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In this lesson, we will continue to talk about the receiving channel of Huawei P40 B3 frequency band

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In the last lesson, we know that the receiving signal of B3 reaches the first pin of this U5201

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We open the circuit diagram

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U5201 amplifies the power of the received signal

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That is, after the electromagnetic wave signal coming from the air becomes an electrical signal,

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it passes through switches and filters along the way.

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Its signal is relatively weak, and it is necessary to amplify the power of the received signal

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After U5201 amplifies its power, it outputs from pins A6, A4, and A8

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It should be amplified, it has been amplified, it should be filtered, it should be filtered

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Then, the next step is to mix the high-frequency signal

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The definition of the receiving signal of A6, A4, A8 is called R X

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R X is to receive

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Let's see if it leads to the RF transceiver

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It leads to the RF transceiver U4401

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By looking at the real thing, it is found that it is Huawei HiSilicon 6365

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This received signal reaches the B5 pin of the RF chip

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This received signal is a very high-frequency signal that contains data such as pictures and videos

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After mixing, it becomes a low frequency signal

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It is transmitted through the US RD L of the RF transceiver and given to the baseband CPU

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If the HUAWEI P40 does not have a separate baseband CPU, it should lead to the big CPU,

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that is, the big CPU contains the baseband CPU.

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Let's take a look, just find one of the lines

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The lines are usually together

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It leads to the A1 pin, Y1 pin, Y5 pin of this chip

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This chip is U300, and SOC is written in the upper left corner of the drawing, which means a large processor CPU

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which means a large processor CPU

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It is given to the baseband CPU inside the big CPU

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The baseband CPU performs a series of processing such as final demodulation, and finally restores the data

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This is the channel of the receiving line of Huawei's P40 in its B3 frequency band

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That's all for this lesson