SU817642A1 - Device for electric geosurvey - Google Patents

Description

one

This invention relates to geoelectrical exploration.

Devices for inductive electrical prospecting are known, including a generator device and pulse converters of a measurable toric field, containing a receiving sensor, gating devices, a drive and a recorder 1.

 However, when measuring pulsed signals of one polarity, the elimination of constant signals in them is difficult.

The closest in technical essence is a device containing a current pulse generator, an ungrounded oscillator and a receiving circuit, a meter consisting of a serially connected strobe key of the output amplifier's pulse key, a drive, a DC amplifier with a converter, and a recorder 2.

The disadvantages of this device are low noise immunity, which is explained by the fact that when a large amplitude disturbance arrives at the meter input, the pulse amplifier becomes saturated and does not react to a change in the input signal. The output of the amplifier from the saturated state is accompanied by a long time, which may exceed the duration of the gating, in addition, the pulse amplifier is broadband, which degrades the signal-to-noise ratio, and ultimately leads to a decrease in measurement accuracy.

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The purpose of the invention is to improve the noise immunity of the device.

The goal is achieved by the fact that in the circuit containing the generator

5 current pulses connected to a generator sensor, a meter connected to a receiving sensor and including a strobe key, serially connected pulse amplifier, output key, storage drive, modulating key, amplifier and recorder for removing the pulse amplifier from the interfering signals, between the gate key and pulsed

5 with an amplifier; a preliminary accumulator and a key are additionally connected in series with each other.

Claims (2)

The drawing shows the block diagram of the device. The device for geoelectromagnetic exploration by the method of transient processes contains a generator 1 of current pulses, consisting of a control circuit 2, a switch 3, a source 4 of direct current, an ungrounded generator 5 and a receiving 6 sensors and a meter 7 consisting of serially connected gate key 8, preliminary accumulator 9 key 10, pulse amplifier 11, output key 12, accumulator 13, modulating key 14, amplifier 15 and registrator 16. The device operates as follows. The switch 3 connects the direct current source 4 to the generator sensor 5. In accordance with the control pulses coming from the output of the control circuit 2 to the input of the switch 3, switching pulses of current occur in the generator circuit, which are separated by a pause in time. During the pauses, the emf of the transient process of the second field, which occurs after disconnecting the generator sensor 5 from the source 4 of the direct current, is measured by the switch 3. The emf of the transient of the secondary field is induced in the receiving sensor 6. Depending on the time of the transient The gate key 8 connects the receiving sensor 6 to the preliminary drive 9, representing in addition to itself an integrating chain. Transient gating is performed at the moments of pulse arrival from control circuit 2 to the gate key 8. Control circuit 2 specifies the delay of the gate pulses and their number. In the preliminary accumulator 9, the potential is proportional to the number of gating pulses and the amplitude of the EMF of the transient process at a given time. After the end of the accumulation key, the pre-accumulator 9 is connected to the input of the pulse amplifier 11 The preliminary accumulation potential 9 is amplified by the pulse amplification 11 and through the output cell: oh 12 accumulates in the accumulator 13, the accumulation is repeated many times. Pos. At the end of the accumulation process, the potential accumulated in accumulator 13 is modulated by key 14, amplified by amplifier 15, and recorded by the recorder 16. The use of new elements of the preliminary accumulator and key distinguishes the proposed device from the known ones, since the impulse amplifier is saturated with interference signals. In addition, the introduction of a preliminary accumulator allows the bandwidth of the pulse amplifier to be narrowed. The narrowing of the passband of the pulse amplifier improves the signal-to-noise ratio. As a result, the noise immunity and, consequently, the accuracy of the measurement of the transient emf increases. The invention The device for geo-prospecting, consisting of a generator of current pulses connected to a generator sensor 4 meter connected to a receiving sensor and including a strobe key, sequentially connected pulse amplifier, output key, storage device, modulating key, amplifier and recorder, during which control The inputs of all switches are connected to the control output of the current pulse generator, characterized in that, in order to improve the noise immunity, a series of The included pre-accumulator and key are connected between the gate key and the pulse amplifier, and the control input of the key is connected to the control input of the output key. Sources of information taken into account in the examination of 1 .. Mizyuk L.Ya. Elements of the transistor circuits of measuring equipment for in-line electrical prospecting. Kiev, Naukova Dumka, 1970 pp. 253-256 2. USSR author's certificate No. 305437, cl. G 01 V 3/10, 1972 (prototype).