Figure 1-4.-Manchester encoding.
through 6 are the decoded address bit, but it is not the
a master clock pulse train. The clock pulse rate is 120
same configuration as the encoded word. Bit 7 is the tag
bit and is always 1 in the decoded word. Bit 8 is the enter
bit and is always 0 for the decoded words.
The ICCG components process binary command
and status words that cause changes in operation and
display configuration. Word exchanges between
components are done by binary word data encoded in
Manchester format.
Manchester Word Encoding
The Manchester word format is a modification of
the 36-bit encoded word generated in the components.
This is done for transmission of the information from
one component to another. The modification is
accomplished by combining the basic 36-bit word with
kHz, and the pulse width is 8.3 microseconds.
Figure 1-4 shows a Manchester encoder equivalent
circuit and its input and output signals. When both inputs
to the first AND gate are 1, the Manchester word bit is
also 1 for the 4.15-microsecond duration of the positive
clock pulse. The resulting Manchester pulse occurs
during the first half of the bit period. The output pulse
of the first AND gate is applied to both the inverter input
and the Manchester word output. The inverter produces
a 0 output to keep the output of the second AND gate at
0, while a Manchester pulse is being produced. Since
the clock pulse is negative during the second half of the
bit period, the output of the second AND gate remains
at 0.
When the basic binary word bit at the first AND gate
is 0 and the clock pulse is 1, the output of the first AND
gate is 0. This causes the output of the inverter to be 1.
1-6
