Vertex Standard FT-2000 ユーザーズマニュアル
Page 50
FT-2000 O
PERATING
M
ANUAL
R
ECEIVER
O
PERATION
(F
RONT
E
ND
B
LOCK
D
IAGRAM
)
The FT-2000 includes a wide range of special features to suppress the many types of interference that may be encountered
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.
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.
The FT-2000’s interference-fighting circuitry begins in its “RF” stages, and continues throughout the entire receiver sec-
tion. FT-2000 allows configuration of the features described below. However, the Sub band (VFO-B) receiver does not
have the DSP (Digital Signal Processor) features.
tion. FT-2000 allows configuration of the features described below. However, the Sub band (VFO-B) receiver does not
have the DSP (Digital Signal Processor) features.
VRF
(S
EE
PAGE
53)
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.
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
EE
PAGE
54)
On the Main (VFO-A) receiver, three automatically-se-
lected Roofing filters, in bandwidths of 15 kHz, 6 kHz,
and 3 kHz, are provided in the 69 MHz First IF, right after
the first mixer. These filters provide narrow-band selec-
tivity to protect the following IF and DSP stages, and the
filters' automatically-selected bandwidths may be manu-
ally changed by the operator, if desired, for special oper-
ating circumstances.
lected Roofing filters, in bandwidths of 15 kHz, 6 kHz,
and 3 kHz, are provided in the 69 MHz First IF, right after
the first mixer. These filters provide narrow-band selec-
tivity to protect the following IF and DSP stages, and the
filters' automatically-selected bandwidths may be manu-
ally changed by the operator, if desired, for special oper-
ating circumstances.
The Sub (VFO-B) receiver’s 40 MHz IF includes a fixed
Roofing filter, with a bandwidth of 15 kHz.
Roofing filter, with a bandwidth of 15 kHz.
CONTOUR Filter
(S
EE
PAGE
55)
The DSP Contour filter is a unique capability on the Main
(VFO-A) receiver, providing either nulling or peaking of
tunable segments of the receiver passband, so as to sup-
press interference or excessive frequency components on
an incoming signal, or to peak those tunable frequency
segments. The amount of nulling/peaking, and the band-
width over which it is applied, are adjustable via the Menu.
(VFO-A) receiver, providing either nulling or peaking of
tunable segments of the receiver passband, so as to sup-
press interference or excessive frequency components on
an incoming signal, or to peak those tunable frequency
segments. The amount of nulling/peaking, and the band-
width over which it is applied, are adjustable via the Menu.
IF SHIFT
(S
EE
PAGE
56)
The passband center frequency response of the IF DSP
filtering may be adjusted using this control.
filtering may be adjusted using this control.
IF WIDTH
(S
EE
PAGE
57)
The width of the IF DSP filtering may be adjusted using
this control.
this control.
IF NOTCH
(S
EE
PAGE
58)
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.
cantly reduce, if not 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
59)
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.
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
59)
When multiple interfering carriers are encountered during
reception, the Digital Notch Filter can significantly reduce
the level of these signals.
reception, the Digital Notch Filter can significantly reduce
the level of these signals.
AGC
(S
EE
PAGE
62)
The AGC system is highly adaptable to changing signal
and fading characteristics, making reception possible un-
der the most difficult conditions.
and fading characteristics, making reception possible un-
der the most difficult conditions.
SLOPED AGC
(S
EE
PAGE
63)
The Sloped AGC system on the Main (VFO-A) receiver,
instead of clamping a fixed upper bound on audio output
across a wide range of input signals, actually allows the
audio output to rise, very gently, with ever-increasing sig-
nal strength. This capability allows you to separate sig-
nals, using your brain, according to signal strength in ad-
dition to slight frequency differences.
instead of clamping a fixed upper bound on audio output
across a wide range of input signals, actually allows the
audio output to rise, very gently, with ever-increasing sig-
nal strength. This capability allows you to separate sig-
nals, using your brain, according to signal strength in ad-
dition to slight frequency differences.
IF Filter Quality Adjustment
(S
EE
PAGE
121)
The “Q” (quality factor) of the IF DSP filters may be ad-
justed using the Menu.
justed using the Menu.
Variable IF Filter Shape Factor
(S
EE
PAGE
121)
You may adjust the shape factor of the receiver IF DSP
filters using the Menu.
filters using the Menu.
C
ONVENIENCE
F
EATURES
ROOFING
FILTER
ROOFING
FILTER
RF
ANTENNA
SELECTOR
1st IF
1st IF
2nd IF
2nd IF
3rd IF (DSP)
69.450 MHz
40.455 MHz
450 kHz
455 kHz
30 kHz
BPF
RF AMP 1
RF AMP 2
1st
IF AMP
1st
IF AMP
2nd
IF AMP
2nd
IF AMP
DSP
UNIT
DET
1st Local
1st Local
3k/6k/15k
15k
2nd Local
2nd Local
3rd Local
CF
CF
IPO OFF
VRF
µ-TUNE
Main Band VFO-A
(
)
Sub Band VFO-B
(
)
OPTION
ATT
THRU