Some pulse characteristics of atmospheric radio noise bursts at 3 MHz

Digital Communication Systems in Impulsive Atmospheric Radio Noise

“…The received signal will be N n(t) = z ai6(t-ti) i=i (1) where the ti are independent random variables uniformly distributed in the interval (0, F) and N is the Poisson random variable. The amplitude ai is assumed to be independent and identically distributed with a pdf as suggested by Shinde [15 ], given by w(a) = 2/ [JT(l + a2)2 ], -°o< a < oo (2) The occupation time of the impulsive noise, when it occurs, has been reported to be of the order of 1 percent [4] . This implies that with the signal bit of the same duration as the noise pulse, the average number of noise pulses for a given number of signal bits will be 1 percent.…”

“…Tuie impulsive nioise nmay arise as a result of sparking in electric systemis oi-natural phenomena like lightning, the latter giving rise to atmospheric radio noise [1][2][3] iis type of noise is usually observed as a number of high amplitude, low duratioin impulses superposed on a relatively weak background [4][5][6][7] Suchi noise is enicountered friom very low frequency bands to even microwave bands [8]. Tihe noise may be predominantly impulsive or continuous depending upon the frequency range of interest, geophysical location, time of day, anid season of the year.…”

Atmospheric noise data for tropical regions

“…The latter has been subsequently called the noise burst level or the noise level and has been expressed in microvolts per meter. The time constants of the noise meter which were first obtained by trial and error were later explained theoretically [Aiya, 1958] [Aiya, 1962;Satyam, 1962;Lakshminarayan, 1962], (4) recording of the AF output arising from noise bursts on magnetic tapes and level recorders [Aiya and Lakshminarayan, 1965], (5)cathode ray oscillographic and other studies of the structure of noise bursts [Shivaprasad, 1971], (6) effect of receiver bandwidth on the amplitude and time parameters of noise bursts [Gupta, 1969[Gupta, , 1971], (7) measurement, use, and statistical relationship between peak, rms, average, and quasi-peak amplitudes of noise bursts [Aiya and Bhanumurthy, 1969;Bhanumurthy, 1971 ], (8) correlation between atmospheric noise levels at different frequencies [Joglekar, 1970], and (9) study and instrumentation for VHF atmospheric noise bursts [Bhat, 1968]. These studies constitute the scientific basis on which the measurements were carried out and data deduced.…”