class MixedModeTLine(SParameters):
"""s-parameters of a mixed-mode, balanced transmission line"""
def __init__(self,f,Zd,Td,Zc,Tc,Z0=50.):
"""Constructor
The port numbering is ports 1 and 2 are the plus and minus terminals on
one side of the line and ports 3 and 4 are the plus and minus terminals
on the other side of the line.
@param f list of float frequencies
@param Zd float or complex differential mode impedance
@param Td float differential (or odd-mode) electrical length (the
differential-mode propagation time.
@param Zc float or complex common-mode impedance
@param Tc float common (or even-mode) electrical length (the common-mode
propagation time.
@param Z0 (optional) float or complex reference impedance (defaults to 50 Ohms).
@note The differential mode impedance is twice the odd-mode impedance.\n
The common-mode impedance is half the even-mode impedance.\n
@note The model is appropriate for a balanced transmission line.\n
@note The s-parameters provided are single-ended.
@note This device builds a model internally and only solves the model
on each access to __getitem__().
"""
import SignalIntegrity.Lib.SParameters.Devices as dev
from SignalIntegrity.Lib.Devices.MixedModeConverter import MixedModeConverter
from SignalIntegrity.Lib.SystemDescriptions.SystemSParametersNumeric import SystemSParametersNumeric
self.m_sspn=SystemSParametersNumeric()
self.m_spdl=[]
self.m_sspn.AddDevice('MM1',4,MixedModeConverter())
self.m_sspn.AddDevice('MM2',4,MixedModeConverter())
self.m_sspn.AddDevice('D',2), self.m_spdl.append(('D',dev.TLineLossless(f,2,Zd/2.,Td,Z0)))
self.m_sspn.AddDevice('C',2), self.m_spdl.append(('C',dev.TLineLossless(f,2,Zc*2.,Tc,Z0)))
self.m_sspn.ConnectDevicePort('MM1',3,'D',1)
self.m_sspn.ConnectDevicePort('MM2',3,'D',2)
self.m_sspn.ConnectDevicePort('MM1',4,'C',1)
self.m_sspn.ConnectDevicePort('MM2',4,'C',2)
self.m_sspn.AddPort('MM1',1,1)
self.m_sspn.AddPort('MM1',2,2)
self.m_sspn.AddPort('MM2',1,3)
self.m_sspn.AddPort('MM2',2,4)
SParameters.__init__(self,f,None,Z0)
def __getitem__(self,n):
"""overloads [n]
@return list of list s-parameter matrix for the nth frequency element
"""
for ds in self.m_spdl: self.m_sspn.AssignSParameters(ds[0],ds[1][n])
return self.m_sspn.SParameters()
def DutUnCalculationAlternate(self,S,portList=None):
"""Un-calcualates the DUT.\n
This calculates the expected raw measured DUT based on the DUT actually calculated.\n
@see DutCalculation
@param S instance of class SParameters of measured DUT from these error-terms.
@param portList (optional) list of zero based port numbers used for the DUT calcualtion
@return instance of class SParameters of the raw measured s-parameters that calculated this DUT
@remark If the portList is None, then it assumed to be a list [0,1,2,P-1] where P is the
number of ports in sRaw, otherwise ports can be specified where the DUT is connected.
@deprecated This method utilizes fixtures and embeds them. Originally, I could not figure out
how to do this with just the error-terms. This was figured out finally and is more efficient, but
this method is retained for comparison of results.
@see DutUnCalculation
"""
self.CalculateErrorTerms()
if portList is None: portList=[p for p in range(self.ports)]
ports=len(portList)
sspn=SystemSParametersNumeric()
sspn.AddDevice('F',2*ports)
sspn.AddDevice('D',ports)
for p in range(ports):
sspn.AddPort('F',p+1,p+1)
sspn.ConnectDevicePort('F',ports+p+1,'D',p+1)
rd=[None for n in range(len(self.f))]
fixtureList=self.Fixtures(portList)
for n in range(len(self.f)):
rm=[[None for c in range(ports)] for r in range(ports)]
sspn.AssignSParameters('D',S[n])
for p in range(ports):
sspn.AssignSParameters('F',fixtureList[p][n])
spp=sspn.SParameters()
for r in range(ports):
rm[r][p]=spp[r][p]
rd[n]=rm
return SParameters(self.f,rd)