The TransmissionResponse calibration type is intended to be used only when the DUT being measured is an amplifier capable of high output power. The high DUT output power requires a large value, high power attenuator at the output and therefore making a traditional 2-port S-Parameters calibration impossible.

This custom calibration in the ATE Systems library allows the user to calibrate stimulus power at the DUT, S21 (mag and phase), S11, and transmission output power (using PNA B receiver). While this calibration could be performed using an FCM or SCM this calibration routine is better adapted to the calibration device DCM (device calibration module). The reason is that the DCM is only in circuit during calibration and then removed post-calibration, so there is no high power RF damage concern for the calibration device.

In order for the transmission response calibration to function it is required that the test setup be capable of making ratioed measurements on port 1 of the PNA and the DUT input is connected to port 1 of the PNA. The output of the DUT is required to be connected to port 2 of the PNA, it is expected (but not required) that there is 30-40dB of attenuation between the DUT and port 2 of the PNA.

At the beginning of the TransmissionResponse calibration all of the traces on the PNA screen are reset and new traces are created as follows:

  • Trace 1 -> R1,1 - Measures the calibrated input power to the DUT
  • Trace 2 -> B,1 - Measures the calibrated output power from the DUT
  • Trace 3 -> S21 - Measures transmission through the DUT (magnitude and phase are both calibrated)
  • Trace 4 -> S11 - Measures input return loss of the DUT

At the conclusion of the TransmissionResponse calibration the PNA source on port 1 will be left in 'Open Loop', see Keysight Documentation on receiver leveling for more information.

An Example:

;******************************************************************************
;Calibration Configuration (TransmissionResponse)
;*******************************************************************************
[Cal_TransmissionResponse]
CalAcquireTimeoutSec = 60
CalSetDescription = TransmissionResponse test
CalSetName = Cal_TransmissionResponse
CalType = TransmissionResponse
ConfigType = Calibration
DirectoryToUse = c:\temp
LoadFilename = TransmissionResponseSetup.csa
SaveFilename = TransmissionResponseCal.csa
PathName = PATH_1
PowerAverageCount = 1
PowerAverageTolerance = 0.2
PowerIterationCount = 30
PowerIterationTolerance = 0.5
PowerLevel2 = 10
PowerLevelOffset = 0.0
PowerSensorPort = 1
ReceiverResponseAttenuation = 0.0
ReceiverStimulusAttenuation = 0.0
SourceAttenuation = 0.0

;******************************************************************************
;Device Configuration (DCM on PNA port 1)
;*******************************************************************************
[DCM_1]
ConfigType = Dcm
IpAddress = 10.11.201.20
IpScpiPort = 5025
IpTracePort = 5007
ResponseTimeoutSec = 60

;******************************************************************************
;Switch Configuration (DCM on PNA port 1)
;*******************************************************************************
[DCMSwitch]
ConfigType = Switch
Device = DCM_1
SwitchIndex = 1

;******************************************************************************
;Path Configuration (RF to DCM)
;*******************************************************************************
[PATH_1]
ConfigType = Path
PnaPort1Device = DCM_1:1,3
PnaPort2Device = DCM_1:3
SwitchPath = DCMSwitch:0

;*******************************************************************************
;PNA Configuration
;*******************************************************************************
[PNA_1]
ConfigType = Pna
DirectoryToUse = C:\Temp
FileTransferTimeoutSec = 60
IpAddress = 10.11.210.1
IpScpiPort = 5025
IpTracePort = 5007
PortCount = 4
ResponseTimeoutSec = 60
VerifyCommands = 0

In this example the TransmissionResponse type calibration is performed using a DCM which is the typical calibration device used for this type of calibration. While an FCM could be utilized, as stated above, the FCM would need to be removed from the circuit after the calibration, which is not the typical configuration for an FCM.

The configuration components of this calibration are:

  • The Calibration configuration        [Cal_TransmissionResponse]
  • The cal device configuration        [DCM_1]
  • The switch configuration        [DCMSwitch]
  • The Path configuration        [PATH_1]
  • The PNA configuration        [PNA_1]

[DCM_1]        The DCM is the calibration device

The DCM calibration device has two or more ports, in this example port 1 on the DCM is connected to port 1 on the PNA and port 3 on the DCM is connected to Port 2 on the PNA. However, this configuration section needs no special parameters and can be setup as any ATE Systems calibration device. For more on the DCM configuration see DCM Config.

[DCMSwitch]        The name used to refer to the switch

Device = DCM_1    The device that controls the switch in this case this is the DCM

SwitchIndex = 1    The DCM has only one switch so its index is 1

The departure from a typical configuration here is that the switch is associated with the DCM and not a MultiSwitch. The switch is part of the DCM calibration device and needs to be set to a thru position at the end of the calibration. The switch configuration is therefore referenced in the Path configuration

[PATH_1]
PnaPort1Device = DCM_1:1,3        Specifies that PNA port1 is connected to DCM port 1, using the THRU3.s2p file if needed.

PnaPort2Device = DCM_1:3        Specifies that PNA port2 is connected to DCM port 3.

SwitchPath = DCMSwitch:1        Specifies that the DCM switch should be put into position 1 (connecting 1 to 3 thru).

The Path is configured for PNA ports 1 and 2, and the switch set to put the device in a 1 to 3 thru state. The switch path references the switch by its defined name in the configuration file as shown above. While port 3 of the DCM is used in this example port 2 could have been used as well.

[Cal_TransmissionResponse]
PathName = PATH_1            Specifies the use of PATH_1 for this calibration

LoadFilename = TransmissionResponseSetup.csa    Specifies the state file to load before running the calibration.

PowerLevel2 = 10            Specifies the stimulus power level on Port 2 to be used

PowerSensorPort = 1            Specifies port 1 on the PNA as the power sensor port

ReceiverAttenuation1 = 0.0        Specifies the receiver attenuation on port 1

ReceiverAttenuation2 = 0.0        Specifies the receiver attenuation on port 2

SourceAttenuation = 0.0         Specifies the source attenuation on port 1

The important thing to note in this configuration is that the power level is not specified but must be preset on the PNA, usually by loading a CSA state file. This calibration is always run on Ports 1 and 2 of the PNA, and port 1 must be connected to the power meter. Other than LoadFileName all the other parameters shown above must be specified.

[PNA_1]

This configuration section needs no special parameters and can be setup as a typical PNA device. For more on the PNA configuration see PNA Config.