skrf.calibration.calibration.EightTerm

class skrf.calibration.calibration.EightTerm(measured, ideals, switch_terms=None, isolation=None, ut_hook=None, *args, **kwargs)

General EightTerm (aka Error-box) Two-port calibration

This is basically an extension of the one-port algorithm to two-port measurements, A least squares estimator is used to determine the error coefficients. No self-calibration takes place. The concept is presented in 1 , but implementation follows that of 2 .

See __init__()

Notes

An important detail of implementing the error-box model is that the internal switch must be correctly accounted for. This is done through the measurement of switch terms.

References

1

Speciale, R.A.; , “A Generalization of the TSD Network-Analyzer Calibration Procedure, Covering n-Port Scattering-Parameter Measurements, Affected by Leakage Errors,” Microwave Theory and Techniques, IEEE Transactions on , vol.25, no.12, pp. 1100- 1115, Dec 1977. URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=1129282&isnumber=25047

2

Rytting, D. (1996) Network Analyzer Error Models and Calibration Methods. RF 8: Microwave Measurements for Wireless Applications (ARFTG/NIST Short Course Notes)

Attributes

T_matrices	Intermediate matrices used for embedding and de-embedding.
biased_error	Estimate of biased error for overdetermined calibration with multiple connections of each standard
caled_ntwk_sets	Returns a NetworkSet for each caled_ntwk, grouped by their names
caled_ntwks	List of the corrected calibration standards
coefs	Dictionary or error coefficients in form of numpy arrays
coefs_12term	Dictionary of error coefficients for 12-term Model
coefs_12term_ntwks	Dictionary or error coefficients in form of Network objects
coefs_3term	Dictionary of error coefficients for One-port Error model
coefs_3term_ntwks	Dictionary of error coefficients in form of Network objects
coefs_8term	Dictionary of error coefficients for 8-term (Error-box) Model
coefs_8term_ntwks	Dictionary of error coefficients in form of Network objects
coefs_ntwks	Dictionary of error coefficients in form of Network objects
error_ntwk	The calculated error Network or Network[s]
family
frequency	Frequency object of the calibration
measured_unisolated
measured_unterminated
normalized_directivity	the directivity normalized to the reflection tracking
nstandards	number of ideal/measurement pairs in calibration
output_from_run	Returns any output from the run().
residual_ntwk_sets	Returns a NetworkSet for each residual_ntwk, grouped by their names
residual_ntwks	Dictionary of residual Networks
total_error	Estimate of total error for overdetermined calibration with multiple connections of each standard.This is the combined effects of both biased and un-biased errors
unbiased_error	Estimate of unbiased error for overdetermined calibration with multiple connections of each standard
verify_12term
verify_12term_ntwk

Methods

__init__	EightTerm Initializer
apply_cal	Apply correction to a Network
apply_cal_to_all_in_dir	Apply correction to all touchstone files in a given directory.
apply_cal_to_list	Apply correction to list of dict of Networks.
apply_cal_to_network_set	Apply correction to a NetworkSet.
embed
from_coefs	Creates a calibration from its error coefficients
from_coefs_ntwks	Creates a calibration from its error coefficients
plot_caled_ntwks	Plot corrected calibration standards.
plot_errors	Plot biased, unbiased and total error in dB scaled.
plot_residuals	Plot residual networks.
pop	Remove and return tuple of (ideal, measured) at index.
remove_and_cal	Remove a cal standard and correct it, returning correct and ideal
renormalize	Renormalizes the calibration error boxes to a new reference impedance.
run	Runs the calibration algorithm.
terminate	Terminate a network with switch terms
unterminate	Unterminates switch terms from a raw measurement.
update_coefs	update current dict of error coefficients
write	Write the Calibration to disk using write()