#!/usr/bin/env python
# coding: utf-8

# This example shows the simulation of a transmission line.
# 

# In[ ]:


import matplotlib.pyplot as plt


import PySpice.Logging.Logging as Logging
logger = Logging.setup_logging()


from PySpice import Circuit, Simulator, plot
from PySpice.Unit import *




# We will drive the transmission line with a pulse source and use a
# standard 50 Ω load.
# 

# In[ ]:


circuit = Circuit('Transmission Line')
circuit.PulseVoltageSource('pulse', 'input', circuit.gnd, 0@u_V, 1@u_V, 1@u_ns, 1@u_us)
circuit.LosslessTransmissionLine('delay', 'output', circuit.gnd, 'input', circuit.gnd,
                                 impedance=50, time_delay=40e-9)
circuit.R('load', 'output', circuit.gnd, 50@u_Ω)

simulator = Simulator.factory()
simulation = simulator.simulation(circuit, temperature=25, nominal_temperature=25)
analysis = simulation.transient(step_time=1e-11, end_time=100e-9)


figure, ax = plt.subplots(figsize=(20, 6))
ax.plot(analysis['input'])
ax.plot(analysis['output'])
ax.set_xlabel('Time [s]')
ax.set_ylabel('Voltage (V)')
ax.grid()
ax.legend(['input', 'output'], loc='upper right')