SU1522421A1 - Device for receiving discrete information - Google Patents

Abstract

The invention relates to radio engineering and can be used in broadband discrete information exchange systems. In order to improve noise immunity with respect to impulse noise, two controlled multi-tap radio-frequency delay lines (LZ) 3, 4, two multi-pass radio-frequency summing blocks (SB) 5,6, two controlled multi-pass video LZ 9, 10, two multi-input video SB 11, 12, controlled LZ 14, expander 16 pulses, multipath LZ 17, key blocks 18, peak detectors 19, drivers of 20 standard signals and block 21 of the calculation of controlled signals. The device is designed to receive complex noise-like signals that have the effect of temporary shortening (squeezing) in matched filters. The impulse noise suppression mechanism consists in purposefully combining the dips in the response of the radio frequency part of the receiver to the effect of impulse noise with the moments of the components of the useful signal. 2 Il.

Description

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The invention relates to radio engineering and can be used in broadband discrete information exchange systems.

The purpose of the invention is to increase the noise immunity with respect to impulse noise.

FIG. 1 shows a structural electrical circuit of the proposed device; in fig. 2 - time diagrams that show his work.

The device for receiving discrete information contains the first 1 and second 2 matched filters, the first 3 and second 4 control multi-tap radio-frequency delay lines, the first 5 and the second 6 multi-pass radio frequency summation blocks, the first 7. And the second 8 linear envelope detectors, the first 9 and second 10 controlled multi-tap video frequency delay lines, the first 11 and second 12 multi-input video frequency summation blocks 11 and 12, the decisive block 13, the controlled delay line 14, 15 clock pulse generator ;, the pulse extender 16 Sov, a delayed multiplex line 17, key blocks 18, peak detectors 19, standard signal formers 20, and a control signal computation block 21.

The device works as follows.

This device is designed to receive complex noise-like signals (PSS), which have the effect of temporary shortening (squeezing) in matched filters. This circumstance allows setting the delay time between the taps of the controlled multi-drop lines 3 and .4 delays much shorter than the duration of the original PSS carrying useful information.

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The reaction form has dips (knots) and bursts (antinodes) in time.

Thus, the impulse noise suppression mechanism consists in purposefully combining the dips in the response of the radio frequency part of the receiver to the effect of the impulse disturbance with the moments of existence of the components of the useful signal.

By impulse noise, I mean a short (significantly less than the signal duration) radio pulse with a random initial phase. Moreover, in order to effectively adapt to impulse noise, their regularity in time is required or, at least, changes in their temporal position must be defined in some way, correlated with time on the measurement and computational procedures when the entire device for receiving discrete information is rearranged.

Consider the operation of a device for the particular case of the presence of two taps () in controlled radio and video frequency delay lines, the carriers of the binary information elements being broadband signals based on linear frequency modulation (LFM), the information unit is displayed by the chirp signal with a growing law frequency changes within the duration of a message, and information zero is the same signal, but with a decreasing (decreasing) law of frequency change.

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Let the receiving device be in synchronism and at some point in time at its input a signal is received in a mixture with impulse noise, matched with the matched filter 1 (see Fig. 2a, the desired signal

formation. As a result, the response is horizontally horizontal, and the impulse noise is vertical hatching). At the output of the matched filter 1, the useful signal is compressed in time, and the impulse noise, on the contrary, stretches in time, which is the impulse response of the filter (see Fig. 26). At the same time, the signal with the disturbance goes to the second information inputs key blocks 18. The threshold voltages of the key blocks 18 are set from the condition of reliable detection of impulse noise and are determined from the ratio of the power of the useful signal and the noise.

The impulse noise filters 1 and 2 overlap in time at the outputs of the corresponding multi-input radio frequency summing blocks 5 and 6. It has been established that the form of the resulting response of the receiver (its radio frequency part) to the impulse noise effect depends on the time delay between the taps of the controlled radio frequency delay lines 3 and 4), which are controlled automatically by signals (commands) from the control calculation unit 21. signals.

horizontal and pulse interference by vertical hatching). At the output of the matched filter 1, the useful signal is compressed in time, and the impulse noise, on the contrary, stretches in time, which is the impulse response of the filter (see Fig. 26). At the same time, the signal with the disturbance goes to the second information inputs key blocks 18. The threshold voltages of key blocks 18 are determined from the condition of reliable detection of impulse noise and are determined from the ratio of the power of the useful signal and interference.

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The signal from the generator of 15 clock pulses, corresponding to the end (count) of the previous information symbol and at the same time the beginning of the next information symbol, according to cTjnaaeT to the pulse expander, and from the output of the last to the input line 17 delay. The pulse expansion time in the pulse expander 16 is determined by the required accuracy of determining the location of the pulse interference in the signal duration limits and, accordingly, by the number of time channels (time gates) of the analysis of pulse interference. The delay time between the taps of the delay line 17 is equal to the duration of the extended pulse.

Thus, in order to view all the temporary positions of the signal, to determine the location of the impulse noise it is necessary to have M analysis channels: (../tft, where 1 s is the duration

the desired signal, and t p is the pulse duration at the expander output. From the output of the delay line 17 (from its taps, the pulses go to the first control inputs of the corresponding key blocks 18. As a result, signals appear at the output of those key blocks 18 in which a temporary coincidence of the pulse interference and the temporary strobe from line 17 occurs. delays: From the outputs of the key blocks, the 18 signals go to the corresponding peak detectors 19, which have the ability to quickly accumulate the input voltage, and then to the corresponding - formers of 20 standard signals that are asymmetric Schmitt triggers. The Schmitt triggers whose voltages will be present will be switched.

Thus, the potential state diagram of Schmitt triggers, enclosed in their output voltages, displays the pulsed disturbance environment, which is further described in block 21 of the calculation of control signals.

At the output of block 21, a signal is generated that corresponds to the optimal value of the delay time t between the taps of the controlled delay lines 3, 4, 9, 10 and 14, at which the response to impulse noise has a minimum power at the moments of the information symbols

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those which provide the best conditions for receiving discrete information. The mixture of the signal with noise at the output of the radio frequency link, which is a serial connection of the controlled radio frequency delay line 3 and the radio frequency summing unit 5, has the form shown in FIG. 2c. Here, the useful signal is represented as two pulses, since, as an example, a delay line of 3 is taken, and the response to pulsed interference is in the form of an amplitude-modulated signal as a result of the addition of two chirped signals that are blocked in time. From the diagram of FIG. 2c, it follows that the components of the useful signal are combined with dips in response to pulse interference.

From the output of the radio frequency summing unit 5, the signal is fed to the input of the linear envelope detector 7, the mixture of the signal with interference at the output of which is shown in FIG. 2g.

Next, the signal arrives; to a video frequency link, which is a serial connection of a controlled video frequency delay line 9 and a video frequency summing unit II.

FIG. 2D shows a diagram of a mixture of a signal with noise on the second (delaying) tap of the delay line 9.

The signal at the output of summing unit 11 is an algebraic sum of signals taken from the taps of the delay line 9 and is shown in FIG. 2nd.

Under the condition that the receiving device is in synchronism, when the clock pulse from the generator of 15 clock pulses corresponds to the maximum of the useful signal, the signal at the output of the decision block 13 has the form shown in FIG. 2g (displays the received information symbol corresponding to the transmitted one). At the same time, only the response to the impulse noise passes through the second matched receiver channel. Moreover, its form and the location of the failures in it will be the same as that of the response to interference on the first agreed channel. As a result, at the time of reference of the information symbol, the interference on the second agreed channel can also be neglected.

Similarly, the device operates in the presence of a useful signal, consistent with the second channel of the receiver.

Claims (1)

Invention Formula Device for receiving discrete The information containing a clock pulse generator, the first and second linear envelope detectors, the decision block and the first and second matched filters, whose inputs are combined and are the input of the device, the output of which is the output of the decision block, characterized in that with respect to noise and interference, two controllable multi-tap radio-frequency delay lines, two multi-input radio-frequency summing blocks, two controllable multi-beam video-frequency delay lines were introduced and, two multi-input video summation blocks, controllable delay lines, pulse extender, multi-tap delay lines, key blocks, peak detectors, standard signal conditioners and a control signal calculation unit, the output of which is connected to the control input of a controlled line-H1-W delays, with the control inputs of the first and second controlled multi-tap video frequency delay lines, and with the control inputs of the first and second controlled multi-tap radio frequency delay lines, to the corresponding inputs of the first and second multi-input radio-frequency summing blocks, respectively, the outputs of which are connected These are connected to the inputs of the first and second, p6th linear envelope detectors, respectively, whose outputs are connected to the signal inputs of the first and second controlled multi-tap video delay lines, respectively, whose taps are connected to the corresponding inputs of the first and second multi-input video summation blocks, whose outputs are connected respectively to the first and the second inputs of the decision block, the third input of which is connected to the output of the controlled delay line, the signal input of which is connected to the output of A clock pulse generator and to the pulse expander input, the output of which is connected to the signal input of a multi-drop delay line, whose taps are connected to the first inputs of the corresponding key blocks, the outputs of which are connected to the inputs of the corresponding peak detectors, the outputs of which are through the corresponding standard signals I are connected to the corresponding inputs of the control signal calculation block, while the second inputs of the key blocks are combined and connected to the combined inputs of the first and second second matched filters, vkody which are connected to the signal, the inputs of the first and second RAKE actuated RF delay lines, the outputs of the first and secondary .rogo linear envelope detector connected to the signal inputs, respectively, and the second multi-input .First. video frequency summing units, and the outputs of the first and second matched filters are connected to. signal inputs of the first and second multi-input radio stations, respectively, of the summing.blocks. and g n t (rig 2