  LE is the low energy telescope of Insight-HXMT. It uses swept charge devices
(SCDs) to detect soft X-ray photons. The time response of LE is caused by the
structure of SCDs. With theoretical analysis and Monte Carlo simulations we
discuss the influence of LE time response (LTR) on the timing analysis from
three aspects: the power spectral density, the pulse profile and the time lag.
After the LTR, the value of power spectral density monotonously decreases with
the increasing frequency. The power spectral density of a sinusoidal signal
reduces by a half at frequency 536 Hz. The corresponding frequency for QPO
signals is 458 Hz. The Root mean square (RMS) of QPOs holds the similar
behaviour. After the LTR, the centroid frequency and full width at half maxima
(FWHM) of QPOs signals do not change. The LTR reduces the RMS of pulse profiles
and shifts the pulse phase. In the time domain, the LTR only reduces the peak
value of the crosscorrelation function while it does not change the peak
position. Thus it will not affect the result of the time lag. When considering
the time lag obtained from two instruments and one among them is LE, a 1.18 ms
lag is expected caused by the LTR. The time lag calculated in the frequency
domain is the same as that in the time domain.
