Tektronix 7D11 DIGITAL DELAY Service Instructions Manual page 8

Section 1-7011 Service
OPERATING INFORMATION
7011 FEATURES
The 7D11 Digital Delay plug-in unit is designed for use
with Tektronix 7000-series Oscilloscope mainframes
equipped with a readout system. The 7D11 uses the
readout system to display the selected delay count on the
CRT. A delayed trigger output is generated by counting
time or events. Digital delay time to one second is read out
in 100-nanosecond increments. Additional analog delay
time from zero to 100 nanoseconds selected from a
cal ibrated front-panel dial provides added resolution. An
"echo" time-delay mode provides a divide-by-two scaler to
read out the "one-way trip" time, up to
l
two seconds, for
radar ranging and TDR applications. Delay time accuracy is
controlled by an internal crystal oscillator; greater accuracy
can be obtained by the use of an external one-megahertz
standard. In the Count by Events mode, the CRT readout
displays the integer number of events from one to 10
7
events at count rates up to 50 megahertz.
The 7D11 can be used to delay a 7B-series time-base unit
in either a runs-after or triggerable-after delay time mode.
Other 7D 11 features include on-screen display of delay
interval by vertical signal or display blanking, trigger
pickoff from vertical amplifier unit, and blanking of the
two leading zeros (count by time mode only).
PRELIMINARY INFORMATION
Installation
The 7D11 is designed to operate in any plug-in compart-
ment of Tektronix 7000-series mainframes. However, cer-
tain modes of operation require the 7D 11 to be installed in
a specific compartment. The unit must be operated in a
horizontal compartment to trigger from a signal applied to
REV. B. OCT. 1974
a vertical amplifier unit. The 7D 11 must be operated in the
A Horizontal compartment to control the delay mode of a
time-base unit in the B Horizontal compartment. Operation
in a vertical compartment is necessary to view the Delay
I nterval Pedestal without the use of external cables.
To install the 7D 11 into a plug-in compartment, push
the unit in until it is seated flush against the front panel of
the mainframe. To remove, pull the release latch to
disengage the 7D11. Continue to pull the release latch to
remove the'unit from the mainframe.
Display
The 7D11 readout display is presented on the CRT of
the mainframe, along with information encoded by the
other plug-in units. Digital delay time (in milliseconds) is
displayed in five to eight digits. The
+
symbol to the right
of the digital display reminds the operator to add any
analog delay time selected by the FINE DELAY (ns) dial to
the delay time. The number of events being counted is
presented in a seven to eight digit display.
The 7D11 readout display appears on the CRT in a
location corresponding to the plug-in compartment used.
The delay time or number of events will be displayed in the
top division of the CRT graticule. The delay-time measure-
ment unit (ms) will be displayed in the bottom division. It
is not necessary to select the 7 D 11 with the mainframe
Vertical or Horizontal Mode switches to view the digital
display. In order to view the Delay Interval Pedestal
waveform, selection with the Vertical Mode switch is
required.
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