VNA

The VNA program has most of the functionality of a modern VNA, program functionality exceeds regular instruments in:

• Configuration

• Interface to device parameter programming through ODBC connections.

• Standard SOLT calibrations; fast TDR and Q calculations.

• Device data storage to either file or SQL database.

• Calibration storage/retrieval to SQL database with standards management and expiration periods. Calibrations are automatic and transparent when using the device DB programming.

• Support programs for creating and managing device parameters, calibrations and standards, ATPs with graphing, limit checking and specification coding.

Operation:

Once the operator has selected start and stop frequency, number of frequency points, parameter and display settings (either manually or through the File/Open function) a sweep can be made by pressing the trigger button. The Continuous/Manual button in the Continuous position will iteratively measure S-parameters when the trigger is also pressed, the operator may work on the device to optimize the reponses. No menu functions will work in continuous mode.

Instrument Configuration:

Configuration is by 2 means, the configuration file “C:\e_factory_LV\e_factory_LV.conf” defines the type of VNA being addressed . These fields may be programed (with simple text editor) as in the following entry:

[vna]

type=2 # 0=NULL/dummy, 1=HP8510, 2=8720, 3=HP 8410

GPIB configuration is done through the National Instruments NI488.2 tools. Using “ibconf” define an instrument “VNA” for the appropriate GPIB address.

Database Configuration:

Main Interface Menus:

File

Open: Load parameter programming. A window will pop up with the database-stored devices, there is no “save” functionality from the VNA program, device parameters must be programmed through “db_programmer”.

Remote Mode: Program will respond to remote commands through TCP/IP. This is the means for running custom programs.

Save Response: S parameter response will be saved as a tab-delimited user-named ASCII file. Results may be viewed with a text editor or imported into a spreadsheet.

Post to DB: S parameter response will be saved into relational DB, operator will be prompted for device identifying information.

Post Cal to DB: Once enabled with SOLT calibration, data will be posted to DB for automatic loading on “Open”

Recall Cal: Load existing calibration from DB

Exit: Terminate program.

Parameter

S11, S12, S22, S21: S-parameter.

Calibrate

Off: Raw, uncorrected data.

Response: Simpled response division, most useful for S12 and S21.

Instrument: Use native instrument calibration, places instrument in LOCAL mode so that operator may calibrate or select an existing instrument calibration. Once instrument is calibrated, VNA program will retake remote control of instrument.

Programmed: Use DB-programmed calibration and standards. If properly programmed calibration exists, a sub-menu will appear for each cal standard.

Mode

Step: Synthesizer step mode.

Ramp: Generator ramp mode.

Plot

Magnitude: Magnitude in DB of S-parameter.

Phase: Phase in degrees of S-parameter.

Smith Chart: Traditional Smith Chart representation of S-parameter.

Time Domain: DB Magnitude response in time domain. TDR parameters defined in TDR section of user panel.

Resonances: Front panel table of response Qs.

Marker

Add: Add frequency marker, note doesn't affect programmed markers or resonance markers.

Del: Delete frequency marker.