Position switched

In this case, only half of the time is spent in the direction of the source. Thus

$$\ensuremath{t_\ensuremath{\mathrm{on}}}= \ensuremath{t_\ens... ...{off}}}= \frac{\ensuremath{t_\ensuremath{\mathrm{onoff}}}}{2},$$ (9)

$$\ensuremath{t_\ensuremath{\mathrm{sig}}}= \frac{\ensuremath... ...}}}{2} = \frac{\ensuremath{t_\ensuremath{\mathrm{onoff}}}}{4},$$ (10)

and

$$\ensuremath{\sigma_\ensuremath{\mathrm{psw}}} = \frac{2\,\e... ...th{\mathrm{tel}}}\,\ensuremath{t_\ensuremath{\mathrm{tel}}}}}.$$ (11)