VNA Master™Programming Manual : VNA Commands : :INPut Subsystem
 
:INPut Subsystem
This subsystem controls characteristics of the input port.
IF Gain Mode Setting
:INPut:GAIN:MODE
Description
Sets the method by which the instrument adjusts the gain of the IF path. In AUTO mode, the instruments adjusts the gain depending on the input signal level in order to maximize the dynamic range of the instrument. For most applications, AUTO mode should be used. For certain types of filter measurements, it may be desirable to keep the gain fixed throughout the filter response. In that case, use this command to set the Gain mode to FIXed. The query version of this command returns the string “AUTO” if the current measurement gain range is currently set to AUTO, and returns the string “FIX” if it is currently set to fixed.
Syntax
:INPut:GAIN:MODE AUTO|FIXed
:INPut:GAIN:MODE?
Cmd Parameter
<char> AUTO|FIXed
Query Response
<char> AUTO|FIX
Default Value
AUTO
Front Panel Access
Shift‑8 (System), Application Options, Meas Gain Range
 
Internal Bias Tee Current
:INPut<port_no>:BIAS:CURRent
Description
Sets the internal bias tee current limit for the specified port. When this limit is exceeded, the Bias Tee trips (turns OFF). <port_no> is the specified internal bias tee port number, 1 to 2. The query version of this command returns either the measured internal current or the set internal current limit (both are returned in milliampere units). To return the measured internal current for the specified port number, send the query command either with no value specified after the “?” (default condition) or with a value of 0 specified after the “?”. Note that the query result for the measured internal current is valid only if the Bias Tee state is set to internal. If a value of 1 is specified after the “?”, then the query version of this command returns the internal current limit that is set for the given port number.
Syntax
:INPut<port_no>:BIAS:CURRent <current>
:INPut<port_no>:BIAS:CURRent? [0|1]
Cmd Parameter
<NRf> <current> (milliampere)
Query Response
<NR3> <milliampere> (returns value in milliampere)
Range
0 mA to 450 mA
Default Value
450 mA when querying the internal current limit (:INPut<port_no>:BIAS:CURRent? 1). The default value for querying the measured current depends upon what is connected to the port.
Default Unit
milliampere (mA)
Front Panel Access
Shift‑3 (Sweep), Configure Ports, Bias Tee Setup, Int Current Limit P1/P2
 
External Bias Tee Current
:INPut<port_no>:BIAS:EXTernal:CURRent?
Description
Returns the external bias tee current. <port_no> is the specified external bias tee port number, 1 to 2.
Syntax
:INPut<port_no>:BIAS:EXTernal:CURRent?
Cmd Parameter
NA (query only)
Query Response
<NR3> (milliampere)
Default Unit
mA
Front Panel Access
NA
External Bias Tee Tripped State
:INPut:BIAS:EXTernal:TRIPped[:STATe]?
Description
Returns whether the external bias tee is tripped. Returns 1 for tripped, otherwise returns 0.
Syntax
:INPut:BIAS:EXTernal:TRIPped[:STATe]?
Cmd Parameter
NA (query only)
Query Response
<boolean> [0|1]
Front Panel Access
NA
 
External Bias Tee Voltage
:INPut<port_no>:BIAS:EXTernal:VOLTage?
Description
Returns the voltage of the external bias tee for the specified port number. <port_no> is the specified internal bias tee port number, 1 to 2.
Syntax
:INPut<port_no>:BIAS:EXTernal:VOLTage?
Cmd Parameter
NA (query only)
Query Response
<NR3> <Volts> (returns value in Volts)
Default Unit
Volts
Front Panel Access
NA
 
Internal Bias Tee Tripped State
:INPut:BIAS:INTernal:TRIPped[:STATe]?
Description
Returns whether the internal bias tee is tripped. Returns 1 for tripped, otherwise returns 0.
Syntax
:INPut:BIAS:INTernal:TRIPped[:STATe]?
Cmd Parameter
NA (query only)
Query Response
<boolean> [0|1]
Front Panel Access
NA
 
Internal Bias Tee Port Selection
:INPut:BIAS:PORT:SELect
Description
Specifies the internal bias tee port.
Syntax
:INPut:BIAS:PORT:SELect 1|2
:INPut:BIAS:PORT:SELect?
Cmd Parameter
<char> 1|2
Query Response
<char> 1|2
Default Value
2
Front Panel Access
Shift‑3 (Sweep), Configure Ports, Bias Tee Setup, Int Port Selection
Bias Tee State
:INPut:BIAS:STATe
Description
Enables or disables the bias tee. Query returns OFF|EXT|INT. For OFF state, query returns OFF (not 0).
Syntax
:INPut:BIAS:STATe OFF|EXTernal|INTernal
:INPut:BIAS:STATe?
Parameter
OFF|EXTernal|INTernal
Cmd Parameter
<char> OFF|EXTernal|INTernal
Query Response
<char> OFF|EXT|INT
Default Value
OFF
Front Panel Access
Shift‑3 (Sweep), Configure Ports, Bias Tee Setup, Bias Tee
 
Internal Bias Tee Voltage
:INPut<port_no>:BIAS:VOLTage
Description
Sets the voltage of the internal bias tee for the specified port number. <port_no> is the specified internal bias tee port number, 1 or 2. The query version of this command returns either the measured internal bias tee voltage or the set internal bias tee voltage (both are returned in Volts). Note that the measured voltage can be slightly different than the set voltage depending on the load conditions. To return the last measured internal bias tee voltage for the specified port number, send the query command either with no value specified after the “?” (default condition) or with a value of 0 specified after the “?”. Note that the query result for the measured internal bias tee voltage is valid only if the Bias Tee state is set to internal. If a value of 1 is specified after the “?”, then the query version of this command returns the internal bias tee voltage that was set for the given port number.
Syntax
:INPut<port_no>:BIAS:VOLTage <voltage>
:INPut<port_no>:BIAS:VOLTage? [0|1]
Cmd Parameter
<NRf> <12 to 32 Volts>
Query Response
<NR3> <Volts>
Range
12 V to 32 V
Default Value
+ 12 V when querying the internal bias tee voltage that was set (:INPut<port_no>:BIAS:VOLTage? 1). The default value for querying the last measured bias tee voltage may be slightly different depending upon what is connected to the port.
Default Unit
Volts
Front Panel Access
Shift‑3 (Sweep), Configure Ports, Bias Tee Setup, Int Voltage P1/P2