hi there,
i m doing a project that need to provide signal to an polarization scrambler.
1st. i need to randomly generate 0 or 1 (square wave).
2nd. i need to do pwm nad make the random signal sinusoidal.
anyone could help me with the code or hardware connection?
thanks a lot
provide signal to an polarization scrambler.
What is this? Link please.
1st. i need to randomly generate 0 or 1 (square wave).
Do you mean the times of the signal need to be random or that the appearance of this wave has to be random?
2nd. i need to do pwm nad make the random signal sinusoidal.
I understand all those words but that makes no sense. What do you want, please explain properly.
Here a starter with all elements you mentioned, but it might be useless as I don't know what a polarization scrambler is
uint8_t pwm_value = 0;
void setup()
{
Serial.begin(115200);
Serial.println("polarization scrambler 0.1");
randomSeed(analogRead(A0)); // to have a bit of a random start
}
void loop()
{
int x = random(2);
pwm_value <<= 1 + x;
analogWrite(9, pwm_value);
// optional
Serial.print(millis());
Serial.println("\t");
Serial.println(pwm_value);
}
oops, redesign 
uint8_t pwm_value = 0;
float signal = 0;
void setup()
{
Serial.begin(115200);
Serial.println("polarization scrambler 0.1");
randomSeed(analogRead(A0)); // to have a bit of a random start
pinMode(4, OUTPUT);
}
void loop()
{
int x = random(2)
digitalWrite(4, x); // your square wave
signal = signal + 0.0001;
if (signal > 2*PI) signal = 0;
int pwm_value = 127 + 127 * sin(signal); // make a sinusoidal pwm value
if (x == 0) pwm_value = 127; // the random square wave works as a gating for the sinus signal making is 0 at random times and sinusoidal the other times.
analogWrite(9, pwm_value);
// optional
Serial.print(millis());
Serial.print("\t");
Serial.print(x);
Serial.print("\t");
Serial.println(pwm_value);
}
I think I did the other way around, I made the sinus signal random. If this is not what you want can you post a drawing of how the PWM signal should look like (OK randomized will always be different) or as grumpy says, we need proper requirements.
Grumpy_Mike:
provide signal to an polarization scrambler.
What is this? Link please.
1st. i need to randomly generate 0 or 1 (square wave).
Do you mean the times of the signal need to be random or that the appearance of this wave has to be random?
2nd. i need to do pwm nad make the random signal sinusoidal.
I understand all those words but that makes no sense. What do you want, please explain properly.
well, thanks a lot for the help.
just ignore the polarization scrambler. it is an optical device..
what i want just are:
1st, use Arduino to generate random signal or random pulse, just 0 or 1, such as 001010010101001001 which the output to an oscilloscope will be square wave.
2nd, do pulse width modulation with the signal to make it sinusoidal.
i might need code and circuit design for this. the output is random sinusoidal signal.
Grumpy_Mike:
@robtillaart where is thei need to do pwm nad make the random signal sinusoidal.
bit?
pseudo random bit sequence i think.
robtillaart:
oops, redesignuint8_t pwm_value = 0;
float signal = 0;
void setup()
{
Serial.begin(115200);
Serial.println("polarization scrambler 0.1");
randomSeed(analogRead(A0)); // to have a bit of a random start
pinMode(4, OUTPUT);
}
void loop()
{
int x = random(2)
digitalWrite(4, x); // your square wave
signal = signal + 0.0001;
if (signal > 2*PI) signal = 0;
int pwm_value = 127 + 127 * sin(signal); // make a sinusoidal pwm value
if (x == 0) pwm_value = 127; // the random square wave works as a gating for the sinus signal making is 0 at random times and sinusoidal the other times.
analogWrite(9, pwm_value);
// optional
Serial.print(millis());
Serial.print("\t");
Serial.print(x);
Serial.print("\t");
Serial.println(pwm_value);
}
I think I did the other way around, I made the sinus signal random. If this is not what you want can you post a drawing of how the PWM signal should look like (OK randomized will always be different) or as grumpy says, we need proper requirements.
Pulse-density modulation - Wikipedia more like the graph on this page. yet its random sine wave based on random 1 or 0
what i want just are:
1st, use Arduino to generate random signal or random pulse, just 0 or 1, such as 001010010101001001 which the output to an oscilloscope will be square wave.
2nd, do pulse width modulation with the signal to make it sinusoidal.
i might need code and circuit design for this. the output is random sinusoidal signal.
add 1 - is done with my code posted, read the signal on pin 4.
add 2 - add a low pass filter (resistor + capacitor) after the pin4 output to get "sort of" Analog out
pin 4 ----[ resistor ] ------X-------||------GND
measure with scope on point X.
robtillaart:
what i want just are:
1st, use Arduino to generate random signal or random pulse, just 0 or 1, such as 001010010101001001 which the output to an oscilloscope will be square wave.
2nd, do pulse width modulation with the signal to make it sinusoidal.
i might need code and circuit design for this. the output is random sinusoidal signal.add 1 - is done with my code posted, read the signal on pin 4.
add 2 - add a low pass filter (resistor + capacitor) after the pin4 output to get "sort of" Analog out
pin 4 ----[ resistor ] ------X-------||------GND
measure with scope on point X.
thanks mate.i ll try the RC, what is the frequency of PWM that i need to do mate to get R and C?