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carrier generator
def carrier_square_wave_generator(gpio, frequency, signal_length):
"""
Generate carrier square wave.
"""
waveform = []
# frequency is number of cycles per second, usually 38 kHz
micro_per_cycle = 1000.0 / frequency # 1 / kHz is millisecond, * 1000 is microsecond
# number of cycles during the signal
# signal_length is in microseconds
num_cycles = int(round(signal_length / micro_per_cycle))
on = int(round(micro_per_cycle / 2.0)) # signal length is in microseconds
sofar = 0
# from zero cycles to target cycles
for c in range(num_cycles):
target = int(round((c+1) * micro_per_cycle)) # target is time in ms
sofar += on
off = target - sofar
sofar += off
# pigpio.pulse(gpio_on, gpio_off, delay)
# gpio_on - the GPIO to switch on at the start of the pulse.
# gpio_off - the GPIO to switch off at the start of the pulse.
# delay - the delay in microseconds before the next pulse.
waveform.append(pigpio.pulse(1<<gpio, 0, on)) # bitwise shift?
waveform.append(pigpio.pulse(0, 1<<gpio, off))
return waveform
# ORIGINAL FUNCTION
def carrier(gpio, frequency, micros):
"""
Generate carrier square wave.
"""
wf = []
cycle = 1000.0 / frequency
cycles = int(round(micros/cycle))
on = int(round(cycle / 2.0))
sofar = 0
for c in range(cycles):
target = int(round((c+1)*cycle))
sofar += on
off = target - sofar
sofar += off
wf.append(pigpio.pulse(1<<gpio, 0, on))
wf.append(pigpio.pulse(0, 1<<gpio, off))
return wf
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