HP 5335A - Page 24

Operation and Programming
3-55. Input Group
3-56. The INPUT GROUP contains the A Channel
and B Channel input BNC ; s , signal conditioning
controls, and triggering controls.
3-57. The SLOPE key determines which edge of the
signal to trigger on. For some functions it also takes
on other uses. For PULSE, the Slope A switch is used
to specify the positive (_/") or negative (”\_) pulse.
For RISE/FALL, it is used to specify whether it is RISE
or FALL time being measured. SLOPE A has a similar
purpose for SLEW. For DUTY CYC, it determines
whether to display the percentage high (_/") or
low (~\J.
3-58. The AC key, when pressed, makes the respective input amplifier ac coupled. This is useful
for ignoring dc offsets on a signal.
3-59. The input impedance of each channel is selected by the Z=1MO/50n key. When in the
5011 position, the input damage level is 5V.
3-60. For inputs greater than the 5V dynamic range, or to reduce the sensitivity of the front end,
the X10 ATTEN key lets you attenuate the signal by a factor of 10. The 5V damage level still applies,
however, when Z = 50. For convenience, the trigger level reading function will arithmetically
multiply the display by 10 when the attenuators are on.
3-61. Triggering (MANUAL/AUTO)
3-62. The HP 5335A has an extensive set of triggering features which make accurate measure¬
ments on input signals easier for the user. Four modes of triggering, listed below, are directly
accessible from the front panel or via the HP-iB. A fifth mode (see paragraph 3-67) is auto¬
matically selected when in the RiSE/FALL A or SLEW A function modes.
Manual Adjustable
Manual PRESET
Auto Adjustable
Auto PRESET
3-63. The Manual Adjustable mode uses the trigger adjustment controls to set the trigger level
anywhere between +5 and -5 volts. The actual trigger levels for both channels can be monitored
by pressing the TRIG LVL function key. When the control is fully ccw (into detent) the Manual
PRESET mode is selected, and the trigger level is set to 0 volts.
3-64. When the Auto Trigger mode is selected, the trigger adjustment controls assume a wholly
different meaning. Pressing the AUTO TRIG key selects the Auto Adjustable triggering mode.
The range of adjustability for the control is now dependent on the amplitude of the input signal,
with the peaks of the input signal nominally setting the control limits.
3-65. Assume, for example, an input signal of 2 volts p-p, with Auto Adjustable triggering
selected. The range of the trigger adjustment control outsideof PRESET will automatically reduce
from ±5V to 0V-—+2V. This allows a much finer control over the trigger level setting. The actual
trigger levels for both channels can be monitored by pressing the TRIG LVL function key.
3-8
Model 5335A