35
Subject to change without notice
29. Trigger Filter Check
– Set time base to 500 μs/div.
– Set attenuator CH 1 to 5 mV/div.
– Connect a 1kHz sine wave signal of 25 mVpp amplitude to
input CH 1 and check for 5 div. Y defl ection.
– Set attenuator CH 1 to 50 mV/div and check for 5mm display
height.
– Select trigger coupling AC, DC, HF, Noise Reject and LF.
– With the exception of HF, the signal must always trigger
the oscilloscope. As in DC trigger coupling mode the peak
value triggering is switched off, turn the LEVEL A/B knob
until stable triggering is performed.
– Set time base to 20 μs/div.
– Set sine wave generator to 50 kHz and 25 mVpp output
amplitude and check for 5 div. Y defl ection.
– Set attenuator CH 1 to 50 mV/div and check for 5mm display
height.
– Select trigger coupling AC, DC, HF, Noise Reject and LF.
– Select trigger coupling from AC, DC, HF, NR and LF.
– Except in LF trigger coupling condition, the signal must
always trigger the oscilloscope. As in DC trigger coupling
mode the peak value triggering is switched off, turn the
LEVEL A/B knob until stable triggering is performed.
30. Time Base A: Extern Trigger Sensitivity
– Connect a 600 mVpp, 50 kHz sine wave signal from a con-
stant amplitude generator via a 2:1 signal splitter and via
50Ω through terminators to the inputs of CH1 and CH4.
– Check that attenuator CH1 (VOLTS/DIV) is set to 200 mV/
div.
– Check that trigger source CH1 is chosen.
– Check that the signal is displayed with 3 div. height on the
screen.
– Check that trigger source “External” is chosen.
– Check that the signal can trigger the time base in AUTOMA-
TIC and NORMAL trigger mode in combination with AC- and
DC-trigger coupling.
– Continue with item 31 without changing the signal parame-
ters.
31. Time Base A: Extern Trigger Bandwidth
– Operate oscilloscope as described under item 24.
– Set the generator frequency to 150 MHz.
– Set attenuator CH 1 (VOLTS/DIV) for approx. 2 to 6 div. signal
display height.
– Check that the signal can trigger the time base in AUTO-
MATIC and NORMAL trigger mode in combination with AC,
DC and HF trigger coupling.
32. Time Base A: Accuracy (Analog)
Preparations:
– Press the PROBE ADJ pushbutton below the CRT to display
the Utilities menu.
– Switch COMP. TESTER On.
– Press the AUTO/CURSOR-MEASURE pushbutton and the
SETTINGS pushbutton at exactly the same time to activate
the Settings Adjust menu.
– Press “Adjust 2” function key to open Adjust 2 menu.
– Press “Timebase” function key to open Timebase menu.
– Press A Timebase function key to open A Timebase
menu.
Note:
The actual time base setting and the required signal
frequency are displayed on the screen.
– Set time mark generator for 100μs spike pulses (alterna-
tively 10 kHz sine wave signal); signal frequency accuracy
0.1 ppm or better.
– Check that the current time base setting is 100 μs/div.
– Connect signal to input CH 1.
– Turn CH 1 VOLTS/DIV knob for a signal height of approxi-
mately 5 divisions.
– Turn LEVEL A/B knob for stable triggering.
Accuracy reading:
The accuracy reading should always be performed in the
following way:
– Set POSITION 1 knob on the front panel for reading of the
pulse peak or sine wave zero crossing at the horizontal
center line of the graticule.
– Move trace with HORIZONTAL knob (front panel) so that the
fi rst pulse peak or sine wave zero crossing coincides with
the fi rst or second vertical graticule line at the left side of
the screen.
– Check that 1 pulse or signal period per division is displayed
and the rightmost pulse peak or zero crossing coincides
with the vertical graticule line as on the left side = 0% er-
ror.
– The maximum acceptable deviation at the 10
th
or 11
th
pulse
or zero crossing is ±3 mm (3%).
Performance Check:
– Set TIME/DIV knob for “TB: 50ns” display.
– Connect a 50ns time mark signal or a 20 MHz sine wave
signal (accuracy 0.1 ppm or better) to the input of CH 1.
– Turn CH 1 VOLTS/DIV knob for a signal height of approxi-
mately 5 divisions.
– Set LEVEL A/B knob on the front panel for stable trigge-
ring.
– Check the accuracy at this setting.
– Turn TIME/DIV knob one step counter clockwise and note
the time base and signal frequency information displayed
by the readout.
– Repeat this procedure until the 500 ms time base setting
has been checked.
– Press Menu Off key to return to “Adjust 2 Timebase”
menu.
– Continue with item 33.
33. Time Base B: Accuracy (Analog)
– Press “B Timebase” function key.
– Set time mark generator for 50μs spike pulses (alternatively
20 kHz sine wave signal); signal frequency accuracy 0.1 ppm
or better.
– Check that the current time base setting is 50 μs/div.
– Connect signal to input CH 1.
– Turn CH 1 VOLTS/DIV knob for a signal height of approxi-
mately 5 divisions.
– Turn LEVEL A/B knob for stable triggering.
Accuracy reading:
The accuracy reading should always be performed in the
following way:
– Set POSITION 1 knob on the front panel for reading of the
pulse peak or sine wave zero crossing at the horizontal
center line of the graticule.
– Move trace with HORIZONTAL knob (front panel) so that the
fi rst pulse peak or sine wave zero crossing coincides with
the fi rst or second vertical graticule line at the left side of
the screen.
– Check that 1 pulse or signal period per division is displayed
and the rightmost pulse peak or zero crossing coincides with
the vertical graticule line as on the left side = 0% error.
Performance Check HM1508-2
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