Control and filtering

lock

A simple lock which computes and applies the feedback to a given parameter using an error signal.

Syntax:
lock name error_signal feedback gain accuracy disabled=false offset=0
Required:

name: Name of newly created lock.

error_signal: An error signal parameter or an object capable of producing a real-type error signal. This is typically a demodulated PowerDetector instance (or the name of the instance).

feedback: A parameter of the model to apply the locks’ feedback signal to.

gain: Control loop gain.

accuracy: Threshold to decide whether the loop is locked.

disabled: If true this lock will not run when the RunLocks() action is used. Explicitly specifying the name of the lock will override this setting, e.g. RunLocks(name).

offset: An offset that is applied to the error signal before it is used.

degree_of_freedom
dof
Syntax:
dof name *node_amplitude_pairs DC=0
amplifier
Syntax:
amplifier name gain=1
filter_zpk
zpk

A zero-pole-gain filter element that is used for shaping signals in simulations. It is a two port element. p1 is the input port and p2 is the output port. Each one has a single node: p1.i and p2.o.

Syntax:
zpk name z p k=none fQ=false gain=1
Required:

name: Name of element in the model

z: A 1D-array of zeros. Use [] if none are required. By default these are provided in units of radians, not Hz.

p: A 1D-array of poles. Use [] if none are required. By default these are provided in units of radians, not Hz.

gain: Overall gain for the filter. Differs from k as this is a Parameter so can be easily switched on/off or varied during a simulation.

Optional:

k: Gain factor for the zeros and poles. If None then its value is automatically set to generate a unity gain at DC.

fQ: When True the zeros and poles can be specified in a tuple of (frequency, quality factor) for each pole and zero. This automatically adds the complex conjugate pair.

filter_butter
butter
Syntax:
butter name order btype frequency gain=1 analog=true
filter_cheby1
cheby1
Syntax:
cheby1 name order rp btype frequency gain=1 analog=true