92 lines
3 KiB
Python
92 lines
3 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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################################################################################
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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'
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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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gamma_swp = np.linspace(-gamma,gamma,gamma_sweep_steps);
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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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h = pp.figure()
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mgr = pp.get_current_fig_manager()
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ax1 = h.add_subplot(2,2,1, projection='smith')
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ax2 = h.add_subplot(2,2,3, projection='polar')
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ax3 = h.add_subplot(2,2,2)
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ax4 = h.add_subplot(2,2,4)
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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 = g1_tune + jw*c1_tune + 1/(jw * l1)
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#print(1/np.mean(np.abs(y_tank)))
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ax1.plot(y_tank, datatype=SmithAxes.Y_PARAMETER, marker="None")
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tf = 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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ax2.plot(np.angle(tf), dB20(tf))
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ax3.plot(f,dB20(tf))
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ax4.plot(f,ang(tf))
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################################################################################
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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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for ax_T in [ax3, ax4]:
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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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h.tight_layout()
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mgr.window.geometry(default_window_position)
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h.show()
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