SU1455897A1 - Device for registering the basic level of pulsed signal - Google Patents

Abstract

The invention relates to geophysics, and more specifically to logging information-measuring systems, such as gamma spectrometry, operating with pulsed neutron radiators. The purpose of the invention is to improve accuracy. The device contains a coupling capacitor, one output of which is the device input, an amplifier, a delay unit, a common bus, differentiating and integrating capacitors, an operational amplifier, a controllable two-pole switch with closable and openable contacts, a sampling-storage unit, a control pulse driver, the first and The second terminals of which are the digital outputs of the device, the output unit, the first and second terminals of which are the analog outputs of the device, the first, second and third resistors, as well as vuhstoronny limiter and a high pass filter having an input connected to the output of the amplifier, and output - with an input of control pulses. The first output of the double-sided limiter is connected to the output of the operational amplifier, and the second to the second output of the integrating capacitor, the first output of the second resistor, the openable contact of the two-pole switch and the input of the output unit. The output of the delay unit is connected to the first output of the differentiating capacitor, and the inverting input of the operational amplifier is connected to the first output of the integrating capacitor and the input of a two-pole switch, the closure contact of which is connected via a third resistor to the output of the storage sampling unit. The device predicts the interference acting during the passage of the information pulse, and subtracts the value of the interference from the resulting signal. This increases the speed of the device and eliminates the time lag of the interference parameters, which improves the accuracy of fixing the base level of the pulse signal. 1 il.

Description

The invention relates to geophysics, and more specifically to logging information-measuring systems, such as gamma-spectrometry.

working with pulsed neutron emitters.

The purpose of the invention is to increase accuracy.

The drawing shows the block diagram of the device.

Device contains input bus 1, splitter 2, differentiating 3 and integrating 4 capacitors, first 5, second 6 and third 7 resistors, amplifier 3, delay unit 9, high pass filter 10, operating amplifier 11, two-way limiter 12, bipolar controlled key 13, the sampling-storage unit | 14, the control pulse driver 15, the output unit 16, the digital outputs 17, J8 and the analog outputs J19 and 20.

The device works as follows.

3, the absence of information pulses, a bipolar controlled 1 KEYCH 13, is in the position shown in the diagram. Passing through the coupling capacitor 2, the interference signal is extracted at the first resistor 3 (matching), amplified by the amplifier 8, delayed in the delay unit 9 and fed to the differentiating capacitor 3. In the position of the bipolar controlled key 13,} the resistor 6 is connected to the negative circuit; the feedback of the operational amplifier 11. The voltage proportional to the derivative of the interference signal, with the opposite sign, is separated on the second resistor 6 - at the output of the operational amplifier 11, and the input output The base unit 16 and, respectively, the analog outputs of the device 19 and 20 receives a zero potential. The latching speed of the base level is determined by the speed of the differential amplifier, which consists of a differentiating capacitor 3, the second resistor 6, the operational amplifier 1 1. Sample storage unit 14 is in Sample mode. The voltage at its output repeats the output signal of the operational amplifier 11 - the value of

ten

15

20

25

thirty

35

40

tea clutter. The lower limit of the passband of the high-pass filter 10 is chosen greater than the upper limit frequency of the interference spectrum, but less than the upper limit of the frequency spectrum of the information pulse signal. The appearance of a signal at the output of the high-pass filter 10 indicates the appearance of an information voltage pulse at the device input. At the same time, at the third output of the control pulse generator 15, a positive pulse appears in duration slightly longer than the duration of the information pulse. At one of the digital outputs 17 or 18, an impulse of a channel characteristic occurs, depending on the polarity of the information pulses. Before the voltage pulse impulse 9 at the output of the voltage pulse (at time tg), the control pulse from the third output of the imaging unit 15 will switch the bipolar control key 13 to the opposite position shown in the diagram, and the sample-storage unit 14 will switch to the Storage mode, at the same time, voltage will be fixed at its output

45

and

m

- | p. “4g

t t

about

where indices 3, 6 resistance R and capacitance C correspond to the positions on

dUn pattern, -

UL

to prod value 0

water disturbance at time t

From this point on, the operational amplifier 11 with the integrating capacitor 4 in the feedback circuit becomes an integrator, and the voltage on the integrating capacitor 4 varies according to the law

and

ee

(t-tj - - -UXt-Tj (assuming R, Rp. where the subscripts 3, 4, 6, 7 of the elements R, C correspond to a pozivodnoe interference signal with the opposite sign on the circuit, U is the amplitude of the pulse signal.

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During the passage of the information pulse, the frequency spectra of the signal and interference overlap, however, the limiting frequency of the spectrum of the information pulse signal is above the upper limit of the frequency spectrum of the quasisynominal wave and continuous

Subtracting the sum of the signal plus the interference of the predicted value of the interference allows it to be almost fully compensated. Bilateral limiter 12 prevents overloading of the op amp P at the time of the passage of the information

0

five

0

five

0

tea clutter. The lower limit of the passband of the high-pass filter 10 is chosen greater than the upper limit frequency of the interference spectrum, but less than the upper limit of the frequency spectrum of the information pulse signal. The appearance of a signal at the output of the high-pass filter 10 indicates the appearance of an information voltage pulse at the device input. At the same time, at the third output of the control pulse generator 15, a positive pulse appears in duration slightly longer than the duration of the information pulse. At one of the digital outputs 17 or 18, an impulse of a channel characteristic occurs, depending on the polarity of the information pulses. Before the voltage pulse impulse 9 at the output of the voltage pulse (at time tg), the control pulse from the third output of the imaging unit 15 will switch the bipolar control key 13 to the opposite position shown in the diagram, and the sample-storage unit 14 will switch to the Storage mode, at the same time, a voltage will be fixed at its output

- | p. “4g

t t

about

35

where indices 3, 6 resistance R and capacitance C correspond to the positions on

dUn -

UL

to meaning

0

water disturbance at time t

From this point on, the operational amplifier 11 with the integrating capacitor 4 in the feedback circuit becomes an integrator, and the voltage on the integrating capacitor 4 varies according to the law

and

ee

(t-tj - - -UXt-Tj (assuming R, Rp. where the subscripts 3, 4, 6, 7 of the elements R, C correspond to the position

Subtracting the sum of the signal plus the interference of the predicted value of the interference allows it to be almost fully compensated. Bilateral limiter 12 prevents overloading of the op amp P at the time of the passage of the information

momentum. After the pulse has passed, the bipolar control key 13 and the storage sampling unit J4 are switched to the initial states. The device, being in the mode of calculating the current value of the derivative of laughter, awaits the appearance of the next information pulse.

Claims (1)

Invention Formula A device for fixing a basic level of a pulse signal containing a coupling capacitor, the first output of which is the device input, an amplifier, a delay unit, a common bus, differentiating and integrating capacitors, an operational amplifier, a controlled double-pole switch with closable and openable contacts, a sampling-storage unit control pulse driver, the first and second outputs of which are input to the digital outputs of the device, the output unit, the first and second terminals of which are analog outputs device, the first, second and third resistors, with one output of the first resistor connected to the common bus, and the other output connected to the second output of the coupling capacitor and through an amplifier to the input of the delay unit, the third output for0 five 0 five 0 The pulse control world is connected to the control inputs of the bipolar key and the sample-storage unit, whose information input is connected to the second output of the second resistor and the output of the operational amplifier, the inverting input of which is connected to the second output of the differentiating capacitor, and the direct bus to the common bus so that, in order to increase accuracy, it contains a two-sided limiter and a high-pass filter, the input of which is connected to the output of the amplifier, and the output is connected to the input of the pulse former The first junction of the two-way limiter is connected to (the output of the operational amplifier, and the second to the second output of the integrating capacitor, the first output of the second resistor, the openable contact of the two-pole switch, and the input of the output unit; the output of the delay unit is connected to the first output of the differentiating capacitor and inverts the input of the operational amplifier is connected to the first output of the integrating capacitor and to the input of a bipolar switch, the closure contact of which is connected to the output th sampling-storage unit.