Tektronix 2247A Operator's Manual page 24

:0
Controls, Connectors, and Indicators
VERT -Selects the trigger signal from the displayed waveforms.
The TRIGGER MODE and VERTICAL MODE switch settings determine
the trigger signal source selection. When VERT Is selected , one or
more of the SOURCE lights will be on to Indicate the trigger signal
source. See Table 2-1 for VERT Trigger SOURCE selections .
CH 1-The signal applied to the CH 1 OR X Input connector is t he
source of the trigger signal.
Table 2-1
VERT Trigger SOURCE
Trigger
ADD
Trigger Source Selected
and
Mode
Vertical
Modes
AUTO On
Algebraic sum of CH 1 and CH 2 input
LEVEL
signals.
or
CHOP Off
Lowest numbered vertical channel
displayed .
NON- On Alternates between displayed vert ical
AUTO
or channels in the following order : CH 1,
LEVEL
Off CH 2, CH 3, CH 4, and ADD.
and
'
ALT
CH 2-The signal applied to the CH 2 Input connector Is the source
of
the trigger signal.
CH
3-
The signal applied to the CH 3 Input connector Is the source of
the trigger signal .
CH 4-The signal applied to the CH 4 input connector Is the source of
the trigger signal.
LINE-The triggering signal is obtained from a sample of th e ac
power-source waveform . This trigger source Is useful when th
2-18
2247 A Operators
I
I
I
®
Controls, Connectors, and Indicators
displayed waveform frequency Is time related to the ac power-source
frequency .
CPLG (Up-Arrow and Down-Arrow) Buttons and Indi-
cators-Select the method of coupling the input trigger signal to the
A or B trigger system as directed by the A/B SELECT button.
Pressing the Up-/Down Arrow buttons selects the trigger coupling as
shown by the CPLG lights .
DC-Couples de and all frequency components of a triggering signal
t o the trigger circuitry.
DC coupling Is useful for most signals, but It Is especially useful for
providing a stable display of low-frequency or low-repetition-rate
signals.
NOISE REJ (Noise Reject)-Couples a!I frequency components of
the Input signal to the trigger circuitry but Increases the peak-to-peak
signal amplitude required to' produce a trigger event .
NOISE REJ coupling Is useful for Improving stability when the trigger
signal Is accompanle' d by low-level noise.
I
HF REJ (High Frequency Reject)-Attenuates high- frequency
triggering signal components above 50 kHz.
HF REJ coupling Is useful for providing a stable display of low-
frequency components of complex waveforms and eliminates high-
frequency Interference from the trigger si~nal . ·
LF REJ (Low Frequency Reject)-Attenuates !'ow-frequency trig-
gering signal components below 100 kHz and blocks the de component
of the trigger signal.
'
LF REJ coupling Is useful for producing stable triggering on the high-
frequency components of complex waveforms and rejecting low-
frequency Interference or power supply hum from the trigger signal.
AC-Attenuates trigger signal frequency components below 50 Hz
and blocks the de component of the signal.
AC coupling Is useful for triggering on ac waveforms that have a large
de offset .
2247 A Operators
2-19