I am trying to build an ultrasonic flow meter with the TDC max35101 and have come upon an issue. When i connect the ultrasonic transducers to the chip, the output pulses are a bit choppy (pic1) generating wrong measurements on the receiver side. It should be a smooth sinusoidal signal so that the comparator has smooth output. When i disconnect the transducers i get the normal pulses (pic2). Why is this happening and what could i do to avoid it. The transducer's capacitance is 1200pF. The circuit is uploaded also.
thanks