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10
“Sub” band
A portion of the output from the UHF-VCO/A
Q1123
(
2SC5006
) is passed through buffer amplifier
Q1124
(
2SC5006
) and diode switch
D1093
(
HVC131
) to the pro-
grammable divider section of the PLL IC
Q1122
(
MB15A02PFV1
), where it is divided according to the fre-
quency dividing data associated with the operating fre-
quency input from the main CPU
Q1104
. It is then sent to
the phase comparator.
A portion of the output from the VHF-VCO/A
Q1126
(
2SC5374
) is passed through buffer amplifier
Q1127
(
2SC5374
) and diode switch
D1097
(
HVC131
) to the pro-
grammable divider section of the PLL IC
Q1122
, where it
is divided according to the frequency dividing data asso-
ciated with the operating frequency input from the main
CPU
Q1104
. It is then sent to the phase comparator.
The 11.7 MHz reference oscillator
X1003
frequency is di-
vided by the reference frequency divider section of
Q1122
into 2340 or 1872 parts to become 5 kHz or 6.25 kHz com-
parative reference frequencies, which are utilized by the
phase comparator.
The phase comparator section of
Q1122
compares the
phase between the frequency-divided oscillation frequen-
cy of the VCO circuit and the comparative frequency, and
its output is a pulse corresponding to the phase differ-
ence. This pulse is integrated by the loop filter into a con-
trol voltage (VCV) to control the oscillation frequency of
the VCOs.
Circuit Description
Power Supply Line
When the user presses and holds in the “Right” VOL knob
for 2 seconds, pin 23 of the main CPU
Q1104
goes “low”
and pin 40 of main CPU
Q1104
goes “high,” which acti-
vates the power switch
Q1078
(2SB1301) and
Q1082
(
2SC4617
), to supply 13.8 VDC to each circuit in the trans-
ceiver.
Summary of Contents for FT-8800R
Page 4: ...4 Exploded View Miscellaneous Parts Note...
Page 5: ...Block Diagram 5...
Page 6: ...Block Diagram 6 Note...
Page 16: ...16 Note...
Page 18: ...MAIN Unit 18 Note...
Page 44: ...44 MAIN Unit Note...
Page 45: ...45 PANEL Unit Circuit Diagram...
Page 50: ...50 PANEL Unit Note...