150 lines
4.9 KiB
Python
150 lines
4.9 KiB
Python
#!/usr/bin/env python3
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import numpy as np
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from matplotlib import rcParams, pyplot as pp
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import LPRDefaultPlotting
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import sys
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sys.path.append("./pySmithPlot")
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import smithplot
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from smithplot import SmithAxes
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################################################################################
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# Define my helper functions.
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def dB20(volt_tf):
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"""Describe signal gain of a transfer function in dB (i.e. 20log(x))"""
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return 20*np.log10(np.abs(volt_tf))
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def ang(volt_tf):
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"""Describe phase of a transfer function in degrees. Not unwrapped."""
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return 180/np.pi*np.angle(volt_tf)
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def ang_unwrap(volt_tf):
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"""Describe phase of a transfer function in degrees. With unwrapping."""
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return 180/np.pi*np.unwrap(np.angle(volt_tf))
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def dB10(pwr_tf):
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"""Describe power gain of a transfer function in dB (i.e. 10log(x))"""
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return 10*np.log10(np.abs(pwr_tf))
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def atan(x):
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return 180/np.pi*np.arctan(x)
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################################################################################
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# Override the defaults for this script
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rcParams['figure.figsize'] = [10,7]
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default_window_position=['+20+80', '+120+80']
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################################################################################
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# Operating Enviornment (i.e. circuit parameters)
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from TankGlobals import *
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################################################################################
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# Now generate the sweep of resonance tuning (gamma, and capacitance)
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# Linear based gamma spacing
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#gamma_swp = np.linspace(-gamma,gamma,gamma_sweep_steps)
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# Linear PHASE gamma spacing
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# First compute the most extreme phase given the extreme gamma
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g1_limit = np.sqrt( g1*g1 - (gamma*gamma) * c1/l1 )
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K_limit = np.sqrt(c1/l1)*1/g1_limit
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phase_limit = np.mod(np.pi/2 - np.arctan( -1/K_limit * 1/gamma ),np.pi) - np.pi
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if abs(phase_limit) < phase_limit_requested:
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print("==> WARN: Phase Beyond bounds, leaving at limits. <==")
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print("==> %.3f requested, but hardware limit is %.3f <==" % \
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(180/np.pi*phase_limit_requested, 180/np.pi*abs(phase_limit)))
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sys.exit(-1)
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else:
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phase_limit = phase_limit_requested
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# This gives us our equal phase spacing points
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phase_swp = np.linspace(-1,1,gamma_sweep_steps) * phase_limit
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# Then use this to compute the gamma steps to produce arbitrary phase given
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# our perfect gain constraint.
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gamma_swp = np.sign(phase_swp)/np.sqrt(np.power(np.tan(np.pi/2 - phase_swp),2)+1) * g1 / np.sqrt(c1/l1)
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# compute correction factor for g1 that will produce common gain at f0
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g1_swp = np.sqrt( g1*g1 - (gamma_swp*gamma_swp) * c1/l1 )
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# and compute how much of a negative gm this requres, and it's relative
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# proportion to the gm of the assumed main amplifier gm.
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g1_boost = (g1_swp - g1)
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g1_ratio = -g1_boost / gm1
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c1_swp = c1 * (1 + gamma_swp)
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## Report System Descrption
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print(' L1 = %.3fpH, C1 = %.3ffF' % (1e3*l1, 1e6*c1))
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print(' Rp = %.3f Ohm' % (1/g1))
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print(' Max G1 boost %.2fmS (%.1f%% of gm1)' % \
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(1e3*np.max(np.abs(g1_boost)), 100*np.max(g1_ratio)))
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y_tank = np.zeros((len(gamma_swp),len(f)), dtype=complex)
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tf = np.zeros((len(gamma_swp),len(f)), dtype=complex)
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for itune,gamma_tune in enumerate(gamma_swp):
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c1_tune = c1_swp[itune]
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g1_tune = g1_swp[itune]
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K = np.sqrt(c1/l1)/g1_tune
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y_tank_tmp = g1_tune + jw*c1_tune + 1/(jw * l1)
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y_tank[itune,:] = y_tank_tmp
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tf_tmp = gm1 / g1_tune * \
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1j*(1+delta) / \
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( 1j*(1+delta) + K*(1 - (1+gamma_tune)*np.power(1+delta,2)) )
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tf[itune,:] = tf_tmp
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tf = tf.T
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# double to describe with perfect inversion stage
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tf = np.column_stack((tf,-tf))
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ref_index = int(gamma_swp.shape[0]/2)
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tf_r = tf / (tf[:,ref_index]*np.ones((tf.shape[1],1))).T
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y_tank = y_tank.T
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print(ang(tf[f==28,:]))
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################################################################################
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h1 = pp.figure()
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h2 = pp.figure(figsize=(5,7))
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mgr = pp.get_current_fig_manager()
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################################################################################
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ax1 = h1.add_subplot(2,2,1, projection='smith')
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ax2 = h1.add_subplot(2,2,3, projection='polar')
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ax3 = h1.add_subplot(2,2,2)
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ax4 = h1.add_subplot(2,2,4)
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ax1.plot(y_tank, datatype=SmithAxes.Y_PARAMETER, marker="None")
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ax2.plot(np.angle(tf), dB20(tf))
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ax3.plot(f,dB20(tf))
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ax4.plot(f,ang_unwrap(tf))
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################################################################################
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ax8 = h2.add_subplot(2,1,1)
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ax9 = h2.add_subplot(2,1,2)
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ax8.plot(f,dB20(tf_r))
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ax9.plot(f,ang_unwrap(tf_r.T).T)
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ax1.set_title('Tank Impedance')
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ax2.set_title('Transfer Function')
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ax3.set_title('TF Gain')
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ax3.set_ylabel('Gain (dB)')
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ax4.set_title('TF Phase')
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ax4.set_ylabel('Phase (deg)')
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ax8.set_title('TF Relative Gain')
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ax8.set_ylabel('Relative Gain (dB)')
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ax9.set_title('TF Relative Phase')
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ax9.set_ylabel('Relative Phase (deg)')
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for ax_T in [ax3, ax4, ax8, ax9]:
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ax_T.grid()
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ax_T.set_xlabel('Freq (GHz)')
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ax_T.set_xlim(( np.min(f), np.max(f) ))
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################################################################################
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h1.tight_layout()
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h2.tight_layout()
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mgr.window.geometry(default_window_position[0])
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h1.show()
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mgr.window.geometry(default_window_position[1])
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h2.show()
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