​In the electricity experiment, sometimes we need more current or voltage power supply, in this condition, several power supplies can be parallel or serial connected to realize this function.

With the increasing power quality problem, more and more people pay attention to power quality. To know more about the power quality, it is necessary to measure, collect, and analyze the data of the power grid.

A network analyzer is of microwave millimeter wave testing instrument that can sweep and measure the signal in a high bandwidth so as to confirm the network parameters.

Modulation plays a very important role in a communication system. It has a great impact on the system's transmission effectiveness and reliability and determines the performance of a communication system.

Nowadays, many arbitrary waveform generators can provide frequency sweep function, basically linear sweep and logarithmic sweep can be realized. Linear sweep means the output frequency changes in constant way of some Hz per second.

Phase noise refers to the random changes in the phase of the system output signal caused by various noises in the system (such as various RF devices).