Waveform Generators

Wavegen

set_sine : Set Sine Wave Frequency for WG, WGbar¶

set frequency of sine wave on WG. Restores waveform type to sine if some other shape had been previously set. WGbar output will also output a sine wave which is 180 degrees out of phase with WG at all times.

parameter	description
frequency	4 to 5000 . Freq in Hz

invokes p.set_wave(freq, 'sine') under the hood.

p.set_wave(100) # 100 Hz sine wave on WG

set_wave : Set Frequency and type of WG waveform out¶

set frequency of wave on WG. Also sets waveform type to ‘sine’/’tria’.

parameter	description
frequency	4 to 5000 . Freq in Hz
type	‘sine’ or ‘tria’

p.set_wave(freq, 'sine')

set_sine_amp : Set Sine Wave Amplitude¶

Set the amplitude of the waveform output on WG

parameter	description
value	2 1x amplitude (3.3V)
	1 1V
	0 100mV

p.set_sine_amp(2) #3.3 V amplitude. +/-3.3V swing

load_equation : Load an arbitrary shape to WG using an equation¶

p.load_equation(self, function, span=None, **kwargs)

Load an arbitrary or preset waveform to the WG waveform generator output.

parameter	description
function	‘sine’ load sine wave
	‘tria’ triangle wave
	a python function of the form lambda x:expression(x)

p.load_equation('tria') # Changes waveform shape to triangle.

Use a python function: First two terms of the fourier expansion of a square wave

from matplotlib import pyplot as plt
import eyes17.eyes
p = eyes17.eyes.open()
# Connect WG to A1

def f1(x):    # First 2 terms of the fourier expansion of a square wave.
	return sin(x) + sin(3*x)/3

p.load_table(f1,[0,2*np.pi]) #Evaluate from 0 to 2*pi
p.set_wave(400) # Set the frequency

#Measure the set waveform and study it.
x,y = p.capture1('A1', 500,10)
plt.plot(x,y)
plt.show()

set_sq1 : Set Square Wave Frequency for SQ1¶

set_sqr1(self, freq, duty_cycle=50)

set frequency of square wave on SQ1.

parameter	description
frequency	0.02 to 100000 . Freq in Hz
duty_cycle	0 to 100. default 50

Set a 1KHz square wave (0 to 5V) output on SQ1 with 10% duty cycle.

p.set_sq1(1000,10)

set_sq2 : Set Square Wave Frequency for SQ2¶

set_sqr2(self, freq, duty_cycle=50)

set frequency of square wave on SQ2.

Warning

This will disable the sine wave output on WG. invoking set_sine will restore the sine wave and disable this.

parameter	description
frequency	0.02 to 100000 . Freq in Hz
duty_cycle	0 to 100. default 50

p.set_sq2(1000)

Fourier Transformation demo

Connect WG to A1, and SQ1 to A2¶

import eyes17.eyes          
p = eyes17.eyes.open()

from matplotlib import pyplot as plt
from eyes17 import eyemath17 as em

p.set_sine(1000)
p.set_sqr1(500)
t,v, tt,vv = p.capture2(5000, 20)   # captures A1 and A2

plt.xlabel('Freq')
plt.ylabel('Amplitude')
plt.xlim([0,10000])

#0.001 is to convert 20uS to mS units
xa,ya = em.fft(v,20*0.001) 
plt.plot(xa,ya, linewidth = 2, color = 'blue')

xa,ya = em.fft(vv, 20*0.001)
plt.plot(xa, ya, linewidth = 2, color = 'red')

plt.show()