SU1737369A1 - Device for determining parameters of output signals of pulsed radio transmitters - Google Patents

Abstract

This invention relates to a radio measuring technique. The purpose of the invention is to expand the functionality. The device contains a matching unit 1, a frequency converter 2, a pulse shaper 3, a reference generator 4, an amplitude detector 5, a voltage-frequency converter 6, a comparator 7, a delay block 8, two multiplexers 9, 19, two timers interval, block 12 start and reset, two time selectors 13, 14, frequency multiplier 15, two pulse counters 16, 17, frequency divider 18, shaper 20 pulses of the end of measurements, shaper 21 pulses of the end of the studied signals, interface unit 22, microcomputer 23, block 24 registration. The goal is achieved by creating another measuring channel, information from which is fed to the microcomputer 23. 1 Il. SP

Description

The invention relates to a radio measuring technique and can be used to automatically determine a set of parameters of the output signals of pulsed radio transmitters, such as emergency beacon transmitters (ARB), as well as to demodulate the phase-shift keyed pulses.

A variety of methods and devices are known for measuring various parameters of pulsed radio signals. Thus, one of them provides for the measurement of the parameters of a bundle of radio pulses: duration, repetition period, and number of pulses in a pack, as well as the possibility of automating the measurement process. A disadvantage of this device is that it measures only temporal parameters.

and does not allow to determine other parameters of radio signals.

Methods are also known for determining the peak power of a pulsed radio signal frequency. However, they all solve local problems and therefore have limited functionality.

The closest in technical essence and the achieved positive effect is a device for determining a set of parameters of the output signals of pulsed radio transmitters, which contains a block of quasi-coherent frequency conversion of the signal under investigation into the low frequency range with a reference frequency generator and an output pulse shaper, amplitude

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a detector, a comparator, a voltage-frequency converter, a digital meter consisting of a time selector and a pulse counter, as well as an exemplary frequency multiplier and divider, time intervals formed from the transformed signal under study and from the output oscillations of the voltage-frequency converter, multiplexer, delay and synchronization blocks, as well as a microcomputer connected to the time interval meter via an interface unit and a registration unit (printer). In this device, an increase in speed in determining all parameters (frequency and parameters of its instability, pulse duration and follow-up period, pulse power and phase shift during phase manipulation in the modulated pulse portion) is achieved by converting all measured values into time intervals, sequential measurement of these intervals by one digital meter, storing the measurement results in the microcomputer and processing the array of measurement results in the pauses between pulses signal.

The disadvantage of the above-considered device is its limited functionality, in particular, the inability to determine the symmetry of phase deviations during phase shift keying (FM) in the modulated part of pulses, the speed of keying and demodulation of the FM signal. The latter is of great importance in automating test procedures, for example, ARB-406 emergency beacon transmitters operating in the COSPAS-SARSAT system

The aim of the invention is to expand the functionality of the device, in particular the possibility of determining the symmetry of phase deviations in FM modulated pulses relative to the phase of the unmodulated signal, phase manipulation speed, demodulation of the FM signal, as well as improving the accuracy of determining the temporal parameters of pulse signals

This goal is achieved by introducing additional units into the above device, forming the second channel for measuring time intervals, working alternately with the first channel when clock signals pulsed into the control inputs are shifted by half a period in one channel of the meter relative to the other.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 and 3 are diagrams for his work.

The device contains a matching unit 1, a frequency converter 2 with a shaper 3 output pulses, a reference generator 4, an amplitude detector 5, a voltage-frequency converter 6, a comparator 7, a delay unit 8, the first 0 multiplexer 9, shapers 10 and 11 dimensions time intervals, block

12 start and reset, temporary selectors

13 and 14, frequency multiplier 15, pulse counters 16 and 17, frequency divider 18,

5 second multiplexer 19, shaper 20 pulses of the end of measurements, shaper 21 pulses of the end of the investigated signals, the interface unit 22, the microcomputer 23 and the recording unit 24.

0 Block 1 matching is made of two

calibrated attenuators such that the input impedance of the device is RBX 50 ohms. The first output of matching unit 1 is connected to the output of the reference generator 5, and the output is connected to the input of the pulse shaper 3, the output of which is connected to the first input of the first multiplexer 9. The input of the amplitude detector 5 is connected to the second output of matching 1, the output of which is connected to the input voltage-frequency converter 6, the output of which is connected to the second input of the first multiplexer 9, and to the input of the comparator 7, whose output is connected to the input

5 block 8 delays and to the inputs formate, lei 20 pulses of the end of measurements and 21

pulses of the end of the investigated signals.

The first output of the block 8 delays connected

to the third (control) input of the first

0 of the multiplexer 9, the output of which is connected to the first inputs of the formers 10 and 11 of the measured time intervals. The second output of the block 8 delays connected to the second input of the imaging unit 11, and the third

5, the output of block 8 is connected to the first input of block 12 for starting and resetting. The first output of the unit 12 is connected to the second (control) input of the imaging unit 10, the second output of the unit 12 is connected to the third input of the formatter. 11, the second output of which is connected to the second input of the unit 12. The outputs of the drivers 10 and 11 are connected in series with the time selector 13 and the pulse counter 16 and the time

5 selector 14 and the counter 17 pulses, respectively. The information outputs of the counters 16 and 17 are connected to the information inputs of the second multiplexer 19, the control inputs of which are connected to the outputs of the drivers 10 and 11, respectively.

The second inputs of the time selectors 13 and 14 are connected to the output of frequency multiplier 15, the second (control) inputs of counters 16 and 17 are connected to the third and fourth outputs of block 12, respectively, and the third (additional) input of counter 17 is connected to the output of frequency divider 18. The inputs of the multiplier 15 and the frequency divider 18, as well as the third input of the block 12 are connected to the output of the reference generator 4. The information outputs of the second multiplexer 19 are connected in series with the interface unit 22, the microcomputer 23 and the registration unit 24. The additional (control) input of the interface unit 22 is connected to the output of the imaging unit 20 pulses of the end of the measurements, the second and third inputs of which are connected to the outputs of the imaging devices 10 and 11, respectively. An additional (control) input of the microcomputer is connected to the output of the driver of 21 pulses of the end of the signals under study.

Consider the operation of the device on the example of determining the parameters of the output signals of pulse radio transmitters ARB-406. The device works as follows. The features of the proposed device appear when measuring in the modulated part of the pulses the phase deviations during the FM and the symmetry of these deviations relative to the phase of the unmodulated signal, the speed of manipulation, as well as during the FM signal demodulation (see Fig. 3, where a is the modulating binary signal, bal, b — corresponding phase deviations).

The studied signal from ARB-406 in the form of radio pulses (see Fig. 2 a) with a duration of Ti 0.44 s, following with a period of Tel Ti + Tp 50 s (Tn - the duration of the pause between adjacent pulses), is fed to the input of the device. Through the matching unit 1, the signal under test is attenuated (a known number of times) at the inputs of frequency converter 2 and the amplitude detector 5. The detected signal at the output of the amplitude detector 5 is video pulses (FIG. 2 b) with amplitude Ud proportional to the amplitude of the signal under study at the input of the Umw device. These video pulses are fed to the input of the comparator 7, which has a predetermined threshold of Do. At the output of the comparator 7, rectangular pulses (Fig. 2c) of standard amplitude are formed, the beginning and end of which correspond to the beginning and end of the radio pulses of the signal under study and which are then used to synchronize the operation of individual units of the device. Front of these pulses through

blocks 8 and 12, the counter 17 is transferred to the mode of measuring the time intervals formed by the shaper 11 of the signals from the output of the first multiplexer

9. Simultaneously, this front triggers a delay block 8, which generates a sequential signal (Fig. 2 g), allowing signals passing through the multiplexer 9 from the output of the measurement channel, including the frequency converter connected in series 2 and the pulse shaper 3, during the first the measurement interval Ti through the first time interval delay Tz1 from

5 of the beginning of the pulse, then the signal (Fig. 2 d), allowing the passage through the multiplexer 9 of signals from the output of the voltage converter 6 - the frequency during the second measuring interval T2 through

0 the second time interval Tz from the beginning of the pulse, and finally the signal (Fig. 2e) allowing the passage through multiplexer 9 of the signals from the output of the frequency conversion channel during the third

5 measuring interval Tz through the third time interval delay Tzz from the beginning of the radio pulse. At the same time, in the first measurement interval Ti in the unmodulated part of the pulse Tn, a series of consecutive frequency measurements are taken by measuring the measured intervals formed by the shaper 11 that are multiples of the period Tdp of the signal T1 under study in converter 2

5GTTPr (with multiplicity of 500), whence fnp 1 / Tprni / Ti1), and the frequency of the signal under study is determined in a computer through a known frequency conversion factor in frequency converter 2. In the second measuring interval T2, the power in the pulse is determined by measuring the amplitude of the pulse at the output of the amplitude detector 5 using an intermediate voltage conversion

5 Od Kd UgPf, (Kd is the amplitude detector transmission coefficient taking into account the attenuation in block 1 matching, Utvh is the amplitude of the signal under study at the device input) at the output of the amplitude detector 5 to the pulse frequency at the output of the voltage converter 6 - frequency:

fnH4 fH + KiUA fH + KlKAUm (W, (1) where fn is the initial frequency value determined by the setting of converter 6 at zero Ud,

Ki is the slope of the conversion characteristic of converter 6.

The counter 17 (together with the driver 11) measures the period of this signal Tpnch

gpcn, whose value is entered into the computer. It calculates the power value according to the formula

Pu (1 / Tpnch - fH) 2 / RBx Kd2, (2)

where RBX is the input impedance of the matching unit 1, equal to 50 ohms.

The values of the coefficients Ki and Cd are determined by calibrating the device over a power measurement channel using an exemplary wattmeter.

In the first and second measurement intervals, the start-up and reset unit 12 generates start-up pulses of the imaging unit 11 and reset of the counter 17 (Fig. 2 g), upon arrival of which the measuring intervals begin to form in the imaging unit 11, which open the time selector 14 and are filled with pulses of short marks time with a TMV1 period of 0.01 µs (with a frequency of respectively fuel 1 / TMB1 100 MHz), coming from the output of the frequency multiplier 15 with a multiplication factor of the reference frequency equal to 20. The magnitude of the TMB1 period determines the minimum error measuring the time intervals formed by the driver 11 within the pulse duration Ti.

A distinctive feature of the proposed device is that, in the third measuring interval Tz, the starting and resetting unit 12 forms, in contrast to the prototype, two sequences of clock pulses with a stable 1 ms Tact time period shifted relative to each other by half the period (see Fig. 2 W and W and Fig. 3 c and d). The magnitude of the period Tact is chosen to have a smaller minimum interval between adjacent phase jumps during FM in the modulated part of the ARB-406 pulses (Tfmmin 1.125 ms). In each of the shifted clock intervals, the shaper 10 and 11 alternately form from the output signal of the converter .2 and shaper 3 overlapping measured intervals Ti and P2 TPR with frequency ratio of P2 30 (see Fig. 3 d and e). These intervals are measured using time selectors 13 and 14, counters 16 and 17, respectively (as well as in the measurement interval Ti). The results of measurements of all values from the information outputs of the counters 16 and 17 are transmitted through the second multiplexer 19 and the interface unit 22 in the microcomputer 23, where they are successively stored until the end of the Ti pulse (and, accordingly, the end of the measurement interval Tz). From the changes in these measured intervals caused by the phase jumps in the FM in them, and from the corresponding changes calculated

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values of the signal frequency Af (see Fig. 3 g), by statistical processing of the array of frequency values obtained in the measuring interval Tz, the computer determines the maximum phase deviations at

FM (Duo and with opposite phase jumps up and down) in the modulated part of the pulses (see. Fig. 3 6).

The pulse duration Ti is defined as the sum of the values of the third delay interval Tzz and the third measuring interval Tz, which is determined by the number of clock halves K, calculated in a computer, located in the interval Tz (as indicated above, it is filled with two sequences of clock pulses, shifted by half the period) and the known period of the Tact, i.e.:

Ti Tzz + K tact T tact / 2. (3)

The duration of the unmodulated part of the pulse Tn is determined by the number itaKi of the first clock interval (in the measuring interval T3), which is hit by the first phase jump at the beginning of the modulated part of the pulse:

Tn TZ3 + takgtakt / 2. (4)

In this case, the error in determining the pulse duration Ti and its unmodulated part Tn, as follows from (3) and (4), is determined practically by the value TiaKt / 2. which is many times larger than the ATzz delay time error - 1 / f 0 in this device.

Due to the overlap of the measured intervals Ti, alternately formed in the measuring interval Tz by shapers 10 and 11 (Teh Chat and Tinech, respectively), which are triggered by two clock pulse sequences (shifted by half the Tact / 2 period), the first phase jump ( Fig. 3) at the beginning of the FM in the modulated part of the pulses will necessarily fall into one of the measured intervals. By the magnitude of the change of this ine

The limit relative to the previous unmodulated intervals is determined (by computer) by the amount of phase deviation at the beginning of the FM (in the first hop) relative to the phase of the unmodulated signal. The magnitude of the first phase deviation at the beginning of the FM and then determined (as a result of statistical processing in the computer of an array of measurement results) is great. rank of phase deviations at opposite

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phase jumps and determine the phase deviation at the FM and the symmetry of these deviations (relative to the phase of the unmodulated signal).

Due to the overlap of the measured intervals Ti, in addition, the proposed device realizes the possibility of demodulating the FM signal, as well as decoding the transmitted message, since any phase jump in the FM will necessarily fall into one of the successive measured intervals (and phase transitions due to the appropriate choice of the multiplicity factor P2, at which the minimum overlap of the adjacent measurement intervals Tichet and Tinech will exceed the maximum nuyu value duration transient switching phase at FM). In this case, an array of measurement results will be formed in the computer, in which the distribution in time of the frequency deviation values corresponding to opposite phase jumps during FM uniquely corresponds to the nature of phase changes during FM and the modulating information signal (see Fig. 3 a, b and g). According to the obtained distribution and with an a priori known form of the FM and digital code, the FM signal is demodulated and the transmitted message is decrypted using a computer.

After demodulation of the FM signal by the received array and by the duration of the modulated part of the pulse (determined by subtracting from the duration of the pulse Ti and the duration of its unmodulated part T, calculated by formulas (3) and (4), the speed manipulation with FM in the modulated part of the pulses (according to the number of bits of information transmitted in the modulated part of the pulses Tm).

At the end of the pulses at the output of the comparator 7, the driver 21 generates pulses on the computer about the end of the input signal (Fig. 2 and). At the same time, the start-up and reset unit 12 transfers the counter 17 to the measurement mode of the pause duration TP, at which the counter 17 counts the pulses of long time stamps with a period of TMB2; 0.1 ms from the output of the frequency divider 18 (with a dividing rate of the reference frequency of 500). This is done to prevent the pulse counter 17 from overflowing with a limited (to reduce the equipment volume) number of its bits, which is based on a given accuracy in determining frequency parameters and taking into account a large pause (about 50 seconds in ARB-406). The duration of the pulse repetition period of the signal under study is determined (in a computer) as the sum of a certain

according to (3) the duration of the pulse Ti and the measured duration of the pause Tn

Tel Ty + Tn. (5)

The error in determining the TSl period,

as follows from (5) and (3), it is almost determined by the error in determining the duration of the pulse Ti which is equal to half the period of the clock pulses of Tact / 2 in accordance with (4). This error is twice less than in the prototype.

When the next pulse of the signal under study appears, the driver 20 generates a pulse of the pause measurement end to the interface unit 22, over which the interface unit 22 transmits the measured value from the counter 17 through the second multiplexer 19 to the computer 23. Similarly, the driver 20 produces these pulses at the end of each

0 measured interval formed by the formers 10 and 11 (the second multiplexer 19 alternately transmits information signals from the outputs of the counters 16 and 17, respectively) within

5, the duration of the pulse Ti when measuring the aforementioned parameters of the pulse signal.

Thus, after the end of the first pulse of the signal under investigation, the device0 determines most of the complex of the listed parameters: the actual value of the signal frequency, the power in the pulse, the pulse duration and its unmodulated part, the FM parameters

5 (maximum phase deviations at opposite phase jumps and their symmetry relative to the phase of the unmodulated signal, as well as the speed of manipulation, and then demodulates the FM signal and decrypts the transmitted message. With the arrival of the second pulse, the pulse duration after measuring the duration is determined pauses. And only to determine parameters such as drift

5 frequencies from pulse to pulse, and mean-square values of frequency deviations from linear drift and short-term frequency instability are carried out in accordance with the specification for ARB-406

0 statistical processing of the frequency measurement results (in the first measuring interval Ti of each pulse in accordance with the proposed algorithm) obtained in a given number of pulses

5 (usually 10-20). The processing of measurement results in a microcomputer takes a short period of time (compared with the pulse period of the ARB-406), so that the determination of the entire set of parameters of the pulse signals in the proposed device is carried out almost in real time (as quickly as possible), t. e. for 15-20 minutes

After final processing of the computer results, it outputs the measured parameters of the pulse signal studied to the recording unit 24 in a predetermined form, for example, in the form of a table with the necessary comments in accordance with the developed program.

The possibility in the proposed device to determine the symmetry of phase deviations in FM, the speed of manipulation, demodulation of the FM signal, as well as the decoding of the transmitted messages greatly extends its functionality compared with the known analogues. In addition, reducing the error in determining the pulse duration of the signal under study Ti and the period of their follow TSL (twice compared to the prototype) allows to increase the accuracy of determining these parameters.

Expanding the functionality of the proposed device in comparison with the known one will significantly reduce the amount of additional equipment required to conduct tests of pulsed radio transmitters during their production and operation, as well as reduce the time required to conduct these tests. This gives an undoubted economic effect and will increase the production, for example, of the portable UHF transmitters of ARB-406 emergency beacons operating in the COSPAS-SARSAT system. These ARBs, as is known, must be equipped with all ships and aircraft, as well as various groups of golfer, geologists, tourists, etc., traveling to remote and sparsely populated areas. Thus, the introduction of the proposed device will help to solve an important social task - saving lives of people in various disasters at sea and on land.

Claims (1)

Invention Formula A device for determining a set of parameters of the output signals of pulse radio transmitters, comprising a matching unit whose input is an input of the device, a reference oscillator, a serially connected frequency converter, the first and second inputs of which are connected respectively to the first output of the matching unit and the output of the reference oscillator, pulse shaper, first multiplexer, first shaper of measured time intervals, the first time selector and the first pulse counter, the pulse shaper of the end of the measurement, the first input of which is connected to the output of the first driver measured time intervals, serially connected interface unit, the first control input of which is connected to the output of the pulse shaping end of measurements, the microcomputer and 0 a registration unit, a series-connected amplitude detector, whose input is connected to the second output of the matching unit, a comparator, a delay unit, the second output of which is connected to the second input 5 of the first multiplexer, and the start-up and reset unit, the first output of which is connected to the second input of the first shaper of measured time intervals, the second input is connected to the second output of the first 0 generator of measured time intervals, frequency multiplier, input and output of which are connected respectively to the output of the reference generator and the second input of the first selector, frequency divider, input 5 of which is connected to the output of the reference generator and the third input of the start-up and reset unit, the driver of the pulses of the end of the studied signals, the output of which is connected to the control input of the microcomputer, 0 control output of which is connected to the second control input of the interface unit, voltage-frequency converter, input and output of which are connected respectively to the output of the amplitude detector and the third input of the first multiplexer, the comparator output to the second input of the pulse generator of the measurements and the input of the driver the pulses of the end of the studied signals, that is, so that, in order to extend the functionality by ensuring the determination of the symmetry of the phase deviation, the speed and demodulation of the phase-shift keyed signal, the second shaper of measured time intervals connected in series are inserted in it, the first input of which is connected to the output of the first multiplexer, the second time selector, the second pulse counter and the second multiplexer, the second input and output of which are connected respectively to the output the first pulse counter and information input of the interface unit, the third output of the unit 5 delays are connected to the second input of the first shaper of measured time intervals, the second output of the start and reset unit is connected to the second input of the second shaper of measured time intervals, the third output is connected to the second input of the first pulse counter, the fourth output is connected to the second input of the second pulse counter, the output of the second generator of the measured time inlays, the second control input of which is connected to the output of the first driver of the measured time intervals, the output of the multiplier pilots at podtervalov connected to the third input of for- 5 keys to the second input of the second time measurement tors, pulse end and the selector, the first control input of the second multiplexer, the second control input coupled to an output of the first shaper of the measured time intervals, the output frequency to a multiplier Tfm, Tfng T (j, Mi Tfm.   L - I - ЈFig. 2 Ch t " 7l B Aif A, fo I u TTDK. J 1 II / 3 j 5 J7 $ W | L71 / 177 G. fJjTTp 35 37 Vt 6 to S 12 g 1.PPPP t Hwt I  ML  20, 22 ОШШ , 28 3S XJ4 38 -L-i..j.-1-.l-jl JШ1-I .- .. I, l. | -I-i-M-i -.i i1-i-j, -i - innhrnn iihminlQn & L innrnnnirn 0 j I. I I i f J Ub five 76 / 3W J 1 II TTp 35 37 , 28 3S XJ4 38 .i i1-i-j, -i - i & L innrnnnirn PP 3l Jtf w. / itnaxm