2-4
IM 701310-01E
Input Coupling ►For the procedure, see section 5.4
If you want to observe just the amplitude of an AC signal, it is best to remove the DC
component from the input signal. On the other hand, there are times when you want
to check the ground level or observe the entire input signal (both the DC and AC
components). In these cases, you can change the input coupling setting. By changing
the input coupling, the method used to input the input signal to the vertical control circuit
(voltage axis) is switched. The following types of input coupling are available.
AC1 MΩ
The input signal is coupled to the attenuator of the vertical control circuit through a
capacitor. This setting is used when you want to observe only the amplitude of the AC
signal, eliminating the DC component from the input signal.
DC1 MΩ
The input signal is directly coupled to the attenuator of the vertical control circuit. Use this
setting if you want to observe the entire input signal (DC component and AC component).
DC50
Ω
The same as for DC1 MΩ above, except that the input impedance is 50
W
. Care is
required, as this reduces the maximum input voltage.
GND
The input signal is coupled to the ground not to the attenuator of the vertical control
circuit. You can use this setting to check the ground level on the screen.
Vertical
control
circuit
Input terminal
1 MΩ
Vertical
control
circuit
Input terminal
DC
1 MΩ
Vertical
control
circuit
Input terminal
50 Ω
DC
50 Ω
Vertical
control
circuit
Input terminal
1 MΩ
AC
1 MΩ
GND
Probe Attenuation/Current-to-Voltage
Conversion Ratio ►For the procedure,
see section 5.6
Normally a probe is used in connecting the circuit being measured to the measurement
input terminal. Using a probe has the following advantages.
• Avoids disturbing the voltage and current of the circuit being measured.
• Inputs the signal with no distortion.
• Expands the voltage range that the DL9000 can measure.
The DL9000 is supplied with 500 MHz passive probes. The supplied probe attenuates
the measured voltage signal by a factor of 1/10. When using the probe, in order to read
the measurement voltage correctly, the attenuation setting on the DL9000 must be set to
match the probe attenuation. The DL9000 automatically recognizes when the supplied
500 MHz passive probes (voltage probes) are connected, and sets the attenuation ratio
to 10 : 1.
In addition to the 10 : 1 setting, the DL9000 has settings for a voltage probe of 1 : 1, 100
: 1, and 1000 : 1, and for a current probe settings of 1 A : 1 V, 10 A : 1 V, and 100 A : 1 V.
When using probes, set the attenuation ratio to match that of the probe.
2.3 Vertical and Horizontal Axes
