Kenwood TS-60S Service Manual page 15

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CIRCUIT DESCRIPTION
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3. Backup circuit
This transceiver has two kinds of data stored in the
microcomputer and EEPROM. User data, such as
memory channel data, is stored in the microcomputer,
and adjustment data, such as metercurves, is stored in
the EEPROM. The EEPROM data is retained when the
power supply voltage is off, but power is required to
retain the microcomputer data. If 14V is not cut off.
power is supplied from the 5VAVR in the digital unit. If
14V is cut off, power is supplied from a lithium battery.
To retain data with the lithium battery, the microcom-
puter must be in backup mode. So, the backup circuit
shown in Figure.14 detects a voltage drop in the 14V
line and outputs a backup request signal to the micro-
computer.
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4.
PLL and DDS control circuit
The TS-60s has three PLLs and two DDSs The
main microcomputer outputs frequency data to the
PLLs and DDSs serially according to the display fre-
quency.
5. TX-RX unit control signal circuit
The microcomputer sends the mode signal, IF filter
select signal, and power signal to the TX-RX unit. It
receives meter signals and standby switch signals
from the TX-RX unit, displays data on the meters, and
performs the transmit operation. The output signal
from the microcomputer goes to the serial-to-parallel
converter (TC9174F). (Fig. 15)
Fig. 14 Backup circuit
Fllfer s~gnal 6XHz
Filter smgnal
Z.4kHz
Filter ltynal 0 5kHz
ABKalgnsl
Power olgnal 'LOW.
Powerr8ynal'MID'
Powsreignal 'HI'
Pawaragnal'MID'
powsr alynal 'LOW'
CWmods signal
SSB madaslgnal
AM
modenlgnal
FM mode agnal
AF A n .,gna1
M37702M4A MONITOR s~gnal
RX BLANKING s8gn.l
DIGITAL UNiT TX-RX UNIT
Fig. 15 TX-RX unit control signal circuit