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dBuV to dB tranformation and question about speed values in zero configuration tool

pavol macura
Prodigy 10 points
Other Parts Discussed in Thread: AFE031

Hello,

we are using developers kit TMDSPLCKIT-V3 C2000 Power Line Modem + Software Zero COnfiguration Tool for our PRIME communication measurements.

We would like to ask some questions about that:

What is the output level VOLTAGE (V or mV) when we transmit signal from PRIME module?

What matematic definition and constants we shoukld use to transform RSSI data from dBuV to dB units?

In LOG file there are some speed values. What is the speed unit and what does this values means (fysical speed, data speed?).


thank you for answers.

  • 0
    Guru 20525 points

    Hello Pavol!

    1 What is the output level VOLTAGE (V or mV) when we transmit signal from PRIME module?

    The level VOLTAGE depends on the gain of transmitter (in AFE031) and load resistance of modem (communication line).

    2 What matematic definition and constants we shoukld use to transform RSSI data from dBuV to dB units?

    RSSI(dBuV) = 20*lg(U/1uV).

    3 In LOG file there are some speed values. What is the speed unit and what does this values means (fysical speed, data speed?).

    Shannon-Hartley theorem states:

    C-channel capacity in bits per second;
    B - channel bandwidth in hertz;
    S - total signal power over the bandwidth, measured in watts or volts squared;
    N - the total noise power over the bandwidth, measured in watts or volts squared;
    S / N - Signal to Noise Ratio (SNR) signal to Gaussian noise ratio, expressed as a power ratio.

    However indicator bandwidth of channel always lower PHY-speed generally greater than 50%, due to many factors, such as duplication of the data and sending technical data do not carry a payload (packet headers particular data transmission protocols, at our case: PRIME-protocol).

    Welcome to http://e2e.ti.com/support/microcontrollers/c2000/f/171/t/254032.aspx.

    Regards,

    Igor


  • 0 in reply to Igor Gorbachev
    Intellectual 310 points

    Good day everyone,

    I would like to know what it is exactly this RSSI parameter.  Since the modulated signal has both positive and negative values, is the RSSI the maximum positive or negative voltage peak of the signal?? I presume this, because in this context I a mean value of the signal does not to seem very useful.

    How can you measure it?

    I appreciate the help!!!

    Regards,

    Diego Ballen Cantor

  • 0 in reply to Diego Ballen Cantor
    Guru 20525 points

    Diego,

    I hope this link will help you.

    Regards,

    Igor

  • 0 in reply to Igor Gorbachev
    Intellectual 310 points

    Hi Igor,

    Thank you. It really helps.

    Now It is clear that this is a voltage level in reference to 1 uV. Now, if I visualize  the PLC signal in an oscilloscope, how can I obtain the RSSI value. I would like to compare this value with the showed by the Zero Configuration Tool.

    Regards,

    Diego

  • 0 in reply to Diego Ballen Cantor
    Guru 20525 points

    Well, for a rough estimate, you can take half the full scope of your signal on the screen.

    Regards,

    Igor