class PowerMeter(object):
""" Creates a power meter object for the Newfocus power meter connected to a DMM."""
def __init__(self,gpibAddr=None):
if gpibAddr==None:
self.dmm=DMM()
else:
self.dmm=DMM(gpibAddr)
def readPower(self,backgroundVoltage=0,n=1):
""" routine to read a single power measurement """
# V=self.dmm.measure()
V=self.bestOfN(n)
return self.voltageToPower(V-backgroundVoltage)
def readPowerAuto(self,tau=200,timeout=10,mode="mean"):
""" read power including automatic error handling """
self.t0=time.time()
# Automatically remeasure if there was a comm. error until timeout occurs
while 1:
try:
power=self._readPowerAuto(tau,timeout,mode)
break
except CommError as e:
if time.time()-self.t0 < timeout:
pass
else:
# If timeout occurs, re-raise the (same) error
raise
del self.t0
return power
def _readPowerAuto(self,tau,timeout,mode):
""" use automatic ranging """
# Hack to get something working
self.dmm.setAuto()
return self.readPower()
def bestOfN(self,n):
""" Hack to take best n readings in case of moving target """
v=zeros((n,1))
for idx in range(n):
v[idx]=self.dmm.measure()
return max(v)
def voltageToPower(self,V):
return max(V*SENSITIVITY/INSERTION_LOSS,0)
class PowerMeter(BasePowerMeter):
""" Creates a power meter object for the Newfocus power meter connected to a DMM."""
def __init__(self, gpibAddr=None):
if gpibAddr == None:
self.dmm = DMM()
else:
self.dmm = DMM(gpibAddr)
def readPower(self, tau=200, mode="mean"):
""" use automatic ranging """
# Hack to get something working
self.dmm.setAuto()
V = self._bestOfN(n)
return self._voltageToPower(V - backgroundVoltage)
def _bestOfN(self, n):
""" Hack to take best n readings in case of moving target """
v = zeros((n, 1))
for idx in range(n):
v[idx] = self.dmm.measure()
return max(v)
def _voltageToPower(self, V):
return max(V * SENSITIVITY / INSERTION_LOSS, 0)
class PowerMeter(BasePowerMeter):
""" Creates a power meter object for the Newfocus power meter connected to a DMM."""
def __init__(self,gpibAddr=None):
if gpibAddr==None:
self.dmm=DMM()
else:
self.dmm=DMM(gpibAddr)
def readPower(self, tau=200, mode="mean"):
""" use automatic ranging """
# Hack to get something working
self.dmm.setAuto()
V=self._bestOfN(n)
return self._voltageToPower(V-backgroundVoltage)
def _bestOfN(self,n):
""" Hack to take best n readings in case of moving target """
v=zeros((n,1))
for idx in range(n):
v[idx]=self.dmm.measure()
return max(v)
def _voltageToPower(self,V):
return max(V*SENSITIVITY/INSERTION_LOSS,0)