The value of 140 ppm corresponds to the frequency error tolerance and describes the properties of a receiver. The greater this value the better.
However, at the transmit side, the frequency accuracy requirement is +-40 ppm (so the frequency error tolerance must be at least 80 ppm). As follows from my experience,
the frequency shift of TI's evaluation boards doesn't exceed 50 kHz.
Regards,
Ilya
