Service manual

Page 4
Contents
1. Introduction
1.1 NEDSP1061-KBD features 5
1.2 Limitations 5
1.3 Audio DSP noise cancellation 6
2. Module description
2.1 Module layout 7
2.2 Connections 7
2.3 Electrical characteristics 8
2.4 Controls 8
2.4.1 Input level 8
2.4.2 Output level 8
2.4.3 Beep volume level 8
2.4.4 Overload LED 8
2.5 Module mounting 9
3. Installation 10
3.1 Introduction 10
3.2 Circuit location 10
3.3 Fitting 11
3.3.1 Audio connections 11
3.3.2 Power connections 12
4. Setup 13
5. Troubleshooting 14
6. Operation 15
6.1 Introduction 15
6.2 Operation 15
6.3 Demonstration mode 16
6.4 Notes about noise reduction 16
6.5 Noise redcution level 17
7. Machining drawings 18
Page 17
6.3.2 Demonstration 2:
Follow the procedure as above. Wait for the second 2
tone beep, then release the key.
In this mode the filter level is set to level 3.
The noise cancellation is switched on for 3 seconds, then
off for 3 seconds. This loops until the user aborts this
mode.
This is a good demonstration for listening noisy SSB
conversations showing the before and after.
6.3.3 Exiting the demonstration mode.
Hold down the button until the 2 tone beep is heard.
Release the button.
After a short delay the LED will flash indicating the stored
level, as during the normal switch on.
6.4 Notes about the noise reduction.
When using the module on level 4 some distortion may
be heard. This is quite normal when listening to high
levels of noise at level 4.
6.5 Noise reduction levels.
leveL noitcudeRenoT
esioNetihW
noitcudeR
1Bd5Bd11
2Bd8Bd31
3Bd12Bd02
4Bd56Bd53