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TX517EVM: Generate different freq. than the ones already on the TX517EVMboard

Sajad Rahmdel
Expert 1705 points
Part Number: TX517EVM
Other Parts Discussed in Thread: TX517

Dear TI friends,

We would like to generate different frequecncy (400 Khz ~ 800 Khz) using TX517EVM. As explained on the user manual, page 10 table 4 (www.ti.com/.../slou317b.pdf), we can generate 4 different frequencies starting from 10Mhz up to 100 Mhz. This range of frequency is good for medical applications. However, we're planning to use TX517EVM for sonar applications. In sonar applications, we typically use a frequency between 400 Khz ~ 800 Khz. Is there a simple way to configure the output frequency of TX517EVM?

As always, thank you for your wonderful support :)

  • 0
    TI__Expert 4145 points

    Hi Sajad,

    The TX517EVM comes with a pre-programmed FPGA controlling the frequencies generated by the EVM. Unfortunately, this particular EVM was not designed to be customer-configurable.

    Sincerely,

    Olu

  • 0 in reply to Olu Sodipe
    Expert 1705 points
    Hi Olu,
    Thanks for the reply, Olu.

    If we use this chip in our upcoming product, we need to know at least this chip can produce a signal in the range of 400 Khz ~ 800 Khz. How can I verify that the TX517EVM has the capability to produce that range of frequencies?
    Alternatively, it would be great if TI could share the pre-programmed FPGA code. TI would benefit from selling this chip on our product and it would accelerate our development time.

    Thank you again :)
  • 0 in reply to Sajad Rahmdel
    TI__Expert 4145 points
    Hi Sajad,

    The TX517 has a maximum update rate of 100MSPS as per Page 1 of the datasheet but it has no minimum frequency requirement.
    This is because the device constructs the transmit signal by PWM spectral shaping.
    Essentially, looking at Page 11 of the datasheet, you can use the OUTA and OUTB pins to form any signal shape you want (formed by their difference).

    Unfortunately, we cannot share the pre-programmed FPGA code.

    Sincerely,
    Olu
  • 0 in reply to Olu Sodipe
    Expert 1705 points
    Hello again,
    We are still looking for a method to change the output frequency of TX517EVM to 400Khz or 800Khz. Would it be possible to control this board externally?

    We were thinking to generate PWM wave using our OMAP L138 LCDK, and then give this PWM wave as input to TX517EVM . Then TX517EVM would generate the output frequency based on the PWM that we gave TX517EVM as input. However, I don't know if it's possible or not.

    Any suggestions or advice is appreciated.
  • 0 in reply to Sajad Rahmdel
    Expert 1705 points
    This last question is very important, so I made a new thread for it. Please give me your answers using the below thread:
    e2e.ti.com/.../613465
  • 0 in reply to Olu Sodipe
    Expert 1705 points

    Hi Olu,

    Are you sure that there is no minimum frequency requirement? Here is the recommended operation conditions for the TX517 according to the user manual (www.ti.com/.../tx517.pdf):

    The INNxx, INPxx input sample rate has a minimum value of 1 Msps, which is higher than our requirement (400KHz). However, I'm not sure if this minimum value is related to the output frequency of the TX517 or not. 

    Thank you 

  • 0 in reply to Sajad Rahmdel
    TI__Expert 4145 points

    Hi Sajad,

    The input and output frequency requirements are different. There is a minimum frequency requirement for the input but not for the output. You can use a high sample rate to create a lower frequency output signal (you'll just have more sample points in a period than for a higher frequency output signal). 

    Sincerely,

    Olu