Does the mobile phone signal amplifier affect human health? Let's get to know

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Does the mobile phone signal amplifier affect human health? Let's get to know

Does mobile phone signal amplifier affect human health? Let's learn about it.


In densely populated cities, the signal is weak. In order to reduce this phenomenon, many people have installed mobile phone signal amplifiers. In particular, the residential areas of many people are very large. Therefore, ordinary low-power mobile phone signal amplifiers cannot meet people's needs, so they are replaced by high-power mobile phone signal amplifiers. Many people have doubts. Does high-power mobile phone signal amplifier have an impact on human health?

1. Function of the circuit

When the output impedance is 50 and the load impedance is terminated with 50, the output amplitude of the output amplifier should be 20VP-P to obtain an amplitude of 10 VP-p. If it is low-frequency amplification, a booster can be added to the operational amplifier to meet the requirements. If it is a broadband amplifier, it needs fast conversion and large output current. The circuit uses a composite amplifier, which requires fast conversion speed and large output current. This circuit uses a composite amplifier, the main amplifier mainly consider the high-frequency characteristics, with an operational amplifier to adjust the DC characteristics, so that the two characteristics coexist, the circuit band is DC ~ 20MHZ. It can be used as a function generator output circuit or as a pulse output amplifier.

2. The working principle of the circuit

The entire circuit is an inverting amplifier, and the AC voltage at the summing junction is amplified by an AC broadband amplifier through C2. The low frequency of the signal amplified by the AC amplifier should be a frequency that the DC operational amplifier cannot respond. The DC VLF signal is inversely amplified by the DC operational amplifier and is sent to the non-inverting terminal of the AC amplifier. The overall frequency characteristic is the two amplified composite signals fed back by resistor R2.

The main amplifier circuit has differential input terminals, and the output of the operational amplifier is input to the non-inverting input terminal. The amplification factor fed back from the output to the summing junction is A =-R2/R1.

The main amplifier circuit is a full-stage symmetrical push-pull circuit. If the DC drift of the operational amplifier is not required, the main amplifier circuit can also use a single tube. The setting of working points at all levels should ensure bandwidth. For example, the collection resistors of TT1 and TT2 adopt low resistance values, and the output amplitudes of TT3 and TT4 are the same. The current should be increased to improve the conversion speed, not the phase compensation between the two.

3. Adjustment

In order to optimize the performance of the circuit, a signal generator or pulse generator with a frequency of 30MHz is required. A 50 ohm termination resistor is connected to the input, and a phase compensation circuit is added to ensure a flat frequency characteristic. The offset adjustment of the output stage is also related to the circuit characteristics, so R15 should be adjusted as needed.

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