HP HP 83491A, Руководство пользователя, Страница: 24 / 62

2-10
Operation
Using Probes with an HP 83491A
Using Probes with an HP 83491A
You can use external passive and active probes with the HP 83491A electrical
clock recovery module. The procedures in this section generate vertical scale
factors. These factors are applied to the calibration of the reference receiver
module’s electrical channel. When selecting a probe, keep in mind that the
input impedance of the HP 83491A is 50
Ω
.
If the probe being calibrated has an attenuation factor that allows the instru-
ment to adjust the gain to produce even steps in the vertical scale factors, the
instrument will do so. Typically, probes have standard attenuation factors such
as divide by 10, divide by 20, or divide by 100.
Because the following procedures include compensation for insertion loss of
the clock recovery module, do not perform the procedure
“To compensate for
module insertion loss” on page 2-9 .
The following probes are available for use with HP 83491A clock recovery
modules:
• HP N1020A TDR probe HP N1020A TDR probe HP N1020A TDR probe HP N1020A TDR probe. This passive probe (1:1, 50
Ω
) provides a fixture for po-
sitioning and holding the probe tip on the device being tested.
• HP 54701A 2.5 GHz active probe HP 54701A 2.5 GHz active probe HP 54701A 2.5 GHz active probe HP 54701A 2.5 GHz active probe. This is a 100k
Ω,
10:1, probe.
• HP 54006A 6 GHz handheld low-impedance probe HP 54006A 6 GHz handheld low-impedance probe HP 54006A 6 GHz handheld low-impedance probe HP 54006A 6 GHz handheld low-impedance probe. This passive probe (10:1,
500
Ω
, 20:1, 1k
Ω
) has an input capacitance of 0.25 pf.
• HP 1163A 1 GHz resistive-divider probe HP 1163A 1 GHz resistive-divider probe HP 1163A 1 GHz resistive-divider probe HP 1163A 1 GHz resistive-divider probe. This passive 500
Ω
probe has an input
capacitance of 1.5 pf.