# Example for quick measurement and fit of a Q factor using stlab.S11fit.
# Takes a user defined label as command line argument to name the output files (one figure, one complex trace and the fit parameters)
import stlab # fitting routines imported here. Callable as stlab.S11fit(...) and stlab.S11func(...)
import numpy as np
# from stlab.devices.RS_ZND import RS_ZND_pna as pnaclass #Import device driver for PNA
from stlab.devices.FieldfoxPNA import FieldfoxPNA as pnaclass # Import device driver for PNA
from matplotlib import pyplot as plt # import graphing library
import sys
try:
tag = sys.argv[1]
except IndexError:
tag = ""
pna = pnaclass(reset=False, verb=True) # Initialize device but do not reset.
pna.SetContinuous(False)
#'addr' is the VISA address string for the device
# Since reset is set to False, this script assumes that the sweep settings are already set before starting
# These could of course be set through member methods of the pna. See driver for options.
data = (
pna.Measure2ports()
) # Set 2 port measurement, trigger measurement and retrieve data. Data is returned as an OrderedDict
# If calibration is used, both calibrated and uncalibrated data is returned
print(data.keys()) # Show available data columns on screen
x = data["Frequency (Hz)"] # Get frequency array from measurement
z = np.asarray(
[a + 1j * b for a, b in zip(data["S21re ()"], data["S21im ()"])]
) # Convert S parameter data from Re,Im to complex array
params = stlab.S11fit(
import stlab
from stlab.devices.FieldfoxPNA import FieldfoxPNA as pnaclass #Import device driver for your desired PNA
import numpy as np
prefix = 'M2' #prefix for measurement folder name. Can be anything or empty
idstring = 'Dev1_powersweep' #Additional info included in measurement folder name. Can be anything or empty
pna = pnaclass(addr='TCPIP::192.168.1.151::INSTR',reset=True,verb=True) #Initialize device communication and reset
pna.SetRange(4e9,8e9) #Set frequency range in Hz
pna.SetIFBW(300.) #Set IF bandwidth in Hz
pna.SetPoints(1001) #Set number of frequency points
powstart = -45.
powstop = -0.
steps = 5
powers = np.linspace(powstart,powstop,steps) #generate power sweep steps
for i,rfpower in enumerate(powers):
pna.SetPower(rfpower) #set pna power
data = pna.Measure2ports() #Trigger 2 port measurement and retrieve data in Re,Im format. Returns OrderedDict
#Add Columns for S parameters in dB
S11dB = 20.*np.log10( [ np.sqrt(np.power(a,2.)+np.power(b,2.)) for a,b in zip(data['S11re ()'],data['S11im ()']) ] )
S21dB = 20.*np.log10( [ np.sqrt(np.power(a,2.)+np.power(b,2.)) for a,b in zip(data['S21re ()'],data['S21im ()']) ] )
npoints = len(data['Frequency (Hz)'])
data['Power (dBm)'] = np.full(npoints,rfpower)
data['S11dB (dB)'] = S11dB
data['S21dB (dB)'] = S21dB
if i==0: #if on first measurement, create new measurement file and folder using titles extracted from measurement
myfile,fullfilename,_ = stlab.newfile(prefix,idstring,data.keys())
stlab.savedict(myfile, data) #Save measured data to file. Written as a block for spyview.