We recently purchase the evaluation board but there appears to be a problem. Even with just a fixed resistor connected between pin pairs 1/2 and 3/4 (i.e. pins 1 and 2 shorted and pins 3 and 4 shorted) the reading appears erratic, jumping between values by over 50%. Connecting an oscilloscope between the pin pairs, it appears the signal is not clean, with a large envelope around small windows of the correct waveform (see picture). Have we just received a damaged board or is there something else we can try to remedy this?