def __init__(self,
f,
offsetDelay=0.0,
offsetZ0=50.0,
offsetLoss=0.0,
terminationZ0=50.0):
"""Constructor
@param f list of frequencies
@param offsetDelay (optional) float electrical length of offset in s (defaults to 0 s)
@param offsetZ0 (optional) float real characteristic impedance of offset (defaults to 50 ohms)
@param offsetLoss (optional) float loss due to skin-effect defined in Gohms/s at 1 GHz (defaults to 0).
@param terminationZ0 (optional) float real impedance of termination.
The result is that the class becomes the base-class SParameters with the s-parameters
of a load standard.
"""
# pragma: silent exclude
from SignalIntegrity.Lib.Parsers.SystemDescriptionParser import SystemDescriptionParser
# pragma: include
sspn = SystemSParametersNumeric(SystemDescriptionParser().AddLines([
'device offset 2', 'device R 1', 'port 1 offset 1',
'connect offset 2 R 1'
]).SystemDescription())
offsetSParameters = Offset(f, offsetDelay, offsetZ0, offsetLoss)
terminationSParameters = TerminationZ(terminationZ0)
sp = []
for n in range(len(f)):
sspn.AssignSParameters('offset', offsetSParameters[n])
sspn.AssignSParameters('R', terminationSParameters)
sp.append(sspn.SParameters())
SParameters.__init__(self, f, sp)
def TerminationL(L,f,Z0=None):
"""Termination (one-port) inductance
@param L float inductance
@param f float frequency
@param Z0 (optional) float of complex reference impedance (defaults to 50 Ohms)
@return the list of list s-parameter matrix for a termination inductance
"""
return TerminationZ(L*1j*2.*math.pi*f,Z0)
def TerminationG(G,Z0=50.):
"""TerminationG
Termination conductance
@param G float conductance.
@param Z0 (optional) float of complex reference impedance (defaults to 50 Ohms).
@return the list of list s-parameter matrix for a termination conductance.
"""
infinity=1e25
try: Z = 1.0/G
except ZeroDivisionError: Z = infinity
return TerminationZ(Z,Z0)
def IdealRelay(ports, position, termination='open', Z0=50.):
"""IdealRelay
An ideal relay with a given number of ports, where the common is always the last port.
I.e. for a given number ports P, port P is always the common connection and ports 1 through
P-1 are the throws of the relay (the ports that get connected to the common) in port order.
The position value ranges from 0 to P-1, where 0 says that none of the throws are connected to
the common, and a value from 1 to P-1 indicates the throw port connected to the common.
Valid terminations are the string 'open', or a number indicating the impedance of the unconnected
port. This impedance is also applied to the common, when no ports are connected.
@param ports int number of ports in the relay (including the common).
@parem position int number from 0 to ports-1 indicating the relay position.
@param float or string (optional, defaults to 'open' termination applied to unconnected ports.
@param float (optional, defaults to 50) reference impedance.
@returns the list of list s-parameter matrix of the ideal relay in the position specified.
"""
if termination == 'open': rho = 1.
else: rho = TerminationZ(termination, Z0)[0][0]
S = [[rho if r == c else 0 for c in range(ports)] for r in range(ports)]
if 0 < position < ports:
S[position - 1][position - 1] = 0
S[position - 1][ports - 1] = 1.
S[ports - 1][position - 1] = 1.
S[ports - 1][ports - 1] = 0
return S