From 17d08cfaed8eb5cb6a14ec3acd64ad98bd4b318b Mon Sep 17 00:00:00 2001 From: Luke Date: Wed, 18 Jul 2018 17:04:35 -0700 Subject: [PATCH] Updated plotting to provide equal spacing of frequency steps. --- TankGlobals.py | 4 +-- tankPlot.py | 78 +++++++++++++++++++++++++++++++++++++++----------- 2 files changed, 63 insertions(+), 19 deletions(-) diff --git a/TankGlobals.py b/TankGlobals.py index 7258f3e..07682b0 100644 --- a/TankGlobals.py +++ b/TankGlobals.py @@ -6,11 +6,11 @@ import numpy as np ##### f0 = 28 bw0 = 6.5 # assumed tuning range (GHz) -bw_plt = 2 # Plotting range (GHz) +bw_plt = 3 # Plotting range (GHz) fbw = bw0/f0 # fractional bandwidth frequency_sweep_steps = 101 -gamma_sweep_steps = 15 +gamma_sweep_steps = 16 gamma = 1 - np.power(f0 / (f0 + bw0/2),2) gamma_limit_ratio = 0.99 # how close gamma can get to theoretical extreme diff --git a/tankPlot.py b/tankPlot.py index 3e7c59b..e07be2f 100644 --- a/tankPlot.py +++ b/tankPlot.py @@ -24,6 +24,9 @@ def ang_unwrap(volt_tf): def dB10(pwr_tf): """Describe power gain of a transfer function in dB (i.e. 10log(x))""" return 10*np.log10(np.abs(pwr_tf)) + +def atan(x): + return 180/np.pi*np.arctan(x) ################################################################################ @@ -38,7 +41,21 @@ from TankGlobals import * ################################################################################ # Now generate the sweep of resonance tuning (gamma, and capacitance) -gamma_swp = np.linspace(-gamma,gamma,gamma_sweep_steps); +# Linear based gamma spacing +#gamma_swp = np.linspace(-gamma,gamma,gamma_sweep_steps) + +# Linear PHASE gamma spacing +# First compute the most extreme phase given the extreme gamma +g1_limit = np.sqrt( g1*g1 - (gamma*gamma) * c1/l1 ) +K_limit = np.sqrt(c1/l1)*1/g1_limit +phase_limit = np.mod(np.pi/2 - np.arctan( -1/K_limit * 1/gamma ),np.pi) - np.pi + +# This gives us our equal phase spacing points +phase_swp = np.linspace(-1,1,gamma_sweep_steps) * phase_limit +# Then use this to compute the gamma steps to produce arbitrary phase given +# our perfect gain constraint. +gamma_swp = np.sign(phase_swp)/np.sqrt(np.power(np.tan(np.pi/2 - phase_swp),2)+1) * g1 / np.sqrt(c1/l1) + # compute correction factor for g1 that will produce common gain at f0 g1_swp = np.sqrt( g1*g1 - (gamma_swp*gamma_swp) * c1/l1 ) # and compute how much of a negative gm this requres, and it's relative @@ -54,27 +71,45 @@ print(' Rp = %.3f Ohm' % (1/g1)) print(' Max G1 boost %.2fmS (%.1f%% of gm1)' % \ (1e3*np.max(np.abs(g1_boost)), 100*np.max(g1_ratio))) -h = pp.figure() -mgr = pp.get_current_fig_manager() -ax1 = h.add_subplot(2,2,1, projection='smith') -ax2 = h.add_subplot(2,2,3, projection='polar') -ax3 = h.add_subplot(2,2,2) -ax4 = h.add_subplot(2,2,4) +y_tank = np.zeros((len(gamma_swp),len(f)), dtype=complex) +tf = np.zeros((len(gamma_swp),len(f)), dtype=complex) for itune,gamma_tune in enumerate(gamma_swp): c1_tune = c1_swp[itune] g1_tune = g1_swp[itune] K = np.sqrt(c1/l1)/g1_tune - y_tank = g1_tune + jw*c1_tune + 1/(jw * l1) - #print(1/np.mean(np.abs(y_tank))) - ax1.plot(y_tank, datatype=SmithAxes.Y_PARAMETER, marker="None") - tf = gm1 / g1_tune * \ + y_tank_tmp = g1_tune + jw*c1_tune + 1/(jw * l1) + y_tank[itune,:] = y_tank_tmp + tf_tmp = gm1 / g1_tune * \ 1j*(1+delta) / \ ( 1j*(1+delta) + K*(1 - (1+gamma_tune)*np.power(1+delta,2)) ) - ax2.plot(np.angle(tf), dB20(tf)) - ax3.plot(f,dB20(tf)) - ax4.plot(f,ang(tf)) + tf[itune,:] = tf_tmp + +tf = tf.T +tf_d = tf[:,1:]-tf[:,:-1] +tf_r = tf / (tf[:,int(tf.shape[1]/2)]*np.ones((tf.shape[1],1))).T +y_tank = y_tank.T +################################################################################ + +h1 = pp.figure() +h2 = pp.figure(figsize=(5,7)) +mgr = pp.get_current_fig_manager() +################################################################################ +ax1 = h1.add_subplot(2,2,1, projection='smith') +ax2 = h1.add_subplot(2,2,3, projection='polar') +ax3 = h1.add_subplot(2,2,2) +ax4 = h1.add_subplot(2,2,4) + +ax1.plot(y_tank, datatype=SmithAxes.Y_PARAMETER, marker="None") +ax2.plot(np.angle(tf), dB20(tf)) +ax3.plot(f,dB20(tf)) +ax4.plot(f,ang(tf)) ################################################################################ +ax8 = h2.add_subplot(2,1,1) +ax9 = h2.add_subplot(2,1,2) +ax8.plot(f,dB20(tf_r)) +ax9.plot(f,ang_unwrap(tf_r.T).T) + ax1.set_title('Tank Impedance') ax2.set_title('Transfer Function') @@ -82,11 +117,20 @@ ax3.set_title('TF Gain') ax3.set_ylabel('Gain (dB)') ax4.set_title('TF Phase') ax4.set_ylabel('Phase (deg)') -for ax_T in [ax3, ax4]: +ax8.set_title('TF Relative Gain') +ax8.set_ylabel('Relative Gain (dB)') +ax9.set_title('TF Relative Phase') +ax9.set_ylabel('Relative Phase (deg)') +for ax_T in [ax3, ax4, ax8, ax9]: ax_T.grid() ax_T.set_xlabel('Freq (GHz)') ax_T.set_xlim(( np.min(f), np.max(f) )) -h.tight_layout() + +################################################################################ +h1.tight_layout() +h2.tight_layout() mgr.window.geometry(default_window_position) -h.show() +h1.show() +mgr.window.geometry(default_window_position) +h2.show()