RU2202853C2 - Device for automatic scanning of radio station signals - Google Patents

Abstract

FIELD: radio engineering; radio supervisor monitoring centers. SUBSTANCE: device used for radio supervisor monitoring centers to analyze signal situation and to detect radio station signals permanently replacing operating frequencies has receiver, control signal shaper, reference frequency unit, signal detector incorporating analog-to- digital converter, digital frequency detector, instant frequency dispersion calculating unit, instant frequency standard dispersions bank, and instant frequency dispersion comparison unit. Signal detection depends on analyses of instant frequency dispersion of signal + noise mixture received, that is, on comparison of value found from instant frequency dispersion calculation unit and that of standard noise dispersion taken from standard instant frequency dispersions bank. EFFECT: enhanced probability of signal detection at varying level of mixture received and at frequent changes of operating frequencies detected by radio stations. 6 dwg

Description

 The invention relates to radio engineering and can be used in radio dispatch monitoring points for analysis of the signal situation and automatic detection of signals from radio stations that constantly change operating frequencies.

 A device for detecting and converting video signals (see USSR author's certificate 856024, class IPC N 04 B 3/46, 1981), containing a matching block, key, integrator, DC amplifier and limiter, the other input of which is connected with the output of the matching unit, as well as the first delay element and a peak detector, the output of which through the driver of the reference signal is connected to the first input of the comparison unit, the second input of which is connected to the output of the second delay element.

 A device is known for receiving tonal frequencies (see USSR author's certificate 1720171, class IPC H 04 Q 1/46, 1989), comprising a matching unit, a pulse shaper, a trigger shaper, a clock pulse generator, two counters, two I elements, two permanent storage units, two counters, an OR element, a register, a comparison unit.

 Also known is a device for the automatic search for radio channels (see USSR author's certificate 1515373, class IPC Н 04 В 1/10, 1989), containing a block of reference frequencies, a receiver, a signal converter, a register, a driver of control signals, a demultiplexer, K additional registers, multiplexer, indicator, distributor, comparison unit, initial installation unit.

 Analogs have a low probability of detection due to the use of a fixed energy threshold for deciding in favor of the presence of a signal in the received signal + noise mixture under conditions of inconsistent level of the received total signal.

 The closest in technical essence to the claimed device (prototype) is a device according to international application WO / 92/22147, class. H 04 V 1/40, comprising a receiver with automatic search for radio frequencies, a signal detector, a reference frequency generator, a driver of the control signal. The disadvantage of the prototype is the low probability of detecting a signal with frequent changes of the operating frequency observed by the radio station in conditions of inconsistency in the level of the received signal + noise mixture.

 An object of the invention is to increase the likelihood of detecting signals under conditions of inconsistent level of the received signal + noise mixture when operating frequencies are changed by the observed radio stations by introducing the connection of the low-frequency output of the radio receiver with the information input of the signal detector and the communication of the command output of the driver of control signals with the remote control input of the receiver and input initial setting "signal detector.

 The problem is solved in that in the device for automatic search for radio signals, containing a receiver, the output of the demodulated signal of which is connected to the information input of the signal detector, the command output of which is connected to the command input of the driver of control signals, the output of the signal of a fixed frequency code of which is connected to the control input of the reference block frequency, the output of which is connected to the heterodyne input of the receiver, the following connections are made: the low-frequency output of the receiver is connected to information to the input of the signal detector, the command output of the driver of the control signals is connected to the input of the remote control of the receiver and the input "initial setting" of the signal detector.

Moreover, the signal detector consists of an analog-to-digital converter, a digital frequency detector, an instantaneous frequency dispersion calculation unit, a bank of instantaneous frequency standard dispersions, and an instantaneous frequency dispersion comparison unit. The input of the analog-to-digital converter is the information input of the signal detector, to the output of which the input of the digital frequency detector is connected. The output of the digital frequency detector is connected to the input of the instantaneous variance dispersion calculation unit. The output of the dispersion calculation unit is connected to the first input of the instantaneous frequency dispersion comparison unit. The output of the bank of reference dispersions of instantaneous frequency, the input of which is the input of the "initial setting" of the signal detector, is connected to the second input of the dispersion comparison unit. The output of the instantaneous frequency dispersion comparison unit is the command output of the signal detector. The claimed device is illustrated by drawings, where
figure 1 is a General structural diagram of the claimed device;
figure 2 - diagram of the driver control signals;
figure 3 is a diagram of a digital frequency detector;
figure 4 - block diagram of the calculation of the variance of the instantaneous frequency;
5 is a diagram of a bank of reference dispersions of instantaneous frequency;
6 is a diagram of a unit for comparing variances of instantaneous frequencies.

The device contains (figure 1):
- receiver 1;
- signal detector 2;
- shaper control signals 3;
- block of reference frequencies 4.

 The signal detector 2 combines an analog-to-digital converter 5, a digital frequency detector 6, an instantaneous frequency dispersion calculation unit 7, an instantaneous reference frequency dispersion bank 8, an instantaneous frequency dispersion comparison unit 9.

 The low-frequency output 1.3 of receiver 1 is connected to the input 5.1 of the analog-to-digital converter 5. The output 5.2 of the analog-to-digital converter 5 is connected to the input 6.1 of the digital frequency detector 6. The output 6.2 of the digital frequency detector 6 is connected to the input 7.1 of the instantaneous dispersion calculation unit 7. Output 7.2 the instantaneous dispersion dispersion calculation unit 7 is connected to the first input 9.1 of the instantaneous frequency dispersion comparison unit 9. The second input 9.2 of the instantaneous frequency dispersion comparison unit 9 is connected to the output 8.2 of the reference dispersion bank m a new frequency 8, the input 8.1 of which is connected to the command output 3.2 of the driver of the control signals 3. The output 9.3 of the dispersion comparison unit of the instantaneous frequency of the signal detector 9 is connected to the command input 3.1 of the driver of the control signals 3. The command output 3.2 of the driver of control signals 3 is connected to the remote control input 1.2 the receiver 1 and the input "Initial installation" 8.1 of the detector 2. Signal output of the code of a fixed frequency 3.3 shaper control signals 3 is connected to the control input 4.1 of the block PORN frequency 4, output 4.2 is connected to the local oscillator input of the receiver 1 1.1.

The following names correspond to the input / output numbers of some blocks:
- input 1.1 of the receiver 1 - heterodyne input of the receiver;
- input 1.2 of the receiver 1 - input remote control of the receiver;
- output 1.3 of the receiver 1 - low-frequency output of the receiver;
- input 3.1 of the driver of the control signals 3 - command input of the driver of the control signals;
- output 3.2 of the driver of the control signals 3 - command output of the driver of the control signals;
- output 3.3 of the driver of the control signals 3 - output of the code signal of a fixed frequency of the driver of the control signals;
- input 4.1 of the block of reference frequencies 4 - the control input of the block of reference frequencies,
- input 5.1 analog-to-digital Converter 5 - information input of the signal detector;
- input 8.1 bank of reference dispersions of instantaneous frequency 8 - input "initial setting" of the signal detector;
- input 9.1 of the unit for comparing variances of instantaneous frequency 9 - the first input of a unit for comparing variances of instantaneous frequency;
- input 9.2 of the unit for comparing variances of instantaneous frequency 9 - the second input of the unit for comparing variances of instantaneous frequency;
- output 9.3 of the instantaneous frequency dispersion comparison unit 9 — command output of the signal detector.

 As a block of reference frequencies 4 and receiver 1, one can use a commercially available radio receiver P-399A Katran or IC-R8500, where these blocks are technically implemented.

 Shaper control signals 3 can be implemented according to the scheme shown in figure 2. The circuit includes a generator 10, a logical element OR 11, a decoder 12. The output of the generator 10 is connected to the first input of the OR element 11. The second input of the OR element 11 is input 3.1 of the driver signal 3. The output of the element 11 is output 3.3 of the driver signal 3. Input the decoder 12 is connected to the keys, allowing you to set one of the three-digit binary combinations. The M-bit output of the decoder 12 is the output 3.2 of the shaper control signals 3.

 As the generator 10 can be applied to any quartz generator of rectangular pulses of the desired frequency. The OR gate 11 and the decoder 12 can be implemented on the K133, K134, K155, K555, K176, K561, K564 series microcircuits.

 As an analog-to-digital converter 5 of the signal detector 2, an analog-to-digital converter of sequential or parallel action, implemented on one of the microcircuits of the K1108, MP7581, K1107, MP7683, MP7684 series, can be used.

 Digital frequency detector 6 can be implemented according to the circuit shown in figure 3. In particular, the circuit includes eight delay elements 13, 16, 17, 18, 19, 20, 21, 22; four adders 14, 15, 28, 29; five multipliers 23, 24, 25, 26, 27; a divider 30 and a device that implements the conversion F (x) = arctg (x) 31. The input 6.1 of the delay elements 13, 16 is the input of a digital frequency detector 6. The first output of the delay element 13 is connected to the first input of the adder 14. The second output of the delay element 13 connected to the inputs of the delay elements 17, 19 and the second input of the multiplier 24. The output of the delay element 17 is connected to the second input of the adder 14. The output of the adder 14 is connected to the second input of the multiplier 23 and the input of the delay element 20, the output of which is connected to the first input of the multiplier 24. Output ele The delay time 19 is connected to the first input of the multiplier 23, the output of which is connected to the first input of the adder 28. The output of the multiplier 24 is connected to the input of the multiplier by "-1" 27, the output of which is connected to the second input of the multiplier 28. The output of the multiplier 28 is connected to the first input of the divider 30. The first output of the delay element 16 is connected to the first input of the adder 15. The second output of the delay element 16 is connected to the inputs of the delay elements 18, 22 and the second input of the multiplier 26. The output of the delay element 18 is connected to the second input of the adder 15. The output of the sums Ora 15 is connected to the second input of the multiplier 25 and the input of the delay element 21, the output of which is connected to the first input of the multiplier 25. The output of the delay element 22 is connected to the first input of the multiplier 26, the output of which is connected to the second input of the adder 29. The output of the multiplier 25 is connected to the first input the multiplier 29. The output of the multiplier 29 is connected to the second input of the divider 30. The output of the divider 30 is connected to the input of the device that implements the conversion F (x) = arctg (x) 31. The output of the device 31 is the output of the digital frequency detector.

 As delay elements, memory registers implemented on K155, K531, K555, K561 microcircuits can be used. All other elements can be performed on combinational combiners and implemented on the K 155, K500, K555, K561 series microcircuits.

 The instantaneous frequency dispersion calculation unit 7 can be implemented according to the circuit shown in FIG. 4. In particular, the circuit includes three delay elements 32, 33, 40; four adders 34, 35, 41, 42; two dividers 36, 43; multiplier 37; counter 38; decoder 39. The input of the delay element 32, 33, the decoder 39 and the first input of the adder 34 are the input 7.1 of the instantaneous frequency dispersion calculation unit 7. The output of the decoder 39 is connected to the input of the counter 38. The output of the delay element 32 is connected to the second input of the adder 34. The output of the adder 34 connected to the first input of the divider 36, the second input of which is connected to the first output of the counter 38. The output of the delay element 33 is connected to the first input of the adder 35, the second input of which is connected to the output of the divider 36. The output of the adder 35 is connected to the first and second inputs a multiplier 37, the output of which is connected to the input of the delay element 40 and the second input of the adder 42. The first input of the adder 42 is connected to the output of the delay element 40. The output of the counter 38 is connected to the input of the adder (subtractor "-1") 41, the output of which is connected to the second input divider 43. The first input of the divider 43 is connected to the output of the adder 42. The output of the divider 43 is the output 7.2 of the dispersion calculation unit of the instantaneous frequency 7.

 As delay elements, memory registers implemented on K155, K531, K555, K561 series microcircuits can be used. Decoder 39 can be implemented on chips of the K155, K555, K561, K564 series. Counter 38 can be implemented on chips of the K155, K500, K531, K555, K561 series. All other elements can be performed on combinational combiners and implemented on chips of the K155, K500, K555, K561 series.

 The instantaneous frequency reference dispersion bank 8 may be implemented as shown in FIG. 5. The circuit includes an encoder 44 and a digital-to-analog converter 45. The M-bit input of the encoder 44 is the input 8.1 of the bank of reference dispersions of instantaneous frequency 8 (the input "initial setting" of signal detector 2). The output of the encoder 44 is connected by an M-bit bus to the input of the digital-to-analog converter 45, the output of which is the output of 8.2 a bank of reference dispersions of instantaneous frequency 8.

 The encoder 44 can be implemented on chips of the K500, K555 series. The digital-to-analog converter 45 can be implemented on chips of the K572, K594, MP7628, MP7633 series.

 The instantaneous frequency dispersion comparison unit 9 can be implemented according to the circuit shown in FIG. 6. The circuit includes a digital-to-analog converter 46 and a comparator 47. The M-bit input of the digital-to-analog converter 46 is the first input 9.1 of the instantaneous dispersion comparison unit 9, the output of which is connected to the first input of the comparator 47. The second input of the comparator is the second input 9.2 of the instantaneous frequency dispersion comparison unit 9. The output of the comparator 47 is the output 9.3 of the unit for comparing dispersions of the instantaneous frequency 9 (command output of the detector 2).

 The digital-to-analog converter 46 can be implemented on chips of the K572, K594, MP7628, MP7633 series. Comparator 47 can be implemented on chips of the K521, K554 series.

 In general, the signal detector can be implemented on a digital signal processor Starter Kit (TMS320C5x) from Texas Instruments.

 The claimed device for the automatic search for radio signals works as follows.

 The receiver sequentially scans the monitored frequencies. The signal detector decides on the presence or absence of a radio signal at a controlled frequency. If a signal is detected, the driver of the control signals generates a control signal to the block of reference frequencies to stop the scanning process by frequencies. The signal detector constantly monitors the presence of a signal at a frequency.

 The operation of the device for the automatic search for signals of radio stations in a structural diagram. The receiver 1 provides the reception of signals at fixed frequencies. From the low-frequency output of the receiver 1, the received signal is fed to the input 5.1 of the analog-to-digital converter 5 of the signal detector 2, which converts the analog signal into the corresponding digital code. The digital code from the output 5.2 of the analog-to-digital converter 5 is fed to the input 6.1 of the digital frequency detector 6, which generates a digital code at the output 6.2, which is proportional to the deviation of the input frequency from the average value. The resulting code is fed to input 7.1 of the instantaneous variance dispersion calculation unit 7, where the variance of the instantaneous frequency of the received signal is calculated. The obtained value is compared in the block for comparing the dispersions of the instantaneous frequency 9 with the dispersion of the instantaneous noise frequency, which is formed in the bank of the standard dispersions of the instantaneous frequency 8. The choice of a specific dispersion of the instantaneous frequency of noise is determined by the code combination filed from the control signal generator 3, depending on the selected width of the analyzed frequency band and set at receiver 1. If a signal is detected, then logic unit is generated at the output 9.3 of detector 2, otherwise - logically zero. If there is a useful signal on the newly tuned frequency at the output 3.3 of the shaper of control signals 3, a logical unit is formed that prohibits further tuning of the receiver 1 in frequency. In the absence of a signal or its disappearance at the operating frequency, a logic zero is generated at the output 3.3 of the control signal generator 3, which allows further tuning in frequency to the receiver 1. The reference frequency block 4 provides the formation of highly stable oscillations for receiving signals at fixed frequencies. The input of the reference frequency block 4 is digital. This input receives the code combination from the output 3.3 of the shaper of control signals 3. Highly stable oscillations are received at the output of the block of reference frequencies 4 to ensure reception at fixed frequencies. Highly stable oscillations corresponding to the ith fixed frequency from the output of the block of reference frequencies 4 are fed to the heterodyne input of the receiver 1.

 Shaper control signals 3 operates as follows. Depending on the selected width of the analyzed frequency band, the switches set one of the binary three-digit combinations, which is fed to the input of the decoder 12. At the output of the decoder 12, an M-bit binary number is generated, which is fed to the remote control input 1.2 of receiver 1 to connect the filter in the receiving path 1 with the appropriate bandwidth. An M-bit binary number is also fed to the input “Initial setting” 8.1 of signal detector 2 for generating a noise dispersion reference value in a bank of instantaneous frequency reference dispersions 8. Generator 10 generates a train of pulses with a frequency equal to the analysis time of one fixed frequency. The analysis time of one fixed frequency corresponds to the duration of one manipulation sending the signal of the received transmission. The output of the generator 10 is connected to the first input of the OR element 11. The second input of the OR element 11 receives zero or single levels from the output 9.3 of the comparison unit 9 of the detector 2. The output of the OR element 11 is connected to the input 4.1 of the block of reference frequencies 4. When an OR element appears at the inputs 11 of the unit level from the output 9.3 of the comparison unit 9 and / or generator 10 at the output of the OR element 11, a unit level is formed, which is fed to the input of the block of reference frequencies 4 and fixes the setting of receiver 1 at the i-th fixed frequency. If the inputs of the element OR 11 are zero, then a logical zero is generated at the output, which is fed to the input of the reference frequency unit 4, allowing the tuning of receiver 1 in frequencies.

The operation of the signal detector 2. From the low-frequency output of the receiver 1, the received signal is fed to the input 5.1 of the analog-to-digital Converter 5, which converts the analog signal into the corresponding digital code. The digital code from the output 5.2 of the analog-to-digital converter 5 is fed to the input 6.1 of the digital frequency detector 6. The digital frequency detector 6 operates as follows. The digital code enters two branches, which are independent detectors. The presence of two detectors and a divider 30 make it possible to achieve independence of the output values of the digital frequency detector from the amplitude of the received signal at its input and, therefore, to increase the accuracy of frequency measurement. The delay elements 13, 17 (16, 18) and the adder 14 (15) implement a 90 ^o phase splitter, made in the form of a non-recursive filter based on a Hilbert converter. At the outputs of the phase splitter (the output of the delay element 13 (16) and the adder 14 (15)), the input signal is presented in the form of quadrature components supplied to the multipliers 23, 24 (25, 26). From the outputs of the multipliers, the data goes to adders 28 (29). The summation results are sent to the divider 30 in order to eliminate the parasitic effect of the amplitude of the received signal on the accuracy of the frequency measurement. The device 31 implements a conversion of the form arctg (x), as a result of which the digital code at the output 6.2 of the digital frequency detector 6 is proportional to the frequency of the received signal.

 The unit for calculating the variance of the instantaneous frequency 7 operates as follows. The decoder 39 and the counter 38 implement the calculation of the number of instantaneous frequency values coming from the digital frequency detector 6. The delay element 32, the adder 34 and the divider 36 implement the calculation of the mathematical expectation of the instantaneous frequency of the received signal. On the adder 35, the difference operation between the current value of the instantaneous frequency and the mathematical expectation, the result of which is squared on the multiplier 37, is implemented. The delay element 40 and the adder 42 implement the operation of summing the multiplication results. On the adder 41, one is subtracted from the instantaneous frequency value to calculate the unbiased estimate of the instantaneous frequency dispersion, the value of which is obtained at the output of the divider 43.

 Bank reference dispersion instantaneous frequency 8 operates as follows. From the output 3.2 of the control signal generator 3, an M-bit binary code is supplied to the input of the encoder 44, which is converted to an M-bit binary number input to the digital-to-analog converter 45. At the output of the digital-to-analog converter 45, a voltage is generated according to the M-bit binary number, which is supplied input 9.2 of the unit for comparing variances of instantaneous frequency 9.

 The unit for comparing variances of instantaneous frequency 9 operates as follows. From the output 7.2 of the instantaneous variance dispersion calculation unit 7, an M-bit binary number is supplied to the input of the digital-to-analog converter 46, which is converted to the corresponding voltage at the output of the digital-to-analog converter 46. The resulting voltage is applied to the first input of the comparator 47. The voltage from the output to the second input of the comparator 47 digital-to-analog Converter 45 block calculating the dispersion of the instantaneous frequency 8. On the comparator 47 is a comparison of voltages. If the voltages are equal (equality of the variance of the instantaneous frequency of the received signal and the reference variance of the instantaneous frequency of the noise), then a logical zero is generated at the output of the comparator 47, indicating the absence of a useful signal in the received signal + noise mixture. If the voltage at the first input of the comparator 47 is less than the voltage at the second input (the dispersion of the instantaneous frequency of the received signal is less than the reference dispersion of the instantaneous noise frequency), then a logical unit is formed at the output of the comparator 47, indicating the presence of a useful signal in the received signal + noise mixture.

 The inventive device provides a search for signals of radio stations, often changing operating frequencies, in conditions of inconstancy of the level of the received mixture signal + noise with a high probability of detection.

References
1. Van Tris G. The theory of detection, estimates and modulation, Volume 1. The theory of detection, estimates and linear modulation. New York, 1968. Trans. from English, ed. prof. IN AND. Tikhonov. M .: Soviet Radio, 1972, 744 p.

 2. Statistical theory and methodology in science and technology. K.A. Brownley. Translation from English M.S. Nikulin, edited by L.N. Bolshev. The main edition of the physical and mathematical literature of the Nauka publishing house, M., 1977.

 3. Handbook of digital circuitry. IN AND. Zubchuk, V.P. Sigorsky, A.N. Shkurko. - K .: Technique. 1990 .-- 448 p.

Claims (1)

 A device for automatically searching for radio station signals, comprising a receiver, a signal detector, the command output of which is connected to the command input of the driver of the control signals, the output of which signal of a fixed frequency code is connected to the control input of the reference frequency unit, the output of which is connected to the heterodyne input of the receiver, characterized in that the low-frequency the output of the receiver is connected to the information input of the signal detector, the command output of the driver of the control signals is connected to the input of the dis the receiver and input control "Initial setting" of the signal detector, the signal detector consisting of an analog-to-digital converter, a digital frequency detector, an instantaneous frequency dispersion calculation unit, the information input of the signal detector is the input of an analog-to-digital converter, the output of which is connected to the digital frequency input detector, the output of the digital frequency detector is connected to the input of the instantaneous frequency dispersion calculation unit, the output of which is connected to the first the input of the instantaneous frequency dispersion comparison unit, the second input of the instantaneous frequency dispersion comparison unit is connected to the output of the bank of instantaneous frequency standard dispersions, the input of which is connected to the command output of the control signal generator and is the input "Initial setting" of the signal detector, the output of the instantaneous frequency dispersion comparison unit of the signal detector is the command output of the signal detector.

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