edges.cal.loss¶
Models for loss through cables.
- class edges.cal.loss.LossFunctionGivenSparams(sparams: SParams)[source]¶
A callable that satisfies the signature for a loss function, from given sparams.
Measurements required to define the HotLoad temperature, from Monsalve et al. (2017), Eq. 8+9.
- edges.cal.loss.compute_cable_loss_from_scattering_params(input_s11: ReflectionCoefficient, sparams: SParams) ndarray[tuple[Any, ...], dtype[float]][source]¶
Compute loss from a cable, given the S-params of the cable, and input S11.
This function operates in the context of a cable (or balun, etc.) that is attached to an input (generally the antenna, or a calibration load). It computes the loss due to the cable, given the scattering matrix of the cable itself, and the S11 of the input antenna/load.
The equations here are described in MIT EDGES Memo #132: https://www.haystack.mit.edu/wp-content/uploads/2020/07/memo_EDGES_132.pdf. We use two of the equations, to be specific: the equation for Gamma_a (the antenna reflection coefficient at the input of the cable), and the equation for the loss, L.
SGM: as far as I can tell, this function doesn’t assume that S12 == S21, though actual calls to this function generally throughout our calibration do make this assumption.
- edges.cal.loss.get_cable_loss_model(cable: CoaxialCable | str | Sequence[CoaxialCable | str]) callable[source]¶
Return a callable loss model for a particular cable or series of cables.
The returned function is suitable for passing to a
Loadas the loss_model.You can pass a single cable (i.e. a
edges.cal.ee.CoaxialCable) or a list of such cables, each of which is assumed to be joined in a cascade. Each should be equipped with a cable length.- Parameters:
cable – Either a string, or a CoaxialCable instance, or a list of such. If a string, it should be a name present in ee.KNOWN_CABLES.