Yaesu FTdx5000 Series Operating Manual page 37

C
ONVENIENCE
R
ECEIVER
The FT 5000 includes a wide range of special features to suppress the many types of interference that may be encoun-
DX
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.
We provide the RF-TUNING Unit (Narrow-bandwidth High-Q RF Filter) for the option.
VRF
( S 53 )
EE PAGE
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, with a
passband much narrower than that provided by traditional
fixed bandpass filters.
R. FLT
( IF Roofing Filters ) ( S
On the VFO-A receiver, three automatically-selected Roof-
ing filters, in bandwidths of 15 kHz, 6 kHz, 3 kHz, 600
Hz, and 300 Hz 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, and
the filters' automatically-selected bandwidths may be
manually changed by the operator, if desired, for special
operating circumstances.
The VFO-B receiver's 40 MHz IF includes a fixed Roof-
ing filter, with a bandwidth of 15 kHz, 6 kHz, and 3 kHz.
CONTOUR Filter
( S
EE PAGE
The DSP Contour filter is a unique capability on the
FT 5000, providing either nulling or peaking of tunable
DX
segments of the receiver passband, so as to suppress inter-
ference or excessive frequency components on an incom-
ing signal, or to peak those tunable frequency segments.
The amount of nulling/peaking, and the bandwidth over
which it is applied, are adjustable via the Menu.
IF SHIFT
( S 56 )
EE PAGE
The passband center frequency response of the IF DSP
filtering may be adjusted using this control.
IF WIDTH
( S 57 )
EE PAGE
The width of the IF DSP filtering may be adjusted using
this control.
ATT
ANTENNA
SELECTOR
Page 50
F
EATURES
O
PERATION
54 )
EE PAGE
55 )
RF
THRU
IPO OFF
OPTION
μ-TUNE
BPF RF AMP 1
VRF RF AMP 2
( F
E B
RONT ND LOCK
IF NOTCH
( S
The IF Notch filter is a high-Q notch filter that can signifi-
cantly reduce, if not eliminate, an interfering carrier. The
Q (sharpness) of the filter may be adjusted using the Menu.
DNR
( D
N
IGITAL
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
N
IGITAL OTCH FILTER
When multiple interfering carriers are encountered during
reception, the Digital Notch Filter can significantly reduce
the level of these signals.
AGC
( S
EE PAGE
The AGC system is highly adaptable to changing signal
and fading characteristics, making reception possible un-
der the most difficult conditions.
SLOPED AGC
The Sloped AGC system, instead of clamping a fixed up-
per bound on audio output across a wide range of input
signals, actually allows the audio output to rise, very gen-
tly, with ever-increasing signal strength. This capability
allows you to separate signals, using your brain, accord-
ing to signal strength in addition to slight frequency dif-
ferences.
IF Filter Quality Adjustment
The "Q" (quality factor) of the IF DSP filters may be ad-
justed using the Menu.
Variable IF Filter Shape Factor
You may adjust the shape factor of the receiver IF DSP
filters using the Menu.
1st IF
69.450 MHz
ROOFING
FILTER
1st
IF AMP
3k/6k/15k
1st Local
1st IF
40.455 MHz
ROOFING
FILTER
1st
IF AMP
15k
1st Local
FT
)
D
IAGRAM
58 )
EE PAGE
) ( S 59 )
R
OISE EDUCTION EE PAGE
) ( S 59 )
EE PAGE
62 )
( S 63 )
EE PAGE
( S
EE PAGE
Main Band VFO-A ( )
2nd IF 3rd IF ( DSP )
450 kHz 30 kHz
2nd DSP
CF
IF AMP UNIT
2nd Local 3rd Local
( )
Sub Band VFO-B
2nd IF
455 kHz
2nd
CF DET
IF AMP
2nd Local
5000 O
DX
PERATING
125 )
( S 125 )
EE PAGE
M
ANUAL