3-7
IM 701450-01E
Making Preparations for Measurements
3
3.4 Connecting the Probe
Signal Input Terminal
Connect the probe (or other input cables such as the BNC cable) to any of the input
terminals (4 terminals marked as CH1 to CH4 on the DL7440 and 8 terminals marked
CH1 to CH8 on the DL7480) at the bottom section of the front panel. The input
impedance is 1 MΩ±1.0% and approximately 20 pF or 50 Ω±1.0%.
CAUTION
• The maximum input voltage for 1-MΩ input is 400 V (DC + ACpeak) or 282
Vrms when the frequency is 1 kHz or less. Applying a voltage exceeding either
of the two values can damage the input section. If the frequency is above 1
kHz, damage may occur even when the voltage is below the value.
• The maximum input voltage for 50-Ω input is 5 Vrms or 10 Vpeak. Applying a
voltage exceeding either of the two values can damage the input section.
DL7440
1 MΩ/20 pF 400 Vpk CAT II 50
Ω 5 Vrms, 10 Vpk
CH
1
CH
2
CH
3
CH
4
DL7480
CH
7
CH
1
CH
2
CH
3
CH
4
CH
5
CH
6
CH
8
1 MΩ/20 pF 400 Vpk CAT II 50
Ω 5 Vrms, 10 Vpk
Precautions to Be Taken When Connecting Cables
• When connecting a probe to the instrument for the first time, perform phase correction
of the probe as described in section 3.5, “Compensating the Probe (Phase
Correction).” Failure to do so will cause unstable gain across different frequencies,
thereby preventing correct measurement. Perform the phase correction on each
channel to which a probe is to be connected.
• Note that if the object being measured is directly connected to the instrument without
using a probe, correct measurements may not be possible due to loading effects.
Probes
Specifications of the Probe (Model 700988) That Comes Standard (after Probe
Phase Correction)
Item Specifications Condition
10:1 Attenuation 1:1 Attenuation
Input resistance/capacity 10 MΩ±2%, 1 MΩ±1.0%, When used on the DL7400
approx. 14 pF approx. 150 pF
Attenuation 10:1±3% – When used on the DL7400
Frequency range DC to 400 MHz DC to 6 MHz When used on the DL7400
Rise time Within 900 ps Within 58 ns When used on the DL7400
Maximum input voltage 600 V (DC+ACpeak) * –
or 424 Vrms,
at a frequency of 100 kHz or less
Connector type BNC BNC –
Total length 1.5 m 1.5 m –
* When using the DL7400 with the attenuation set to 1:1, use the probe at a voltage less than
or equal to the maximum input voltage of the DL7400.
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