Kenwood TS-2000, Руководство по обслуживанию

Страница: 5 / 171

5
TS-2000/X
144MHz LO1
When the VHF band is operating in the main band, the
VHF REF VCO (Q441) generates 36.057 to 37.288MHz (K),
36.450 to 36.842MHz (E). (See Table 2, Frequency Configu-
ration.)
The output signal from the DDS (IC406) is input to pin 8
of the PLL IC (IC411) for VHF REF and divided into 1/16 in
IC411 to produce comparison frequency fø 2 of 563 to
583kHz (K), 569 to 576kHz (E).
The output signal from the VCO (Q441) goes to pin 6 of
IC411 and its frequency is divided into 1/64 in IC411, com-
pared with the signal with comparison frequency fø 2 by a
phase comparator, and is locked.
The VHF REF PLL output signal is fed to pin 8 of IC410 as
a reference frequency, and divided into 1/30 in IC410 to pro-
duce comparison frequency fø 1 of 1202 to 1243kHz (K),
1215 to 1228kHz (E).
The VHF LO1 VCO (Q433) generates 183.895 to 193.895
MHz (K), 185.795 to 187.895MHz (E) in receive mode and
183.795 to 193.795MHz (K), 185.795 to 187.795MHz (E).
The VCO (Q433) output signal goes to pin 6 of IC410, and
its frequency is divided into 1/N1 in IC410 and compared
with comparison frequency fø 1 by a phase comparator. The
frequency is locked and LO1 is generated.
The DDS (IC406) sweeps output frequency (9.014 to
Display frequency LO1 OUT IC410 : VHF REF IC411 : DDS output (MHz)
f
RX
(MHz) (MHz) LMX2306TMX (MHz) LMX2306TMX IC406 : AD9835BRU
Start Stop R1 N1 N2 R2
142.000000 (K) 146.999999 (K) LO1 30 153 VHF REF 64 16 f
DDS
144.000000 (E) 146.000000 (E) = f
RX
+ IF
=
(f
RX
+ IF)
*R1 =
VHF REF
*R2
147.000000 (K) 151.999999 (K) 156 N1 N2
IF = RX : 41.895
TX : 41.795
9.321MHz (K), 9.112 to 9.210MHz (E)) in 10Hz steps by
equation f
DDS STEP
(Hz) = (10*R1)/(N1*4) and in 1Hz steps
by equation f
DDS STEP
(Hz) =(1*R1)/(N1*4), the LO1 covers
the frequencies of 183.895 to 193.895 MHz (K), 185.895 to
1 8 7 . 8 9 5 M H z ( E ) i n r e c e i v e m o d e a n d 1 8 3 . 7 9 5 t o
193.795MHz (K), 185.795 to 187.795MHz (E) in transmit
mode in 10Hz or 1Hz steps.
The PLL output signal is changed by the switching circuit
of Q469 (receive) and Q470 (transmit) so that the output
amplifier and low-pass filter correspond to VHF band trans-
mission and reception.
In receive mode, the signal is amplified by the broad-
band amplifier (IC415), and passes through a low-pass filter.
The impedance is converted by an attenuator and the signal
is output to the RF unit (X57-606) as the first local oscillator
RXLO1.
In transmit mode, the signal is amplified by the broad-
band amplifier (IC416), and passes through a low-pass filter.
The impedance is converted by an attenuator and the signal
is output to the RF unit (X57-606) as the first local oscillator
TXLO1.
When the VHF is not operating, Q436 is turned OFF with
a signal from the serial-parallel IC (IC404) and VHF LO1 VCO
(Q433) stops operation.
430MHz LO1
When the UHF band is operating in the main band, the
UHF REF VCO (Q431) generates 378.105 to 418.105MHz
(K), 388.105 to 398.105MHz (E) in receive mode and
378.205 and 418.205MHz (K), 388.205 to 398.205MHz (E).
(See Table 3, Frequency Configuration.)
The output signal (8.328 to 8.475MHz (K), 8.344 to
8.469MHz (E)) from the DDS (IC407) passes through a ce-
ramic filter (CF400), is input to pin 8 of the PLL IC (IC412) for
UHF and divided into 1/16 in IC412 to produce comparison
frequency fø of 520 to 530 kHz.
The output signal from the VCO (Q431) goes to pin 6 of
IC412 and its frequency is divided into 1/N in IC412, com-
pared with comparison frequency fø by a phase comparator,
and is locked.
The DDS (IC407) sweeps output frequency (8.328 to
8.475MHz (K), 8.344 to 8.469MHz (E)) in 10Hz steps by
equation f
DDS STEP
(Hz) = 10*R/N and in 1Hz steps by equa-
tion f
DDS STEP
(Hz) = 1*R/N, the LO1 covers the frequencies
of 378.105 to 418.105MHz (K), 388.105 to 398.105MHz (E)
in receive mode and 378.205 to 418.205MHz (K), 388.205 to
398.205MHz (E) in transmit mode in 10Hz or 1Hz steps.
The PLL output signal is changed by the switching circuit
of Q471 (receive) and Q472 (transmit) so that the output
amplifier and low-pass filter correspond to UHF band trans-
mission and reception.
In receive mode, the signal is amplified by the broad-
band amplifier (IC415), and passes through a low-pass filter.
The impedance is converted by an attenuator and the signal
is output to the RF unit (X57-606) as the local oscillator sig-
nal RXLO1.
In transmit mode, the signal is amplified by the broad-
band amplifier (IC416), and passes through a low-pass filter.
The impedance is converted by an attenuator and the signal
is output to the RF unit (X57-606) as the local oscillator sig-
nal TXLO1.
When the UHF is not operating, Q434 is turned OFF with
a signal from the serial-parallel IC (IC404) and UHF VCO
(Q431) stops operation.
Table 2 Main VHF band frequency configuration
CIRCUIT DESCRIPTION