Last Updated: August 29, 2007
How are the Measurements in the RF Channel Measurement Suite Made?
RF Channel Measurement Suite Results Configuration Parameters
The RF Channel measurement suite contains a collection of measurements which are all made using the filter you select. The following measurements are included in the RF Channel measurement suite:
Channel Power (see Channel Power (CPOW) Measurement Description)
Frequency Error (see Frequency Error (FERR) Measurement Description)
IQ Capture (see IQ Capture Measurement Description)
QPSK EVM (see QPSK EVM Measurement Description)
Power versus Time (see RF Channel Power versus Time (PVT) Measurement Description)
The
Measurement Interval and the Trigger
Delay parameters are both coupled to the setting of the Filter
parameter.
For each filter the settings of these parameters are unique. Therefore,
changing the setting of the filter results in these other parameters being
updated to a new set of corresponding values.
It is recommended that you change these parameters in the following order:
Filter
Measurement Interval
Trigger Delay
The sample rate of the measurements is automatically determined by the choice of filter:
|
Filter |
Sample Frequency |
|
1 kHz |
21.973 kHz |
|
30 kHz |
60 kHz |
|
100 kHz |
250 kHz |
|
300 kHz |
600 kHz |
|
640 kHz |
1.28 MHz |
|
1.23 MHz |
2.46 MHz |
|
1.6 MHz |
3.2 MHz |
|
3.84 MHz |
7.68 MHz |
|
5 MHz |
10 MHz |
|
GSM Tx Power (300 kHz) |
320 kHz |
|
WCDMA Mean Power (4.97 MHz) |
5.25 MHz |
This parameter sets the type of filter for the RF Channel measurement suite.
The GSM Tx power and W-CDMA mean power filters are both compliant with their respective standards. These filters are more efficient and therefore improve test time for their respective technologies. It is recommended that you use the technology specific filters (GSM Tx power and W-CDMA mean power) except in certain situations where out-of-channel performance is of great importance. For example, you would not use the technology specific filters if there is a very large signal in an adjacent channel.
The GSM Tx power filter has the same noise bandwidth as the 300 kHz filter, however the sampling frequency is lower (320 kHz versus 600 KHz) so that power measurements with this filter are faster.
The W-CDMA mean power filter is the same filter that is used in the W-CDMA Fast Device Tune measurement. This filter has approximately the same noise bandwidth (4.97 MHz) as the 5.0 MHz filter, however the sampling frequency is lower (5.25 MHz versus 10 MHz) so that power measurements with this filter are faster.
The 1.6 MHz filter is a very sharp filter and is useful for making TD-SCDMA power measurements.
The QPSK EVM measurement requires you to use the 5 MHz filter setting.
It is recommended that you set this parameter before setting the Measurement Interval and Trigger Delay. For more information refer to How are the Measurements in the RF Channel Measurement Suite Made?.
SCPI command: SETup:RFCHannel:FILTer[?]
This parameter sets the measurement interval for the RF Channel measurement suite.
It is recommended that you set the Filter before setting this parameter. For more information refer to How are the Measurements in the RF Channel Measurement Suite Made?.
SCPI command: SETup:RFCHannel:INTerval[:SELected][?]
This parameter sets the multi-measurement count for the RF Channel measurement suite.
SCPI Command: SETup:RFCHannel:COUNt[:SNUMber][?]
This parameter sets the trigger state to single trigger mode or continuous trigger mode for the RF Channel measurement suite.
SCPI command: SETup:RFCHannel:CONTinuous[?]
This parameter sets the trigger source for the RF Channel measurement suite.
SCPI command: SETup:RFCHannel:TRIGger:SOURce[?]
This parameter sets the trigger delay in seconds for the RF Channel measurement suite.
It is recommended that you set the Filter and the Measurement Interval before setting this parameter. For more information refer to How are the Measurements in the RF Channel Measurement Suite Made?.
SCPI command: SETup:RFCHannel:TRIGger:DELay[:SELected][?]
This parameter sets the timeout value in seconds for the RF Channel measurement suite.
SCPI command: SETup:RFCHannel:TIMeout[:STIMe][?]
This parameter sets the crest factor for the Dynamic Power, RF Channel, and Spectrum Monitor measurements. Changing the setting within this measurement setup automatically changes it for the other measurements. The crest factor allows the test set to range correctly and therefore helps prevent over-ranging. The higher the crest factor the less likely that an over-range will occur, however the dynamic range is decreased.
SCPI command: SETup:GPMeas:CFACtor[:SELected][?]
This parameter sets the format of the IQ Capture measurement results.
SCPI command: SETup:RFCHannel:IQCapture:FORMat[?]
The parameters on the Display Configuration tab allow you to configure the following attributes of the RF Channel measurement suite on the test set's front panel:
Enable or disable different measurement result views.
Select whether or not to show each measurement result view on the Summary tab.
Select the order for displaying each measurement result view on the Summary tab.
Select which measurement result views should be expanded on individual tab pages.
Refer to the following individual measurement result descriptions:
Typically, the RF Channel measurement suite performs autoranging. If the measured signal is within +3 dB and -3 dB of the expected input level with ≤ 4 dB crest factor then autoranging is not performed and the fastest measurement time is achieved.
The RF Channel measurement suite will complete and meet its measurement accuracy specifications when the signal meets the following input signal conditions:
Input signal level is between -60 dBm and +35 dBm.
Triggering choices available for the RF Channel measurement suite are Immediate, Rise, Fall, and External.