【 Weak current College 】 light converts the analog signal to digital signal

Daily life in signal if light continuous smooth control signals, a variety of audio signals and TV signals are analog signals. Analog signal is a continuously changing amplitude versus time. Analog signals are able to truly reflect the essence of nature, but difficult to control, a pair of conductors can only transmit a signal.
The analog signal into a digital signal is not continuous (or pulse signal) is multiplexing technology base, therefore DMX512 first problem to be solved is to convert the analog to digital (A/D converter) or opposite to digital conversion to analog (D/A conversion). A/D conversion has three steps: sampling and quantization and coding.
① sampling (Sampling)
According to the principle of information theory, a frequency sine wave for fs continuous signal information is totally contained in frequency is 2 x the discontinuity of pulse signal, that fp (pulse frequency) = 2fs.
If you want to keep the scope of 20Hz ~ 20KHz analog audio signal transformation is not continuous pulse signal (the binary signal), pulse sampling frequency should be at least 40KHz (analog signal in the highest frequency 2 x), their period Tp = 1/fp = 1/40KHz = 25 μ s
Professional lighting dimming control signal frequency than the audio signal of the highest frequency is low, so its sampling frequency may be lower.
② quantization (Quantigation)
Analog signal sampling sampling points to be addressed after the signal amplitude of readout. The continuous change of signal amplitude accuracy at a differential signal amplitude read sampling point known as the "quantitative".
In order to meet the needs of digital circuits, readout method generally uses binary method.