Radio Shack TRS-80 III - DATA ELECTRONICS

INDEX SINGLE SIDED
Dr
ECT
:! HEAD ASSE91
DC STEPPER MOTO
INDEX
PULSE
~~2~.
PULSE SHAPING
<g> -I
NETWORK
l": : .~~
I BAND
~~
DRIVE
WRITE
'f£R' I
PROTECT
I
INDEX
D.C DRIVE
I
~
~
TRACK
00
<Ci--
~,
CH
"
DRIVE J
MOTOR
1----.
ENABLE
I SPINDLE DRIVE
INTERFACE
1
I CONTROL
CONTROL
I
DIRECTION
I
POSITIONER I
STEP
CONTROL :
~----- ....
I
WRITE BUSY
WRITE
WRITE/ERA
DATA
CURRENT SOU
AND WAVEF
GENERAT
WRITE ENABLE
READ DATA
READ AMPLIFIER
ITIZER
FIGURE 4. FUNCTIONAL BLOCK DIAGRAM
DATA ELECTRONICS
Information can be recorded on the diskette using a double-
frequency code.
Figcrre 5 illustrates the magnetization pro-
files
in each bit cell for the number sequence shown.
All signals required to control the data electronics are pro-
vided by the user system and are shown
in the Block Dia-
gram (Figure 4). These control signals are:
* SELECT
The erase gaps provide
an erased guard band on either side
of the recorded track. This accommodates the tolerances
in track positioning.
* WR ITE ENAB LE
* WRITE DATA
The
READ DATA composite signal is sent to the user
system
via the interface.
~
I
I
I
1
I
BIT CELL
-H
I
I
I
I
I
BIT PATTERN
NWRITEDATA
a
I
I
I
I
iii
I I I I I I I I i I I I I I I
I I I I : : I : I : : : : : :
I I I I I I 1 I I I I I I I I
I,........,., ~I I~I n: I :,.--;---'\1 pi
MAGNETIZATION I \. '_ r--..-l----JI 1 ~
J U' I I I I I\.......!...-): : :U, ~L
1 I I I 1 : : : : I : : 1 I :
I I 1 I 1 , 1 I I I I ; 1 I 1
MAGNETIC ELEMENTS _~IF-~I'-~',-~;..".-¥I ;.......:.,' ......,;~_+;..".~' ;;........;._~;;.......:..' ......,;~_..;;JoIr-...;}jIF---
S S S S
FIGURE 5. FM RECORDING
98