Other Parts Discussed in Thread: MSP430FR6047
Hi,
The following document: www.ti.com | tidudo7 shows the reference design for an ultrasonic flow transmitter reference design employing MSP430FR6047.
The document specifies that the OP-AMP used in the receiving and transmitting stage should be the same to avoid a differential time of flight in the presence of no flow (Section 2.2.2, paragraph 1).
But why would there be a difference in propagation delay?
For example in Upstream, the following is the signal path (both electrical & US):
MCU -> TX Stage(OP-AMP1) -> US Transducer 1 -> US Transducer 2 -> RX Stage(OP-AMP2) -> MCU
Again in Downstream, the signal path would be:
MCU -> TX Stage(OP-AMP1) -> US Transducer 2 -> US Transducer 1 -> RX Stage(OP-AMP2) -> MCU
As we can see from the above, both the downstream and upstream would have the same signal path and will not show a difference in time of flight for upstream and downstream with zero flow.
Does the document mean a different scenario?
What could be missing from the above explanation?
Thanks in advance