SU1277415A1 - Device for searching noise-like signal - Google Patents

Abstract

The invention relates to telecommunications. The purpose of the invention is to improve noise immunity. The device contains two mixers 1 and 6, a 2-frequency synthesizer, a narrow-band filter 3, an adjustable amplifier 4, a block 5 time compression of the signal (BXC), correlators 7, a generator of 8 copies of the input signal, block 9 of the selection of the maximum signal, the threshold block 10, an amplitude detector 11, an integrator 12, a storage unit 13, two phase detectors 14 and 15, a phase shifter 16, a discrete analogue delay line 17 (DALZ), a minimum value signal analyzer 18 and a voltage dividing unit 19. The input spectrum information is read from DALZ 17 and divided into BDN 19 by the minimum spectral density obtained in analyzer 18. The output voltage of BDN 19 is controlled by the gain of amplifier 4. At the time a narrowband interference occurs in filter passband 3 the gain of amplifier 4 is reduced by a factor of ft, where | U is the ratio of the interference power spectral density to the desired signal. The detected narrowband interference is suppressed using amplifier 4 and is not passed to mixer 6. The goal is achieved by introducing amplifier, detector 11, integrator 12, storage unit 13, DALZ 17, analyzer 18, and BDN 19. Examples are given to accomplish BVCS 5 and correlators 7 2 z. P. f-ly, 3 ill. "Lt-fn (L ka 4 cl ai.t

Description

The invention relates to telecommunications and can be used in broadband radio communication systems to search for a noise-like signal.

The purpose of the invention is to improve noise immunity.

Figure 1 shows the structural electrical circuit of the device for searching for a noise-like signal; Fig. 2 is a structural electrical block diagram of a time signal compression; FIG. 3 are timing diagrams explaining the operation of the device for searching for a noise-like signal.

The device for searching for a noise-like signal contains the first mixer 1, a synthesizer 2 frequencies, a narrowband filter 3, an adjustable amplifier 4, a block 5 for time compression of the signal, a second mixer 6, correlators 7, an generator of 8 copies of the input signal, a block 9 for selecting the maximum signal, a threshold block 10, amplitude detector 11, integrator 12, storage unit 13, first and second phase detectors 14 and 15, phase shifter 16, discrete-analog delay line 17 (DALS), minimum value signal analyzer 18, voltage dividing unit 19.

The correlating tori 7 contain the first and second multipliers 20 and 21, the first and second integrators 22 and 23, the shaper 14 of the signal of the sum of squares of voltages.

The time signal compression unit 5 contains a reference oscillator 25, a first frequency divider 26, a write counter 27, a second frequency divider 2B, an analog-digital converter 29, a first switch 30, a digital-analog frequency converter 32, a second and third switches 32 and 33 , the first and second operational storage units 34 and 35, the counter of 36 address readings, the third and fourth dividers 37 and 38, the counter 39 pulses.

The device for searching for a noise-like signal operates as follows.

The input signal is in the form of a mixture x (s) of the desired signal and interference at the intermediate frequency c, which is

f (2k + 1) F ,,

 where F is the clock frequency of the noise-like signal,, 1,2,3 ..., is fed to the input of the block 5 time compression. In block 5 for time compression, the signal is rectified with a frequency, and successive sections of messages are filled with the duration (Fig. 3a)

Tj, 4 (N + n) / F3, where N is the length of the transmitted random

sequences; n is the number of correlators 7.

The first 4N samples of each message segment are read 2t times with a frequency F where, and over time samples of the input signal x (t) that are compressed in time are reconstructed 2 times

 (Fig.Z, D).

MF

The output signal of the time compression unit 5 is fed to the first mixer 1, where it is mixed with the output signal of a 2 frequency synthesizer with a stepwise varying frequency value (Fig. 3b). The step of changing the frequency of the synthesizer is 2 frequencies

and the number of frequencies is m.

First mixer output

I is filtered by narrow-band filter 3. The square of the output envelope of the narrow-band filter 3 comes from the output of the amplitude detector

II integrator 12. Reset pulses for integrator 12 are formed by a block 5 of time compression and have

follow-up period equal to the duration of the compressed input signal. The integrator 12 accumulates the energy of frequency components (FIG. 3b), which are stored by the storage unit 13 (FIG. 3 and read from it to the discrete-analog delay line 17 and the analyzer 18. The minimum frequency components are selected in the analyzer 18 (FIG. 3 |). In

DALZ 17 sweep spectrum

input signal (fig.Zi). I

The whole process of reading information from the temporary compression unit 5 is divided into two stages (Fig. 3d).

At the first stage of analyzing the spectrum of the input signal, the correlators 7 are in the initial state. In this mode, the energy of the frequency components of the input signal is measured and selected

their minimum value. In the processing mode (Fig. 3g) of the input signal, the energies of the spectral components are compared with the minimum

level. Depending on the result of the comparison, the spectral components are processed or not processed in the correlators 7. To do this, the spectrum information is read from DALZ 17 (FIG. 3) and is divided in block 19 into 1 and the minimum level of spectral density obtained in the analyzer 18. The output the voltage of the dividing unit 1 controls the gain of the controlled amplifier 4. When a narrowband interference hits the passband of the narrowband filter 3, the gain of the adjustable amplifier 4 decreases by K times where (- from Observation of the power spectral density of the interference and the desired signal. Thus, the detected narrowband interference is suppressed by adjustable amplifier 4 and not passed to the second mixer 6. If there is no narrowband interference in the input signal spectrum, the gain of the controlled amplifier 6 remains unchanged and the signal from the output of the narrowband filter 3 is unchanged at the input of the second mixer 6, where it is mixed with the output signal of the 2 frequency synthesizer.

Thus, at each mixing of the compressed input segment, the output of the second mixer 6 allocates one of its frequency components, which is fed to the information inputs of the first and second phase detectors 14 and 15. The reference input of the first phase detector 14 is fed to the reference input of the first phase detector The SRC SRC output of the block 5 is temporary compression, and to the reference input of the second phase detector. The a15 - oscillations shifted by 90 ° in the phase shifter 16.

The demodulated frequency components from the outputs of the first and second phase detectors 14 and 15 are fed to the inputs of the correlators 7, each of which consists of two channels containing multipliers 20 and 21, integrators 22 and 23, and a driver 24. On the second inputs of multipliers 20 and 21 copies of a pseudo-random sequence from generator 8 with a clock frequency of F / 4. The installation inputs of the integrators 22 and 23 and at the same time the analyzer 18 receives a signal from block 5 time

j 0 5 about 5

5 0 5

five

Lb4

 compression (fig.Zg). The signal for synchronization of the generator 8 (Fig.), Which serves to link in phase the generated sequence with the readable signal, is also a reset signal for the analyzer 18.

In integrators 7, the resulting values of the correlation convolutions of the reference signal (Fig. 3) with all frequency components of the input signal, which are equivalent to the convolution of the reference signal with the input signal (Fig. 3m), accumulate. The squares of the output signals of the integrators 7 are added to the imaging unit 24 and fed to the selection unit 9, where they are compared with each other and the maximum one is compared with the threshold in the threshold unit 10. If the maximum signal of the correlators 7 exceeds the threshold, then the device for searching the noise-like The signal goes to the mode of adjustment and reception of information. The phase of the signal is determined in this case by the moment of the beginning of the recording of the next segment of the input signal (FIG. 3) and the number of the correlator 7 with the maximum value of the convolution.

Block 5 temporary compression (Fig, 2) works as follows.

A noise-like input signal with a spectral width, inputted to an analog-digital converter 29, is digitized and recorded in the first or second operational storage units (RAM) 34 and 35.

The sampling rate is chosen in accordance with the Kotelnikov theorem and is equal to. A sampling frequency is formed by dividing the frequency of the reference oscillator 25 in the first divider 26 by E. The continuity of signal processing is ensured by the two-step organization of the operation of the RAMs 34 and 35.

At that time, 5 when samples of the next message segment are stored in RAM 34, from RAM 35 you have read out-. Borki of the previous segment and vice versa.

To ensure the operation of the RAM 34 and 35 counters 27 and 36 are formed

A-A write and read addresses.

Moreover, counter 27 reads yes the numbers 4 (N + n), and counter 36 reads up to the number 4N. The transfer signal of the counter 27, divided by two in the second divider 28, is the control pulse of the write-read modes for the RAM 34 and

35. At the same time, the transfer signal of counter 27 serves to install correlators 7, enables the analyzer 18 to work, synchronizes counter 36, counter 39 per ton, and the third divider 37 by two. The transfer signal of the counter 39, divided into two in the third divider 37, is used to set up the analyzer 18 and to synchronize the generator 8.

The second and third switches 32 and 33, controlled by the direct and inverse write-read signals, serve to switch the write and read addresses, as well as the memory selection signals. The signals read from RAM 34 and 35 through the first switch 30 are fed to a digital-to-analog converter 31, where they are converted to analog form. The time compression unit 5 generates a signal by dividing the signal of the reference generator 25 by 4 in the fourth divider 38.

Claims (3)

The invention relates to telecommunications and can be used in broadband radio communication systems to search for a noise-like signal. The purpose of the invention is to improve noise immunity. Figure 1 shows the structural electrical circuit of the device for searching for a noise-like signal; Fig. 2 is a structural electrical block diagram of a time signal compression; Fig. 3 shows timing diagrams explaining the operation of a device for searching a noise-like signal. The device for searching a noise-like signal contains the first mixer 1, 2 frequency synthesizer, narrowband filter 3, adjustable amplifier 4, block 5, time compression of the signal, second mixer 6, correl tori 7, generator 8 copies of the input signal, block 9 for selecting the maximum signal, threshold unit 10, amplitude detector 11, integrator 12, storage unit 13, first and second phase detectors 14 and 15, phase shifter 16 discrete-analogue line 17 rzhki (DALZ), the minimum signal value analyzer 18, voltage dividing unit 19. The correlating tori 7 contain the first and second multipliers 20 and 21, the first and second integrators 22 and 23, the shaper 14 of the signal of the sum of squares of voltages. The time signal compression unit 5 contains a reference oscillator 25, a first frequency divider 26, a write counter 27, a second frequency divider 2, an analog-digital converter 29, a first switch 30, a digital analog frequency converter 32, a second and third switch 32 and 33, the first and second operational storage units 34 and 35, the read address counter 36, the third and fourth dividers 37 and 38, the pulse counter 39. The device for searching for a noise-like signal operates as follows. The input signal is in the form of a mixture x (s) of the useful signal and interference at the intermediate frequency η constituting f (2k + 1) F, where F is the clock frequency of the noise-like signal,, 1,2,3 ..., is fed to the input block 5 temporary compression. In block 5 for time compression, the signal is sampled at a frequency, and successive sections of messages are filled with the duration (Fig. 3a) Tj, 4 (N + n) / F3, where N is the length of the transmitted random sequence; n is the number of correlators 7. The first 4N samples of each message segment are read 2m times with frequency F, where, and time-compressed segments of input signal x (t) of duration (Fig. 3, D) are restored 2 times. The output signal of the time compression unit 5 is fed to the first mixer 1, where it is mixed with the output signal of the frequency synthesizer 2 with a stepwise varying frequency value (Fig. 3b). The step of changing the frequency of the synthesizer 2 frequencies is equal to the number of frequencies equal to t. The output signal of the first mixer I is filtered by narrowband filter 3. The square of the envelope of the output signal of the narrow-band filter 3 comes from the output of the amplitude detector II integrator 12. The reset pulses for the integrator 12 are formed by block 5 time compression and have a follow-up period equal to the duration of the compressed input signal. The integrator 12 accumulates the energy of frequency components (FIG. 3b), which are stored by the storage unit 13 (FIG. 3 and read from it to the discrete-analog delay line 17 and the analyzer 18. The minimum frequency components are selected in the analyzer 18 (FIG. 3 |). In DALZ 17, an input spectrum sweep is formed (Fig. 3i). The whole process of reading information from time compression unit 5 is divided into two stages (Fig. 3g). At the first stage of analyzing the input signal spectrum, the correlators 7 are in the initial state. This mode measures the energy components of the input signal and selects their minimum value. In the processing mode (Fig. 3g) of the input signal, the energies of the spectral components are compared with the minimum level. Depending on the comparison result, the spectral components are processed or not processed in the correlion toros 7. For this, the information about the spectrum is read from the DALZ 17 of FIG. 3N) and is divided in block 19 into a minimum level of the spectral density obtained in the analyzer 18. The output voltage is and dividing controls the gain controlled amplifier 4. When the coefficient of narrowband ingress noise in the passband of the narrowband filter 3 the gain controlled amplifier 4 is reduced by K times, where (- ratio of power spectral density of interference and the useful signal. Thus, the detected narrowband interference is suppressed by adjustable amplifier 4 and not passed to the second mixer 6. If there is no narrowband interference in the input signal spectrum, the gain of controlled amplifier 6 remains unchanged, and the signal from the output of narrowband filter 3 without the changes are fed to the input of the second mixer 6 where it is mixed with the output signal of a 2 frequency synthesizer. Thus, at each mixing of the compressed input segment, the output of the second mixer 6 allocates one of its frequency components, which is fed to the information inputs of the first and second phase detectors 14 and 15. The reference input of the first phase detector 14 is fed to the reference input of the first phase detector The RC RMS of the output of the block 5 is a time compression, and the input of the second phase detector is on the reference. 15 oscillation shifted by 90 ° in the phase shifter 16. Demodulated frequency components from the outputs of the first and second phase The corpors 14 and 15 are fed to the inputs of the correlators 7, each of which consists of two channels containing multipliers 20 and 21, integrators 22 and 23, and driver 24. Copies of a pseudo-random sequence from the generator 8 with a clock frequency F are received at the second inputs of the multipliers 20 and 21. /four. The installation inputs of the integrators 22 and 23 and at the same time the analyzer 18 receive a signal from the block 5 time compression 1b4 (Fig. 3g). The signal for synchronization of the generator 8 (Fig.), Which serves to link in phase the generated sequence with the read signal, is also a reset signal for the analyzer 18. In the integrators 7, the resulting values of the correlation convolutions of the reference signal (Fig. Zl) with all frequency input signal components, which are equivalent to the convolution of the reference signal with the input signal (Fig. 3m). The squares of the output signals of the integrators 7 are added to the imaging unit 24 and fed to the selection unit 9, where they are compared with each other and the maximum one is compared with the threshold in the threshold unit 10. If the maximum signal of the correlators 7 exceeds the threshold, then the device for searching the noise-like The signal goes to the mode of adjustment and reception of information. The phase of the signal is determined in this case by the moment of the beginning of the recording of the next segment of the input signal (FIG. 3) and the number of the correlator 7 with the maximum value of the convolution. Block 5 temporary compression (Fig, 2) works as follows. An input noise-like signal with a spectrum width, input to the analog-digital converter 29, is digitized and recorded in the first or second operational storage units (RAM) 34 and 35. The sampling frequency is selected in accordance with the Kotelnikov theorem and is equal to. The sampling frequency is formed by dividing the frequency of the reference generator 25 in the first divider 26 by E. The continuity of signal processing is ensured by the two-stroke organization of the operation of RAM 34 and 35. At that time 5, when RAM 34 stores samples of the next message segment, RAM 35 reads you-. Borki of the previous segment and vice versa. To ensure the operation of RAM 34 and 35, the counters 27 and 36 form the write and read addresses A-A. Moreover, counter 27 reads yes the numbers 4 (N + n), and counter 36 reads up to the number 4N. The transfer signal of the counter 27 divided into two in the second divider 28 is the control pulse of the write-read modes for RAM 34 and 35. At the same time, the transfer signal of the counter 27 serves to set the correlators 7, enables the analyzer 18, synchronizes the counter 36, the counter chick 39 per ton, the third divider 37 into two. The transfer signal of the counter 39, divided into two in the third divider 37, serves to set up the analyzer 18 and to synchronize the generator 8. To switch the write and read addresses, as well as the signals for selecting the memory cells serve the second and third switches 32 and 33, controlled by mym and inverse signal Record. The signals read from RAM 34 and 35 through the first switch 30 are fed to a digital-to-analog converter 31, where they are converted to analog form. The time compression unit 5 generates a signal by dividing the signal of the reference generator 25 by 4 in the fourth divider 38. Claim 1. An apparatus for searching for a noise-like signal comprising serially connected temporal signal compression unit, first mixer and narrowband filter, serially connected frequency synthesizer, second mixer and a first phase detector, a serially connected maximum signal selection unit and a threshold unit, a serially connected phase shifter and a second phase de The vector, as well as the generator of copies of the input signal and the correlators whose reference inputs are connected to the corresponding outputs of the generator of the copies of the input signal, the combined first information inputs and the combined second information inputs of the correlators are connected respectively to the outputs of the first and second phase detectors, the outputs of the correlators connected to the corresponding inputs of the signal maximum selection block, the reference output of the signal time compression block is connected to the reference inputs of the generator of copies of the input signal, the first phase detector and the phase shifter input, the first controlling: the outputs of the signal time compression unit are connected to the corresponding inputs of the frequency synthesizer, the output of which is connected to the reference input of the first mixer, the second control output of the signal time compression unit is connected to the installation input of the input signal copy generator , and the output of the second mixer is connected to the information input of the second phase detector, with the input of the time compression unit being the input of the device, and the second The output of the maximum signal selector and the output of the threshold block are respectively the outputs of the channel number and the presence of a device signal, characterized in that, in order to improve noise immunity, serially connected amplitude detector, integrator, storage unit, discrete analog delay line, block dividing voltage and an adjustable amplifier, as well as a signal analyzer by the maximum value, while the output of the narrow-band filter is connected to the input of the amplitude detector and information This input of an adjustable amplifier, the output of which is connected to the information input of the second mixer, the first additional control output of the temporal signal compression unit is connected to: the Reset input of the integrator and the control inputs of the storage unit and the discrete-analog delay lines, the second additional control output of the time compression unit The signal is connected to the combined inputs. Reset correlators and the input. Permission to record the signal analyzer by the minimum value, information and installation th inputs of which are respectively connected to the output of the memory block and the second interim tucking yuschemu output signal compression unit and the signal output analyzer of the minimum value is connected to the control input of the voltage dividing. 2. The device according to claim 1, about tl and the fact that the block of time compression of the signal is made in the form of a series-connected reference oscillator, the first frequency divider, the write address counter, the second frequency divider, the first switch and the digital-analog converter, the second the switch and the first operative storage unit, connected in series by the third switch and the second operative 712774 a memory unit, serially connected readout address counters, pulse counters and the third frequency eliminator, as well as an analog-to-digital converter and a fourth frequency divider, the clock input of which is combined with the clock inputs of the read address counter, the second and third switches and connected to the output of the reference generator Yu torus, the output of the first frequency divider is connected to the additional clock inputs of the second and third switches and to the clock input of the analog-digital converter, the outputs 15 of which are They are connected to the corresponding information inputs of the first and second operational storage blocks, the outputs of which are connected to the corresponding information inputs of the first switch, the address outputs of the write address counter are connected to the corresponding information inputs of the second and third switches, 25 additional information inputs address outputs of the read address counter, transfer output of the write address counter is connected to the installation inputs of the read address counter, t Vani, a pulse counter, third, and fourth frequency dividers, a direct output of the second frequency divider is connected to the control inputs of the first operational memory unit, and the second switch, the second inverse output of the frequency divider is connected to the control inputs of the second random access memory unit and 158 the third switch, the analog-to-digital converter input is the input of the signal time compression unit, the output of the digital-to-analog converter and the outputs of the pulse counter bits are respectively the information output and control outputs of the signal time compression unit, the transfer output of the readout address counter and the direct output of the second frequency divider is the first, second and third additional control outputs of the time-frame unit, respectively. these signals, and the fourth frequency divider output is a reference output signal compression time unit. 3. The device according to claim 1, characterized in that the correlator is made in the form of two channels, each of which contains a series-connected multiplier and an integrator, as well as a signal generator of the sum of squares of voltages, the first and second inputs of which are connected to the outputs of the integrators the first inputs of the multipliers are respectively the first and second information inputs of the correlator, the combined second inputs of the multipliers are the reference input of the correlator, the combined setup inputs of the integrators are the setup input of the correlator, and the output of the sum-of-squares voltage driver is the output of the correlator. U /// 7 /////////////// 7 7 /////////////// // /// L  I I ... t ...... (... | ... | I | ... 1 ... | .1-1-1 I at I i i. I I I I | ... 1 ... | ... | I i Ana / ius / l4 / iVU ... and. KL i 1 i i i i n cztrrm I I I m Treatment R .З