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CC1310: Question about Antenna Diversity

Masato Miyashiro
Expert 1500 points
Part Number: CC1310

Hi,

I was talking about antenna diversity at this forum. (See URL below)
e2e.ti.com/.../2107862
Since the previous thread has become long, I make a new thread.

As for this problem, additional questions came from my customers.
Could you give me advice?

1, You answered that Antenna Diversity worked with CC1310EMK without problems, but did you use the whip antenna?
    Or did you use the PCB antenna?

2, The antenna control signal when receiving search is toggled at 360 u second.
     I feel that time is short for measuring power with each antenna, but is it the expected behavior? Or is it mis-coding?

3, Do I have to set preamble settings to the same value for both transmitter and receiver?
    Is the setting of nPreamBytes in CMD_PROP_RADIO_DIV_SETUP related to the preamble on the receiving side too?


I appreciate your response.

Best Regards,
Miyashiro

  • 0
    TI__Genius 14860 points

    Hi,

    Masato Miyashiro said:
    3, Do I have to set preamble settings to the same value for both transmitter and receiver?
        Is the setting of nPreamBytes in CMD_PROP_RADIO_DIV_SETUP related to the preamble on the receiving side too?

    The preamble settings are important for the transmitter so that it knows how many bits/bytes to send. The receiver does not check any preamble length, but it needs a preamble to settle the AGC and do frequency offset tracking. So the preamble must be "long enough". The preamble length is also used when calculating the RX time stamp. If you don't set the same preamble length on both sides, then your RX timestamp will have a (fixed) offset.

    I leave the other questions up to Siri.

  • 0 in reply to Richard W.
    TI__Guru* 86241 points

    Hi Masato

    1)

    The test setup used for testing the antenna diversity patch is described in the CC13xx Antenna Diversity Application Report (http://www.ti.com/general/lit/swra523). It uses the Pulse Antennas that comes with the SimpleLink™ CC1310 Evaluation Module Kit.

    2)

    With the default settings, the PreTimeout = 10 symbols (state in the app report). If you are running 50 kbps, this means that PreTimeout = 10/50000 = 200 us. In addition comes processing time, so a switching time of 360 us sounds reasonable.

    3)

    What Richard writes is correct when not using antenna diversity but is not correct when using the patch. The preamble length is used to set the syncTimeout (the time in the Sync Search state in the Flow Chart shown in Figure 1 in the app report)

    BR

    Siri

  • 0 in reply to Siri
    Expert 1500 points
    Hi Richard, Siri,

    Thank you for your reply.

    I understood your comments, so I will answer to my customer.
    I appreciate it.

    Best Regards,
    Miyashiro