Various external interference, processing industry and weather interference, etc., the influence of the modulated wave is mainly manifested as parasitic amplitude modulation, forming noise. The frequency modulation system can eliminate the parasitic amplitude modulation caused by interference by the method of limiting amplitude. In the AM system, the amplitude of the amplitude-modulated signal is changed, so it cannot be limitedIt is difficult to eliminate external interference. In addition, the larger the signal-to-noise ratio of the signal, the stronger the anti-interference ability.
Rotate the quad variable capacitor to the maximum capacity, that is, accept the lowest frequency (535KHz), adjust the magnetic core of the intermediate frequency transformer B2, so that the radio can receive the 535KHz amplitude modulation signal output by the signal source, and then move the coil position on the magnetic rod, so that the sound is maximum and the wax is sealed.
The input signal of the mixing circuit is two high frequency signals, the output IF signal is the difference between two high frequency signals, and the filter is a bandpass filter; The input signal of an amplitude-modulation circuit is a high-frequency signalAnd a low frequency signal, output as a modulated high frequency signal. The filter should be a high-pass filter; The input of the detector circuit is a modulated high-frequency or intermediate frequency signal, the output is a low-frequency signal, and the filter is a low-pass filter.
Mixing changes the amplitude-modulated signal sent by the input circuit into an intermediate-frequency modulation signal, and the signal they carry is unchanged, that is, the frequency of the amplitude-modulated signal into an intermediate-frequency signal, but its amplitude change law does not change. Regardless of the frequency of the input high-frequency signal, the frequency after mixing is fixed, and our country stipulates that it is 465 KHZ. Intermediate amplifier amplifies an IF amplitude modulation signal to the level required by a detector>
1, put the mobile phone with wireless charging function on the wireless charging board, the position should be placed, you can charge, note that some wireless charging panel supports different mobile phone models, to choose wireless charging panel according to your mobile phone model.
2, first of all, you need to ensure that the mobile phone is supporting wireless charging, because wireless charging requires the hardware support of the mobile phone built-in wireless induction coil. Connect the wireless charging board with the data cable to the charger, the general mobile phone charger can be used, the charging board will have a light prompt after the general connection, and then put the mobile phone on the charging board.
3, the phoneThe standard charger and data cable are connected to the wireless charger, and then put the mobile phone directly (vertically) or horizontally in the center position of the wireless charger base, wireless charging can be achieved, the indicator light will have a breathing effect, 5 seconds later, plug and play, convenient and quick.
4, wireless charger usually needs to be connected to the power supply, can be connected through the USB interface or power adapter. Once connected to the power supply, you can place the device that needs to be charged on the wireless charger, make sure there are no obstacles between the device and the charger, and start charging. During wireless charging, the charger sends electromagnetic waves to the deviceThe antenna coil inside the device receives and converts it into electrical energy for charging.
5, Enter My device First, in the mobile phone service My page, click and select to enter "My device". Click to view device parameters Click to select View Device parameters and proceed to the next step. Select Fast Charge Select Fast Charge to check whether the current mobile phone supports wireless charging.
Wireless chargingPCBA is an electronic component used to realize wireless charging function, which mainly includes a circuit board (PCB) and various electronic components installed on the circuit board. Together, these components form part of a complete wireless power transmission system, which is responsible for converting electrical energy into wireless signals and transmitting them to receiving devices. Wireless charging technology usually works on the principle of electromagnetic induction or magnetic resonance.
Wireless charging emission Circuit Board (PCBA) is an electronic component used to implement wireless charging function. It is one of the core components of the wireless charging system, responsible for converting electrical energy to wirelessThe energy signal is transmitted. PCBA usually consists of multiple components, including power supplies, inductors, circuit control chips, filters, and connectors.
PCBA (Printed Circuit Board Assembly, Printed Circuit Board Assembly) refers to the installation of various electronic components to the PCB (Printed Circuit Board, Printed Circuit Board, Printed Circuit Board) by surface mount technology (SMT) or plug-in technology (THT). Printed circuit board), and carry out welding, testing and other processes. Specifically, the PCBA includes the followingSeveral main steps: Raw material preparation: Prepare the PCB board and the required electronic components.
This shielding cover plate is made of precision PCB board, covered with a layer of shielding copper foil, its main role is to effectively reduce electromagnetic radiation interference, to ensure the stability and safety of wireless charging. Going further, we will find that inside the aluminum shielding shell, three wireless charging coils are arranged, which are tightly fixed on the PCBA shielding cover, forming the core part of wireless charging.