What is differential signaling?
Differential signaling is a technique for electronic transmission information using two different signals. For comparison, only one signal uses with one end signal. Differential signaling is effective for both analog signaling and digital signaling. Some audio systems still use analog systems, but most communication protocols such as Ethernet, Universal Serial BUS (USB), RS-422 and RS-485 use digital signaling. This technique allows the receiver to ignore the absolute voltage of signals that may differ significantly when traveling between the transmitter and the receiver. Therefore, differential signaling is a much more reliable method of electronic information transmission than signaling with one end. This is an advantage with low electronic devices as mobile and portable phones. These devices continue to be towards lower supply of voltage to reduce undesirable radiation and save energy.
high logical levels in a single -fired digital systemis the supply voltage (VS). The low logical level in this system is ground voltage or 0 volts (V). The difference between the two levels of voltage is therefore vs - 0 v = vs . The voltage in a pair of differential signals is of the same size, but the opposite polarity, so the voltage is +vs and –V. This means that the difference in the voltage between these two signals is (+vs) - (–VS) = 2VS , which doubles the noise immunity of the signal.
Single signals, such as RS-232, have the advantage that they require only one conductor. The voltage of at least 12 volts indicates a signal and the voltage of less than three volts indicates a lack of signal. This provides a certain noise immunity for singing-end signal because natural electricity sources rarely produce three volts.
The primary disadvantage of the signal with one end is that it cannot work at high speed. Induction and capacitance are electrical effects that tend to cancel youSokofrequency signals, thereby limiting the signal speed with one end. This type of signal also requires higher voltage levels to prevent high errors during transmission.
Computers generally use differential signaling to minimize the effects of electromagnetic interference. These devices use direct current that cannot be projected by interference. A low -voltage computer and a high -level power pipe often share the same soil. This can cause the electrical lines to cause significant voltage in the signal line, causing interference.