JVC DD-9 A - Newly Developed Computer B.E.S.T. System

DD-9A/B/C/E/J/U
Features of New B.E.S.T. System
ee,
® Bias Level Setting System with MOL Balance Taken into = Comparison Table between KD-A66 and DD-9
Consideration cree
With an 8 kHz variable normal or chrome tape, the dif- pia pee
ference
in
bias
level
between
MML
(333
Hz)
and
MOL
eae
Bias
level
(B)
Coincident
point
of
7
kHz
and
1
kHz
The
bias
level
is
lowered
by
A
dB
due
to
the
(10
kHz)
is
set
to
12
dB,
while
with
a
metal
tape,
it
is
set
(2)
8
steps
bias
current
characteristics,
as
the
MOL
bal-
to around 8 dB. The MOL balance is thereby stabilized. penne || Detection at R channel ance is considered.
4 a peak point?
eee
:
Wes
16
steps
= High-accuracy Bias, Equalization and Sensitivity Level — Average value between R and L channels
Is there the
Setting System set bias point? eae : Se ;
a Medium-frequency Coincident point of 4 kHz and 1 kHz
2 Rh ee
The accuracies of bias, sensitivity, medium and high fre-
quency equalization levels are greatly improved through
average calculation of reading error.
8 steps
Average value between R and L channels
Coincident point of 12.5 kHz and 1 kHz](1) Coincident point of 12.5 kHz and 1 kHz
(2) 8 steps (2) 16 steps
Detection at R and L channels Recording is performed 3 times at each step.
(3) Average value between R and L channels
Equalization level {medium
frequency) adjustment
equalization level
(EQ M)
FIRST BIAS
ds the response
at 1 kHz/4 kHz
flat?
NO.
High-frequency
equalization level
(EQ H)
= Second Bias System
Recording/playback
With a special tape, the respective levels are readjusted sensitivity adjustment
by this system, thus their accuracies are assured.
(1) (1) Coincident point of recording and playback
at 1 kHz
(2) 16 steps
(3) Average value between R and L channels
Coincident point of recording and
playback at 1 kHz
(2) 8steps
(3) Detection at R channel
About 25 sec
Tape sensitivity
level
(S)
Are the
recording and playback
sensitivities equal with
each other?
NO
= 4-bit 1-chip 2k ROM Microcomputer
Equalization level (high
frequency) adjustment
Required time About 30 sec (This time differs slightly according
to the tape used.)
4-bit 1-chip 2k ROM 4-bit 1-chip 2k ROM
1s the response
at 1 kH2/12.5 kHz
flat
NO
Set
B.E.S.T.
j
]
a
Indications
PRESET/ERROR,
RUN/READY
B,
EQM,
S.EQH,
PRESET,
ERROR
Memory
Not
provided
Temporary
memory
1s the
response
NO
.
atl HL
2:
RHE
te
a
A/D
conversion
Peak-hold
type
Soft
peak-hold
type
4
Equalization
level
(medium
frequency)
adjustment
Grant
Bias
level
setting
Bias
level
setting
L
channel
7
EHO
LHe
INO
—
‘
channel
at
; oS
Zz
BkH2
ne
lat?
oi
'
a
nil
|
fe
Recording/playback
sensitivity
MOL
balance
nas aie
T
aa
;
;
|
adjustment
‘
'
.
.
.
|
|
|
Phy
ae
non
ips
2
With
the
linearity
characteristics
of
the
tape
and
the
fre-
|
MOL
difference
annEaI
BESIABOLEEE
cea
rl
ty
a
:
r
.
ot
eye
a
¢
quency
components
of
the
input
signals
taken
into
con-
REC
ON
ias
level
detectin
i
Are
the
i
‘
:
R
channel
Bias
level
detecting
point
L
channel
Bias
level
detecting
point
8
Fecording
and
playback.
No
=
sideration
to
record
musical
signals
at
good
balance,
the
315
Hz
10
kHz
”n
«
|
Spon
emnert
difference
between
the
low-frequency
(315
Hz,
K3
:
3%)
i
MOL
and
high-frequency
(10
kHz)
saturation
MOL
(or
Medien
frequency,
eqilalization
Tape
sensitivity
level
setting
i
.
:
3s
id
(
)
{
lel setting
Equalization
Jevel
(high
SOL)
is
set
to
12
dB
on
normal
tapes
and
8
dB
on
high-
|
frequency)
adjustment
\
performance
tapes
such
as
metal
tapes,
etc.
Output
es
Lg
ee
sinned
ina
ico
Thus,
the
maximum
recording
level
is
determined
and
& 6
(ket,
T
1
kHz/12.5
a
i j
i
i
{hie
cial
le
nll
cele
ul
|
allele
fiat?
2
oe
the
bias
current
is set
with
a
MOL
difference.
A dB
;
SS
Ce
eee
eas
sae
4
feieorer
Practically,
a
signal
of
8
kHz
is recorded
based
upon
the
I
Medium-frequency
equalization’?
(Reference
level}
Tape
sensitivity
level
Set
B.E.S.T.
?
;
:
,
level
detecting
point
detecting
point
data
of
various
tapes
and
the
MOL
balance
is
determined
8
kHz
j
é
na
NA
!
by
the
bias
current
characteristics
for
this
signal.
Bias
current
I
:
\
High-frequency
equalization
level
setting
High-frequency
equalization
level
setting
R
chinnel
L
channet
REW
on
12.5
kHz
tie
Fig
5
Fig
6
eT}
ero
A.
CHANNEL
©
1
2
3
4
5
6
bs
J
* UL
CHANNEL
©
1
2
STOP
L sTop
Returns
qsthe
start
position
“a
R-ch
high-frequency
equalization
“<
L-ch
high-frequency
equalization.
level
detecting
point
level
detecting
point
REWIND
REWIND
REWIND
Fig. 4
No. 4198