Table 3 4: Repetition Encodings - Tektronix 11801C User Manual

11801C User Manual
H TIFF Compacted sends a compressed TIFF image using PackBits
compression. Note that some application software will not accept Rev.
6.0 compressed TIFF Class P images. Screen formats are the same as
for TIFF.
H Binary mode bytes of pixel data are sent as a stream of binary values
without delimiters.
H Binary Compacted mode pixel data are compressed before being sent.
See the discussion of compression, below.
H BinHex mode converts every four bits into a hexadecimal character.
Each line is terminated by a new line character.
H BinHex Compacted mode pixel data are compressed and then con
verted into BinHex characters.
Title Block consists of three character strings terminated by new line
characters. The first line contains the firmware version numbers, time and
date, and the 11801C ID number. The second and third lines give the num
ber of pixels per display line and the number of display lines, respectively. In
Binary mode, the title block is terminated by a NULL character.
Pixel Data Compression
block. Without compression, each data byte contains a single three bit pixel.
With compression, two pixels are stored in the six low order bits of the data
byte, and the two high order bits are a repetition encoding with the following
meaning:

Table 3 4: Repetition Encodings

Bit 7 Bit 6
0 1
1 0
1 1
0 0
If the second byte of the pixel block has a value in the range 4-225, it is the
pattern repetition count. If the value is 1 3 decimal, it is the high order bits of
a 10 bit repetition count, and the third byte of the pixel block contains the
eight lower order bits.
Output Port
The Output Port selector allows you to choose GPIB, RS232C, or Centron
ics (the PRINTER connector). The selection must match the rear panel
connection.
significantly reduces the size of the pixel data
Meaning
Pattern repeats once
Pattern repeats twice
Pattern repeats three times
Following byte(s) contain repetition count
Hardcopy
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