Tektronix VM700T, Руководство пользователя

Страница: 83 / 138

Waveform Mode
3- 8
VM700T Option 01 (NTSC) & Option 11 (PAL) User Manual
Precision Mode : provides a higher-accuracy display for waveforms with rise
times between 5 MHz and 6 MHz. However, the system update rate is slowed
when Precision mode is on. This mode is useful for cursor measurement of fast
edges as found on 1T pulses.
Locked Waveform : when highlighted, this key disengages knob movement.
Moving the knob resets the calculation when accumulating averages, and resets
the screen when in Screen Memory mode. This soft key prevents this from
happening accidentally. It also changes cursor mode to make the knob move the
cursors if they are unlocked from the waveform.
Fixed IRE (NTSC Only)
: When highlighted, overrides the Zero Carrier Pulse
and Bar Reference selections in the current Measurement Locations file, and
fixes the IRE scale to 0 IRE = 0 Volts, 140 IRE per Volt.
This choice provides soft keys to select any of six filter characteristics or no
filter. When filters are engaged, measurement or timing information may become
less reliable.
Pressing the Filter Select soft key brings up the following submenu:
No Filter : displays the waveform without any filtering (default).
High-pass Filter : removes luminance from the signal. The pass band is
approximately 2.5 MHz to 6 MHz.
Low-pass Filter : removes chrominance from the signal. The pass band is
approximately 0 MHz to 1 MHz.
Diff Step Filter
: removes chrominance from the signal, then displays the
direction and relative size of signal transitions.
LF Noise 7.5 kHz/10 kHz/15 kHz : removes all signal information above the
specified frequency.
Pressing the Clamp Couple soft key brings up the following submenu:
Position Backporch : sets the clamp position to the back porch and the clamp
level to 0.0 Volts.
Position Sync Tip : sets the clamp position to the sync tip and the clamp level to
--0.3 Volts (--0.29 V for NTSC).
Clamp Slow
: selects slow clamp speed. This allows hum effects to be visible,
but is useful for coping with large DC offsets on an input signal.
Clamp Fast : selects fast clamp speed. This removes DC offset, hum, and bounce
effects from the signal.
DC Coupling : selects DC coupling (no clamping).
Filter Select
Clamp Couple
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com