User`s guide

122 53220A/53230A User’s Guide
4 53220A/53230A Input Signal Conditioning
Input Impedance
The input impedance of the 53220A/53230A counter can be set to either 50Ω
or 1 M
Ω using the command:
INPut[{1|2}]:IMPedance {<impedance>|MINimum|MAXimum|
DEFault}
INPut[{1|2}]:IMPedance? [{MINimum|MAXimum|DEFault}]
(query form)
The 50
Ω and 1 MΩ impedances allow for impedance matching (termination)
and
bridging applications respectively.
Using Probes If using a 1:1 or 10:1 probe, the input impedance of the counter
should be set to match the compatibility (e.g. 50
Ω, 1 MΩ, high Z) of the probe.
See “Setting the Probe Factor” for more information.
Following a reset (*RST) or front panel preset (Preset), the impedance is set to
1 M
Ω. CONFigure and MEASure do not change the input impedance setting.
Impedance Example
//period measurement of expected 10 MHz signal,
//maximum resolution, use channel 1
CONF:FREQ 0.1E6,MAX,(@1)
INP:IMP 1.0E6 //set impedance to 1 Mohm