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RF430CL330H load modulation

PhilM5
Intellectual 1680 points

Other Parts Discussed in Thread: RF430CL330H

Hi,

We are running a prototyping with RF430CL330H used as a tag, and,  are looking for possible details on the modulation used in transmit. 

In the device spec, we read about "load modulation" , but no details seems available .

Could you please share some details about this modulation (switching load of x Ohms, current source of y µA... ) ?  

When we observe the signals, we see a some sort of modulated bursts et would like to get more details on level of modulation of the tag.



Plot typical (modulation ask 10%)

Thanks & Regards

  • 0
    TI__Guru* 91336 points

    that looks like a tad more than 10% to me

    see below for example of the modulation depth (from the reader, for the downlink to the tag)

    here is a zoom in of that

    load modulation refers to the uplink back (also called the response) from the tag

    let us know if you need a screen shot or some training material on that. 

  • 0 in reply to Josh Wyatt
    Prodigy 10 points
    Hi,
    I will appreciate if you have a screen shot of the response from the tag, load modulation depth value in typical condition or/and worse case.
  • 0 in reply to Christophe Duchemin
    TI__Guru* 91336 points

    see attached. the (uplink) response from the tag is BPSK (as you most likely know) this is fairly hard to capture on a scope and is best after the decoder does its work (you can see the demodulated signal coming out of the MOD pin if you set register 0x1A correctly) , but i have attached some older plots to give you something to reference. i must also point out that the modulation depth is for the downlink not the uplink