5-9
IM 701510-01E
Setting the V
ertical and Horizontal
Axes
5
CAUTION
If a clock signal exceeding the maximum input voltage is input to the each
terminal, damage to the internal circuits of the instrument may result.
When “EXT CH4” is selected (available on DL1540/DL1540L)
Input a clock signal to the CH4 input terminal on the front panel. The clock signal must
conform to the specifications given below.
Item
Specifications
Frequency range
40 Hz to 80 MHz
Input level
2 div p-p or higher
Input impedance
1 M
Ω
Minimum pulse width
5 ns or more for both High and Low levels
Threshold level setting range for detection of edge : Voltage equivalent to
±
5 div
Points to note when sampling using an external clock
• The clock signal must be continuous. No burst signal is allowed.
• If the frequency of the clock signal is out of specification, a warning message “External
Clock too slow” or “External Clock too fast” will be displayed at the top of the screen.
When the internal clock is switched to the external clock, no waveforms will be displayed
until the clock conforms to the specifications.
• Only real-time sampling mode is available.
• Envelope mode cannot be set.
• Display of waveforms is not possible in roll mode.
• No function to divide the clock signal is available.
• Since the time axis setting cannot be changed, expand the time axis if you want to change
the display range. For a description of expanding waveforms, refer to page 7-4.
• Trigger delay setting is invalidated.
• The time measured by the cursor measurement or automated measurement function is
expressed in the number of pulses of the clock signal. No unit is displayed.
5.7 Selecting the Timebase
