Samsung MM-28 Service Manual page 17

5-1-5 Mirror Circuit
After RFI signal is amplified by mirror amp, mirror signal is held in peak and bottom circuit. The following of
100KHZ traverse is possible in peak hold circuit and the loss of track count due to defect is counted in bottom
hold circuit. Mirror output beyond 2KHz is. ÒLÓ at track on disc, ÒHÓ at interval between track on disc, ÒHÓ
when the defect beyond 1.4ms is detected.
The time constant for the mirror hold must be sufficiently large than of the traverse signal
IRF
5-1-6 EFM Comparator
The EFM comparator converts a RF signal into a binary signal
As the asymmertry due to variations in disc manufacturing can not be eilminated by thr AC coupling alone,
the reference voltage of EFM comparator is controlled utilizing the fact that the generation probability of 1,0
50% each in the binary EFM signals.
Samsung Electronics
38K
17K
75
-
Peak and
Bottom
+
Hold
19K
40K
RFI 77
19K
100K
-
1.5K
+
2.5K
17K
-
+
96K
-
+
100K
20K
85K
Special Circuit Descriptions
1 MCP
39 MIRROR
EFM
1
ASY
39
5-3