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SN65HVD62: Question of OOK Modulator & Demodulator for the AFE031+SN65HVD62

Wayne Chen (ex FAE)
Guru 15950 points
Part Number: SN65HVD62
Other Parts Discussed in Thread: AFE031

Hi Sirs,

Would you please advise of the AFE031 and SN65HVD62 support customer's requirements below? 

Physical serial communication, OOK modulator & demodulator that carried on DC Power Line 12V as the following:
• Link speed: 9600 Baud
• Asynchronous serial link
• Data configuration: 8-bit, no parity, 1 stop bit
• Signaling: NRZ (mark=high)
• Modulation scheme: On/Off Keying (OOK) on 2.6MHz carrier, ON=logical zero

Besides, Asynchronous transmission protocol following above requirements will create bursts of 2.6MHz carrier frequency with following characteristic:
• No carrier in idle state, Rx line high
• Burst of carrier on every zero bit, length per bit (nominal): 104.2 microseconds
• In current implementation signal amplitude is approx. 3V
• Length of active state is equal to number of bytes in packet times 10-bit length (transmit data byte = start bit + 8 payload bits + 1 stop bit)

Thank you and Best regards,

Wayne Chen
04/15/2017

  • 0
    TI__Guru 62910 points
    Hi Wayne,

    The HVD62 receiver is designed with a narrow bandpass filter centered at 2.176 MHz, so any input signals at a 2.6-MHz carrier may be heavily attenuated. Do you know the expected input signal level? Would it be 3 V, or could it be lower?

    Regards,
    Max
  • 0 in reply to Max Robertson
    TI__Intellectual 840 points
    Hi Wayne,


    I ran SN65HVD62 at 2.6MHz and was still able to pass data. You get a reduction in the amplitude at that frequency. I saw a reduction from about 2.17V to 1.4V for the modulated output signal, with maximum gain of +6dbm, between 2.1MHz and 2.6MHz respectfully. But the minimum voltage you need on the TXout/RX line is about 300mV to cause the state to change on the RXout pin.


    Regards
    Daniel Noel