import warnings
import numpy as np
import skrf
import pyvisa
from collections import OrderedDict
from collections.abc import Iterable
from . import abcvna
from . import keysight_pna_scpi
[docs]class PNA(abcvna.VNA):
"""
Class for modern Keysight/Agilent Performance Network Analyzers
"""
DEFAULT_VISA_ADDRESS = "GPIB::16::INSTR"
NAME = "Keysight PNA"
NPORTS = 2
NCHANNELS = 32
SCPI_VERSION_TESTED = 'A.09.20.08'
[docs] def __init__(self, address=DEFAULT_VISA_ADDRESS, **kwargs):
"""
initialization of PNA Class
Parameters
----------
address : str
visa resource string (full string or ip address)
kwargs : dict
interface (str), port (int), timeout (int),
:param address:
:param kwargs:
"""
super(PNA, self).__init__(address, **kwargs)
self.resource.timeout = kwargs.get("timeout", 2000)
self.scpi = keysight_pna_scpi.SCPI(self.resource)
# self.use_binary()
self.use_ascii()
[docs] def use_binary(self):
"""setup the analyzer to transfer in binary which is faster, especially for large datasets"""
self.resource.write(':FORM:BORD SWAP')
self.resource.write(':FORM:DATA REAL,64')
self.resource.values_format.use_binary(datatype='d', is_big_endian=False, container=np.array)
[docs] def use_ascii(self):
self.resource.write(':FORM:DATA ASCII')
self.resource.values_format.use_ascii(converter='f', separator=',', container=np.array)
@property
def echo(self):
return self.scpi.echo
@echo.setter
def echo(self, onoff):
if onoff in (1, True):
self.scpi.echo = True
elif onoff in (0, False):
self.scpi.echo = False
else:
raise warnings.warn("echo must be a boolean")
@property
def active_channel(self):
old_timeout = self.resource.timeout
self.resource.timeout = 500
try:
channel = self.scpi.query_active_channel()
except pyvisa.VisaIOError:
print("No channel active, using 1")
channel = 1
finally:
self.resource.timeout = old_timeout
return channel
@active_channel.setter
def active_channel(self, channel):
"""
Set the active channel on the analyzer
Parameters
----------
channel : int
Notes
-----
There is no specific command to activate a channel, so we ask which channel we want and then activate the first
trace on that channel. We do this because if the analyzer gets into a state where it doesn't recognize
any activated measurements, the get_snp_network method will fail, and possibly others as well. That is why in
some methods you will see the following line:
self.active_channel = channel = kwargs.get("channel", self.active_channel)
this way we force this property to be set, even if it just resets itself to the same value, but then a trace
will become active and our get_snp_network method will succeed.
"""
# TODO: Good chance this will fail if no measurement is on the set channel, need to think about that...
mnum = self.scpi.query_meas_number_list(channel)[0]
self.scpi.set_selected_meas_by_number(channel, mnum)
return
[docs] def sweep(self, **kwargs):
"""
Initialize a fresh sweep of data on the specified channels
Parameters
----------
kwargs : dict
channel ("all", int or list of channels), timeout (milliseconds)
trigger a fresh sweep on the specified channels (default is "all" if no channel specified)
Autoset timeout and sweep mode based upon the analyzers current averaging setting,
and then return to the prior state of continuous trigger or hold.
"""
self.resource.clear()
self.scpi.set_trigger_source("IMM")
original_timeout = self.resource.timeout
# expecting either an int or a list of ints for the channel(s)
channels_to_sweep = kwargs.get("channels", None)
if not channels_to_sweep:
channels_to_sweep = kwargs.get("channel", "all")
if not type(channels_to_sweep) in (list, tuple):
channels_to_sweep = [channels_to_sweep]
channels = self.scpi.query_available_channels()
for i, channel in enumerate(channels):
sweep_mode = self.scpi.query_sweep_mode(channel)
was_continuous = "CONT" in sweep_mode.upper()
sweep_time = self.scpi.query_sweep_time(channel)
averaging_on = self.scpi.query_averaging_state(channel)
averaging_mode = self.scpi.query_averaging_mode(channel)
if averaging_on and "SWE" in averaging_mode.upper():
sweep_mode = "GROUPS"
number_of_sweeps = self.scpi.query_averaging_count(channel)
self.scpi.set_groups_count(channel, number_of_sweeps)
number_of_sweeps *= self.NPORTS
else:
sweep_mode = "SINGLE"
number_of_sweeps = self.NPORTS
channels[i] = {
"cnum": channel,
"sweep_time": sweep_time,
"number_of_sweeps": number_of_sweeps,
"sweep_mode": sweep_mode,
"was_continuous": was_continuous
}
self.scpi.set_sweep_mode(channel, "HOLD")
timeout = kwargs.get("timeout", None) # recommend not setting this variable, as autosetting is preferred
try:
for channel in channels:
import time
if "all" not in channels_to_sweep and channel["cnum"] not in channels_to_sweep:
continue # default for sweep is all, else if we specify, then sweep
if not timeout: # autoset timeout based on sweep time
sweep_time = channel["sweep_time"] * channel[
"number_of_sweeps"] * 1000 # convert to milliseconds, and double for buffer
self.resource.timeout = max(sweep_time * 2, 5000) # give ourselves a minimum 5 seconds for a sweep
else:
self.resource.timeout = timeout
self.scpi.set_sweep_mode(channel["cnum"], channel["sweep_mode"])
self.wait_until_finished()
finally:
self.resource.clear()
for channel in channels:
if channel["was_continuous"]:
self.scpi.set_sweep_mode(channel["cnum"], "CONT")
self.resource.timeout = original_timeout
return
[docs] def upload_twoport_calibration(self, cal, port1=1, port2=2, **kwargs):
"""
upload a calibration to the vna, and set correction on all measurements
Parameters
----------
cal : skrf.Calibration
port1: int
port2: int
calibration error terms reference
# forward = (1, 1), reverse = (2, 2)
"directivity": "EDIR",
"source match": "ESRM",
"reflection tracking": "ERFT",
# forward = (2, 1), reverse = (1, 2)
"load match": "ELDM",
"transmission tracking": "ETRT"
"isolation": "EXTLK"
"""
self.active_channel = channel = kwargs.get("channel", self.active_channel)
calname = kwargs.get("calname", "skrf_12term_cal")
calibrations = self.scpi.query_calset_catalog(cnum=channel, form="NAME")
if calname in calibrations:
self.scpi.set_delete_calset(cnum=channel, calset_name=calname)
self.scpi.set_create_calset(cnum=channel, calset_name=calname)
cfs = dict()
for coef, data in cal.coefs_12term.items():
cfs[coef] = skrf.mf.complex2Scalar(data)
for eterm, coef in zip(("EDIR", "ESRM", "ERFT"), ("directivity", "source match", "reflection tracking")):
self.scpi.set_calset_data(channel, eterm, port1, port1, eterm_data=cfs["forward " + coef])
self.scpi.set_calset_data(channel, eterm, port2, port2, eterm_data=cfs["reverse " + coef])
for eterm, coef in zip(("ELDM", "ETRT", "EXTLK"), ("load match", "transmission tracking", "isolation")):
self.scpi.set_calset_data(channel, eterm, port2, port1, eterm_data=cfs["forward " + coef])
self.scpi.set_calset_data(channel, eterm, port1, port2, eterm_data=cfs["reverse " + coef])
self.scpi.set_active_calset(1, calname, True)
[docs] def get_snp_network(self, ports, **kwargs):
"""
return n-port network as an Network object
Parameters
----------
ports : Iterable
a iterable of integers designating the ports to query
kwargs : dict
channel(int) [ default 'self.active_channel' ]
sweep(bool) [default True]
name(str) [default \"\"]
f_unit(str) [ default \"GHz\" ]
raw_data(bool) [default False]
Returns
-------
Network
general function to take in a list of ports and return the full snp network as a Network object
"""
self.resource.clear()
# force activate channel to avoid possible errors:
self.active_channel = channel = kwargs.get("channel", self.active_channel)
sweep = kwargs.get("sweep", True)
name = kwargs.get("name", "")
f_unit = kwargs.get("f_unit", "GHz")
raw_data = kwargs.get("raw_data", False)
ports = [int(port) for port in ports] if type(ports) in (list, tuple) else [int(ports)]
if not name:
name = "{:}Port Network".format(len(ports))
if sweep:
self.sweep(channel=channel)
npoints = self.scpi.query_sweep_n_points(channel)
snp_fmt = self.scpi.query_snp_format()
self.scpi.set_snp_format("RI")
if raw_data is True:
if self.scpi.query_channel_correction_state(channel):
self.scpi.set_channel_correction_state(channel, False)
data = self.scpi.query_snp_data(channel, ports)
self.scpi.set_channel_correction_state(channel, True)
else:
data = self.scpi.query_snp_data(channel, ports)
else:
data = self.scpi.query_snp_data(channel, ports)
self.scpi.set_snp_format(snp_fmt) # restore the value before we got the RI data
self.scpi.set_snp_format(snp_fmt) # restore the value before we got the RI data
nrows = int(len(data) / npoints)
nports = int(np.sqrt((nrows - 1)/2))
data = data.reshape([nrows, -1])
fdata = data[0]
sdata = data[1:]
ntwk = skrf.Network()
ntwk.frequency = skrf.Frequency.from_f(fdata, unit="Hz")
ntwk.s = np.empty(shape=(sdata.shape[1], nports, nports), dtype=complex)
for n in range(nports):
for m in range(nports):
i = n * nports + m
ntwk.s[:, m, n] = sdata[i * 2] + 1j * sdata[i * 2 + 1]
ntwk.frequency.unit = f_unit
ntwk.name = name
return ntwk
[docs] def get_list_of_traces(self, **kwargs):
self.resource.clear()
traces = []
channels = self.scpi.query_available_channels()
for channel in channels:
meas_list = self.scpi.query_meas_name_list(channel)
if len(meas_list) == 1:
continue # if there isnt a single comma, then there aren't any measurements
parameters = dict([(meas_list[k], meas_list[k + 1]) for k in range(0, len(meas_list) - 1, 2)])
meas_numbers = self.scpi.query_meas_number_list()
for mnum in meas_numbers:
name = self.scpi.query_meas_name_from_number(mnum)
item = {"name": name, "channel": channel, "measurement number": mnum,
"parameter": parameters.get(name, name)}
item["label"] = "{:s} - Chan{:},Meas{:}".format(
item["parameter"], item["channel"], item["measurement number"])
traces.append(item)
return traces
[docs] def get_traces(self, traces, **kwargs):
"""
retrieve traces as 1-port networks from a list returned by get_list_of_traces
Parameters
----------
traces : list
list of type that is exported by self.get_list_of_traces
kwargs : dict
sweep (bool), name_prefix (str)
Returns
-------
list
a list of 1-port networks representing the desired traces
Notes
-----
There is no current way to distinguish between traces and 1-port networks within skrf
"""
self.resource.clear()
sweep = kwargs.get("sweep", False)
name_prefix = kwargs.get("name_prefix", "")
if name_prefix:
name_prefix += " - "
channels = OrderedDict()
for trace in traces:
ch = trace["channel"]
if ch not in channels.keys():
channels[ch] = {
"frequency": None,
"traces": list()}
channels[ch]["traces"].append(trace)
if sweep is True:
self.sweep(channels=list(channels.keys()))
traces = []
for ch, ch_data in channels.items():
frequency = ch_data["frequency"] = self.get_frequency()
for trace in ch_data["traces"]:
self.scpi.set_selected_meas_by_number(trace["channel"], trace["measurement number"])
sdata = self.scpi.query_data(trace["channel"], "SDATA")
s = sdata[::2] + 1j * sdata[1::2]
ntwk = skrf.Network()
ntwk.s = s
ntwk.frequency = frequency
ntwk.name = name_prefix + trace.get("parameter", "trace")
traces.append(ntwk)
return traces
[docs] def get_frequency(self, **kwargs):
"""
get an skrf.Frequency object for the current channel
Parameters
----------
kwargs : dict
channel (int), f_unit (str)
Returns
-------
skrf.Frequency
"""
self.resource.clear()
channel = kwargs.get("channel", self.active_channel)
sweep_type = self.scpi.query_sweep_type(channel)
if sweep_type in ["LIN", "LOG", "SEGM"]:
freqs = self.scpi.query_sweep_data(channel)
else:
freqs = np.array([self.scpi.query_f_start(channel)])
frequency = skrf.Frequency.from_f(freqs, unit="Hz")
frequency.unit = kwargs.get("f_unit", "Hz")
return frequency
[docs] def set_frequency_sweep(self, f_start, f_stop, f_npoints, **kwargs):
f_unit = kwargs.get("f_unit", "hz").lower()
if f_unit != "hz":
f_start = self.to_hz(f_start, f_unit)
f_stop = self.to_hz(f_stop, f_unit)
channel = kwargs.get("channel", self.active_channel)
self.scpi.set_f_start(channel, f_start)
self.scpi.set_f_stop(channel, f_stop)
self.scpi.set_sweep_n_points(f_npoints)
[docs] def get_switch_terms(self, ports=(1, 2), **kwargs):
self.resource.clear()
p1, p2 = ports
self.active_channel = channel = kwargs.get("channel", self.active_channel)
measurements = self.get_meas_list()
max_trace = len(measurements)
for meas in measurements: # type: str
try:
trace_num = int(meas[0][-2:].replace("_", ""))
if trace_num > max_trace:
max_trace = trace_num
except ValueError:
pass
forward_name = "CH{:}_FS_P{:d}_{:d}".format(channel, p1, max_trace + 1)
reverse_name = "CH{:}_RS_P{:d}_{:d}".format(channel, p2, max_trace + 2)
self.create_meas(forward_name, 'a{:}b{:},{:}'.format(p2, p2, p1))
self.create_meas(reverse_name, 'a{:}b{:},{:}'.format(p1, p1, p2))
self.sweep(channel=channel)
forward = self.get_measurement(mname=forward_name, sweep=False) # type: skrf.Network
forward.name = "forward switch terms"
reverse = self.get_measurement(mname=reverse_name, sweep=False) # type: skrf.Network
reverse.name = "reverse switch terms"
self.scpi.set_delete_meas(channel, forward_name)
self.scpi.set_delete_meas(channel, reverse_name)
return forward, reverse
[docs] def get_measurement(self, mname=None, mnum=None, **kwargs):
"""
get a measurement trace from the analyzer, specified by either name or number
Parameters
----------
mname : str
the name of the measurement, e.g. 'CH1_S11_1'
mnum : int
the number of number of the measurement
kwargs : dict
channel (int), sweep (bool)
Returns
-------
skrf.Network
"""
if mname is None and mnum is None:
raise ValueError("must provide either a measurement mname or a mnum")
channel = kwargs.get("channel", self.active_channel)
if type(mname) is str:
self.scpi.set_selected_meas(channel, mname)
else:
self.scpi.set_selected_meas_by_number(channel, mnum)
return self.get_active_trace_as_network(**kwargs)
[docs] def get_active_trace_as_network(self, **kwargs):
"""
get the active trace as a network object
Parameters
----------
kwargs : dict
channel (int), sweep (bool)
Returns
-------
skrf.Network
"""
channel = self.active_channel
sweep = kwargs.get("sweep", False)
if sweep:
self.sweep(channel=channel)
ntwk = skrf.Network()
sdata = self.scpi.query_data(channel)
ntwk.s = sdata[::2] + 1j * sdata[1::2]
ntwk.frequency = self.get_frequency(channel=channel)
return ntwk
[docs] def create_meas(self, mname, param, **kwargs):
"""
Create a new measurement trace on the analyzer
Parameters
----------
mname: str
name of the measurement **WARNING**, not all names behave well
param: str
analyzer parameter, e.g.: S11 ; a1/b1,1 ; A/R1,1
kwargs : dict
channel(int)
"""
channel = kwargs.get("channel", self.active_channel)
self.scpi.set_create_meas(channel, mname, param)
self.display_trace(mname)
[docs] def display_trace(self, mname, **kwargs):
"""
Display measurement name on the analyzer display window
Parameters:
mname : str
the name of the measurement, e.g. 'CH1_S11_1'
kwargs : dict
channel(int), window_n(int), trace_n(int), display_format(str)
Keyword Arguments
----------------
display_format : str
must be one of: MLINear, MLOGarithmic, PHASe, UPHase, IMAGinary, REAL, POLar, SMITh,
SADMittance, SWR, GDELay, KELVin, FAHRenheit, CELSius
"""
channel = kwargs.get('channel', self.active_channel)
window_n = kwargs.get("window_n", '')
trace_n = kwargs.get("trace_n",
max(self.scpi.query_window_trace_numbers(window_n)) + 1)
display_format = kwargs.get('display_format', 'MLOG')
self.scpi.set_display_trace(window_n, trace_n, mname)
self.scpi.set_selected_meas(channel, mname)
self.scpi.set_display_format(channel, display_format)
[docs] def get_meas_list(self, **kwargs):
"""
Convenience function to return a nicely arranged list of the measurement, parameter catalogue
Parameters
----------
kwargs : dict
channel : int
Returns
-------
list
list of tuples of the form: (name, measurement)
Return a list of measurement names on all channels.
If channel is provided to kwargs, then only measurements for that channel are queried
"""
channel = kwargs.get("channel", self.active_channel)
meas_list = self.scpi.query_meas_name_list(channel)
if len(meas_list) == 1:
return None # if there isnt a single comma, then there arent any measurements
return [(meas_list[k], meas_list[k + 1]) for k in range(0, len(meas_list) - 1, 2)]
@property
def ntraces(self):
"""
Get the number of traces on the active channel
Returns
-------
int
The number of measurement traces that exist on the current channel
Notes
-----
Note that this may not be the same as the number of traces displayed because a measurement may exist,
but not be associated with a trace.
"""
meas_list = self.scpi.query_meas_number_list(self.active_channel)
return 0 if meas_list is None else len(meas_list)
class PNAX(PNA):
NAME = "Keysight PNA-X"
NPORTS = 4
NCHANNELS = 32