Resolution Speed Wavelength Three-Row Scan - Biophysical Ultrasound: Echo Timing and Acoustic Interfaces Step by Step

Sound speed itself sets wavelength before frequency or cycle count are ever applied. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Every earlier resolution row held sound speed fixed at twelve

Every earlier resolution lesson in this book kept sound speed at 12 metres per second and only ever varied frequency or cycle count. Here frequency stays fixed and cycle count stays fixed; sound speed itself is the source factor that rescales the checked wavelength.

\lambda={c\over f},\quad \Delta d={N\lambda\over 2}

Three sound speeds give three exact wavelength budgets

The frequency and cycle count never change across these rows. Sound speed alone rescales wavelength, pulse length, and the axial resolution limit together.

\begin{array}{c|c|c|c}c&f&\lambda&\Delta d\\6&3&2&2\\12&3&4&4\\18&3&6&6\\\end{array}

The middle row is the book's own checked twelve-meter speed

The final display follows the same checked wavelength and cycle count as the diagram; sound speed is the only factor this scan changes.

12/3=4