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Part Number: TDC1000-TDC7200EVM
I am trying to get time of flight measurements for wind speed using a 40 kHz transducer, but it seems I can't get any valuable data from the EVM board. For testing at the moment, I am still using TOF_MEAS_MODE in Mode 0. I also tried using Mode 2 with two transducers.
I made the following changes
Settings
1. Set frequency to 40 kHz by setting MCU clock to 1.2632 MHz and divide by 32 using TX_FREQ_DIV
2. Use LNA_FB in resistive mode
Alterations to TDC1000-7200EVM
1. I swapped out capacitors C32 and C27 (bandpass filter) so it would pass frequencies between 40 – 200 kHz, so C32 is 500 pF and C27 is 1nF
2. I changed C42 and C43 (going to transducer) to 820 Ω resistors
When I measure the signal at COMP_IN on the board, I can detect some signal that has frequencies at the driving frequency, but the TOF doesn't seem to change when I move an object closer or further from the transducer. The only way I can get the COMP_IN signal to change is by physically touching the transducer.
Is what I am observing just ringing in the electrical line? Do I not observe a real reflected wave pulse because the amplitude is too small? Any help on what I can do to get a better signal would be greatly appreciated :)
Settings for TDC1000
Start signal and the COMP_IN signal in Mode 0
