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Sony ICF-7600DA Service Manual page 7

Fm/lw/mw/sw pll synthesized receiver

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NAMING
DESCRIPTION
AM OSC
SIGNAL
INPUT
GROUND
Receives an AM local-oscillator signals, i,e., the VCO signal from 0.5 MHz to 40 MHz of
0.2 Vp-p minimum.
This port is selected when the direct frequency-dividing system or the Pulse-Swallow system
is used and, at the same time, the HF command is executed. These two systems are, how-
ever, different one another as shown below.
INPUT LEVEL
(MINIMUM)
0.1 Vp-p
DIVIDING
RATIO
16 to (2'?-1)
1,024 to
(2'7-1)
INPUT FRE-
QUENCY
0.5 to 15 MHz
DIVIDING SYSTEM
DIRECT
PULSE-SWALLOW
(HF COMMAND
EXECUTED)
*0.5 to 40 MHz
This terminal is pulled down to the groung level when the Pulse-Swallow system is used
together with the VHF-command execution, i.e., the VCOH (FM) terminal is selected.
A capacitor coupling is needed due to the inclusion of alternate current amplifiers inside
this chip.
The ground-return terminal! of this device.
ERROR
OUTPUT
ERROR
OUTPUT
Transmits the error signal of the PLL system. When the resultant frequencies obtained by
dividing the local-oscillator frequencies are higher than the reference frequency, an "H"
(high)-level signa! is output from this port. When these are lower, on the contrary, an "L"
(low)-level signal is output from this port. When these divided frequencies just coincide
with the reference frequency, this port becomes in a floating state. These output signals
from this port then go through the external lowpass filter to the varactor diodes in the
tuned circuits in these frontends of the receiver, The same output waveform as the terminal
E01 is obtainable from the next terminal E02, pin 26, and so these two are user-selectable.
When the PLL is disabled, i.e., when the system is set by the PLL commands or the CE
terminal, pin 27, is set to the ''L" (low)-level, these E01 and E02 terminals become in the
floating states.
XO
XI
CHIP
ENABLE
Receives the state-selection signals for this device.
When set at "H" (high), this device works, and vice versa. The PLL section of this device
becomes forcively in a disabled condition in the duration of wider than 140 psec of the "L"
dow)-level state. The duration, however, of shorter than 140 usec is not taken into account.
The programmes are using the CKSTP commands. The CKSTP commands are effective only
when the state of this CE is in an "L"' (low) condition. When this CE terminal is in an "1H"
state, these programmes work like under NOP commands.
When the CKSTP commands are executed when this CE terminal is in an "'L" (low) level,
the internal clock generator and the internal CPU are disabled. In this disabled condition,
the RAM-memory backupings can be made under a very-low current consumption of 3 uA
maximum. In this condition, these display-output signals LCD1 through LCD16 and the
COMI COM3 become in the eff-display mode, i.e., the ''L"' (low) state.
When the level of this CE terminal is changed from "'L" to "H", this device is reset and its
programmes start from the location ''0" (zero). In this state, the Port A becomes in the
input mode.
CRYSTAL
OSCILLATOR
PA3
THRU
PAO
PORTA
(K-ENTER)
(DAT-R)
(REQ-R)
(RES-R)
(ENTER-KEY
IN)
(ENCODER
DATA IN)
(ENCODER
REQUEST)
(ENCODER
RESET)
An external quartz-crystal oscillator connects to these terminals to obtain 75 kHz signal
generator for the devices.
4-bit I/O (Input/Output) ports. These ports enable the device designate input or output bit
by bit. The each designation is, in turn, performed by the contents in the location "1 FH" in
the 'BANK 0 (zero)" in the data memory (RAM), called as a "'PAIO word". At these
instances as the power-on, clock stoppage and the initial setting of the CE terminal from
"L" to "H", these terminals automatically become in the input ports.
Under the port-operation commands like ''IN", "OUT", "SPB", '""RPB" commands, etc.,
the PAO port coincides with the least significant bit of the registor or the operand, the
PA3 coincides with the most-significant bit of them. The same applies to the port B and
Port C respectively.
In this set, the PA3 (K-ENTER) port receives these return signals from the momentary
ENTER and alternate BUZZER keys and the key matrix is as shown below.
KEY
SOURCE
DAT-S
RES-R
ENTER
BUZZER __|
In this set, PA2 through PAO are used to receive and transmit these signals to perform the
readings of information from the tuning rotary encoder.
K-ENTER

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This manual is also suitable for:

Icf-7700