Yaesu FTDX5000 CAT BOOK, Operating Manual

Page: 52 / 148

Page 50 FT
DX
5000 O
PERATING
M
ANUAL
R
ECEIVER
O
PERATION
(
F
RONT
E
ND
B
LOCK
D
IAGRAM
)
The FT
DX
5000 includes a wide range of special features to suppress the many types of interference that may be encoun-
tered on the HF bands. However, real world interference conditions are constantly changing, so optimum setting of the
controls is somewhat of an art, requiring familiarity with the types of interference and the subtle effects of some of the
controls. Therefore, the following information is provided as a general guideline for typical situations, and a starting point
for your own experimentation.
Yaesu provides the optional RF- μ TUNING Unit (Narrow-bandwidth High-Q RF Filter) for additional protection from
strong signal interference.
VRF
(
S
EE PAGE
54
)
On the 1.9 - 28 MHz amateur bands, Yaesu’s powerful
VRF (Variable RF Filter) preselector circuit provides ex-
cellent suppression of out-of-band interference. The pass-
band is much narrower than that provided by traditional
fixed bandpass filters.
R. FLT
(
IF Roofing Filters
) (
S
EE PAGE
56
)
On the VFO-A receiver, Roofing filters, in bandwidths of
15 kHz, 6 kHz, 3 kHz, 600Hz, and 300 Hz (optional in
some models), are provided in the 9 MHz First IF, right
after the first mixer. These filters provide narrow-band se-
lectivity to protect the following IF and DSP stages. The
15 kHz, 6 kHz, or 3 kHz filters are automatically selected
for typical operating modes, and may be manually changed
by the operator, if desired, for special operating circum-
stances.
The VFO-B receiver 40 MHz IF includes three Roofing
filters, with bandwidths of 15 kHz, 6 kHz, and 3 kHz.
CONTOUR Filter
(
S
EE PAGE
58
)
The DSP Contour filter is a unique capability of the
FT
DX
5000 , providing either nulling or peaking of tunable
segments of the receiver passband. The Contour filter can
suppress interference, or excessive frequency components
on an incoming signal, or it can peak those tunable fre-
quency segments. The amount of nulling/peaking, and the
bandwidth over which it is applied, are adjustable via the
Menu.
IF SHIFT
(
S
EE PAGE
60
)
The passband center frequency response of the IF DSP
filtering may be adjusted using this control.
IF WIDTH
(
S
EE PAGE
61
)
The width of the IF DSP filtering may be adjusted using
this control.
IF NOTCH
(
S
EE PAGE
63
)
The IF Notch filter is a high-Q notch filter that can signifi-
cantly reduce, or eliminate, an interfering carrier. The Q
(sharpness) of the filter may be adjusted using the Menu.
DNR
(
D
IGITAL
N
OISE
R
EDUCTION
) (
S
EE PAGE
64
)
The DSP’s Digital Noise Reduction (DNR) feature uti-
lizes sixteen different mathematical algorithms to analyze
and suppress different noise profiles encountered on the
HF/50 MHz bands. Choose the selection that provides the
best noise suppression, which concurrently will allow the
signal to rise up out of the noise.
DNF
(
D
IGITAL
N
OTCH FILTER
) (
S
EE PAGE
64
)
When multiple interfering carriers are encountered during
reception, the Digital Notch Filter can significantly reduce
the level of these signals.
AGC
(
S
EE PAGE
67
)
The AGC system is highly adaptable to changing signal
and fading characteristics, making reception possible un-
der the most difficult conditions.
SLOPED AGC
(
S
EE PAGE
68
)
Instead of limiting a wide range of audio output signals to
a fixed upper bound, the sloped AGC system actually al-
lows the audio output to rise, very gently, with ever-in-
creasing signal strength. This capability allows you to men-
tally separate signals, according to signal strength, in ad-
dition to slight frequency differences.
IF Filter Quality Adjustment
(
S
EE PAGE
131
)
The “Q” (quality factor) of the IF DSP filters may be ad-
justed using the Menu.
Variable IF Filter Shape Factor
(
S
EE PAGE
131
)
You may adjust the shape factor of the receiver IF DSP
filters using the Menu.
C
ONVENIENCE
F
EATURES
ROOFING
FILTER
ROOFING
FILTER
RF
SCOPE IF OUT
RF
1st IF
1st IF 2nd IF
2rd IF (DSP)
3rd IF (DSP)
9 MHz
40.455 MHz 455 kHz
30 kHz (SSB/CW)
24 kHz (AM/FM)
30 kHz (SSB/CW)
24 kHz (AM/FM)
BPF
BPF
RF AMP/
IPO
1st
IF AMP
1st
IF AMP
DSP
UNIT
DSP
UNIT
1st Local
1st Local
300Hz
600Hz
3kHz
6kHz
15kHz
3kHz
6kHz
15kHz
2nd Local
2nd Local
3rd Local
CF
VRF
VRF
µ-TUNE
VFO-A Receiver
VFO-B Receiver
OPTION
ATT
ATT
THRU
THRU
A
N
T
E
N
N
A
S
E
L
E
C
T
O
R
RF AMP/
IPO
2nd
IF AMP
3rd
IF AMP