3-7
IM 701510-01E
Before Starting Observation and Measurement of W
aveforms
3
3.6
Connecting a Probe
Input Terminals
A probe (or an input cable such as a BNC cable) must be connected to one of the input
terminals (CH1 to CH4, CH1 and CH2 for DL1520/DL1520L) located on the lower section
of the front panel.
The input impedance is 1 M
Ω
±
1.5% and approximately 25 pF.
CAUTION
The maximum input voltage is 250 V (DC + ACpeak) or 177 Vrms when the
frequency is 1 kHz or less. Never input a voltage exceeding this level, as it
could damage the input section of the instrument. If the frequency exceeds 1
kHz, the input section may be damaged even when the voltage is below 250 V.
1
2
3
4
CH
CH
CH
1M
Ω
/25pF
≤
250Vpk
CH
Example (DL1540/DL1540L)
Points to Note when Connecting a Probe
• When connecting a probe to the instrument for the first time, perform phase correction of
the probe as described in the next section on page 3-7. Failure to do so may result in
unstable gain across different frequencies, thereby preventing correct measurement.
Calibration must be performed for each channel.
• If the object to be measured is connected to the instrument directly, without using a
probe, correct measurement cannot be performed due to the load effect.
Probe
Specifications for the probe (700998) supplied with the instrument (after
calibration)
Item
Specifications
Conditions
Setting 10:1
Setting 1:1
Input impedance/capacitance 10 M
Ω
±
2%/approx. 14 pF
1 M
Ω
±
1.5%/approx. 100 pF When used with this instrument
Attenuation ratio
10:1
±
2.5%
—
When used with this instrument
Frequency band
DC to 150 MHz
DC to 6 MHz
When used with this instrument
Rise time
2.4 ns or less
58 ns or less
When used with this instrument
Maximum input voltage
600 V (DC + ACpeak)
*1
—
or 424 Vrms,
Frequency is 100 kHz or lower
Connector type
BNC
BNC
—
Total length
1.5 m
1.5 m
—
*1 When the probe's attenuation ratio is “1:1,” never input voltage exceeding the maximum input voltage of this instrument.
When using a probe other than the one supplied with the instrument
To measure a signal which contains harmonics of approximately 150 MHz, use a probe with
a frequency band of 150 MHz or higher.
Correct measured values cannot be displayed if the probe’s attenuation ratio is not “1:1”,
“10:1”, “100:1” or “1000:1”.
When a probe other than 1 M
Ω
probe (for example a 50
Ω
probe) is to be used, connect a
through-type 50
Ω
terminator
*2
for impedance matching.
*2 When placing an order for the 50
Ω
terminator as the one supplied with the instrument, quote the
number “700976”.
Setting the probe attenuation
Follow the operating procedure given in Section 5.3 “Setting the Probe Attenuation” (page
5-4) so that the probe’s attenuation matches the one displayed below “Probe” in the soft key
menu which appears when the INPUT key is pressed. If they do not match, measured values
cannot be read correctly.
