Tektronix 7D14, Instruction Manual

Page: 10 / 133

7D14
SECTION
2
OPERATING INSTRUCTIONS
Change information, if any, affecting this section will be found at the rear of this manual.
General
The 7D14 Digital Counter plug-in unit operates with the
readout system of Tektronix 7000-series Oscilloscopes to
measure frequency or frequency ratio, and to totalize
(count number of events). To effectively use the 7D14, the
operation and capabilities of the instrument should be
known. This section describes the function and operation
of the controls and connectors, and gives first-time and
general operating information.
Installation
The 7D14 is designed to operate in any plug-in compart­
ment of Tektronix 7000-series oscilloscopes. However,
certain modes of operation require the 7D14 to be installed
in a specific compartment. The unit must be operated in a
Horizontal compartment to count a signal which is being
displayed on the CRT (see Counting a Displayed Signal).
Operation in a Vertical compartment is necessary to view
the 7D14 Trigger Indicator Display on the CRT (see Trigger
Indicator Display).
To install the 7D14 into a plug-in compartment, push
the unit in until it is seated flush against the front panel of
the oscilloscope. To remove, pull the release latch to dis­
engage the 7D14. Continue to pull the release latch to
remove the unit from the oscilloscope.
Display
The digital readout display for the 7D14 is presented on
the CRT of the oscilloscope in which the unit is operated,
along with information encoded by the other plug-in units.
This display is written by the CRT beam on a time-shared
basis with the analog waveform displays.
The digital display for the 7D14 will appear on the CRT
in a location corresponding to the plug-in compartment
used. The measurement data portion of the display will be
in the top division of the CRT graticule area and the
measurement units (MHz or kHz), when displayed, will
appear in the bottom division.
It is not necessary to select the 7D14 with the oscillo­
scope Vertical or Horizontal Mode switches to view the
digital display. However, in order to view the 7D14 Trigger
Indicator Display, selection with the Vertical Mode switch
is required.
The readout display of the measurement data consists of
four to eight digits depending on the measurement being
made. All zeros to the left of the most significant digit are
blanked out.
The measurement units and decimal position in the dis­
play are determined by the MEASUREMENT INTERVAL
pushbutton selected. When the measurement range in use is
exceeded, the display is preceded by a "greater than"
symbol (>).
CONTROLS AND CONNECTORS
The major controls and connectors for operation of the
7D14 are located on the front panel of the instrument.
These are shown in Fig. 2-1. Two auxiliary functions are
provided by controls located inside the instrument. A de­
scription of the function and/or operation of the controls
and connectors follows.
Measurement Interval Controls
MEASUREMENT
INTERVAL
1 ms — 10 s (one
millisecond through
10 seconds)
MANUAL GATE
GATE Indicator
Seven self-cancelling pushbutton
switches that select internal, exter­
nal, or manual gate.
Selects one of five measurement
intervals from the internal time­
base gates. A time-marker output
with a period equal to the selected
interval is provided at the MONI­
TOR connector.
ON: Initiates gate interval (start
count), and holds the gate open
for totalizing.
OFF: Terminates gate interval (stop
count), and starts display time.
Also selects external gating
signal from the EXT GATE con­
nector.
Lights during the active gating
interval.
2-1