skrf.calibration.calibration.EightTerm

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

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_cal_to_list Apply correction to list of dict of Networks.
embed
from_coefs Creates a calibration from its error coefficients
from_coefs_ntwks Creates a calibration from its error coefficients
plot_caled_ntwks Plots corrected calibration standards
plot_errors Plots 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 currect dict of error coefficients
write Write the Calibration to disk using write()