Hello,
The Higher Powers in the company I work for decided we should start developing some software related to LTE; in the process of this, we have to set up a test base station and carry out some tests, two of which involve a TX power of 10 W.
Being the only one with an EE degree, I was quickly handed out the task of coming up with what we need, but by knowledge of RF is rather scarce. I did take a course on microwaves in uni, but it was quite a while ago and mostly related to burning things, not sending information, so I am rather confused by all this telecom finery. 10W is about an order of magnitude below anything I studied back then.
I am currently tring to realize if this PA:
Background story: we are going to use an Ettus Research SDR box (here:
Unfortunately, I'm stuck with the three following issues:
- What noise figure should I be looking for (ball-park)? All the PAs I've looked for that are supposed to be good for LTE have a fairly smaller NF than this one. I presume this would depend on e.g. the frequency band, bandwidth and number of carriers, but I have no quantitative formulation for this yet :-(.
- Is there a good rule of thumb regarding the relation between IP3 and the 1 dB compression point when LTE is concerned?
- I'm not sure how I can get from the information provided in the datasheet to the EVM and ACLR figures, so that I can tell if I am within 3GPP's specs.
I would very much apreciate if someone could give me a few pointers about what/were to read in order to get an answer to these problems. I realize this is quite basic; even with my having forgotten most of what I learned about microwave systems, I can grok the physical phenomenae behind RF circuits, but I have zero experience designing telecom systems, and with components being this expensive, I cannot be wrong too many times in a row. Unfortunately, prior to this, I simply haven't had any interest in mobile communication, so my engineering formation can only get me this far.
If anyone else has had to do this before, I'm glad to hear any other tips you may have. If we ever end up in the same area of the globe, I'll be more than happy to provide a beverage of your choice :-).
Thank you very much!