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TIDM-02009: General question on resolver sampling SIN/COS

Mark Feller
Intellectual 870 points
Part Number: TIDM-02009

Hello,

Are there recommendations or requirements for trying to align the SIN/COS sampling with EXC or some other operation parameter?

For example, should I try to sample at the peak of the EXC waveform?  Is it necessary to sample at the same frequency as the EXC waveform?

For example, EXC is running at 10kHz, but SIN/COS sampling is done at 16kHz.  In this case, the SIN/COS sampling will not be aligned with any particular part of the EXC waveform.

Thanks!

  • +1
    TI__Expert 6025 points

    Hi Mark,

    I apologies for the delay in responding to your thread. I thought I have posted an answer, but just realized it did not went thought successfully.

    For the sampling of Sin / Cos signal in resolver implementation, there are two ways of doing it. 

    Option 1: You sample sin/cos signal at peak. It can be either the positive peak only or both positive and negative peak, which means your sampling frequency will be EXC frequency or EXC frequency x 2.

    Option 2: You can sample the sin / cos signal at a frequency much higher (say 16-20 times higher) than the EXC frequency and run the sampled signal through some type of filter. From the filter output, you can then extract the magnitude of the sin and cos signal.

    Your proposal of sampling at 16 kHz with a 10 kHz EXC frequency will not work. If you have to sample at such frequency, then I would suggest changing your EXC frequency to match it. Thanks.

    Han