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The question of HF Power Amplifier

bob peng
Prodigy 30 points
Other Parts Discussed in Thread: TRF7970A

Hello, I reference sloc132 design has a based on TRF7970A of high power circuit board, using TI provides of source program (sloc300a), and according to TRF7970A of DATASHEET description set the register 0x0B of BIT6 and 0x09 of BIT3 to 1。using spectrum analyzer observation output power has reached 4W, antenna using 50*30CM of high performance antenna, but reads the tag of ISO15693 of effect is is poor, only several CM, Could you tell me how it should be configured in order to improve performance (>50CM). Could you give the program of the designed sloc132 ?

Thanks,

Regards,

Bob

  • 0
    TI__Mastermind 38590 points

    Hi Bob,

    What size tag are you using?  The reader antenna is pretty large, so do not expect small tags to work very well.  The field will not couple properly with a small antenna tag.  if you are using a small tag size, try with something larger, like a 76mm x 45mm. 

    Did you also follow the design guide and offset the antenna tuning to prevent the transmitter from saturating the receiver inputs?  This is described in section 4.3.

  • 0 in reply to Eddie LaCost
    Prodigy 30 points

    Thank you for your reply, the tag size is 8.5*5.5CM, just like a credit card.I think that this tag is not a problem.

    I measured waveform with almost as referred to in section 4.3.

    I think the problem is that TRF7970A is not configured correctly, for example, in the case of remote read the tag should use single carrier or double-deck carrier?

    AM Detector (Rx inputs configured for sub-carrier input), and the AM Detector (Rx inputs not configured for sub-carrier input) which method should I use for this work? Do I need to use AGC control? And so on

    Thanks,

    Regards,

    Bob 

  • 0 in reply to bob peng
    Prodigy 65 points
    Hi Bob,
    I am also concerned about this issue，Did this problem been solve now?
    Thanks,
    Regards,
    Yuan
  • 0 in reply to user4397992
    Prodigy 30 points

    Hi, Yuan

        I have solved this problem,but not use the TRF7970A,I use a separate FM mixer to demodulate the received signal, and decode the signal by a mcu

  • 0 in reply to bob peng
    Intellectual 260 points
    Hi Bob,

    Could you describe the method?

    Thanks,
    Chiase