Timewave DSP-599zx, Operating Manual

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DSP-599zx Audio Noise Reduction Filter
March 6, 1997 1-9
Adaptive Multi-tone and Manual Notch Filtering
(Tone noise reduction)
The DSP-599zx has both an automatic notch filter and a manually tuned fil-
ter. The automatic multi-tone filter removes multiple heterodynes almost
completely. The aggressiveness is adjustable.
The manual notch filter is selectable for either as a dual notch filter for data
signals and a narrow bandwidth filter for CW signals and heterodynes. The
center frequency of the filter is easily set. This filter can be used either to re-
move a single tone or to remove mark/space data tones.
CW Mode
The CW Mode digitally processes analog CW (Continuous Wave) signals
for Morse code reception. Independently selectable processing techniques
include noise reduction, tunable bandpass filtering, notch filtering and auto-
matic gain control.
Bandpass Filters
The DSP-599zx has a fully tunable bandpass filter for use in the CW mode.
The LCD display shows the center frequency and bandwidth of the filter as
the operator tunes with front panel controls. Narrow band signals like CW
and RTTY require a bandpass filter with steep skirts and linear phase re-
sponse. Linear phase response maximizes the usable signaling rate for a giv-
en bandwidth and minimizes ringing often heard on other extremely sharp
crystal and audio filters. The DSP-599zx CW filter has skirts so steep that a
signal literally falls off the edge of the passband as you tune through a CW
signal.
Bandwidths for the bandpass filter range from 10 Hz to 600 Hz, and center
frequencies range from 200 to 2095 Hz. The narrow filter bandwidths are
Function
6
Shift
5
AGC
3
Bypass
Data
DSP-599zx
CW Voice
Mode
1
Random
4
Tone
2
599-027
Setup
Test
Rcl/ Store
Spkr/ Chan
High Pass
Center Freq
Timewave
Low Pass
Bandwidth
Function
6
Shift
5
AGC
3
Bypass
Data
DSP-599zx
CW Voice
Mode
1
Random
4
Tone
2
599-007
Setup Test
Rcl/ Store
Spkr/ Chan
High Pass
Center Freq
Time