Description

YalRF is an open-source circuit simulator written in Python. The package contains an API for netlist description and circuit simulation. The generated data can be easily post-processed using numpy and Jupyter Notebooks.

The main goal of this project is to implement a stable and powerful multi-tone harmonic balance engine with support to autonomous circuits.

Another goal will be to integrate YalRF with the scikit-rf / openEMS / SignalIntegrity packages.

Example of usage:

import matplotlib.pyplot as plt
from yalrf import Netlist
from yalrf.Analyses import MultiToneHarmonicBalance

net = Netlist('Peltz Oscillator')

# circuit parameters
vcc = 10
r = 200e3
l = 0.5e-3
c = 10e-9
re = 50e3

# VCC
net.add_idc('I1', 'nx', 'gnd', dc=vcc)
net.add_gyrator('G1', 'nx', 'nvcc', 'gnd', 'gnd', 1)

# tank circuit
net.add_resistor('R1', 'nvcc', 'nb', r)
net.add_inductor('L1', 'nvcc', 'nb', l)
net.add_capacitor('C1', 'nvcc', 'nb', c)

# emitter resistance
net.add_resistor('RE', 'ne', 'gnd', re)

# bjts
q1 = net.add_bjt('Q1', 'nb', 'nvcc', 'ne')
q2 = net.add_bjt('Q2', 'nvcc', 'nb', 'ne')

q1.options['Is'] = 1e-16
q1.options['Bf'] = 200
q1.options['Br'] = 1
q2.options = q1.options.copy()

numharmonics = 10
freq = 80e3
V0 = 0.1

hb = MultiToneHarmonicBalance('HB1')
hb.options['maxiter'] = 100

converged, freqs, Vf, _, _ = hb.run_oscillator(net, freq, numharmonics, V0, 'nb')

hb.print_v('nb')
hb.plot_v('nb')
plt.show()

Dependencies

conda install python numpy scipy matplotlib

Acknowledgements

The API for netlist description was based on ahkab. Many device models currently used were referenced from the Qucs documentation.

TODO List

Analysis Related:

• add variable time-step for transient analysis and other integration methods
• expand two-tone harmonic balance to multi-tone
• expand harmonic balance NR for autonomous analysis instead of using scipy optimize
• PSS analysis (shooting method)
• S-parameter and LSSP
• AC noise analysis
• transient noise sources
• nodeset for DC analysis
• expand API of each analysis to process internal data

Modelling Related:

• complete implementation of mosfet
• add transformer
• add current probe
• add controlled switch (relay)
• transmission lines
• S-Parameter and Y-Matrix blocks
• noise modelling
• more behavioral models (sum, subtract, multiply, exponential, polynomial)

API and Code Related:

• current of bjts and diodes are currently stored inside the model (need to fix!)
• move integration to transient analysis
• review log messages to see if the type make sense (info, warning, error)
• exception handling instead of all the ifs and elses
• check at the top of each YalRF.add_device() call if the device name already exists in the netlist
• check if the netlist has at least one purposely placed gnd node
• subcircuit support
• remove devices from netlist
• input sanitizaiton can be largely improved
• there is a lot of waste in memory and performance that can be improved
• increment the test suite comparing the results with Xyce