TDEV in terms of power spectral density

The TDEV can also be expressed [1] in terms of the one sided power spectral density $S_{\varphi}(f)$ of its random phase deviation $\varphi$  

$$TDEV(\tau)= \sqrt{\frac{2}{3(\pi \nu_{nom}n)^2}\int_{0}^{f_h... ...phi}(f)\frac{\sin^{6}(\pi n \tau_0 f)}{\sin^2(\pi \tau_0 f)}df}$$ (29)

where $\nu_{nom}$ is the nominal frequency of the timing signal and $S_{\varphi}(f)\approx 0$ for f>f_h   (i.e. f_h is the high frequency cut-off described in section 4.1). Given that the single sided power spectral density of the time error

$$x(t)=\frac{\varphi(t)}{2 \pi \nu_{nom}}$$

can be expressed as

$$S_x(f)=\frac{1}{(2 \pi \nu_{nom})^2}S_{\varphi}(f)$$

the above equation (4.5) can be expressed in terms of the power spectral density of the time error x(t)  

$$TDEV(\tau)= \sqrt{\frac{8}{3n^2}\int_{0}^{f_h}S_x(f)\frac{\sin^{6}(\pi n \tau_0 f)}{\sin^2(\pi \tau_0 f)}df}$$ (30)