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Page 9

2.3

Pin functions.

The basic operation of the NEDSP pins are described
below. More detailed descriptions can be found later in
this manual.

Pins 1-3 DSP filter level set.

These pins allow remote setting of the noise cancellation
level. If  these pins are used, then remove the preset
jumpers JP1 - JP3 from the PCB.

Pin 5.

Supply voltage.

Supply voltage 5-15VDC

Pin 7

0V

0V pin.

Pin 8

Noise cancellation on/off

Connecting this pin to 0V inhibits the noise cancellation.
Leave this pin floating to enable noise cancellation.

Pin 9

Audio input.

Audio signal to be processed.

Pin 10

Audio out

DSP processed signal out from the module.

For optimum performance, keep all leads as short as
possible. Use screened leads for the audio signal.

Page 16

5.

A

pplication Notes.

5.1

Noise cancellation On/Off indication.

Figure 7. Red/Green LED indication of noise cancellation.

In the above example a tricolour LED (or separate Red
and Green LEDs) are used to give a visual indication of
the noise cancellation mode. The green LED will
illuminate when the noise cancellation is on, and the red
when off.

NEDSP 1061

0V

7

Noff

8

+V

0V

Red

Green

R1

R2

Noise 

cancellation

Off

DPDT 

switch

Summary of Contents for NEDSP1061-PCB

Page 1: ...nstallation and Operating Manual 1061 108D Issue C DSP Noise Cancelling Products Page 24 bhi ltd PO Box 318 Burgess Hill West Sussex RH15 9NR tel 44 0 845 217 9926 fax 44 0 845 217 9936 sales bhi ltd com www bhi ltd com bhi bhi bhi bhi bhi DSP Noise Cancelling Products ...

Page 2: ...d 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 implied warranties of merchantability or fitness for 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 wi...

Page 3: ...3 Pin functions 9 2 4 Controls 10 2 5 Electrical characteristics 10 3 Installation 11 4 Functions 4 1 Noise reduction levels 13 4 2 Pre setting different DSP levels 13 4 3 Remote setting of DSP level 14 4 4 Noise cancellation on off 15 5 Application notes 5 1 Noise cancellation indication 16 5 2 Remote adjustment of level 17 5 3 Driving a low impedance load 19 5 4 Audio bypass 19 Index 20 Page 22 ...

Page 4: ...ation 8 levels of noise reduction Noise cancellation can be preset or remotely set during operation 5 15V supply range 4 6dB on board gain Wide range of connection possibilities Mounting holes 1 2 Limitations This module is designed to pass speech Other signals such as data music and morse CW will to some degree pass through but the integrity of these signals cannot be guaranteed This module is de...

Page 5: ...pins to the circuit use them purely for mechanical fixing Other options Use a right angled pin header to mate with a 10 way wired connector Wire the PCB directly and mount using the four fixing holes Page 20 Index A Application Notes 16 Audio bypass 19 Audio input 9 Audio out 9 B Buffered output stage 19 C Copyright 2 D Disclaimer 2 Driving a low impedance load 19 DSP filter level set 9 E Electric...

Page 6: ...or use dual polarity power supply Figure 12 Buffered output stage 5 3 Driving a low impedance load If the target system loads the output of the DSP module it may necessary to buffer the output This can be achieved with a single op amp 10 7 9 NEDSP 1061 Audio out Audio In 0V V 5 Audio out Audio in Relay Contacts Power off bypass switch Vin Relay Coil Protection Diode Figure 13 Audio bypass 5 4 Audi...

Page 7: ...ge of input voltages but to keep the power dissipation and heat down it is advisable to use as low as possible supply voltage The power supply input is reverse polarity protected Page 18 NEDSP 1061 N0 1 N1 2 N2 3 0V 7 micro controller Figure 10 Control using a microcontroller The module can be controlled with a microcontroller As the DSP employs internal pull ups it is not necessary to drive the m...

Page 8: ...l p p u S 6 C N t c e n n o c t o n o D 7 V 0 n o i t c e n n o c V 0 8 f f o N n i p f f o n o n o i t a l l e c n a c e s i o N 9 n I t u p n i o i d u A 0 1 t u O t u p t u o o i d u A Table 1 NEDSP1061 connection functions Page 17 5 2 Remote adjustment of noise cancellation level NEDSP 1061 N0 1 N1 2 N2 3 0V 7 0V C 1 2 4 BCD Complement switch This page illustrates various options for altering ...

Page 9: ...s pin floating to enable noise cancellation Pin 9 Audio input Audio signal to be processed Pin 10 Audio out DSP processed signal out from the module For optimum performance keep all leads as short as possible Use screened leads for the audio signal Page 16 5 Application Notes 5 1 Noise cancellation On Off indication Figure 7 Red Green LED indication of noise cancellation In the above example a tri...

Page 10: ...l w o L r e g g i r t 8 0 V I h g i H n I h g i h t u p n i t n e r r u c e g a k a e l t u p n I 0 1 0 3 0 6 A u I w o L I w o l t u p n i t n e r r u c e g a k a e l t u p n I 0 1 0 3 0 6 A u Table 2 NEDSP1061 Electrical characeristics 2 5 Electrical characteristics Page 15 l e v e L 2 N 1 N 0 N 1 V 0 V 0 V 0 2 V 0 V 0 V 3 3 3 V 0 V 3 3 V 0 4 V 0 V 3 3 V 3 3 5 V 3 3 V 0 V 0 6 V 3 3 V 0 V 3 3 7 V...

Page 11: ... J 2 P J 1 P J 1 n O n O n O 2 n O n O f f O 3 n O f f O n O 4 n O f f O f f O 5 f f O n O n O 6 f f O n O f f O 7 f f O f f O n O 8 f f O f f O f f O 4 3 Remote setting of DSP filter level Remote setting of the DSP level can be achieved through the PCB connections This allows the DSP filter level to be changed during operation If remote DSP setting is used remove the jumpers from the module These...

Page 12: ...ying a push to talk button insert the NEDSP1061 in to the audio path before the button Audio in Audio out Input signal level Original signal level NEDSP1061 635mV rms Max Output level Post processing Pre processing Gain 1 7 50mV rms Page 13 4 Functions 4 1 Noise reduction levels 8 levels of noise reduction are available The amount of noise and tone reduction is shown in the table below l e v e L n...

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