Agilent Technologies 53220A, Руководство пользователя

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53220A/53230A User’s Guide 125
53220A/53230A Input Signal Conditioning 4
Setting the Probe Factor
For better access to test points on the device under test (DUT), Agilent recom-
mends its N2870A , N2873A , and N2874A Passive Probes for use with the
53220A/ 53230A counter. The 35 MHz (BW) N2870A 1:1 probe and the
500 MHz N2873A and 1.5 GHz N2874A 10:1 probes are popular accessories
commonly used with Agilent oscilloscopes.
When using probes with the counter, specifying a probe factor references and
displays threshold levels and p-p levels relative to actual levels on the DUT,
rather than to the level at the channel input. The probe factor is set with the
command:
INPut[{1|2}]:PROBe {<factor>|MINimum|MAXimum|DEFault}
INPut[{1|2}]:PROBe? [{MINimum|MAXimum|DEFault}]
(query form)
Probe
factor
settings are
1
for a 1:1 probe (N2870A), and
10
for a 10:1 probe
(N2873A or N2874A). When set to 1, the counter ranges are 5V and 50V. When
set to 10, the counter ranges are 50V and 500V.
Probe Input Compatibility
The input compatibility of the N2870A and N2873A
probes is 1 M
Ω
respectively. The compatibility of the N2874A is 50
Ω
. Each is
compatible with the counter’s 20 pF input capacitance. When using a probe,
the counter input impedance should be set accordingly (1M
Ω
, 50
Ω
).
CONFigure
and
MEASure
do not change the probe factor setting. Following a
reset (
*RST
) or an instrument preset (
SYSTem:PRESet
or
Preset
key), the
probe factor is set to 1.