I want to test a new wireless modulation method that is different from any existing methods like FSK or ask ..., which I can use with Arduino. Do you know any RF module with programmable modulation and how I can do it ?
I'd have a look at Nordic's nrf5 series. But this begs the question....why?
Can you program your own softdevice into the Nordic chips? I guess I never thought if they let you do that.
I don't know for sure, but their tech support is relatively approachable and between how commonly used their modules are and the variety of products they offer, I thought it was the first option that could be checked.
CC1101 is probably best if you are looking for community support
Thank you for your response. This is part of a research project I'm conducting. I've developed a new wireless modulation method that I want to test on a real device.
Ah, okay, I see. Well, sounds interesting, but there's not much I can recommend. Maybe get in touch with your local HAM community?
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ALL RF modulation schemes have names which one are you interested in?
Take a deep dive into the data sheets of the available radio chips, and check whether it is possible to implement your method on any of them.
Or, design and test a low frequency version of your method using available components.
You might get better answers if you can reveal some clues as to what type of 'modulation' you are actually trying to implement.
This seems to be a guessing game. There are three RF parameters that I know of that can be "modulated".
- Amplitude modulation. This includes On-Off keying of the RF envelope.
- Frequency modulation. This varies the RF frequency of the RF signal.
- Phase modulation. This varies the starting time of each RF cycle.
Any other "modulation" will be a combination of the above.
So, where does your modulation method fit into the list?
I am working on a combination of frequency and amplitude modulation. My goal with this test is to study the behavior of radio signals with frequent frequency changes.
Ok, then find a module for frequency modulation. Amplitude modulation can be as easy as varying the voltage, plus and minus, applied to a circuit.
Most radio chips support FSK (frequency shift keying), as that is very well understood, and very popular. There are conventional analog FM radio chips as well.
Are you quite certain that your proposed modulation method is "new"?
What's new in what I'm doing is the modulation scheme itself, not just the modulation, and its resistance to noise and interference. But that's not my issue at the moment. What I want to know is how to programmatically choose the transmission frequency of the signal. My code looks like this, for example: send(data, frequency).
It would be wise to pick a radio module first.
This is the subject of this discussion. I'm looking for an RF module with programmable modulation. If you could advise me on one
Semtech SX1276 or SX1278
The majority of 'radio modules' are SPI based.
Typically to set the modulation frequency you write to the contents of the devices registers.
A frequency change is not instantaneous of course, so how fast you want the output frequency to change would depend on the module type.
Sounds like you're better off with a more bare-bones approach. Use something like a suitable PLL synthesizer to make the frequencies you need; maybe even use an array of them and switch between them, or use one that can sufficiently rapidly switch over from one frequency to the next. Use that mechanism to do your modulation. Feed signal into a power amp and antenna as required for your testing.
I don't think it makes much sense to look at 'radio modules' as we generally use them in Arduino projects. The added value of such modules is that they handle modulation, but also signal quality, error recovery, data conditioning and a whole host of other aspects for us. The 'drawback' is that we don't have much/any influence on this - but that's also the advantage. We don't need to worry about it.
Since your interest is in a modulation scheme as such, all the higher-level protocol stuff that a radio module adds would just get in the way of your testing, or at the very least it would be superfluous.
Hence my earlier suggestion to link up with HAM enthusiasts in your region; if you can find a local HAM group, there are bound to be people interested and working on this. In case HAM is not 'alive' where you are, refer to the products of any of the semiconductor manufacturers focused on RF applications; e.g. Google turns up Renesas, but there are several others that offer similar products. For some of those products, evaluation boards may be available that you can use as a starting point for your testing.