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many of document I have read it that tell me this module has 2MHz and Data rate equal to 10Kbps and using ASK modulation how did it transfer 10Kbps on 2MHz what my question is why did used a large BW to transfer a small Data

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    \$\begingroup\$ Excuse me, but I have some difficulties to see that "this module" and it's datasheet is also totally behind the horizon. Can you insert an exact type number and a link to the datasheet (advertisements are not interesting, only manufacturer's original data) \$\endgroup\$
    – user136077
    May 14, 2020 at 12:14
  • \$\begingroup\$ I didn't found the data sheet about this module but I have Research Paper ajer.org/papers/v5(10)/ZW05010358362.pdf \$\endgroup\$
    – blacky
    May 14, 2020 at 12:23
  • \$\begingroup\$ No data sheet = no sale. \$\endgroup\$
    – Andy aka
    May 14, 2020 at 12:39
  • \$\begingroup\$ this module has 2MHz What does that mean? You seem to totally not understand what this module does (it is a simple on/off 433 MHz transmitter) and how it is used to transfer the data to the receiver (a 433 MHz superhet receiver). Hint: ASK modulation is used, look that up. If you would understand how it works then you would know that the Bandwidth doesn't matter as long as the transmitted frequency lies within the receiver's bandwidth. If all this doesn't make sense to you then I suggest taking a course in "Wireless communications". \$\endgroup\$ May 14, 2020 at 13:06
  • \$\begingroup\$ Bimpelrekkie i have large BW I got the high data rate what my question is why is there large BW and small data rate \$\endgroup\$
    – blacky
    May 14, 2020 at 15:53

1 Answer 1

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You gave in a comment link http://www.ajer.org/papers/v5(10)/ZW05010358362.pdf which leads to nonexistent or non-accessible page. Wayback machine knows it:

https://web.archive.org/web/20180713142750/http://www.ajer.org/papers/v5(10)/ZW05010358362.pdf

The article is beginner level hobbyist's text at best. The article tells how to have a data link between 2 Arduinos and it shows some images of available low cost radio modules. Nothing there claims 2MHz bandwidth need.

I believe the whole www.ajer.org (=American Journal of Engineering Research) site is a kind of bad joke (or was if it's permanently vanished) But it's only my belief. It's personnel list had no sign of staff who has an established professional status in United States.

Your transmitter is quite the same as this or even simpler: http://www.hezkyden.cz/shop/vysilac-434-mhz-saw/ The bandwidth depends on how fast the oscillator is switched on and off in binary ASK modulation. Here the control is non-existent. In addition the oscillator needs some time to stabilize. To avoid unwanted frequency band usage the transmitter should be designed for it ie. smoothly enough starting and decaying output and no oscillator cold start after zeros

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  • \$\begingroup\$ Cannot understand. Sorry! What system did already transmit and receive perfectly 2 megabits per second so that the performance is really verified? And what is claimed to be 10 kilobits per second and by whom? \$\endgroup\$
    – user136077
    May 14, 2020 at 14:32
  • \$\begingroup\$ in this module why have a large BW and a small data rate to transmit zeros and ones \$\endgroup\$
    – blacky
    May 14, 2020 at 14:56
  • \$\begingroup\$ It can work with some not especially narrow band receiver at higher data rate when the transmission distance is short and there's no interfering other signals. If you have proper filtering in receiver for 10kBits/s it surely doesn't work at 2MBits/s. Does your system pass 2MBits/s? What's the distance? \$\endgroup\$
    – user136077
    May 14, 2020 at 15:03

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