Sharp MZ-3500 - Manual (Page 48)

M Z 3500
Example 2: CE330S (light passing through the notch
is sensed and decoded as write protect)
(Double side, Double density)
Write enabled
Light IS interrupted by the label
Write protected
- inhibit notch
Two types of write protection are used and attention
must bepaid to the presience of the label because it may
cause a wrong result if the label is used improperly.
5) Media recording methods
Two recording methode are used:
• FM method (Single density)
This method is called the freqency modulation ( F M )
or double frequency (DF). Clock and data are written
on the media which requires that a clock bit that
precede the data.
1
0
D c
il
c
JLJLJl 0
n
(C: clock, D; data)
Waveforms of data written or read in the FM mode are shown below.
U
C D C D
Write data
(WD)
Write current
Residual magnetic
flux on the media
Read waveform
Differentiate
waveform
Shaped waveform
Read data (RD)
Write current; The write data is input to the flipftop and
is inverted each time a pulse is received to change the
direction of writing current.
at a change of magnetic flux. The waveform is than
shaped to obtain read data identicil t-j tlie write data.
Data cycle will be 4/js.
- .=).^ -