Differential Logic Families

Single-ended signal transmission techniques can be susceptible to, and emitting, noise. This can be overcome by increasing the voltage, but that increases the power consumption and results in lower speeds due to the voltage swing. Single-ended transmission lines also tend to attenuate the signal; again, this can be overcome by increasing the transmission voltage. Differential signals overcome these difficulties by transmitting a pair of complementary signals (opposite polarities) for every bit sent. The receiver detects differences between the two signals and any noise common to both signals is rejected. Differential transmission techniques are influenced less by line attenuation because of their greater noise immunity and, because of this, are ideal for transmitting at higher data rates over longer line lengths.