Kenwood TS-990S Operation Manual - Page 135

Adjusting The Rtty Threshold Level Of Psk Decoding, Displaying The Scope To Check Psk Tuning, Fft

Page 135 highlights

ADJUSTING THE RTTY THRESHOLD LEVEL OF PSK DECODING The background noise on a signal when no RTTY data is being received may be erroneously recognized as a letter, causing unnecessary text to be displayed. The threshold level should be adjusted to reduce or eliminate this symptom. If there are many erroneous detections due to noise, increase the threshold level. d • If [THLD] (F5) is unavailable in the function key guide, press [MORE] (F1). An alternate key guide will appear. 4 Press [-] (F4) or [+] (F5), or rotate the MULTI/CH control to adjust the level. Pressing and holding [(RESET)] (F1) resets the configured parameter to the default. The default is "10". 5 Press [ ] (F1). 6 Press [ESC] to exit. 1 Select Group No. 2, "Decoding & Encoding", from the Menu screen. 2 Access Menu 09, "FFT Scope Averaging (PSK Decode)". 3 Press [SELECT] (F4) to allow editing of the parameter box. 4 Press [-] (F4) or [+] (F5) to select one from "0" to "9". Increasing the parameter maximizes the noise component. The default is "0". 5 Press [ ] (F1). 6 Press [ESC] to exit. Contents Index 5-55

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5-55
ASSISTING YOUR SMOOTH QSO 5
Index
Contents
ADJUSTING THE RTTY THRESHOLD LEVEL OF
PSK DECODING
The background noise on a signal when no RTTY data is
being received may be erroneously recognized as a letter,
causing unnecessary text to be displayed. The threshold
level should be adjusted to reduce or eliminate this
symptom. If there are many erroneous detections due to
noise, increase the threshold level.
[F1]~[F7]
[FSK/PSK/REV]
[ESC]
[MULTI/CH]
1
Press
[FSK/ PSK/ REV]
to enter PSK mode.
2
Press
[DECODE]
(F3) to open the
PSK Encode/
Decode
screen.
3
Press
[THLD]
(F5) to allow editing of the threshold
level.
The threshold level configuration below the Waterfall
display can be changed.
If
[THLD]
(F5) is unavailable in the function key guide,
press
[MORE]
(F1). An alternate key guide will appear.
4
Press
[-]
(F4) or
[+]
(F5), or rotate the
MULTI/CH
control to adjust the level.
Pressing and holding
[(RESET)]
(F1) resets the configured
parameter to the default. The default is "10".
5
Press
[
]
(F1).
6
Press
[ESC]
to exit.
DISPLAYING THE SCOPE TO CHECK PSK
TUNING
FFT SCOPE
The transceiver is equipped with an audio FET scope
allowing you to observe the tuned status of the transceiver
in PSK (FSK) mode. The audio FET scope appears in the
PSK Encode/Decode
screen.
If there are multiple signals present in the band, you can
tune the target signal to be a 1500 Hz tone.
In PSK mode, you need to make an accurate zero-in. The
vector scope appears on the sub screen. By observing the
FFT scope and vector scope, you can zero-in on the target
signal.
AVERAGING THE WAVEFORM IN THE FFT SCOPE
The waveform to be displayed on an FFT scope can be
averaged. Waveform averaging reduces the effects of
random noise, allowing you to observe the target signal.
[F1]~[F7]
[FSK/PSK/REV]
[ESC]
[S.DISP]
1
Select Group No. 2, "Decoding & Encoding", from the
Menu
screen.
2
Access Menu 09, "FFT Scope Averaging (PSK
Decode)".
3
Press
[SELECT]
(F4) to allow editing of the parameter
box.
4
Press
[-]
(F4) or
[+]
(F5) to select one from "0" to "9".
Increasing the parameter maximizes the noise component.
The default is "0".
5
Press
[
]
(F1).
6
Press
[ESC]
to exit.