SU546834A1 - Device for recording lightning discharges - Google Patents

Description

one

The invention relates to meteorological instruments, in particular to devices for recording lightning discharges.

Devices for recording lightning discharges are known that react to an abrupt change in the electromagnetic field caused by a lightning discharge. Such devices consist of appenenia, a detector, a filter, an amplifier, a threshold device, a one-shot, amplifier, a recording device and a control device (1, 2).

The frequency characteristic (1.6–40 kHz) of this lightning counter is such that, along with the discharges, the cloud — the earth also records part of the inter-cloud discharges and responds to electromagnetic radiation caused by non-thunderstorm discharges (industrial lags, etc.) d.)

Also known is a lightning counter, which consists of a series-connected antenna, filter, threshold device, one-shot, amplifier and recording device (3). There is a control device for checking the operability of the device. The frequency characteristic (0.1-2.5 kHz) of this counter is such that it preferentially reacts on the electrostatic component of the electromagnetic field of the lightning discharge, which decreases inversely proportional to

cube distance Although this counter is preassigned to register the cloud-ground lightning discharges, it also registers some of the inter-cloud discharges and responds to electromagnetic radiation caused by non-lightning discharges.

To improve the selection of ground-based bits and improve the noise-resistance of the proposed device, there is a parallel circuit containing a series-connected filter and a threshold device, and another two similar circuits, each of which contains a filter with its frequency response, selected from the frequency spectrum Dov, and threshold device. A matching device is introduced at the input of these three parallel circuits, and a matching circuit is introduced at the output. The signal about the presence of a thunderstorm cloud ––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– only message from above all threshold channels from the three of the three channels pa diagram circuit, signal that the device is a light source device.

Claims (3)

The drawing shows a block diagram of the described device, comprising an antenna 1, a control device 2, a matching device 3 and three parallel channels 4, 5, 6, of which each one consists of a filter, a detector, an amplifier and a threshold device, respectively. Channel 4 includes filter 7, detector 8, amplifier 9, threshold device 10. Channel 5 consists of filter I, detector 12, amplifier 13, threshold device 14. Channel 6 contains filter 15, detector 16, amplifier 17, threshold device 18 In addition to these stages, the device contains a coincidence circuit 19, a pulse expander 20, an amplifier 21, and a registering device 22. When lightning is cloud-ground in the surrounding space, an alternating electromagnetic field appears in a very wide frequency range. These electromagnetic oscillations are sensed by antenna 1 and are fed to matching device 3, which is designed to match the high output impedance of antenna 1 with the input resistances of channels 4, 5, 6. Each of the three parallel channels 4, 5, 6 operates in the desired frequency range. Channel 4 using filter 7 is sensitive to very low frequency electromagnetic oscillations from 200 to 2000 Hz, which are fed to the input of filter 7 from a matching device 3. Further, these signals are detected so that the signal at channel 4’s output appears as in positive, and with negative impulses arriving at its input. From the output of the detector 8, signals arrive at the amplifier 9, and if their amplitude exceeds a predetermined level, then a signal appears at the input of the threshold device 10, which acts on the first input of the coincidence circuit 19. Channel 5 is similar in structure to channel 4, but its filter 11 skips higher frequencies from 5 to 10 kHz. From the output of channel 5, the signal arrives at the second input of the coincidence circuit 19. Filter 15 of channel 6 has a resonant frequency of 465 kHz, which is used as an intermediate frequency in broadcast receivers. Otherwise, the construction of channel 6 is similar to the construction of channels 4, 5. From the output of channel 6, the signal arrives at the third input of the coincidence circuit 19; In the event that a thunderstorm discharge occurs from the cloud to the earth, the outputs of the channels 4, 5, 6 simultaneously generate pulses, which leads to the appearance of a signal at the output of the coincidence circuit 19, which noctynacT on the pulse spreading circuit 20. The pulse expansion circuit 20 is designed to generate a pulse with a duration of 1 s, which eliminates the registration of a multi-component lightning discharge in the form of several pulses. From the output of the expander 20, the signal is fed to the amplifier 21, and, amplifying to the required level, is fed to the input of the recording device 22. Since the spectral density of the electromagnetic field caused by inter-cloud lightning discharges and no lightning-like interferences, has its own characteristics compared to the spectral the density of thunderstorm cloud-ground discharges, inter-cloud thunderstorm discharges and no-thunderstorm interferences can not simultaneously lead to the appearance of signals at 4, 5, 6 channel passes. However, the coincidence circuit 19 does not work and the indicated signals will not be registered. To check the device's operability, the control device 2 serves, which, when triggered, supplies the input of the matching device 3 with a pulse corresponding in shape and frequency spectrum to those pulses that are actually induced in the antenna during lightning discharges cloud-ground. The presence of three parallel channels, each of which contains a filter with its own frequency response, a detector, an amplifier and a threshold device, and the operation of these three channels on a single coincidence circuit leads to an improved selection of ground bits, increasing the noise immunity of the device due to the most complete using the features of the spectral density of thunderstorm cloud-to-ground discharges. The frequency characteristics and sensitivities of channels 4, 5, 6 are selected in such a way that with lightning discharges the cloud - the earth within a radius of several tens of kilometers at the outputs of channels 5, 4, 6 are simultaneously signals. This leads to the triggering of the coincidence circuit 19 and the registration of the specified bits. In case of intercloud lightning discharges, signals at the output of channel 4 (0.2–2 kHz) and at the output of channel 6 (465 kHz) are possible; such discharges will not be recorded. From industrial noise, signals can appear at the output of channel 4 and channel 5 (5-10 kHz), since, as a rule, the maximum spectral density of such interference lies at low frequencies. Such signals in the proposed device will also not be recorded. Claims device for recording lightning discharges comprising an antenna, a filter, a threshold device, a pulse expander and a recorder connected in series, characterized in that, in order to improve noise immunity and improve the selection of ground bits, the threshold threshold device is connected in parallel similar chains, each of which contains a filter and a threshold device, as well as a matching device and a matching circuit included the first at the input and the second at you during the course of three parallel circuits, whose passbands are chosen different, but lying in the frequency spectrum, characteristic of ground-based discharges. Sources of information taken into account in the examination: 1. Auth. swith № 138078, M. CL. G 01W 1/00, 1960. 2. W. W. Seemuller and F. H. Segel. Amodern lightning discharge counter Journal of Applied Meteorology, 1968, 7, No. 4, p. 679-683. 3. S. A. Prentice. Compteur de coups de fourde CIGRE Electra, 1972, No. 22, p. 149-171 (prototype).