3 – General Operation
3-6
March 6, 1997
two other common receiver problems. The first is increase the level of weak
signals when receive system gain is low. In the process of maintaining the
constant level, the signal processor can add up to 36 dB of gain to the DSP-
599zx signal path. In some situations, this increased gain will also notice-
ably increase the background noise level.
The second common problem is receiver desensing by the AGC action of
strong signals in the passband of the receiver. The receiver selectivity may
not be sufficient to separate a strong signal from a weak signal, but the DSP-
599zx may easily separate the two signals. (This is a receiver problem be-
cause the weak signal couldn’t be heard without the highly selective DSP fil-
ter.) Since the stronger signal controls the gain of the receiver via the AGC,
the stronger signal effectively modulates the weaker signal.
Depending upon the relative AGC time constants of the DSP-599zx and the
receiver, the DSP-599zx can help remove the AGC induced modulation. Ex-
periment with changing the receiver AGC setting from Fast to Slow, Slow
to Fast, or even turning off the receiver AGC. Try the same changes if
“Pumping” of the signal levels occurs as a result of AGC interaction be-
tween the receiver AGC and the DSP-599zx AGC when listening to normal
signals.
Leaving the AGC on all the time is not necessarily the best solution. You
will find situations when you will have a better audio signal with AGC off.
Noise Reduction
Press
[Random]
to enable random noise reduction. The LED next to the
key lights when the feature is on.
Power Switch/Gain Adjust Control
The gain knob on the front panel of the DSP-599zx is the power switch/gain
adjust control. The gain control simultaneously controls both channels' vol-
umes. Within Setup, you can adjust the relative volume of channel
A
with
respect to channel
B
. This adjustment ranges from equal levels to the inac-
tive channel off.
Turning off or removing power from the DSP-599zx automatically de-ener-
gizes a bypass relay and forces the DSP-599zx into the bypass mode.
Function
6
Shift
5
AGC
3
Bypass
Setup
Test
Data
DSP-599zx
CW
Voice
Mode
Rcl/
Store
Spkr/
Chan
1
Random
4
Tone
2
599-034
High Pass
Center Freq
Time
Summary of Contents for DSP-599zx
Page 1: ...DSP 599zx Audio Noise Reduction Filter Operating Manual March 6 1997 TECHNOLOGY INC ...
Page 56: ...4 Voice Mode 4 8 March 6 1997 ...
Page 62: ...5 CW Mode 5 6 March 6 1997 ...
Page 92: ...8 Troubleshooting 8 4 March 6 1997 ...
Page 96: ...Appendix B Glossary A 4 March 6 1997 ...
Page 98: ...Appendix C Product Warranty A 6 March 6 1997 ...
Page 100: ...Appendix D Electromagnetic Interference A 8 March 6 1997 ...
Page 102: ...Appendix E Schematic Diagrams A 10 March 6 1997 ...
Page 103: ...DSP 599zx Audio Noise Reduction Filter March 6 1997 A 11 ...
Page 104: ...Appendix E Schematic Diagrams A 12 March 6 1997 ...
Page 105: ...DSP 599zx Audio Noise Reduction Filter March 6 1997 A 13 ...
Page 106: ...Appendix E Schematic Diagrams A 14 March 6 1997 ...
