Anyone know what is the specification I need to take into account when I am going buy a Laser Diode and Photodiode for communication uses?
eg. Sending Analogue signal from Laser Diode to a Photodiode/Phototransistor.
so how about i just use a laser diode with 650nm or 850nm to transmit the DIGITAL modulated signal?
ANY consideration i need to take into my account? or any laser does work on transmitting the DIGITAL signal as well?
A laser is just a source of coherent light ..... so, if your transmission system involves light modulation, thehn yes, any laser can be used, as far as you can modulate them on/off ..... the rest depends only from the receiver system and signal processing ..... you need to know if you need an unconditional system or a feedback controlled system ..... mean, basically, a "transmit and don't care if the data become received" system, or a "transmissit and check that the data become delivered correctly" system ..... and choose your components and systems in consequence of this need ....
Thanks for the advice..
after i tested in analog direct transmit from my audio, it does works..
but somehow, the intensity of the laser light will be constant when the audio sound in high pitch... so i cant really get my signal at the receiver.
any solution on it?
i used the transistor 2N2222, voltage divider at Base when the audio signal goes in.