Other topics about Advanced Calibration
To perform 8-term error model calibration using an external PC (measuring raw measurement data using the E5071C, calculating error term using external PC and then performing correction with calculated error terms and measured raw data), the procedure described in this section must be followed. When you use this method, the measurement specification is not satisfied.
In most cases, users do NOT need to follow the below procedure as these considerations have already been performed on 8-term error model calibration in E5071C.
When users perform 12-term error model calibration using external computer such as SOLT calibration, users do NOT need to take following procedure.
In its default setting, the E5071C applies "system calibration" to the measured S-parameter data. Because the "system calibration" is applied only to the S-parameter measurement data and NOT to the absolute value measurement data, it interferes with 8-term error model calibration when calculating error coefficients on external computer. You need to turn OFF this state, all the time for calibration and measurement.
The system calibration can be turned off by executing SCPI.SYSTem.CORRection.STATe
Once the E5071C receives this command, it will keep this setting until preset. This state is saved in the state file.
There is a software conversion function called "virtual bridge" on E5071C. The default setting of this state is ON, and this state interferes with 8-term error model calibration when calculating error coefficients on external computer. You need to turn OFF this state, all the time for the calibration and the measurement.
This function only exist on frequency 3 GHz, 4.5 GHz, 6.5 GHz and 8.5 GHz options. It's not necessary to consider "virtual bridge" on E5070A/71A/70B/71B, and E5071C frequency 14 GHz and 20 GHz options.
The virtual bridge can be turned off by the command: SERVice:ADJust:VIRTual:BRIDge[:STATe] {ON|OFF|1|0}.
Since this command is under service menu, the "SVC" indicator is turned on when the ENA sets virtual bridge OFF.
Once the ENA receives this command, it will keep this setting until preset.
The state of "virtual bridge" is NOT saved in the state file, and the default state of the "virtual bridge" is ON. So you need to send the command to turn OFF the state, every time you recall the state file.
There is a hardware function called "RF ranging mode" on E5071C. The default setting of this state is AUTO, and this state interferes with 8-term error model calibration when calculating error coefficients on external computer. You need to turn off the "RF ranging Auto mode".
The "RF ranging mode" can be changed by the command: SERVice:ADJust:SENSe[Ch]:SWEep:RF:RANGe:PORT[Pt]:AUTO {ON|OFF}. This command applies to each channel and measurement port.
This function only exist on frequency 3 GHz, 4.5 GHz, 6.5 GHz and 8.5 GHz options. It's not necessary to consider "virtual bridge" on E5070A/71A/70B/71B, and E5071C frequency 14 GHz and 20 GHz options.
Since this command is under service menu, the "SVC" indicator is turned on when the ENA sets RF range auto mode OFF. Once the ENA receives this command, it will keep this setting until preset.
The state of "RF ranging mode" is NOT saved in the state file, and the default state of the "RF ranging mode" is AUTO. So you need to send the command to set state to AUTO OFF, every time you recall the state file.
You need to keep the state of "RF range Auto Mode" as OFF, all the time for calibration and measurement using this method
Once the ENA receives above command, it will keep this setting until preset.
Since the "RF ranging" is hold during the measurement, the system dynamic range of the E5071C will degrade by 6dB, as a result of the 8-term calibration performed externally. However, there is NO dynamic range degrade by 8-term error model calibration with internal calibration of the ENA.
Assume you perform 4-port TRL calibration on channel1, you need to send following command before calibration. Also, you need to keep this state all the time for calibration and measurement.
SYSTem:CORRection:STATe OFF 'system correction off
SERVice:ADJust:VIRTual:BRIDge:STATe OFF 'virtual bridge off
SERVice:ADJust:SENSe1:SWEep:RF:RANGe:PORT1:AUTO OFF 'RF ranging mode to manual on port1
SERVice:ADJust:SENSe1:SWEep:RF:RANGe:PORT2:AUTO OFF 'RF ranging mode to manual on port2
SERVice:ADJust:SENSe1:SWEep:RF:RANGe:PORT3:AUTO OFF 'RF ranging mode to manual on port3
SERVice:ADJust:SENSe1:SWEep:RF:RANGe:PORT4:AUTO OFF 'RF ranging mode to manual on port4
Once you preset the system, you need to resend all of the above commands.
Once you save and recall the state using this method, you need to resend all of the above commands except for system correction off.