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Antenna Diversity - dev kits and evaluation of performance?

Other Parts Discussed in Thread: CC2590, CC8530

HI All,

i'm interested in the antenna diversity for my purepath application. Interested to see if there are any development boards for this and/or if anyone out there has successful implementation. If so what are the observed performance gains in given applications?

Thanks in advance,

James.

  • Hi James,

    I am also interested to know what performance gains are to be had from using antenna diversity.

    It sounds like the cc85xx can test rssi of each antenna before TX of packet from the user guide but thats a guess !! its all quite unclear.

    I am assuming that the protocol master is programed in wireless configurator ( radio section ) to check the best antenna of the protocol slave. since Its only possible to select this option on protocol master !

    the user guide states ''Only protocol slaves support the antenna switch control''

    this would make sence since you ussually want antenna diversity on a reciever ? but what about if you designing a multiple radio mic solution. the multi-channel reciever would be protocol master and therefore would NOT support diversity ? or do they expect the radio mics to have to multiple antenna ?

    or is it the Protocol Slave that slects the best antenna on the protocol master ???

    I am ordering the parts and going to have a go at building the diversity refernce design ! but I'm not sure wich end of the link to add the actual antenna switch !!!

    Anyway, I'll guess I'll just have to try both ways and see what works.. anyone else have a clue ?

    Also would be very interested in buying a pre-made dev board of this example for testing with the switched antenna on board, anyone ??

    Perhaps someone from TI could comment here on advantages ? it would save us a lot of trouble to know if there are any !

    Thanks,

    BEN

  • Hi James,

    it sound in the user guide like the diversity antenna helps with channel fading, but how well is unclear.
    What would it cost to have someone build the dievrsity example do you think? I dont mind splitting the cost if its cheap enough ?

    ben
  • HI Ben,

    Nice to hear someone else is facing similar questions. My application is also a multiple microphone design transmitting back to one protocol master. In this situation it would be great to have diversity on both ends.

    I'll dig out the ref design again and see what the dev costs may be.

    Where you based?

    James.

  • Hi James,

    I'm getting a few quotes to get the REF design made up. I'm not using the TI dev kit but the ref design should plug strieght into that cc85xxDK for testing I guess since the connectors look the same?

    I don't think you will get diversity antenna at both ends with this design. looking at it more closely it appears to only supports hardware diversity antenna at the protocol slave end the protocol master detects which antenna is best for the slave (sender in a mics case) to TX on.

    thats my vauge understanding of it anyway ! I could well be very wrong !!!

    anyway, if I get some reasonable quotes for 6 boards I could send you a couple.. I would be using CC8530 & CC2590 PA with no on board codec.

    Later I would add a codec to the board if the design has advantages..

    TI ? could you please save us the trouble and let us know roughly what gains can be expected from this diversity design??

    that way would could skip the antenna testing and get strieght to designing a diversity MIC TX pcb ?

    I'm based in Japan and the UK. mainley in Japan this year. Can you private message me on this forum ? not sure how too.

    Let me know also what kind of prices you can find to build this diversity example.


    BEN

  • PS. I'd love to build this myself but since its all Surface mount stuff & a 4 layer board I think its way out of my skill zone ! :)

    BEN
  • OK, I ordered the parts and built the anntena switch curcuit. I shielded this switch curcuit area since I did'nt follow the multilayer design. There is a slight improvement in link quality. I tested  ' stero slave diversity MIC -- Master stero output ' there was no improvement in range. I used uncompressed audio and not SLAC.

    There is the issue that best link quality requires audio from master to slave and yet diversity only works on the slave?

    More than one mic dictates that you need to impliment diversity on each slave Mic TX. Is it worth it? well the range of the cc8530 + PA is'nt that impressive to me. indoors I struggle to pass through 1 lightly constructed wall and one person. partially blocking the antenna can block the signal entirely. PTP line of sight can be 100 meters but add movement or 1 person partialy blocking the antenna and the link has dropouts. I have yet to test operation in SLAC mode but I am less interested in this quality degregation. rubber duck Antennas where positioned 1 quarter wave length appart at 35 degrees pointing away from each other. Also tried 90 degrees. Cost of 4 layer example diversity board is about 650 USD for 4 piece and my pre tests say to me its not worth it. perhaps if it was worth it TI would have made a diversity demo board for the DEV kit. The fact they have'nt and don't comment on diversity link advanteges?

    either way I don't know of any other SOC that does PTP audio so for the moment as well so I am partially stuck. The link is'nt strong enough for me to design a working product although the quality of the audio in the link is very good. 16ms latency for uncompressed audio does seam a little high though? wifi links can be down to 5ms? anyway perhaps thats a comment for another forum.


    anyway, hope this helps if anyone is thinking of trying diversity mode in purepath. would love to here of anyone who has tried the example 4 layer board and found better improvements?