Tektronix 7613 User Manual

Circuit Description—7613/R7613 Service
Decimal-point location en-
coded during this time-slot
- no display
First possible character dis-
played on CRT at this loca-
tion
First number of measure-
ment normally displayed at
this location
00 0.0,0.0,0.0 0 0
\
Co
Always
skipped Decimal point
even if Decimal point location No. 7
no data location No. 4 {column 7)
encoded (column 4)
Decimal point
location No, 6
Decimal point
P {column 6)
location No, 3
Decimal point
{column 3) hi
location No. 5
(column 5}
position current from the Decimal Point Logic and Char-
acter Position stage is added to the X (horizontal) input
signal to space the characters horizontally on the CRT (see
previous discussion). The Ready signal at pin 13 (coincident
with Vertical/Horizontal Channel Switch OFF Command)
activates this stage when a character is to be displayed on
the CRT.
Fig. 3-36. Readout word relating 10 possible character locations to
the decimalt-point instructions that can be encoded and the resulting
display.
of the Format Generator through R2280 raises the decimal
point so it appears between the displayed characters.
When decimal-point data is encoded, the CRT is un-
blanked so a readout display is presented. However, since
row 7 does not activate any of the five Character
Generators, the CRT beam is not deflected but instead
remains in a fixed position to display a decimal point
between the characters along the bottom line of the
readout word. After the decimal point is produced in the
addressed location, the CRT beam returns to the location
indicated by the Character Position Counter to produce the
remainder of the display.
Format Generator
The X- and Y-deflection signals produced by the
Character Generator stage, are connected to pins 2 and 7
respectively of Format Generator U2284. The Channel
Address No. 2 code from the Channel Counter is also
connected to pins 1, 8, and 15 of this stage. The Channel
Address No. 2 code directs the Format Generator to add
current to the X and Y signals to deflect the CRT beam to
the area of the CRT which is associated with the plug-in
channel that originated the information (see Fig. 3-24). The
Channel Address No. 2 Code and the resultant word
positions are shown in Table 3-4. In addition, the character
3-48
TABLE 3-4
Channel Address No. 2 Code
Pin 11 Pin 8 Pin9 Channel
U2250 U2250 U2250 Displayed
LO LO LO Channel 1
Left Vertical
LO LO HI Channel 2
Left Vertical
LO HI LO Channel 1
Right Vertical
LO HI HI Channel 2
Right Vertical
HI LO LO Channel 1
Horizontal
HI LO HI Channel 2
Horizontal
Y-Output Amplifiers
The Y-output signal at pin 6 of U2284 is connected to
the Y-Output Amplifier Q2287-Q2299. This stage provides
a low impedance load for the Format Generator while
providing isolation between the Readout System and the
Vertical Amplifier. Vertical Separation adjustment R2291
changes the gain of this stage to control the vertical
separation between the readout words displayed at the top
and bottom of the graticule area.
X-Output Amplifier
The X-Output Amplifier 02286-02296 operates simi-
larly to the Y-Output Amplifier to provide the horizontal
deflection from the readout signal available at pin 4 of
U2284. The gain of this stage is fixed by the values of the
resistors in the circuit.
Display Sequence
Fig. 3-37 shows a flow chart for the Readout System.
This chart illustrates the sequence of events which occurs in
the Readout System each time a character is generated and
displayed on the CRT.
7613

Tektronix 7613 Specifications

General

Brand	Tektronix
Model	7613
Category	Test Equipment
Language	English