Create an SMC Embedded LO Measurement

This VB Script example creates a SC21 SMC measurement for a mixer with an Embedded LO.

To make an embedded LO measurement:

Set the LO frequency for each stage to the nominal frequency of the embedded LO. Set the LO source to "Not Controlled".
Calibrate as usual at the end of the measurement setup. To do this, copy the Calibration section from Create and Cal an SMC Measurement.

The following are the mixer settings:

Single-stage Fixed LO's - Uncomment the Blue lines to measure DUAL stage mixers.
Swept Input and Output
Set Input and LO frequencies - Calculate the Output frequencies

The SCPI commands in this example are sent over a COM interface using the SCPIStringParser object. You do NOT need a GPIB connection to run this example.

This VBScript (*.vbs) program can be run as a macro in the VNA. To do this, copy the following code into a text editor file such as Notepad and save it on the VNA hard drive as SMC.vbs. Learn how to setup and run the macro.

Dim app

Dim scpi

' Create / Get the VNA application.

Set app = CreateObject("AgilentPNA835x.Application")

Set scpi = app.ScpiStringParser

scpi.Parse "SYSTem:PRESet"

' Create a Scalar Mixer Forward Measurement

'First, delete all measurements on the channel

scpi.Parse "CALC:PAR:DEL:ALL"

'Create a forward scalar mixer measurement and configure it in

'channel 1. The first parameter is a unique

'identifying string (specified by the user) to allow subsequent

'commands to be directed at this specific measurement.

scpi.Parse "CALC:CUST:DEF 'My SC21', 'Scalar Mixer/Converter', 'SC21'"

'Setup the new measurement as the 2nd trace in the active window

scpi.Parse "DISP:WIND:TRAC2:FEED 'My SC21'"

'Make the new trace the active measurement

scpi.Parse "CALC:PAR:SEL 'My SC21'"

' Setup Stimulus - Points and IFBW are channel settings

scpi.Parse "SENS:SWEep:POINts 21"

scpi.Parse "SENS:BANDwidth 1e3"

'Perform single sweep

scpi.Parse "SENS:SWE:MODE SING;*OPC?"

' Mixer settings

' Input settings (swept)

scpi.Parse "SENS:MIX:INPut:FREQ:MODE SWEPt"

scpi.Parse "SENS:MIX:INPut:FREQ:STAR 3.6e9"

scpi.Parse "SENS:MIX:INPut:FREQ:STOP 3.9e9"

' LO1 settings (fixed)

scpi.Parse "SENS:MIX:LO1:FREQ:MODE FIXED"

scpi.Parse "SENS:MIX:LO1:FREQ:FIX 500e6"

scpi.Parse "SENS:MIX:LO1:NAME 'Not controlled'"

' Dual-stage - LO2 settings (fixed)

' Uncomment these lines for dual stage mixer

'scpi.Parse "SENS:MIX:STAGE 2"

'scpi.Parse "SENS:MIX:LO2:FREQ:MODE FIXED"

'scpi.Parse "SENS:MIX:LO2:FREQ:FIX 500e6"

'scpi.Parse "SENS:MIX:LO2:NAME 'Not controlled'"

' Output settings (calculated)

scpi.Parse "SENS:MIX:OUTP:FREQ:SID LOW"

scpi.Parse "SENS:MIX:CALC Output"

scpi.Parse "SENS:MIX:APPLY"

' Changing the following default settings is usually not necessary

scpi.Parse "SENS:MIX:ELO:TUN:MODE BROadband"

scpi.Parse "SENS:MIX:ELO:TUN:IFBW 30e3"

scpi.Parse "SENS:MIX:ELO:TUN:INT 1"

scpi.Parse "SENS:MIX:ELO:TUN:ITER 5"

scpi.Parse "SENS:MIX:ELO:TUN:SPAN 3e6"

scpi.Parse "SENS:MIX:ELO:TUN:TOL 1"

' Enable embedded LO

scpi.Parse "SENS:MIX:ELO:STAT 1"

'Single sweep does the same as "Find Now"

'from the ELO dialog

scpi.Parse "SENS:SWE:MODE SING;*OPC?"

'Perform Calibration here as usual