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This lesson talks about the principles of Huawei's B41 band 4G reception and transmission

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Let's look at its reception first

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Its reception is from the antenna base,

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that is, the high-frequency electromagnetic wave signal coming from the air is sensed by the antenna,

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and becomes a high-frequency electrical signal, which reaches the antenna

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It contains the B41 band

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This high-frequency electrical signal passes through the filter Z5603 to filter out clutter,

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and then comes out from one pin to the double-pole four-throw switch

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This double-pole four-throw switch has two external lines

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After reaching its three feet, the 3 pin and 6 pin are turned on,

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and then reach the filter, and filter out the clutter again

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Continue to receive the signal, reach the large antenna switch,

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and switch the received signal to the receiving line

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Pin 31 is the main receiver of the B41 frequency band. In fact, it is also the frequency band of 5G N41

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The receiver of this B41 band continues to go through a single pole double throw switch

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The switch is turned on, after 5 and 3 are turned on, pin 5 enters and pin 3 exits

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This received signal is again filtered

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The received signal must reach the H9 pin of the receiving amplifier

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After the power is amplified internally, it is output from the A8 pin and given to the RF transceiver

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The radio frequency transceiver here removes this high-frequency carrier and gives it to the large CPU

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The baseband CPU inside the large CPU demodulates the signal

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This is the receiving line

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Let's look at the transmission line

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The information including pictures and videos from the baseband CPU is sent to the RF transceiver through UL

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RF transceivers generate high frequency carrier waves

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After the high-frequency carrier is generated, this information is carried on the high-frequency carrier

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to form a specific frequency band signal

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Such as the formation of high-frequency HB

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HB contains the B41 frequency band, which is actually formed by the emission of B41,

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which is a high-frequency electrical signal

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This electrical signal reaches the amplifier

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The power amplifier includes both the low frequency band, the mid frequency band, and the high frequency band

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The power amplifier amplifies the power of this high-frequency signal, and it will go out from pin 37

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This transmit signal is filtered out by the filter, and the first pin enters the third pin and comes out

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Go through another filter and finally reach the antenna switch

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The transmitted signal reaches the 42 pin of U5101 antenna switch

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The 42-pin and 38-pin of the antenna switch are turned on

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After conduction, the transmit signal is filtered again by the filter

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It goes to pin 16 of the DP4T switch and goes out on pin 3

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After another filter, 1 pin goes in, 3 pins go out

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Finally, the transmitted signal reaches the antenna base J5603

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The antenna is installed on the antenna base

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The antenna turns this high-frequency signal into a high-frequency electromagnetic wave signal

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and transmits it into the air, and the base station receives it

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This is the entire receive and transmit channel

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There is an obvious feature in the circuit of this Huawei machine, the filter is used more

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Also, the small switches it uses include small double-pole four-throw switches,

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single-pole double-throw switches, and even some circuits use double-pole double-throw switches.

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This is the receiving and transmitting channel of Huawei's B41 frequency band

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That's all for this lesson