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##

## Dual-Slope (integrating) ADC

##

#########################################################################################

# IMPORTS ===============================================================================

import numpy as np

import matplotlib.pyplot as plt

from pathsim import Simulation, Connection

from pathsim.blocks import (

Integrator, Adder, Amplifier, Scope, Source,

Constant, Switch, SampleHold, Comparator

)

from pathsim.events import Schedule, ZeroCrossingDown

from pathsim.solvers import RKBS32

# SYSTEM SETUP AND SIMULATION ===========================================================

v_ref = -0.5 #dac reference

f_clk = 20 #sampling frequency

T_clk = 1.0 / f_clk #sampling period

K = 0.1

#blocks that define the system

src = Source(lambda t: 0.3*np.sin(2*np.pi*t)+0.5)

sah = SampleHold(T=T_clk)

ref = Constant(v_ref)

swt = Switch(None)

sub = Adder("+-")

itg = Integrator()

fbk = Amplifier(K)

sco = Scope(labels=["src", "sah", "swt", "itg"])

blocks = [src, sub, ref, swt, fbk, itg, sah, sco]

#connections between the blocks

connections = [

Connection(src, sah, sco[0]),

Connection(sah, swt[0], sco[1]),

Connection(ref, swt[1]),

Connection(swt, sub[0], sco[2]),

Connection(fbk, sub[1]),

Connection(sub, itg),

Connection(itg, fbk, sco[3])

]

#timing logic through events

events = [

ZeroCrossingDown(

func_evt=lambda *_: itg.engine.get(),

func_act=lambda *_: [itg.reset(), swt.select(None)]

),

Schedule(

t_start=0,

t_period=T_clk,

func_act=lambda *_: swt.select(0),

),

Schedule(

t_start=T_clk*0.2,

t_period=T_clk,

func_act=lambda *_: swt.select(1),

)

]

#simulation with adaptive solver

Sim = Simulation(

blocks,

connections,

events,

dt_max=T_clk*0.01,

Solver=RKBS32

)

# Run Example ===========================================================================

if __name__ == "__main__":

Sim.run(1)

Sim.plot()

plt.show()