mwavepy.network | index /home/alex/docs/python/path/mwavepy/network.py

`Provides the Network class and related functions.`

Modules
`` |  |
mwavepy.mathFunctions numpy | os pylab | scipy.stats mwavepy.touchstone |

Classes
`` |  | __builtin__.object Network
class Network(__builtin__.object)
`` | `Represents a n-port microwave network. the most fundemental properties are: s: scattering matrix. a kxnxn complex matrix where 'n' is number of ports of network. z0: characteristic impedance f: frequency vector in Hz. see also frequency, which is a Frequency object (see help on this class for more info) The following operators are defined as follows: '+' : element-wise addition of the s-matrix '-' : element-wise subtraction of the s-matrix '*' : element-wise multiplication of the s-matrix '/' : element-wise division of the s-matrix '**': cascading of 2-port networks '//': de-embdeding of one network from the other. various other network properties are accesable as well as plotting routines are also defined for convenience, most properties are derived from the specifications given for touchstone files.`
| Methods defined here: __add__(self, other) `element-wise addition of s-matrix` __div__(self, other) `element-wise complex division of s-matrix` __eq__(self, other) __floordiv__(self, other) `implements de-embeding another network[s], from this network see de_embed` __getitem__(self, key) `returns a Network object at a given single frequency` __init__(self, touchstone_file=None, name=None) `constructor. takes: file: if given will load information from touchstone file name: name of this network.` __mul__(self, a) `element-wise complex multiplication of s-matrix` __ne__(self, other) __pow__(self, other) `implements cascading this network with another network` __repr__(self) __str__(self) __sub__(self, other) `element-wise subtraction of s-matrix` add_noise_polar(self, mag_dev, phase_dev, **kwargs) `adds a complex zero-mean gaussian white-noise signal of given standard deviations for magnitude and phase takes: mag_mag: standard deviation of magnitude phase_dev: standard deviation of phase [in degrees] n_ports: number of ports. defualt to 1 returns: nothing` change_frequency(self, new_frequency, **kwargs) flip(self) `swaps the ports of a two port` interpolate(self, new_frequency, **kwargs) `calculates an interpolated network. defualt interpolation type is linear. see notes about other interpolation types takes: new_frequency: **kwargs: passed to scipy.interpolate.interp1d initializer. returns: result: an interpolated Network note: usefule keyward for scipy.interpolate.interp1d: kind : str or int Specifies the kind of interpolation as a string ('linear', 'nearest', 'zero', 'slinear', 'quadratic, 'cubic') or as an integer specifying the order of the spline interpolator to use.` multiply_noise(self, mag_dev, phase_dev, **kwargs) `multiplys a complex bivariate gaussian white-noise signal of given standard deviations for magnitude and phase. magnitude mean is 1, phase mean is 0 takes: mag_dev: standard deviation of magnitude phase_dev: standard deviation of phase [in degrees] n_ports: number of ports. defualt to 1 returns: nothing` nudge(self, amount=1e-12) `perturb s-parameters by small amount. this is usefule to work-around numerical bugs. takes: amount: amount to add to s parameters returns: na` plot_polar_generic(self, attribute_r, attribute_theta, m=0, n=0, ax=None, show_legend=True, **kwargs) `generic plotting function for plotting a Network's attribute in polar form takes:` plot_s_all_db(self, ax=None, show_legend=True, *args, **kwargs) `plots all s parameters in log magnitude takes: ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not *args,**kwargs - passed to the matplotlib.plot command` plot_s_complex(self, m=None, n=None, ax=None, show_legend=True, *args, **kwargs) `plots the scattering parameter of indecies m, n on complex plane takes: m - first index, int n - second indext, int ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not *args,**kwargs - passed to the matplotlib.plot command` plot_s_db(self, m=None, n=None, ax=None, show_legend=True, *args, **kwargs) `plots the magnitude of the scattering parameter of indecies m, n in log magnitude takes: m - first index, int n - second indext, int ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not *args,**kwargs - passed to the matplotlib.plot command` plot_s_deg(self, m=None, n=None, ax=None, show_legend=True, *args, **kwargs) `plots the phase of a scattering parameter of indecies m, n in degrees takes: m - first index, int n - second indext, int ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not *args,**kwargs - passed to the matplotlib.plot command` plot_s_deg_unwrap = plot_s_deg_unwrapped(self, m=None, n=None, ax=None, show_legend=True, *args, **kwargs) plot_s_deg_unwrapped(self, m=None, n=None, ax=None, show_legend=True, *args, **kwargs) `plots the phase of a scattering parameter of indecies m, n in unwrapped degrees takes: m - first index, int n - second indext, int ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not *args,**kwargs - passed to the matplotlib.plot command` plot_s_mag(self, m=None, n=None, ax=None, show_legend=True, *args, **kwargs) `plots the magnitude of a scattering parameter of indecies m, n not in magnitude takes: m - first index, int n - second indext, int ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not *args,**kwargs - passed to the matplotlib.plot command` plot_s_polar(self, m=0, n=0, ax=None, show_legend=True, *args, **kwargs) `plots the scattering parameter of indecies m, n in polar form takes: m - first index, int n - second indext, int ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not *args,**kwargs - passed to the matplotlib.plot command` plot_s_rad(self, m=None, n=None, ax=None, show_legend=True, *args, **kwargs) `plots the phase of a scattering parameter of indecies m, n in radians takes: m - first index, int n - second indext, int ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not *args,**kwargs - passed to the matplotlib.plot command` plot_s_rad_unwrapped(self, m=None, n=None, ax=None, show_legend=True, *args, **kwargs) `plots the phase of a scattering parameter of indecies m, n in unwrapped radians takes: m - first index, int n - second indext, int ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not *args,**kwargs - passed to the matplotlib.plot command` plot_s_smith(self, m=None, n=None, r=1, ax=None, show_legend=True, chart_type='z', *args, **kwargs) `plots the scattering parameter of indecies m, n on smith chart takes: m - first index, int n - second indext, int r - radius of smith chart ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not chart_type: string determining countour type. options are: 'z': impedance contours (default) 'y': admittance contours *args,**kwargs - passed to the matplotlib.plot command` plot_vs_frequency_generic(self, attribute, y_label=None, m=None, n=None, ax=None, show_legend=True, **kwargs) `generic plotting function for plotting a Network's attribute vs frequency. takes:` read_touchstone(self, filename) `loads values from a touchstone file. takes: filename - touchstone file name, string. note: ONLY 'S' FORMAT SUPORTED AT THE MOMENT all work is tone in the touchstone class.` write_touchstone(self, filename=None, dir='./') `write a touchstone file representing this network. the only format supported at the moment is : HZ S RI takes: filename: a string containing filename without extension[None]. if 'None', then will use the network's name. if this is empty, then throws an error. dir: the directory to save the file in. [string]. Defaults to './' note: in the future could make possible use of the touchtone class, but at the moment this would not provide any benefit as it has not set_ functions.` Data descriptors defined here: __dict__ `dictionary for instance variables (if defined)` __weakref__ `list of weak references to the object (if defined)` f `the frequency vector for the network, in Hz.` frequency `returns a Frequency object, see frequency.py` inv `a network representing inverse s-parameters, for de-embeding` number_of_ports `the number of ports the network has.` passivity `passivity metric for a multi-port network. It returns a matrix who's diagonals are equal to the total power received at all ports, normalized to the power at a single excitement port. mathmatically, this is a test for unitary-ness of the s-parameter matrix. for two port this is ( |S11|^2 + |S21|^2, |S22|^2+|S12|^2) in general it is S.H * S where H is conjugate transpose of S, and * is dot product note: see more at, http://en.wikipedia.org/wiki/Scattering_parameters#Lossless_networks` s `The scattering parameter matrix. s-matrix has shape fxnxn, where; f is frequency axis and, n's are port indicies` s11 s12 s21 s22 s_db `returns the magnitude of the s-parameters, in dB note: dB is calculated by 20*log10(|s|)` s_deg `returns the phase of the s-parameters, in radians` s_deg_unwrap `returns the unwrapped phase of the s-paramerts, in degrees` s_mag `returns the magnitude of the s-parameters.` s_rad `returns the phase of the s-parameters, in radians.` s_rad_unwrap `returns the unwrapped phase of the s-parameters, in radians.` t `returns the t-parameters, which are also known as wave cascading matrix.` y z0 `the characteristic impedance of the network. z0 can be may be a number, or numpy.ndarray of shape n or fxn.`

Functions
`` |  | average(list_of_networks) `calculates the average network from a list of Networks. this is complex average of the s-parameters for a list of Networks takes: list_of_networks: a list of Networks returns: ntwk: the resultant averaged Network [mwavepy.Network]` cascade(a, b) `DEPRECATED. see connect_s() instead. cascade two s-matricies together. a's port 2 == b's port 1 if you want a different port configuration use the flip() fuction takes: a: a 2x2 or kx2x2 s-matrix b: a 2x2, kx2x2, 1x1, or kx1x1 s-matrix note: BE AWARE! this relies on s2t function which has a inf problem if s11 or s22 is 1.` connect(ntwkA, k, ntwkB, l) `connect two n-port networks together. specifically, connect port 'k' on ntwkA to port 'l' on ntwkB. The resultant network has (ntwkA.nports+ntwkB.nports -2) ports. The port index's ('k','l') start from 0. Port impedances are taken into account. takes: ntwkA: network 'A', [mwavepy.Network] k: port index on ntwkA [int] ( port indecies start from 0 ) ntwkB: network 'B', [mwavepy.Network] l: port index on ntwkB [int] returns: ntwkC': new network of rank (ntwkA.nports+ntwkB.nports -2)-ports note: see functions connect_s() and innerconnect_s() for actual S-parameter connection algorithm. the effect of mis-matched port impedances is handled by inserting a 2-port 'mismatch' network between the two connected ports.` connect_s(S, k, T, l) `connect two n-port networks together. specifically, connect port 'k' on network 'S' to port 'l' on network 'T'. The resultant network has (S.rank + T.rank-2)-ports takes: S: S-parameter matrix [numpy.ndarray]. k: port index on S (port indecies start from 0) [int] T: S-parameter matrix [numpy.ndarray] l: port index on T [int] returns: S': new S-parameter matrix [numpy.ndarry] note: shape of S-parameter matrices can be either nxn, or fxnxn, where f is the frequency axis. internally, this function creates a larger composite network and calls the innerconnect() function. see that function for more details about the implementation` csv_2_touchstone(filename) `converts a csv file saved from a Rhode swarz and possibly other takes: filename: name of file returns: Network object` de_embed(a, b) `de-embed a 2x2 s-matrix from another 2x2 s-matrix c = b**-1 * a note: BE AWARE! this relies on s2t function which has a inf problem if s11 or s22 is 1.` flip(a) `invert the ports of a networks s-matrix, 'flipping' it over note: only works for 2-ports at the moment` func_on_networks(ntwk_list, func, attribute='s', *args, **kwargs) `Applies a function to some attribute of aa list of networks, and returns the result in the form of a Network. This means information that may not be s-parameters is stored in the s-matrix of the returned Network. takes: ntwk_list: list of mwavepy.Network types func: function to operate on ntwk_list s-matrices attribute: attribute of Network's in ntwk_list for func to act on *args: passed to func **kwargs: passed to func returns: mwavepy.Network type, with s-matrix the result of func, operating on ntwk_list's s-matrices example: averaging can be implemented with func_on_networks by func_on_networks(ntwk_list,mean)` impedance_mismatch(z1, z2) `returns a two-port network for a impedance mis-match takes: z1: complex impedance of port 1 [ number, list, or 1D ndarray] z2: complex impedance of port 2 [ number, list, or 1D ndarray] returns: 2-port s-matrix for the impedance mis-match` innerconnect(ntwkA, k, l) `connect two ports of a single n-port network, resulting in a (n-2)-port network. port indecies start from 0. takes: ntwk: the network. [mwavepy.Network] k: port index [int] (port indecies start from 0) l: port index [int] returns: ntwk': new network of with n-2 ports. [mwavepy.Network] note: see functions connect_s() and innerconnect_s() for actual S-parameter connection algorithm.` innerconnect_s(S, k, l) `connect two ports of a single n-port network, resulting in a (n-2)-port network. takes: S: S-parameter matrix [numpy.ndarray] k: port index [int] l: port index [int] returns: S': new S-parameter matrix [numpy.ndarry] This function is based on the algorithm presented in the paper: 'Perspectives in Microwave Circuit Analysis' by R. C. Compton and D. B. Rutledge The original algorithm is given in 'A NEW GENERAL COMPUTER ALGORITHM FOR S-MATRIX CALCULATION OF INTERCONNECTED MULTIPORTS' by Gunnar Filipsson` inv(s) `inverse s-parameters, used for de-embeding` load_all_touchstones(dir='.', contains=None, f_unit=None) `loads all touchtone files in a given dir takes: dir - the path to the dir, passed as a string (defalut is cwd) contains - string which filename must contain to be loaded, not used if None.(default None) returns: ntwkDict - a Dictonary with keys equal to the file name (without a suffix), and values equal to the corresponding ntwk types` one_port_2_two_port(ntwk) `calculates the two-port network given a symetric, reciprocal and lossless one-port network. takes: ntwk: a symetric, reciprocal and lossless one-port network. returns: ntwk: the resultant two-port Network` plot_uncertainty_bounds(ntwk_list, attribute='s_mag', m=0, n=0, n_deviations=3, alpha=0.3, *args, **kwargs) `plots mean value with +- uncertainty bounds in an Network attribute, for a list of Networks. takes: ntwk_list: list of Netmwork types [list] attribute: attribute of Network type to analyze [string] m: first index of attribute matrix [int] n: second index of attribute matrix [int] n_deviations: number of std deviations to plot as bounds [number] alpha: passed to matplotlib.fill_between() command. [number, 0-1] *args,**kwargs: passed to Network.plot_'attribute' command returns: None Caution: if your list_of_networks is for a calibrated short, then the std dev of deg_unwrap might blow up, because even though each network is unwrapped, they may fall on either side fo the pi relative to one another.` plot_uncertainty_bounds_s_deg(*args, **kwargs) `this just calls plot_uncertainty_bounds(attribute= 's_deg',*args,**kwargs) see plot_uncertainty_bounds for help` plot_uncertainty_bounds_s_mag(*args, **kwargs) `this just calls plot_uncertainty_bounds(attribute= 's_mag',*args,**kwargs) see plot_uncertainty_bounds for help` s2t(s) `converts a scattering parameters to 'wave cascading parameters' input matrix shape should be should be 2x2, or kx2x2 BUG: if s -matrix has ones for reflection, thsi will produce inf's you cant cascade a matrix like this anyway, but we should handle it better` t2s(t) `converts a 'wave cascading parameters' to scattering parameters input matrix shape should be should be 2x2, or kx2x2` two_port_reflect(ntwk1, ntwk2, **kwargs) `generates a two-port reflective (S21=S12=0) network, from the 2 one-port networks takes: ntwk1: Network on port 1 [mwavepy.Network] ntwk2: Network on port 2 [mwavepy.Network] returns: result: two-port reflective network, S12=S21=0 [mwavepy.Network] example: to use a working band to create a two-port reflective standard from two one-port standards my_media= ... two_port_reflect(my_media.short(), my_media.match())` write_dict_of_networks(ntwkDict, dir='.') `writes a dictionary of networks to a given directory`

Data
`` |  | ALMOST_ZER0 = 1e-06