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CC8520 Audio Drop at 768 Audio Samples

Hyun Sung Cho
Prodigy 15 points
Other Parts Discussed in Thread: CC8520, CC2590, CC2591

Hi!

I have built Wireless MIC using CC8520+CC2590.  My board transmits streo audio from Slave to Master using 48KHz sampling.

When I use 768 samples of audio latency at 48KHz audio, I have found  audio drops. If I changed audio sample to 1024 latency there is no audio drop. I'm using firmare V1.3  Also, when I use Wifi at laptop and mobile phone,significantly incrasing audio drops.

Our company staying office building and there is more than 10 access point in here.

Do you think it is normal situation of audio drop at 768 latency?

  • 0
    TI__Mastermind 21125 points

    Hi Hyun, 

    Latency is a direct trade-of between audio robustness. It is very hard to give a recommendation to what is acceptable in regards of range, latency and robustness, especially since the environment changes as well. 

    A couple of things that, potentially, can improve your situation:
    - Use SLAC instead of PCM16/PCM24 as streaming format - SLAC requires way less bandwidth and allows for more retransmissions for the same latency setting.
    - Antenna diversity in the slave. Seems that you have built your board already, but antenna diversity can improve the situation
    - Depending on the ADC/CODEC chosen you might consider mixing the two ADC inputs internally in the ADC/CODEC and send a mixed mono stream over the wireless link (with only half the bandwidth needed you will gain quite a few more re-transmission attempts.

    Hope this gives some insight to the trade-offs and choices you have.
    Please let me know if you have more questions.

    Best regards,
    Kjetil 

  • 0 in reply to Kjetil
    Prodigy 240 points

    Hello Kjetil and Hyun,

    what happens if you change CC2590 to CC2591 and increase the output level from 14dBm to 20dBm?

    Will you be able to use the lowest latency settings when using a higher power level?

    best regards,

    Esa

  • 0 in reply to Esa Harma
    TI__Mastermind 21125 points

    Hi Esa. 

    There is nothing that prevents you using the lowest latency settings with higher output levels (going from CC2590 to CC2591). 
    By changing the latency settings you are in effect trading directly against the number of re-transmissions the protocol is able to deliver and this translates directly into experienced range.

    Note however that some of the regulations (ETSI in Europe, ARIB in Japan and the Korean regulations) have limits to how high output power you can have for a solution like us. For US market and FCC you can go up to 20 dBm.

    Kjetil