Abstract: An auxiliary control circuit (100) for a power amplification module, a power amplification module, and a communication device. The auxiliary control circuit (100) for the power amplification module comprises a main control chip (201), a current detection chip (12), and a precision adjustment unit (14). The precision adjustment unit (14) is connected in parallel to a precision control resistor of the current detection chip (12), and a switch control terminal of the precision adjustment unit (14) is electrically connected to the main control chip (201) and is used for adjusting an output voltage amplification factor of the current detection chip (12) when a switch signal outputted by the main control chip (201) is received. A detection input terminal of the current detection chip (12) is used for accessing a voltage to be measured of a power amplifier transistor power supply circuit (102) of the power amplification module.

Abstract: A redundant backup near-end machine, a far-end machine and a system of a digital optical fiber repeater is disclosed. It includes a near-end machine, a far-end machine and an optical fiber, and the near-end machine includes a near-end duplexer module, at least two near-end digital monitoring modules, and a near-end optical interface board module. The near-end optical interface board module includes a near-end digital optical module, and each near-end digital monitoring module is connected in parallel between the near-end duplexer module and the near-end optical interface board module. The far-end machine includes a far-end optical interface board module, at least two far-end digital monitoring modules, a power amplifier module, and a far-end low noise amplifier duplexer module. The far-end optical interface board module includes a far-end digital optical module.

Abstract: A redundant backup near-end machine, a far-end machine and a system of a digital optical fiber repeater is disclosed. It includes a near-end machine, a far-end machine and an optical fiber, and the near-end machine includes a near-end duplexer module, at least two near-end digital monitoring modules, and a near-end optical interface board module. The near-end optical interface board module includes a near-end digital optical module, and each near-end digital monitoring module is connected in parallel between the near-end duplexer module and the near-end optical interface board module. The far-end machine includes a far-end optical interface board module, at least two far-end digital monitoring modules, a power amplifier module, and a far-end low noise amplifier duplexer module. The far-end optical interface board module includes a far-end digital optical module.