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I don't understand how an ESP8266 can use 2.4 GHz WiFi when its clock is less than this.

This question came to me because when looking for a microcontroller. I always find it weird that 400 MHz+ is a top of the line microcontroller.

The Arduino uses 16MHz and can still use a WiFi module. How or what did i get wrong?

Note: while the question How is the esp8266 is able to generate 2.4 GHz wifi signals? sounds close it is definitely not my question.

To clear it up more, the WiFi signal is sent across 2.4 GHz frequency when the ESP sends or especially receives signals, how could it take info from 2.4 GHz while it only uses 80 MHz?

The answer (as I understand) is that it doesn't use the 2.4 GHz as the data it adds the data with some type of circuit to it, so for example the data exchange can't exceed the clock of the processor (not considering the clock cycles to make this data and process it) so simply a signal of 2.4 GHz carries another small signal of data.

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    \$\begingroup\$ Have a read about PLLs. I think your question is likely answered here: electronics.stackexchange.com/questions/373961/… \$\endgroup\$
    – DiBosco
    Commented Feb 23, 2022 at 12:12
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    \$\begingroup\$ Does this answer your question? How come esp8266 is able to generate 2.4 GHz wifi signals \$\endgroup\$
    – DiBosco
    Commented Feb 23, 2022 at 12:14
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    \$\begingroup\$ I think that does answer your question. Again, read up about PLLs, then reread the answer. If there's something specific you don't understand then ask again, phrasing your question carefully. \$\endgroup\$
    – DiBosco
    Commented Feb 23, 2022 at 12:41
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    \$\begingroup\$ Simplistically, a radio signal at 2.4GHz is not carrying information at 2.4Gbps - there's a difference between the radio's carrier frequency (2.4GHz) and its information content. There's no need for the radio TX & RX equipment to be able to send & receive data at the radio's carrier frequency. \$\endgroup\$
    – brhans
    Commented Feb 23, 2022 at 13:11
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    \$\begingroup\$ The tone frequency in Morse code is not related to how fast someone keys Morse code. \$\endgroup\$
    – HandyHowie
    Commented Feb 23, 2022 at 15:15

2 Answers 2

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In these WiFi chip or modules, there are usually 2 components. There is the processor/controller side and the RF side.

The processor/controller side will interface to your board or processor. This is typically done either through UART or SPI, some will even have a USB interface.
Think of it as a regular microcontroller with registers for configuration. This controller will then handle all interface and control of the RF circuitry. All you have to do worry about is telling the controller how you want the Wifi to work.

The RF side will then handle all frequencies and modulation.

So the 80 Mhz is for the controller side. And your interface to that with any data rate you want. for instance, you can use SPI with 1 MHz, depending on your system.
All you have to do is tell the controller how and what Access point, data etc.

This makes it easier for you and you don't have to become a RF expert.

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  • \$\begingroup\$ but what if a big chunk of data was transmitted like the full 2.4Ghz is all 1s or zeros how would it be able to read 2.4G bits per second \$\endgroup\$
    – AhmedH2O
    Commented Feb 23, 2022 at 13:52
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    \$\begingroup\$ 2.4 Ghz is the frequency, not the data rate. The data rate is typically 1 Mbits/s and up. Think of it like a car radio. You tune to a specific frequency, like 100.7 Mhz. Now Audio is in the kHz range (this is like data rate). So what happens is the audio is modulated with the 100.7 MHz. Same thing happens with digital data. Ones and zeros are modulated on the 2.4 Ghz. This is over simplified but the idea is there. \$\endgroup\$ Commented Feb 23, 2022 at 13:57
  • \$\begingroup\$ oh ok thanks, so the data is a small wave added to the wifi 2.4GHz ? \$\endgroup\$
    – AhmedH2O
    Commented Feb 23, 2022 at 13:58
  • \$\begingroup\$ Correct. When you send data to the wifi module, the module will place your data into TCP data packet, then into IP data packet, then into a wifi data packet, which modulated onto the 2.4GHZ. Typically this is limited to 1500 bytes. Google OSI model, which is the typical data layering. \$\endgroup\$ Commented Feb 23, 2022 at 14:05
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As noted in comments, there are a couple points you miss:

The Arduino uses 16MHz and can still use a WiFi module. How or what did i get wrong?

Those 16 MHz are for the Arduino itself, but the Wi-fi module is another piece of hardware.

Speaking of ESPxxx, it can be seen as two (or more) modules in the same die. Now the question remains: where do those 2.4 GHz come from? Reply: in any way the designers found suitable. Probably they use a PLL but, in a different situation, one could use whatever oscillator, perhaps an RC oscillator.

how could it take info from 2.4 GHz while it only uses 80MHz?

Well, we decided that 2.4 GHz is generated in some way. As noted in comments, the carrier frequency does not impose a bitrate on the modulating signal or, probably, the data rate is well lower than the carrier. In fact, the Wi-fi trasfer rate is measured in Mb/s (maybe 10, 50? 100? I'm not sure).

But, apart from this fact, in such hi-tech communication technologies it is the hardware that reads data from the carrier and store them in some internal buffer; the processor then, with its latency and its speed will read that data.

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  • \$\begingroup\$ ok so for example can I read this data on 20MHz oscillisope if i use maybe some passive components (maybe a filter?) to get the data out of 2.4GHz signal ? \$\endgroup\$
    – AhmedH2O
    Commented Feb 23, 2022 at 14:04
  • \$\begingroup\$ @AhmedH2O I don't think it's possible with Wifi, but to clarify the concept take a TV infrared remote control. It emits infrared light (a carrier with very high frequency) but the bitrate of the information is very low (1200/2400 baud?). In that case you can use a scope to see the data, using passive components (a photodiode) and perhaps little else. \$\endgroup\$ Commented Feb 23, 2022 at 14:14
  • \$\begingroup\$ Ok it makes more sense now, thanks for the help \$\endgroup\$
    – AhmedH2O
    Commented Feb 23, 2022 at 14:16

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