SU1166321A1 - Device for measuring amplitude-frequency response of communication channel - Google Patents

Abstract

A DEVICE FOR MEASURING AMSHTYTUDNA-FREQUENCY CHARACTERISTICS OF COMMUNICATION CHANNELS, containing a serially connected program module, a measuring generator and the first adjustable quadrupole connected to the input of the forward channel, the measuring unit, connected in series the first threshold unit and the first control unit, the second input and the output, the measuring unit, the first threshold unit and the first control unit, the second input and the output and the output control unit, the second input and the output channel and the output unit, the second unit and output, and the output unit and the control unit, connected in series to the first threshold unit and the first control unit. with the output of the program block and watts (the input of the first regulated even “fechpolo”, the input of the first threshold block is connected to the output of the reverse channel It is connected to the first input of the measuring unit, the second and control inputs of which are connected respectively to the input of the forward channel and the output of the first threshold unit, the switch and the second threshold unit whose inputs are combined, and the output of the second threshold unit connected to the control the input of the switch, the output of which is connected to the input of the return channel, characterized in that, in order to increase its accuracy by means of additional regulation, the first and second elements AND, the pulse sweater, NOT and a third threshold unit, a second control unit and a second quadrupole regulator, connected in series with the forward link connected to the input of the third threshold unit and to the second input of the second regulated quadrupole, the output of which (/) is connected to the second inputs of the switch and the second psfogov block, the output of which is connected to the inputs of the pulse shaper and the element is NOT, the output of which is connected to the first inputs of the first and second elements AND, the output of which is connected to the second input torogo control unit, the third input of which soedibo nen yield first AND, KD second input coupled to an output of the pulse shaper, the second output of the third threshold unit connected to the third input of the first AND gate and to the second input of the second member I.

Description

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The invention relates to a multi-channel communication technique and can be used in monitoring the deviation of the residual attenuation of communication channels.

A device for measuring 5 characteristics of communication channels is known, which contains a oscillating frequency generator at its distant end, a first matching unit at the far end, the output of which is connected via a voltage calibrator connected in series, an amplitude detector and a voltage-frequency converter to the first input of the second unit matching, the second input of which is connected to the output of the voltage calibrator through an extension cord, at the receiving near end of the code of the matching block is connected via serial connection An upper filter and an amplitude detector to another input of the adder and the first input of the second switch, the second input of which is connected to the output of the adder and the first input of the first switch, and the third to another output of the frequency detector and another input of the first switch, and the output of the matching unit is also connected to a series-connected limiter and said frequency detector, and the output of the second switch is connected to the indicator input, while the voltage calibrator is in the form of a pair tionary connected limiter amplitude and the high pass filter 1.

The closest to the invention in technical essence and the achieved result is a device for measuring the amplitude-frequency characteristics of communication channels, comprising a serially connected program block, a measuring generator and the first adjustable quadrupole connected to the input of the forward channel, a measuring block sequentially connected by the first threshold the block and the first control unit, the second input and output of which are connected respectively to the output of the program block and the second input of the first control Rui quadripole, the threshold input of the first unit is connected to the return duct and the outlet is connected to a first input of the measuring unit and the second control inputs of which are respectively connected to the input

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the forward channel and the output of the first threshold unit, the switch and the second threshold unit, whose inputs are combined, and the output of the second threshold unit is connected to the control input of the switch, the output of which is connected to the input of the reverse channel 2 J.

A disadvantage of the known devices is low accuracy.

The purpose of the invention is to improve the accuracy of the device by additional adjustment.

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The goal is achieved by the fact that, in a device for measuring the amplitude-frequency characteristics of communication channels, which contain series-connected software, measure the HF generator to the first controlled quadrupole connected to the input of the forward channel, the measuring unit connected in series, the first the threshold unit and the first control unit, the second input and output of which are connected respectively to the output of the program block, and the second input of the first adjustable four-port network, the input of the first poro The new unit is connected to the output of the return channel and connected to the first input of the measuring unit, the second and control inputs of which are connected respectively to the input of the forward channel and the code of the first threshold unit, the switch and the second threshold unit whose inputs are combined, and the output of the second threshold unit with the control input of the switch, the output of which is connected to the input of the reverse channel, the first and second elements AND, the pulse shaper, the element NOT and the third threshold unit connected in series are entered, the second control unit and the second adjustable quadrupole, while the output of the forward channel is connected to the input of the third threshold unit and to the second input of the second adjustable quadrupole, the output of which is connected to the combined inputs of the switch and the second threshold unit, the output of which is connected to the inputs of the pulse shaper and the element NOT The output of which is connected to the first inputs of the first and second elements And, the output of which is connected to the second input of the Second control unit, the third input of which is connected to the output of the first About element And, the second input of which is connected to the output of the pulse generator, the second output of the third threshold unit is connected to the third input of the first element And and to the second input of the second element I. Figure 1 shows the structural electrical circuit of the proposed device in Figure 2 - diagrams of junctions explaining the operation of the device The device for measuring amplitudes, but the frequency characteristics of the gsm channels contains a software block t, a measuring generator 2, the first regulator1 quadrupole 3, the first threshold unit 4, the first control unit 5, measuring unit 6, switch 7, second threshold unit 8, second adjustable quadrupole 9, third threshold unit 10, HE element 11, pulse generator 12, first 13 and second 14 And elements, second control unit 15, trigger 16, pulse generator 17, and elements OR 18; In addition, forward 19 and reverse 20 channels are shown. The device works as follows. The clock pulse received from the program block t is set. frequency and) (Fig. 2a) of the measuring generator 2 and using the first control unit 5 to set the first adjustable quadrupole 3 to the maximum attenuation position. Then, with a delay (about 2030 ms) from the first control unit 5 at the time point (Fig. 2b), a sequence of pulses starts to arrive at the second input of the first controllable four-pole 3, resulting in a voltage (level) of the measuring signal at its output linear law increases. Similarly, the measurement signal is biased at the outputs of the direct channel 19 and the second adjustable quadrupole 9 (Fig. 2b), with a positive half-wave arriving at the output of the second adjustable four-pole network 9 due to a delay in the direct channel 19 at time tL . At this time, another half-wave begins to arrive at the input of the direct channel 19 (Fig. 28). When the measurement signal reaches a predetermined level (the trigger level of the third threshold unit 10) at time tj, the third threshold unit 10 is triggered, with the result that a short pulse arrives at its first output, and a positive polarity at the second constant signal. A short impulse arriving at the input of the second control unit 15 sets the trigger 16 of the latter to a position in which, using the element 18, connected to the output of the trigger 16, the second control unit 15 (FIG. 21) enters the drive from time t2 constant This negative signal of setting the second adjustable quadrupole 9 to the position of a predetermined attenuation (for example, 20 dB) with the prohibition of its adjustment. The change in the signal level at the output of the second regulated signal of the rehpoljnik 9 is ensured only by its change at the input of the direct channel 19. The process of increasing the voltage of the measuring device by decreasing the attenuation of the first adjustable four of the polarizer 3 continues, which leads to a corresponding change in the voltage of the measuring signal at both the input and the and at the output of the second regulated quadripole 9. At the same time, the positive half-wave of the measuring signal, as well as the signal as a whole, goes to the output of the second variable The quadrupole 9 is delayed by t, which is caused by the signal delay in the forward direction of signal transmission. After some time, at the moment of time t., The voltage at the output of the second adjustable four-port 9 reaches a predetermined (nominal) value at which the second horn unit 8 is activated and switches on the switch 7. The second moment of horn unit 8 coincides with the maximum positive Half waves at this time point (FIG. 2B) at the output of the first adjustable four-port 3 already have a maximum of another positive half wave, with a delay equal to the delay t of the previous half wave, appears And the output of the direct channel 19, and it means, and at the output of the second regulated quadripole 9, but with its higher voltage value. Moreover, the appearance of a half-wave at the input and output of the second adjustable quadrupole 9 cannot be forbidden, even if it could stop at the time C the process of adjusting the first adjustable four-pole battery 3. In fact, it is possible to stop the process of adjusting the first adjustable four-pole 3 only at time t (Fig. 25 ,, i.e., from the leading edge of the positive half-wave, which through switch 7 via the return channel 20 is post-down to the output of the latter with a delay equal to At time t4, when it occurs By the power of the first control unit 5, stopping the voltage regulation process (the level of the measuring signal, at the output of the first adjustable circuit driver 3 already has another positive half-wave, the voltage of which is higher than that of the preceding half-waves, which necessarily comes with its even greater magnitude the output of the return channel 20, followed by the same half of the subsequent half-wave with the same value, the voltage (level) of which is measured alternately (or simultaneously) by the measuring unit 6 on input direct 19 and output reverse 20 channels. Thus, the deviation from the nominal attenuation value of the forward and reverse communication channels is estimated with a certain accuracy, determined primarily by the overshooting of the voltage of the measuring signal at the output of the first adjustable four pole 3. The accuracy of the attenuation estimate increases with decreasing control speed of the measurement signal, but in this case, the entire attenuation measurement process lengthens accordingly, which is allowed within known limits. By introducing new blocks and connections, the elimination of measurement errors caused by an overshoot of the PERSON value (Fig. 25) of the voltage of the measuring signal at the output of the first four adjustable pole 3 (forward channel input 19) is achieved. This value of overshoot AUju, passed through a loop consisting of a forward channel 19, a second adjustable quadrupole 9, switch 7 and a reverse channel 20, at the output of switch 7 becomes equal to 4U (Fig.) And at the output of the reverse channel 20 / jU ( fige). If the value is set, then at the output of the return channel 20 the overshoot is equal to zero, and thus the attenuation of the reverse channel can be measured without an error related to the overshoot, i.e. measure instead of the previously measured U.ji. By subtracting, the error dU is easily determined, which is further used to refine the measurement of the readout of the forward channel 19. Usually, in telecommunications, the measurement of the attenuation of the communication channels is made by estimating the level of the measuring signal in decibels. In the case of measuring, the level is more convenient, since determining the value of the AR of error associated with the overshoot of the level of the measuring signal, at the output of the return channel 20 in decibels, simultaneously set Ichin overshoot also equal AP inlet forward channel 19.Ranee poluchennsh measurement result of attenuation of the forward channel 19 is simply subtracting refines pogreshnostiLR. 1. After measuring the Level (voltage) of the measuring signal at the input of the first adjustable quadrupole 3 and the output of the return channel 20 at the time point -t (Fig. 2b), a sharp change (increase by 1015 dB) of the attenuation of the first adjustable quadripole 3 is made with the prohibition of adjustment its attenuation on command in the form of a clock pulse of the corresponding polarity from program block 1. This leads to a jump-like change (decrease by the same amount (10-15 dB) of the measurement signal level at the input of the direct channel 19 and yes with a delay equal to tg-t-; also to a decrease in its level at the output of the forward channel 19 and at the output of the second adjustable quadrupole 9 (Fig. 2c), which leads to a corresponding triggering (change of signal 1 by O) of the connected to its output of the second, threshold unit 8 (FIG. 2d). It is this signal change from 1 to O at the output of the second threshold unit 8 while simultaneously maintaining the polarity of signal 1 at the second output of the third threshold unit 10 allows: formed by the imaging unit 12 pulses (fig.2zh) short pulse n give through the first AND gate 13 to the input of the second control unit 15. A short impulse fails trigger 1.6. to the initial state, in which the prohibition on adjusting the attenuation of the second adjustable quadrupole 9, which is in the maximum attenuation position (Fig. 2), is removed, using the element OR 18 and the pulse generator 17. At the same time, the signal O at the output of the second threshold unit 8 is inverted by the element 11 11 into the signal 1 and through the second element I 14, the second input of which is still stored from 1 from the third threshold unit 10, is fed to the third input of the second control unit 15. The arrival of this signal permits the pulse generator 17 to apply short positive pulses through the OR element to the output of the second control unit 15 (Fig. 2) and then to the input of the second adjustable quadrupole 9. Under the action of the incoming pulses, the decay i sweeps of the latter changes (decreases) with determined by the frequency of arrival of pulses, which causes a corresponding change (increase) in the level of the measuring signal u). When the level of the measuring signal i) reaches a predetermined (nominal) value, the second threshold unit 8 is triggered at the moment of time and the signal 1 at its output instead of O (fig.2d) turns on the switch 7 of the switch 7 (fig.2d). At the same time, the signal 1 is inverted by the element HE 11, as a result of which the third input of the second control unit 15 instead of the signal O arrives and the latter understands prohibits the further supply of pulses to the input of the second adjustable flow terminal 9 (FIG. 2). The damping adjustment of the latter is immediately stopped and the nominal level of the measuring signal w) is set at its output (Fig. 2b). The measuring signal w nominal level through the switch 7 (Fig.2i) is fed to the input of the reverse channel 20 and further with a certain delay equal to C (rfc 2e) of the signal propagation time on the reverse channel 20, to the output of the latter. The first threshold unit 4 is triggered and sends a signal to the measuring unit 6 to measure the level of the measuring signal at the output of the return channel 20. The resulting evaluation of the damping of the return channel 20 (in Fig. 2e) is more accurate and devoid, unlike the previously obtained error associated with the overshoot of the same measurement signal and). at the input of the direct channel 19. Subtracting the result (more accurate) of the attenuation of the return channel 20 from the previously obtained (less accurate), get the value of the resolution, which is then in turn subtracted from the measurement result of the attenuation of the forward channel 19, is obtained a more accurate estimate of the attenuation of the forward channel 19. Then, at the instant of time, the flow of the measurement signal and) from the measurement generator 2 ceases and after some time t. -t, the measurement signal of frequency o is received, and the measurement process is repeated as described. Thus, by additional adjustment, the measurement f04HocTb is increased, since the error caused by overshooting the first adjustable quadrupole is eliminated.

Claims (1)

DEVICE FOR MEASURING THE AMPLITUDE-FREQUENCY CHARACTERISTICS OF COMMUNICATION CHANNELS, comprising a series-connected program unit, a measuring generator and a first adjustable four-terminal connected to the input of the direct channel, a measuring unit, series-connected the first threshold block and the first control unit, the second input and output of which are connected respectively to the output of the program unit and the second input of the first adjustable four-terminal, the input of the first threshold block is connected to the output of the return channel and connected to the first input of the measuring unit, the second and control inputs of which are connected respectively to the input of the direct channel and the output of the first threshold block, the switch and the second threshold block, the inputs of which are combined, and the output of the second threshold block is connected to the control input of the switch , the output of which is connected to the input of the return channel, characterized in that, in order to increase its accuracy by additional regulation, the first and second elements And, the pulse shaper, the element NOT and the last the third threshold unit, the second control unit and the second adjustable four-terminal are connected, the direct channel output being connected to the input of the third threshold block and the second input of the second adjustable four-terminal, the output of which is connected to the combined inputs of the switch and the second threshold block, the output of which is connected to the inputs the pulse shaper AND element NOT, the output of which is connected to the first inputs of the first and second elements AND, the output of which is connected to the second input of the second control unit, rety input coupled to an output of the first AND gate, a second input coupled to an output of the pulse shaper, the second output of the third threshold unit connected to the third input of the first AND gate and to the second input of the second member I. SU ,,,. 1166321 '1 11663