Resolution Cycles Pulse-Length Three-Row Scan - Biophysical Ultrasound: Echo Timing and Acoustic Interfaces Step by Step

Cycle count lengthens pulse length before the axial limit is halved. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

4 meters of pulse gives limit 2

The wavelength stays 4. Cycle count 1 stretches pulse length to 4 and axial limit to 2.

4\cdot1=4,\quad \Delta d=2

8 meters of pulse gives limit 4

The wavelength stays 4. Cycle count 2 stretches pulse length to 8 and axial limit to 4.

4\cdot2=8,\quad \Delta d=4

16 meters of pulse gives limit 8

The wavelength stays 4. Cycle count 4 stretches pulse length to 16 and axial limit to 8.

4\cdot4=16,\quad \Delta d=8

More cycles lengthen the pulse before the limit is halved

The speed and frequency fix wavelength at four meters. Cycle count changes pulse length first, then the axial limit is half the pulse length.

\begin{array}{c|c|c|c}N&\lambda&N\lambda&\Delta d\\1&4&4&2\\2&4&8&4\\4&4&16&8\\\end{array}