Vert Trigger Source - Tektronix 2245A Operator's Manual

Controls, Connectors, and Indicators
Trigger
and
V ertical
M odes
AUTO
LEVEL
or
CHOP
NON­
AUTO
LEVEL
and
ALT
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 the ac
power-source waveform. This trigger source is useful when the dis­
played waveform frequency is time related to the ac power-source
frequency.
( 3 8 )
CPLG (U p -A rro w
to rs —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 dc and all frequency components of a triggering signal
to 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 R eject)—Couples all frequency components of
the input signal to the trigger circuitry but increases the peak-to-peak
signal amplitude required to produce a trigger event.
2-16
Table 2-1

VERT Trigger SOURCE

ADD
Mode
On
Algebraic sum of CH 1 and CH 2 input
signals.
Lowest numbered vertical channel
Off
displayed.
On Alternates between displayed vertical
or channels in the following order: Ch 1,
Off Ch 2, Ch 3, CH 4, and ADD.
and D ow n-A rrow )
Trigger Source Selected
B uttons and Indica­
2245A Operators