Operating Information; Preliminary Information; Installation; Controls And Connectors - Tektronix 7B92 Instruction Manual

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Section 1-7892 Service
OPERATING INFORMATION
The 7B92 Dual Time Base unit operates with a Tektronix 7900-Series oscilloscope and a 7 A-Series amplifier unit to form a
complete high-frequency oscilloscope system. To effectively use the 7B92, its operation and capabilities should be known.
Brief operating information is given in this section. For more detailed instructions, refer to the 7B92 Operators Manual.
PRELIMINARY INFORMATION
Installation
The 7B92 is designed to operate in the horizontal
compartment of the oscilloscope. This instrument can also
be installed in the vertical plug-in compartment to provide a
sweep that runs vertically on the CRT. However, when used
in this manner, there is no retrace blanking or internal
triggering, and the unit may not meet the specifications
given in the Operators Manual. The. instructions in this
manual are written for use of the 7B92 in the horizontal
plug-in compartment.
Before proceed ing with installation, check the settings of
the Variable Selector multi-pin connector and the Main-
frame Selector multi-pin connector (see Fig. 1-1). The
Variable Selector determines whether the front-panel
VARIABLE control operates in conjunction with the
Delaying or Delayed Sweep. The Mainframe Selector
determines the oscilloscope in which the 7B92 is to be
operated; any 7900-Series Oscilloscope, or any other
7000-Series Oscilloscope.
CONTROLS AND CONNECTORS
General
All controls required for the operation of the 7B92,
except the Variable Time/Division Selector and Mainframe
Selector, are located on the front panel of the instrument.
To make full use of the capabilities of this instrument, the
operator should be familiar with the function and use of
each control. A brief description of the front-panel controls
and connectors is given here. More detailed information is
given in the 7 B92 Operators Manual. Fig. 1-2 shows the
front-panel controls and connectors of the 7B92.
G)
Main Triggering Controls
LEVEL. Selects the amplitude point on the trigger signal
where sweep triggering occurs when operating in the
AUTO, NORM, or SINGLE SWEEP MAIN TRIGGERING
MODE. When operating in the HF SYNC MAIN TRIG-
GERING MODE, the LEVEL control adjusts the frequency
of the trigger generator to synchronize with the triggering
signal to provide a stable display.
SLOPE. Permits triggering on the positive or negative-
going portion of the trigger signal in all positions of the
MAIN TRIGGERING MODE switch except HF SYNC.
TRIG'D Light. Indicates that the sweep is triggered and
will produce a display with the correct setting of the
POSITION control and the controls of the associated
vertical units and oscilloscope.
MODE. Four pushbutton switches to select the desired
triggering mode. Selected mode is indicated by lighted
pushbutton.
AUTO. Triggered sweep is initiated by the applied
trigger signal at a point selected by the LEVEL control
and SLOPE switch when the trigger signal repetition rate
is above 30 hertz and within the frequency range
selected by the COUPLING switch. The sweep free-runs
to provide a reference trace under the following condi-
tions: When the LEVEL control is outside the amplitude
range, the trigger repetition rate is outside the frequency
range selected by the COUPLING switch, or the trigger
signal is inadequate.
HF SYNC. Sweep initiated by trigger signals with
repetition rates above 100 megahertz and within the
range selected by the COUPLING switch. Stable displays
can be obtained when the LEVEL control adjusts the
frequency of the trigger generator to the frequency (or
subharmonic) of the trigger signal frequency. When the
LEVEL control is adjusted to frequencies between
subharmonics, the sweep free- runs.
NORM. Sweep initiated by the applied trigger signal at a
point selected by the LEVEL control and SLOPE switch
over the frequency range selected by the COUPLING
switch. Triggered sweep can be obtained only over the
amplitude range of the applied trigger signal. When the
LEVEL control is outside the amplitude range, the
trigger repetition rate is outside the frequency range
selected by the COUPLING switch, or the trigger signal
is inadequate, there is no trace.
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