Below the mean, the distribution is roughly normal. Above the mean, the straight line of the log-log plot indicates that the relative frequency is inversely proportional to the square of the normalised amplitude.
Blanking parameters are shown in the diagram right. Dwell time is the re-triggerable blanking period: Blanking is triggered when the amplitude exceeds the threshold and output remains blanked for the dwell time. If the threshold is exceeded again during the dwell period, the dwell timer is restarted. This is intended to prevent short bursts of output during the zero crossings of the sferic waveform, and to remove any long tail of the sferic which may be below the threshold but still within the wanted passband.
The smoothing period S is the time period over which the blanking steps are smoothed. A cos^2 smoothing envelope is pre-triggered by the start of a blanking period. After the dwell period expires, the signal is restored with a sin^2 envelope.
Signal amplitude is about half that of the mean noise in 1.8mHz bandwidth.
Prior to blanking, the signal is band-limited to 4-8kHz.
The histogram of the band-limited signal is below:
Below the mean, the distribution is roughly normal. Above the
mean, the straight line of the log-log plot indicates that the
relative frequency is inversely proportional to the square of
the normalised amplitude.
Step blanking. 1.8mHz bandwidth. Range of dwell times. No smoothing period.
No dwell time, blanking and clipping compared.
Smoothing test. No dwell time, range of smoothing periods.
