Philips PM3055 Operation Manual page 46

GLOSSARY OF TERMS
ALT: Alternate display. To display more than one vertical channel, the display switches over from one channel
to another at the end of each time-base sweep. Is suitable for the higher sweep speeds (more than 0,1 ms/div).
ALT TB: Alternate time-base. To display the main time-base signal and the delayed time-base signal. The
horizontal deflection switches between MTB and DTB at the end of each time base sweep.
AUTO: The MTB generator is free-running 100 ms after the last trigger pulse. This means that even in the
absence of trigger pulses a line is written on the screen. As soon as triggers appear, the time-base circuit
switches to the normal trigger mode (cannot be employed for signals with low repetition rates, 20 Hz or
lower).
CHOP: Chopped display. To display more that one vertical channel, the display switches over from one
channel to another at a fixed (chopper-) frequency. The channel that is displayed is also selected as_a trigger
source. Is suitable for the lower sweep speeds (less than 0,1 ms/div).
COMP: Composite triggering. Offers a stable display of two signals applied to channel A and B that are not
time related. Works only in conjunction with the ALT-display mode.
DTB: Delayed time-base. Views an expanded display which can be positioned anywhere along the 10 div.
of the main sweep. The delay time-base multiplier control (DTM) determines the starting point of the DTB.
HOLD OFF: During the HOLD OFF time, the MTB cannot be started by a trigger pulse. When the HOLD
OFF control is not in CAL-position, the HOLD OFF time can be increased in order to obtain a stable display
in digital and computer applications, where complex pulse patterns need to be measured. When a complex
pulse pattern is displayed and this pattern is also used for triggering, a multiple-picture display may occur.
These effects can be corrected by adjusting the HOLD OFF control to increase the hold-off time, so that
certain trigger pulses do not start the MTB,
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MAT 942
INPUT COUPLING: Input coupling, can be a.c.— or d.c.—coupled.
AC-coupled: only the a.c.—component of the input signal is fed to the attenuator, via a blocking capacitor.
This mode can be used when a signal with an a.c. component that is superimposed on a high d.c. voltage
must be displayed.
DC—coupled: the complete input signal (both a.c. and d.c. components) is fed to the attenuator.
AC~-COUPLING DC-COUPLING
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10 Hz FULL BANDWIDTH EERE QUENCY FULL HANDWIDTH
—w- FREQUENCY
MAT 2142