass through, but the integrity of these signals
cannot be guaranteed.
1. Introduction.
Page 36
<This page is intentionaly blank>

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual
Page 6
Figure 1. Mounting options
1.3 Module connection and mounting
The module is supplied with a pre-wired 2.1mm power
connector. The centre pin is positive. The audio in and
out are pre-wired pairs of wires, ready to be connected
intheaudiopath.Theheatsink doubles upasamounting
bracket.
This module is designed to be driven from a high level
signal, capable of driving a load of 22W.
(The module can be easily modified to be driven from a
low power signal, see section 3.3 for more information).
The module can be mounted
using the supplied self adhesive
foam pad. Ensure that none of
the circuit pins can make contact
with any metallic parts.For improved heat dissipation
and a more rigid mechanical
fixing the heatsink can be
reversed and used as a bracket.
Note that the heatsink is at 0V
potentialandthereforemayhave
to be electrically insulated from any other metallic parts.
Alternativelythemodulehasfour
fixing holes which allow it to be
fixed to pillars.
(See section 6 for hole details
and physical dimensions).
1. Introduction.
Using the heatsink
as bracket
Self adhesive
pad
Mounting using
PCB pillars
Page 35
6. Physical dimensions.
6.2 Template.
The following drawing shows the sizes and positions of
holesforthekeyboard.
Figure 36. Keyboarddrilling detail .
Nottoscale
alldimensionsinmm
29.8
18.5
13.4
6.7
6.7
10.9
5.5
4mm 4mm 4mm
3mm CSK
to5mm

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual Page 7
1. Introduction.
If the installation has limited
space, and is housed in a metal
enclosure, the heatsink can be
removed, and the module
mounted directly on the chassis.
Thevoltageregulator needstobe
correctly insulated as the tab is
connected to 0V. Insulate both
the regulator and mounting
screw. For improved heat
dissipationusea suitable thermal
pastebetween the power devices
and the mounting.
Figure 2.
Direct mounting.
Figure 3. Keyboard mounting 1.
The keyboard is
mountedthroughthe
enclosure to provide
an easy to use
interface. The
module is supplied
with a label to place
over the keyboard.
When the enclosure is thick enough the keyboard is
retained using a countersunk screw (supplied), which is
hidden by the label, see figure 3 above. Do not over
tighten the mounting screw.
keyboard
Front panel
label
Retaining
screw
Front
panel
Insulator
Insulator
Voltage
Regulator
1.4 Keyboard mounting.
(not supplied)
(not supplied)
Page 34
6. Physical dimensions.
Figure 34. Keyboard dimensions.
Figure 35. Power connector hole size.
29.8
25.3
20.2
13.4
6.8 9.5 4.7
7.5
3.2
10.9
5.5
3
8mm diameter

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual
Page 8
Figure 4.
Keyboard mounting 2.
If the enclosure is too
thin to incorporate a
countersunk screw
(such as fitting into
sheetmetal)then it can
be retained by a
instrument head
screw.
The label needs to be
cut out to allow the
screw to pass through
from the outside. This
can be easily achieved
byapplyingthelabel to
the panel, then carefully cutting around the screw hole,
with a sharp knife. Again do not over tighten the screw.
Nut &
washer
Front panel
label
keyboard
Retaining
screw
Front
panel
1.5 Sounder mounting.
Cutasmallpieceofthe
self adhesive foam
(supplied)to mount the
sounder.
Do not cover the small
hole in the face of the
sounder.
For best results mount
the sounder where it
can radiate sound to
the outside the case,
for example on an air
vent. Figure 5. Sounder mounting
Sounder
Backing paper
Backing
paper
Self adhesive
foam
Case
Keep this
hole clear
Cut hole
for screw
1. Introduction.
Page 33
6. Physical dimensions.
Components fitted to
rear of PCB
Figure 32. Overall dimensions.
Figure 33. Hole dimensions of power devices - for direct
mounting applications.
16.1
5.3
17.9
16.4
Viewed from
the end of
the module
34.2
64.4
5.8

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual Page 9
1.6 DSP Noise cancellation.
The bhi DSP processes the incoming signal and then
differentiates the speech from the noise. The unwanted
noise and interference is then attenuated to leave only
thespeech.The followingdiagramsaretakenfrom actual
audio signals and illustrate how the signal is being
processed.
Figure 6. Noise cancellation.
Original signal.
Speech with a lot of
background noise
Processed speech.
Speech with reduced
noise
Speech Noise Reduced noise
1. Introduction.
Page 32
23.4
2.97
30.3
34.3
36.5
49.6
2.97 Pin 1
3mm dia
6. Physical dimensions.
6. Physical Dimensions
Figure 31. Mounting hole positions.
Top
6.1 Physical dimensions.
The following diagrams detail the physical dimensions
of the module. All dimensions are in mm.

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual
Page 10
2. Module description.
Figure 7. NEDSP1062-KBD block diagram
1
3
8
Polarity
protection
Internal
pull up
resistors
Input level
set
In
9
overload
detect
Digital to analogue
conversion
Output level
set Power Amp
BCD
DSP level select
Xtal
Clock generator
DSP core
5V
5V
Regulator
Latch
12V
regulator
3.3V
regulator
3.3V 12V Relay
Drive
Relay 1
ON
14
Analogue to
Digital conversion
7
0V
10
12
6
Power supply
section
PCB
Connections
13
5
J3
Input
Load
resistor
Agnd
Agnd
Vin
NC
NO
NO
NC
DSP
3V3 0V
PCB
microcontroller 4
Keyboard
interface
8
N/C
N/C
Relay 1 Out
11
2.1 Block diagram.
2. Module description.
Page 31
Figure 30. bhi label.
5. Applications.
5.3 bhi Label.
Supplied with the module is a square bhi label. Fix the
label on the top of the speaker enclosure as shown.
bhibhi
bhibhi
bhi
DSP
Noise
Cancellation

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual Page 11
2.2 Module Layout.
The following diagram shows the layout of the
NEDSP1062-KBD module.
Pin No. Name Description Notes
4N/C Do not connect Not used
5Vin Supply voltage 12 - 18VDC power in
6N/C Do not connect Not used
70V 0V connection 0V power connections
9In Audio input Audio signal in to be processed
10 Out Audio output Procesed audio signal out
11 Agnd 0V for input audio signal Analogue ground for audio in
12 Agnd 0V for output audio signal Analogue ground for audio out
Table 1. NEDSP1062 connection functions
2. Module description.
Figure 8. NEDSP1062-KBD connections and controls
Input
level set
(P2)
Output
level set (P1)
Input overload
indicator LED
Mounting
holes
Audio
bypass
relay
Thefollowingtablegivesadescription ofthepinfunctions.
Note:
Wiring obmitted for clarity
Sounder
volume (P3)
2.3 Pin functions.
Page 30
Figure 29. Photograph of complete installation.
Sounder
NEDSP module
(screwed to the case,
using an existing hole)
Input
selector
switch
Filter
PCB
DSP
connections
Keyboard
5. Applications.

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual
Page 12
2.4 Controls.
2.4.1PCB.
Thelevelcontrolsprovideadjustmentfor the audio levels
enteringandleaving themodule.The modules arefactory
set to the maximum level.
Turning the potentiometers clock wise will decrease the
levels. These potentiometers do not have end stops, so
it is possible to set them in a position where the audio
will be lost.
Audible indication of operation is provided by an piezo
sounder. The volume of this sounder can be varied by
potentiometer P3. The sounder volume is independent
of the incoming audio volume.
2.4.2Keyboard.
The keyboard controls all of the module functions
including power on/off.
2. Module description.
Figure 9. NEDSP1062-KBD keyboard.
Powerbutton
(powerand
Audiobypass)
DSPlevel
button
Tricolour
LED
Mountinghole
Page 29
5. Applications.
NEDSP1062
Line out
Input
Selector
Input
PCB
Power
Red
White
Black
Brown
0V
HeadphonesFilter Blue
Black 0V
Line out
Keyboard
YellowYellow
43
1 25
123
12 21
43
Black Black
9
11
10 12
Connections to
module
Black
Red
BlueRed
Figure 28. Circuit diagram of installation in Kenwood
SP31.
The module is inserted into the circuit before the filter PCB. Identify the yellow wire connecting the input selector switch to the filter board. Break the wire and connect the NEDSP1062-KBD as shown below. Insulate the wires with the supplied rubber sleeves. Identify the black wire from the input PCB and connect as shown below, again insulating the connections. The fitting kit includes cable ties to tidy up the wiring of the installation. The photograph on the next page shows the complete installation. Mount the keyboard and power connector as shown elsewhere in this manual. The square bhi label can be fitted to the top of the case.

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual Page 13
2.5 Electrical characteristics.
Symbol Parameter Test Conditions Min. Typ. Max. Units
VsSupply voltage 12 16 18 V
IqsQuiescent current Vs= 12V
Vs= 16V
Vs = 18V
4.6
6.8
7.1 mA
Iqon Quiescent current DSP on
no load no signal
Vs= 12V
Vs= 16V
Vs= 18V
143
160
161 mA
ELECTRICAL CHARACTERISTICS
(Vs=16V, Tamb= 25ii
ii
iC unless otherwise stated)
DC CHARACTERISTICS
AC CHARACTERISTICS
Symbol Parameter Test Conditions Min. Typ. Max. Units
PoOutput power
d = 10%
f = 1KHz RL= 8W
RL= 4W
12V
1.16
1.7
16V 18V
2.06
3.17
Vs
W
W
ViInput sensitivty
4Wload
f = 1KHz PO= 0.5W
PO= 1.0W
PO= 2.0W
60
90
130
mV
ViInput sensitivty
8Wload
f = 1KHz PO= 0.5W
PO= 1.0W
PO= 2.0W
81
117
180
mV
BFrequency response
(-3dB) Po= 1W
RL= 8W50 4300 Hz
dDistortion f = 1KHz PO= 0.2 - 2.4W R L= 8W
PO= 0.2 - 2.4W R L= 4W0.8
0.8 %
RiInput resistance 21 22 23 W
GvVoltage gain f = 1KHz 27 dB
n Efficiency f = 1KHz PO= 3W R L= 4W
PO= 2W R L = 8W33
38 %
ANALOGUE CHARACTERISTICS
Symbol Parameter Test Conditions Min Typ Max. Units
TdSystem delay 26 mS
2. Module description.
Table 2. Electrical characteristics 1
Page 28
5. Applications.
DSP
Keyboard
5.2 Kenwood SP31.
Figure 25. NEDSP1062-KBD installed in a Kenwood
SP31.
This section
describes the general
fitting of the
NEDSP1062-KBD
module in the
Kenwood SP31
loudspeaker. This
installation retains the
operation of the
internal filters.
Figure 26. Suggested
location of keyboard.
Figure 27. Suggested
location of power
connector.
Suggested location for
mounting the power
connector
This photograph
shows the
suggested location
for mounting the
keyboard.

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual
Page 14
-20
-15
-10
-5
0
5
0 1000 2000 3000 4000 5000 6000
Figure 10. Frequency response
Frequency(Hz)
Output (dB)
0
2
4
6
8
10
12
00.511.522.533.5
Figure 11. Distortion vs. Output power
Distortion
Output power (W)
VS= 16V
f = 1KHz RL = 8W
RL = 4W
2. Module description.
RL = 8W
VS= 16V
P = 1W
-3dB
Page 27
Figure 24. Complete installation in the Yaesu SP8.
DSP
module
Input
PCB
Power
connector
5. Applications.

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual Page 15
Figure 12. Sensitivity.
0
0.5
1
1.5
2
2.5
0 50 100 150 200
Input voltage (mV)
Output power (W)
RL = 8W
RL = 4W
VS= 16V
f = 1KHz
2. Module description.
Page 26
Figure 23. Circuit diagram of installation in Yaesu SP8.
5. Applications.
NEDSP1062
Filter
unit Switch
unit Phone
jack unit
1 2
Black
Red
1 22
1
Keyboard
connector
Black Black
9
11 12
10
Connections to
module
JP2002 JP3001
Red Blue
The NEDSP1062 module in this application is inserted between the filter unit and the phone jack unit. Locate the 2 wire connector on the switch unit (JP2002). Break the wire to pin 1 and wire as shown in the diagram. Insulate the connection with the supplied rubber sleeve. Break the wire on pin 2 on JP2002 and connect as shown in the diagram and again insulate with a rubber sleeve. The fitting kit includes cable ties to tidy up the wiringofthe installation.The photographonthenext pageshowsthecomplete installation. Mount the keyboard and power connector as shown elsewhere in this manual. The square bhi label can be fitted to the top of the case.

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual
Page 16
Figure 13. Basic connection diagram
3.1 Installation overview.
The NEDSP1062-KBD module is inserted into the path
of noisy audio. The input and output level controls allow
the module to be fine tuned to suit most applications.
3. Installation
Audio in
Power amp
+
-
Break Circuit
here
Audio Out
(Loudspeaker)
The input to the module is loaded at 22Wto provide a
dummyloadto theprecedingcircuit.Thiscanberemoved
if required, such as using the module in applications
where the audio source is provided by a low level, low
power signal source. More information on this can be
found in section 3.3 in this operating manual.
If Vin is less than approx. 13.8V ensure the power supply
is well decoupled otherwise the power supply rejection
ratio will deteriorate. Best results are obtained in the
range of 13.8V - 16Vdc.
Audio in
NEDSP1062Power amp
+
-
IN
Agnd Agnd
OUT
Keyboard
Power
10
12
9
11
Black
Piezo
sounder
Blue
Red
Black
3. Installation.
Page 25
5. Application Notes.
5. Applications.
This section provides information into installing the
NEDSP1062-KBD into Amateur radio speaker units.
Figure 20. NEDSP1062-KBD
installed in a Yaesu SP8.
5.1 Yaesu SP8.
This section describes
the general fitting of
the NEDSP1062-KBD
module in the Yaesu
SP8 loudspeaker. This
installation retains the
operation of the
internal filters. DSP
Keyboard
Figure 21. Suggested location of
power connector
Figure 22. Suggested location
of keyboard.
This photograph
shows the
suggested location
for mounting the
keyboard.
Suggested location for
mounting the power
connector

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual Page 17
3.2 Module setup.
3. Installation.
3.2.2 Suggested set up procedure:
Basic setup procedure.
Connect input source and output device.
Ensure the NEDSP1062-KBD is switched off.
Set the audio source to a typical audio level.
Switch on the NEDSP1062-KBD.
Adjust the input control (P2) until the overload LED
illuminates. Reduce the level by approx. 1/4 turn.
Adjust the output level to the desired level.
Hold down the DSP button and adjust the volume
of the sounder to suit using P3.
Toobtain thebestresultsfromthenoisereductionthe
moduleshouldbesetuptogiveoptimumperformance.
Theinputsensitivitycontrolhasarangeof 0.70mW -
3Wtoprovide2W(W)output.
Undercertainconditions,RFbreakthrough can
sometimesoccur.To minimize this, theinputlevel(P2)
may need to be reduced or go to the FAQ page on the
bhiwebsiteanddownloadtheFAQonRFbreakthrough.
Undercertainconditionsthe DSP can create a small
amountofnoise, normally whentheunithasno signal
applied.You should not be able to hear this noise when
a signal is applied.
Both the input and output levels are adjustable on the
module.Thisallowseasyintegrationintothetargetsystem.
3.2.1Overview.
Page 24
4. Operation.
4.4 Noise reduction levels.
4or8levelsofnoise reduction are available.Theamount
of noise and tone reduction is shown in the table below.
Level
(4) Level (8) Tone Reduction White Noise Reduction
1 4dB 9dB
12 5dB 11dB
3 6dB 13dB
2 4 8dB 15dB
5 16dB 17dB
3 6 21dB 20dB
7 25dB 24dB
4 8 65dB 35dB
Table 4. Tone and noise reduction levels.
The column marked level (4) shows the noise and tone
reduction when operating the module with 4 levels, and
the level (8) column for 8 levels.
Holding down the DSP select button will continuously
change the DSP level. When the desired level has been
reached, release the button. The module will retain this
level until it is changed.

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual
Page 18
The NEDSP1062-KBD requires a signal of 125mV rms
or greater for optimum performance. Signals lower than
thismaybeusedbutthenoise cancellation performance
will decrease, as the signal levels drops. If the unit is
used with low level signals such as microphones, the
signal will need amplifying before applying it to the
NEDSP1062-KBD.
Due to the adaptive nature of the noise cancellation a
small delay may be heard when the audio signal
changes. For optimum performance provide the module
with a constant signal where possible.
When switching on the unit a thump may be heard in the
loudspeaker.
3. Installation.
Figure 14. Input circuit -
module powered down
22
W
OUT
12
Agnd
Agnd
9
10
V
Audio
Input
NEDSP1062
R6
IN
Load
11
The audio input to the
module is loaded at
22W. This load is
effectively connected
across the output load
when the unit is
switched off
(bypassed).
This will reduce the
impedance presented
to the audio source.
For example:
8W will reduce to 5.9W
4Wwill reduce to 3.4W
3.2.3Change to output load.
3.2.4Other signal considerations.
Page 23
4. Operation.
Start
Noise cancellation
On
Wait 1.5 Seconds
Noise cancellation off
Highest
Level?
Normal operation
No
Yes
Increase DSP
noise cancellation
level
Start
Noise cancellation off
Noise cancellation
On
Wait 3 Seconds
No
Yes
DSP button
pressed?
2 tone beep
Normal operation
Wait 3 Seconds
Demonstration 2.
The module switches
the noise cancellation
on for 3 seconds then
off for 3 seconds. This
is a good demonstra-
tion of the before and
after effects of remov-
ing the noise.
Demonstration 1.
The module switches the
noise cancellation on for 1.5
seconds, then off for 1.5
seconds. It will then move to
the next level and repeat the
process.
This mode is particularly
effectiveat demonstrating the
different DSP levels.
Alternatively pass a clean
audio signal through the
module to see hear how little
the DSP alters the speech.
Note:
To exit the demonstra-
tion modes hold down
the DSP button until a
2 tone beep is heard.
Figure 19.
Demonstration
modes.
4.3 Demonstration modes.

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual Page 19
Figure16.Circuitmodificationforlowpowersignaldrive.
3.3 Driving from a low signal source.
The input to the module has a low impedance. This is to
provide correct loading to any power circuits driving it. If
the module needs to be driven from a low power signal
then it must be modified in the following manner.
Cut the
leg on this
resistor
3. Installation.
22
W
OUT
12
Agnd
Agnd
9
10
Load
V
Audio
Input
NEDSP1062
R6
IN
11
Circuit
modification
Figure 15. Physical modification for low power signal
drive.
Note:
Wiring
omitted for
clarity.
Page 22
4. Operation.
To listen to the demonstration modes, or change the
number of DSP levels it is necessary to put the module
into the set up mode.
To do this, ensure the module is Off. Press and hold the
DSP level button. Turn on the module and a 2 tone
beep will be heard indicating that the module is in the
set up mode.
Releasing the button after the first 2 tone beep will enter
demonstration mode 1.
Releasing after the second 2 tone beep will enter
demonstration mode 2.
Keeping the button depressed with change the number
of levels available. 4 beeps will indicate 4 level mode
and 8 beeps 8 levels. Release the button when the
desired level is reached.
The module will return to normal operation after this.
ThecolouroftheLEDwill indicate the mode of operation.
DSP mode 4 Levels 8 Levels
OFF RED ORANGE
ON GREEN GREEN
Table 3. LED mode indication.

NEDSP1062-KBD Operating ManualNEDSP1062-KBD Operating Manual
Page 20
4. Operation.
4. Operation.
4.1 Keyboard.
The keyboard has 2 buttons and a tricolour LED.
4.1.1Power button.
Thepowerbuttonswitchedthemoduleonandoff.When
the module is off, the audio bypasses the module, so
the circuit will behave as if the module isn’t present.
Switching the power on routes the audio through the
module.
Note: If the power is on and the DSP is switched off, the
audiostillpassesthroughtheDSP-butwithout anysignal
processing.
A single press on the button switches on, and a single
press will switch off. Also with the power connected and
the module switched off the circuit will still draw 6mA.
4.1.2DSP level button.
This button is used to set the following:
•DSP on/off
•DSP level
•4 or 8 levels of noise cancellation
•Demonstration modes
Figure 17. NEDSP1062-KBD keyboard.
Powerbutton
(powerand
Audiobypass)
DSPlevel
button Tricolour LED
Page 21
Power up
DSP button
pressed
2 tone sound
DSP button
pressed
2 tone sound
2 tone sound
Demonstration
2
Demonstration
1
No
Yes
No
Yes
No
Yes
DSP button
pressed
DSP button
pressed
2 tone sound
DSP button
pressed
Change
4 or 8 levels
Normal
operation
No
Yesbeep number
of DSP levels
Yes No
DSP button
pressed
Yes
No
4. Operation.
4.2 Set up.
The following flow chart shows the functions of the DSP
button.
Releasing the DSP button
at this point the module
goes in to demonstration
mode 1
Keep the button down
until the desired level
has been reached, then
release the button. The
module will continously
scroll through 4 and 8
levels until the button is
released.
Figure 18. 4/8 level setting.
Holding down the DSP
button when switching on
causes the module to enter
the set up mode.
This is indicated by a 2
tone beep.
Releasing the DSP button
at this point the module
goes in to demonstration
mode 2