Last Updated: August 29, 2007
This topic explains how to set up the measurement parameters:
For more information on the conventions used in the programming examples click here.
In this step you set up the conditions under which the measurements operate. You do this by configuring measurement parameters. Refer to the following descriptions:
There are two different types of measurement parameters:
Generic Measurement Parameters
Measurement-Specific Measurement Parameters
The SETup subsystem is used to configure measurement parameters. Each individual measurement parameter can be set and queried using the associated SETup subsystem command. The general hierarchy of the SETup subsystem command structure is as follows:
SETup:<measurement mnemonic>:<measurement parameter> <parameter setting/value>
Generic measurement parameters are not used by all measurements. Refer to the topics in the SCPI Commands books for the detailed list of parameters for individual measurements.
There are three types of generic measurement parameters:
Measurement count parameters (used by most measurements)
Measurement timeout parameters (used by all measurements)
Measurement trigger parameters (used by most measurements):
Trigger arm (used by all measurements)
Trigger source (not applicable to analog measurements)
Trigger delay (not applicable to analog measurements)
The measurement count parameters control measurement averaging. The STATe command turns averaging on or off, and the NUMBer command determines the number of averages. The SNUMber command is a complex command which allows you to turn averaging on and set the number of averages in one command.
|
Parameter |
Command Syntax |
|
Measurement Count State |
SETup:<measurement mnemonic>:COUNt:STATe <ON|1|OFF|0> |
|
Measurement Count Number |
SETup:<measurement mnemonic>:COUNt:NUMBer <numeric value> |
|
Measurement Count Number and State |
SETup:<measurement mnemonic>:COUNt[:SNUMber] <numeric value> |
Measurement timeout parameters control the maximum time that a measurement executes. TIMe sets the amount of time and STATe determines if the timeout is in use. The STIMe command is a complex command which enables you to set both parameters in one command.
|
Parameter |
Command Syntax |
|
Measurement Timeout Time and State |
SETup:<measurement mnemonic>:TIMeout[:STIMe] <numeric value>[<suffix>] |
|
Measurement Timeout State |
SETup:<measurement mnemonic>:TIMeout:STATe <ON|1|OFF|0> |
|
Measurement Timeout Time |
SETup:<measurement mnemonic>:TIMeout:TIME <numeric value>[<suffix>] |
Note that is also important to set a VISA timeout value longer than any of the measurement timeout values you set. For example, if the longest measurement timeout value you set is 5 seconds, the following code would set a VISA timeout value of 10 seconds.
TestSet.IO.Timeout = 10000
There are three measurement trigger parameters. They control the arming of a measurement, the source of the trigger, and the trigger's delay. Some measurements also have a trigger qualifier and a trigger threshold.
The trigger arm parameter determines whether the test set makes one measurement and then stops (single), or automatically re-arms upon completion of one measurement and repeats the process (continuous). The recommended setting when writing a control program is single (CONTinuous OFF).
The trigger source parameter selects the source of the measurement trigger signal.
The trigger delay parameter controls the delay between the trigger event (the point in time at which the trigger signal is received) and the start of sampling. Negative values indicate that the sampling should occur prior to the trigger event.
|
Parameter |
Command Syntax |
|
Measurement Trigger Arm |
SETup:<measurement mnemonic>:CONTinuous <ON|1|OFF|0> |
|
Measurement Trigger Source |
SETup:<measurement mnemonic>:TRIGger:SOURce <AUTO|IMMediate|PROTocol|RISE> |
|
Measurement Trigger Delay |
SETup:<measurement mnemonic>:TRIGger:DELay <numeric value>[<suffix>] |
You can set the Trigger Arm for all measurements to single (CONTinuous OFF) using the SETup[:ALL]:CONTinuous:OFF command.
For more information on triggering refer to Triggering of Measurements.
Measurement-specific measurement parameters set up operating conditions for a specific measurement.
Refer to the topics in the SCPI commands books for the detailed list of measurement parameters for individual measurements.
This step gives an example, based on the GSM/GPRS/EGPRS Cal Application, of how you can configure measurement, or measurement suite parameters.
'
' Configure Power and Modulation Quality Measurement Suite parameters for GSM and GPRS.
'
' Set Power and Modulation Quality suite trigger arm to single.
TestSet.WriteString("SETup:PMODulation:CONTinuous OFF")
' Set Power and Modulation Quality suite multi-measurement count to 100.
TestSet.WriteString("SETup:PMODulation:COUNt 100")
' Set VISA timeout to 10 seconds. This timeout should be longer than the
' following measurement timeout value.
TestSet.IO.Timeout = 10000
' Set Power and Modulation Quality suite timeout to 5 seconds.
TestSet.WriteString("SETup:PMODulation:TIMeout 5S")
' Set the time offsets for the Power versus Time power measurement.
TestSet.WriteString("SETup:PMODulation:PVTime:TIME -28uS,-10uS,321.2uS,552.8uS,570.8uS")
' Set the burst synchronization mode to Midamble.
TestSet.WriteString("SETup:PMODulation:SYNC MIDamble")
' Set the confidence level to 90% and the confidence level state to On.
TestSet.WriteString("SETup:PMODulation:PFERror:CONFidence 90PCT")
'
' Configure Output RF Spectrum Measurement Suite parameters for GSM and GPRS.
'
' Set output RF spectrum suite trigger arm to single.
TestSet.WriteString("SETup:ORFSpectrum:CONTinuous OFF")
' Set Output RF Spectrum suite timeout to 5 seconds.
TestSet.WriteString("SETup:ORFSpectrum:TIMeout 5S")
' Set the fast measurement state to On for the ORFS Modulation measurement.
TestSet.WriteString("SETup:ORFSpectrum:MODulation:FAST ON")
' Set the number of averages for ORFS modulation and the 30 kHz reference power to 25.
TestSet.WriteString("SETup:ORFSpectrum:MODulation:COUNt 25")
' Configure modulation offset.
TestSet.WriteString("SETup:ORFSpectrum:MODulation:FREQuency 200kHz")
' Set the number of averages for the ORFS Switching measurement to 15.
TestSet.WriteString("SETup:ORFSpectrum:SWITching:COUNt 15")
' Configure switching offsets.
TestSet.WriteString("SETup:ORFSpectrum:SWITching:FREQuency 200kHz,400kHz")
'
' Configure RF Channel Measurement Suite parameters.
'
' Set RF Channel suite trigger arm to single.
TestSet.WriteString("SETup:RFCHannel:CONTinuous OFF")
' Set the state to on and the multi-measurement count value to 150.
TestSet.WriteString("SETup:RFCHannel:COUNt 150")
' Set RF Channel suite timeout to 5 seconds.
TestSet.WriteString("SETup:RFCHannel:TIMeout 5S")
' Set RF Channel suite filter to 1 kHz.
TestSet.WriteString("SETup:RFCHannel:FILTer BWKHZ1")
' Set trigger delay time to 1.5 ms for the 1 kHz filter.
TestSet.WriteString("SETup:RFCHannel:TRIGger:DELay:BWKHZ1 1.5mS")