VNA Data acquisition example

This notebook demonstrates how to acquire two port sparameters and wave parameters using pyMez

Importing the pyMez API

In [1]:
from pyMez import *

Importing pyMez, this should take roughly 30 seconds
Importing Code.DataHandlers.GeneralModels
It took 0.68 s to import Code.DataHandlers.GeneralModels
Importing Code.DataHandlers.HTMLModels
It took 0.19 s to import Code.DataHandlers.HTMLModels
Importing Code.DataHandlers.NISTModels
It took 2.297 s to import Code.DataHandlers.NISTModels
Importing Code.DataHandlers.TouchstoneModels
It took 0.013 s to import Code.DataHandlers.TouchstoneModels
Importing Code.DataHandlers.XMLModels
It took 0.157 s to import Code.DataHandlers.XMLModels
Importing Code.DataHandlers.ZipModels
It took 0.008 s to import Code.DataHandlers.ZipModels
Importing Code.InstrumentControl.Experiments
It took 0.84 s to import Code.InstrumentControl.Experiments
Importing Code.InstrumentControl.Instruments
It took 0.019 s to import Code.InstrumentControl.Instruments
Importing Code.Utils.Names
It took 0.016 s to import Code.Utils.Names
It took 4.221 s to import all of the active modules

Inspecting the GPIB bus to discover the instruments attached

In [2]:
whos_there()

Rohde&Schwarz,ZVA67-4Port,1312700403101122,3.90
 is at address GPIB0::20::INSTR

Creating a control class instance for this vna

If there is an instrument description in pyMez/instruments then static metadata about this instrument will be loaded into the class, otherwise it will function as intended without the static metadata

In [3]:
vna=VNA("GPIB::20")

Taking a two-port scattering parameter sweep with the preset values

The returned data will be in a touchstone style class

In [4]:
vna.initialize()
s2p=vna.measure_sparameters()

Plotting the data

The touchstone style class has a show method that will display the two-port parameters in real-imaginary (RI), magnitude-angle (MA) or decibel-angle (DB)

In [5]:
s2p.show(format="RI");

Taking two-port wave parameters

Taking two port wave parameters works the same way, but uses the methods .initialize_w2p and .measure_w2p

In [6]:
vna.initialize_w2p()
w2p=vna.measure_w2p()

Plotting the two-port wave parameters

The W2P class also has a show method. It is a child of the AsciiDataTable class

In [7]:
w2p.show();

Changing the frequency of the sweep

set_frequency must have a start and stop defined, either number_points or step has to be specified, and the type is optional (defaults to LIN, LOG is the other possibility). The ability to use segmented sweeps relies on add_segment. The start, stop and number of points is added to the segment table. The attribute vna.frequency_table holds the table that is written to the vna.

# this form works
vna.set_frequency(start=10**9,stop=10*10**9,number_points=101,type="LOG")
# This also works
vna.set_frequency(start=10**9,stop=10*10**9,step=10**8)
In [18]:
vna.initialize(reset="False")
In [20]:
vna.set_frequency(10**9,10**10,101)
In [25]:
s2p=vna.measure_sparameters()
In [27]:
# Note these sparameters are messed up on port 1
# This was due to a bad jumper on the front panel
s2p.show();