6
CX-958
10) EFM Circuit
This circuit is used for converting the RF signal to
digital signal consisting of “0” and “1”. The RFO signal
from Pin 75 is externally AC coupled, entered to Pin 74,
then applied to the EFM circuit.
Loss of the RF signal due to scratches or stains on the
disc, or vertical asymmetry of the RF due to variations
in the discs manufactured can’t be eliminated by AC
coupling alone. This circuit, therefore, controls the
reference voltage ASY on the EFM comparator by use
of the fact that “0” and “1” appear fifty fifty in the EFM
signal. By this arrangement, the comparate level is
constantly maintained at almost center of the RFO
signal level. The reference voltage ASY is generated
when the EFM comparator output is passed through
the low pass filter. The EFM signal is output from Pin
71. It is a 2.5 Vp-p amplitude signal centering on REFO.
74
RFI
40k
40k
C213
3900pF
72
71
ASY
EFM
40k
40k
15k
75k
2k
R202
10k
R203
39k
C211
0.1
µ
F
C210
3300pF
EFM. SIG
Fig.9 : EFM CIRCUIT
Содержание DEH-1350B
Страница 6: ...4 DEH 2350 1350 2 2 EXTERIOR B A ...
Страница 8: ...6 DEH 2350 1350 2 3 CD MECHANISM MODULE C D ...
Страница 25: ...23 DEH 2350 1350 ...
Страница 27: ...25 DEH 2350 1350 5 6 7 8 5 6 7 8 D C B A A FRONT 1 2 3 1 2 FM AM TUNER UNIT SIDE A ANTENNA PRE OUT ...
Страница 28: ...26 DEH 2350 1350 1 2 3 4 1 2 3 4 D C B A A 4 5 6 3 2 1 1 2 3 6 5 4 A TUNER AMP UNIT ...
Страница 29: ...27 DEH 2350 1350 5 6 7 8 5 6 7 8 D C B A A 1 2 3 6 5 4 4 5 6 3 2 1 FRONT SIDE B ...
Страница 31: ...29 DEH 2350 1350 1 2 3 4 1 2 3 4 D C B A B B CN601 A SIDE B KEYBOARD UNIT ...
Страница 33: ...31 DEH 2350 1350 1 2 3 4 1 2 3 4 D C B A CLAMP SIDE B CONTROL UNIT C C ...
Страница 40: ...38 DEH 2350 1350 Grating waveform Ech Xch 20mV div AC Fch Ych 20mV div AC 45 0 75 60 30 90 ...