Imaging Measurement Cross Scans

Echo Time Depth Three-Row Scan

halve the round trip

Changing echo time at fixed wave speed makes the depth relation visible. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Four seconds round trip gives eight metres

At speed 4 m/s, round trip time 4 s gives half-time 2 s and depth 8 m.

4⋅(4/2)=84\cdot(4/2)=8
Echo depthA round-trip time is halved before speed turns it into depth.round tripdepth8

Six seconds round trip gives twelve metres

The same speed with round trip time 6 s gives depth 12 m.

4⋅(6/2)=124\cdot(6/2)=12
Echo depthA round-trip time is halved before speed turns it into depth.round tripdepth12

Eight seconds round trip gives sixteen metres

Round trip time 8 s gives half-time 4 s and depth 16 m. Three rows make the two-way rule visible.

4⋅(8/2)=164\cdot(8/2)=16
Echo depthA round-trip time is halved before speed turns it into depth.round tripdepth16