Advertisement
I
connected to the R-2R ladder resistor
for D-A
( digital-analog) conversion'
o VSS (pin 35)
The LSI ground terminal'
. cHl -ffi
(pin36 -Pin42)
minimum).
NOTE:
ïii
automatic
search tuning function -inco,rporated
in
ine t'czzoz
LSI is not u"nà in the SX-700L' Further-
Àore,
description of
functions of non-used terminals
has been deleted-
sx-7clclL
automatically). The SX'?00L has been
desigrred
;;t*"
un- to 1 FM frequencies,11$ 7 AM
fre'
;;";Â
(including both MW and LW broadcastins
frequencies).
o Preset Memory
The preset memory for manuall{ tÏl"d
stations
involves A-D conversion (to a 10-bit digital
code)'
u"J tft" storage of an approximate value,
in the LSI
i;;;il;s
a îesolution-of
approx' 1/4000 when
ii"
ti"""tuning
function
described later is in-
cluded).
--
Oigii"f
encoding of
the
tuning
voltage is
achieîed in the following way' The
LSI 10-bit
up/down counter code output obtained
from pin
;E';.
pin 34 (B10 - 81) is D-A converted (digital
"od"
ôrru"rted into analog quantity) by the
R-2R
fuAJ"t resistor, and then compared with
the tuning
voltage (during manual tuning mode) by
a voltage
"àÀpî*uiot,
tLe result being applied to pin 18
(M-U/D).
If the ladder resistor output voltage is
lower
than the tuning voltage (manual tuning)'
the pin
ig l"p"t
is swilched to high level, resulting in the
LSI lb-bit up/down counter counting up
and the
ladder resistor output
voltage being increased'
ti tfre ladder resistoi output voltage is higher
than
ihe tuning voltage, a low level input- is
applied to
pi" fg, rËsulting in the 10'bit up/down counter
counting down, and the ladder resistor
output
vottæe
"Ueing
decreased' In this way' the up/down
"orrrrl",
10-bit code is immediately approximated
;; ;h" tuning voltage (manual tuning)'
and then
frequencY.
o Direct Tuning bY Memory Read'Out
Band Switching ( LW/MW/FM)
FUNCTION switch operation results
in one of
the band designator terminats pin
5
Fq)'
pi" g
ffi,
;; pi" T [f,W) ueing lonnecte!,P.f:t1
ii:.' :'#"ilâ io' t# reueJ), therebv,.switching
ifr;
bï-zôôï-ilth"
selected band' Although, an1?
r e m a i n s o n d u r i n g n o r m a l o p e r a t i o n ' - i t i s t u r n e d
;;i;h""
the POWER switch is set to STAND
BY'
;;;;;
the AC line Power suPPlY is cut'
so
;;*;;t
is stopped during memorv. hold
mode'
il;;y
t"a"ci"i
the power consumption level'
Manual Tuning
The SX-700L is switched to
manual tuning
^"Jwhen
pin 16 (M-ANU) is.switched to low
ilu"f uv turniàg the MANUAL switch
on'
'-
ïd;"
the TUNING knob is turned' the
variable
resistor coupled to the TUNING
knob is activated'
,àr"ru"g in a change in the DC
voltage applied to
pin 12 (Manu Tune)' Th
via an analog switch inct
and aPPears again at Pin
'equency. During manual
-iND) is switched to low
reing turned on to light uP
the dial Pointer LED'
Preset Tuning
When the MEMORY switch
and PRESET switch
are both tumed on togt
broadcasting frequencY
?00L memory' And w
onlY is turned on, a broa
stored in the memory
r
o
Hide quick links:
Advertisement
