單端 (Single-End) 和平衡 (Balanced) 操作之間的差異是否有一個簡單的解釋？
Is there a simple explanation of the difference between single-ended and balanced operation? 寫:
In this context, the terms "single-ended" and "balanced" describe the type of electrical interface between components: i.e. preamplifiers and power amplifiers.
Single-ended interfaces use a "common" conductor (shield, ground or instrument chassis) as a signal return path. Balanced lines, on the other hand, use two dedicated conductors to provide forward and return paths for signal. The ground connection in balanced configurations is accomplished by means of a third, dedicated, ground conductor.
Any two components in your system will, most likely, have a measurable voltage difference between their chassis.
When a single-ended cable is connected between these two components, this voltage difference will appear along the common conductor (shield) of the interconnect. As a result, the shield will now carry the parasitic ground noise current between the two chassis. Since the shield is directly in the signal path, the voltage drop along the ground conductor will be combined with the signal that the interconnect carries. The result will be added noise and distortion introduced directly into the signal path.
In a balanced system, a separate shield or ground conductor will be used to connect the two chassis together, reducing the voltage difference between them. But the voltage drop across the shield will not add to the signal, because this third conductor does not carry the signal. What flows through the balanced interconnect is a clean signal, separated from extraneous ground current and noise. Additional benefits are derived from the fact that balanced circuits are inherently symmetrical. The balanced nature of the internal circuit greatly reduces transient demand on the component power supply, further improving signal integrity and noise immunity.