Panasonic AJ-908 camera will amplify the audio recorded by wireless microphone, and there will be electric current sound. Is this normal?

First of all, have you set the audio input port of the camera? Generally, the microphone input of professional cameras is in the form of card tap, which is connected with a voice amplifier. If a microphone is connected to send a low-level signal, the signal is amplified by a voice amplifier to get the corresponding level; If the line signal (high level) is on, there is no need to amplify it, otherwise it will be distorted.

The current sound may be a high-level signal (the output of the wireless microphone receiver is a high-level signal), but when selecting the microphone input, mic mode is used instead of line mode, which will amplify the noise level.

If the setting is correct, check the cable from the wireless receiver to the camera to see if the head is manufactured in a balanced way. If it is unbalanced, there may be interference sound.

Finally, there is the problem of grounding. If your wireless microphone receiver is powered by AC and your camera is powered by AC, when the two devices use different electricity (for example, power is taken from different sockets), there will be a problem of zero-ground voltage difference, which will interfere with the sound.