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THVD8000: Multiple carrier frequency on the same bus

Andrei Bucsa
Prodigy 50 points
Part Number: THVD8000

Hi,

I'm wondering if is possible to use multiple transmitters (that transmit simultaneous) using different carrier frequencies on the same bus?

I find no information on demodulator bandwidth so I'm wondering if is possible such topology with no interference.

Thanks,

Andrei

  • +1
    TI__Mastermind 46607 points

    Hi Andrei,

    So unfortunately you can't really have multiple carrier frequencies on the same bus for 3 main reasons.

    1. While we don't explicitly define the bandwidth of the demodulator - I can say that it doesn't have a very high Qo value - so it isn't very selective at any frequency - the FSET pin will setup the demodulators bandpass filter to have wide pass band centered at modulation frequency. 

    2. That coupled with the +/-25% carrier frequency tolerance possible makes FDMA (Frequency Division Multiple Access) type communication schemes very hard to work reliably with THVD8000. 

    3. THVD8000 has a low resistive output impedance - meaning that regardless of modulation frequency chosen  if two drivers attempt to access the same bus they will have a ton of attenuation and it could be a considered a "short" case. The drivers would be protected from damage but any receiver would just read the short as a logic "1". So this could trigger false data. 

    Please let me know if you have any more questions!

    Best,

    Parker Dodson

  • 0 in reply to Parker Dodson
    Prodigy 50 points

    Thanks and Most Appreciated!