Block Diagram Of Counter Ic; Digit Signal - Pioneer SX-3900 Service Manual

D 5
D 4
0 3
V c c
G N O
F i o . 4 - 1 0 B l o c k D i a g r a m o f C o u n t e r
l C ( P D 5 0 0 9 )
An outline of the composition of
PD5009 is
given in block diagram form in Fig' 4-10' With
the
FL tube a - g segments (anode) for each
digit con-
nected in parallel, the D1
- D5 time division pulse
;i;"dr
(rel nig. 4-11) applied to each grid (inde-
G;J""i
grid ior each digit) result in .the digits
being Iit up in succession from the left
hand side'
nacf," aigit is lit up for 1ms during each
5ms inter-
tul. Pin"no.? of PD500g is the brightness
selector
terminal. The time division pulse width
is set to
;00u; for H level input signals, and to
200ps for
L Ievel signals, therety varying the degree
of FL
tube brightness (by varying the segment
lighting
perioa).
"Note
that since the power indicator FL
iune is driven by static drive, the degree
of bright-
,r"rr rrruy be varied by changing the
grid voltage'
ffre f.f ZUHz crystal oscillator generates
the
basic signal used in the preparation
of the time
aiuirlon.-p.tlse signal and the counter
gate circuit
control signal.
F R O M - -
P R E S C A L A R
T a b l e 1
Terminals S1
- 54 (pin nos'3 - 6)^are used in
d"i;;;tt";
reception mode' The 2 reception
;;d"t
emptoved in the SX-3900 (see
Table 1) are
;;;;;;J
bv varving the combination of
input
;;;i;
iH uni l;'
-rri"
s different IFs during FM
;.;;
)re required in coping witir ]f
offset in the
IF ceramic filter stage, 53 and
54 being preset
arrring FM mode acc-ording to
the ceramic filter
characteristics.
"^'Aftfto.,gft
the SX-3900 FM stage quartz-lock
.Vrt"-
is
"capable
of locking any frequency within
;ir;FM bani, the 10kHz digit
(digit in the second
d e c i m a l p l a c e ) i n t h e F M f r e q u e n c y d i s p l a y w i l l
appear onlY as 5 or 0'
.*htu
fr"qrrerr"y display FL tube-also
incorporates
ttre iUNf-fqC ana
^SiCXaL
inclicators' And al-
though the segments (anode)
for these indicators
ur" ,iuti" driven uy itre corresponding
drive cir-
",ritr,
tf," grid is driven according to
the D3 time
liilit"
pu"lse timing, thereby placing the segments
;;J",
djnamic a'iul' ttt addition' the
AM and FM
i n d i c a t o r s i n t h e l r e q u e n c y d i s p l a y s e c t i o n a r e l i t
according to the OS timing'
while the kHz and
MHz indicators are lit according to
the D1 timing'
D I G I T D R I V E R
B R I G H T N E S S
S E L E C T I O N
M U L T I P L E X E R
c o N T R O L C I R C U I T L A T C H
L O A D
G A T E
P R E S E T A A L E 5 ' D I G I ' T
D E C I M A L C O U N T E R
D E C I M A L
C O U N T E R
2 2 - B l T
x 1 6
R O M
l n t e r m e d i a t e f r e q u e n c Y
1 0 . 6 7 M H 2
' 1 0 . 7 0 M H 2
1 0 . 7 3 M H 2
F i g . 4 - 1 1 D i s i t S i g n a l