SU1109917A1 - Device for adaptive correcting in frequency region with displaying characteristics - Google Patents

Abstract

DEVICE ADAPTIVE COMPENSATION JJ frequency domain display characteristics comprising a comb filter, each of h which outputs connected to the input of the corresponding correction element, the first outputs of odd elements .korrektsii connected to inputs of the first adder unit vscheleni tuning combination unit changes correction rate display unit and n control channels, the first input of each of the n control channels is connected to the corresponding output of the tuning combination unit, the second input of each The control channel is connected to the second output of the corresponding correction element, and the third input of each of the control channels n is connected to the output of the correction rate change block, the first output of each of the control channels n is connected to the second output of the corresponding correction element, the second output of each control channels - to the corresponding input of the display unit. characterized in that, in order to improve the correction accuracy and convergence rate, a decisive block and second and third adders are inserted into it, with the outputs of even correction elements connected to the inputs of the second adder, and the outputs of the third and second adapters to the inputs of the third and second the adder is connected to the input of the decision block, the inputs of the block of the tuning combination and the block for changing the correction speed are combined and connected to the output of the decision block, the output of the first adder is connected to the second input b The change in the speed of the KW response, each of the n control channels, is designed as a series-connected subtractor and a counter, the first input of the subtractor is the first input of the control channel, the second input of the subtractor is the second input of the control channel, the clock input from the counter, and the third the input of the control channel, and the block for changing the correction rate contains a series-connected subtractor and a counter, the first output of which is the output of the block for changing the speed of correction; s, the input of which is connected to a second output counter, and a delay element, said first input of the subtractor is correcting the first input of the speed change unit and to the second input of the subtractor output of the delay element is connected, whose input is the second input of the speed correcting unit changes.

Description

I, the invention relates to communications and can be used in communication links. There is a correction device containing controlled phase loops that are controlled by a tracking unit that operates during the transfer of working and} t.1 However, the device performs the following correction only phase response characteristic (FF) j does not perform amplitude-frequency correction characteristics (AFC) and n displays the distortion of frequency characteristics. The closest to the proposed is an adaptive correction device in the frequency domain with display of characteristics, containing a comb filter, each of the P outputs of which are connected to the input of the corresponding element, the first outputs of the odd correction elements are connected to the inputs of the first adder, and the block is tuned combinations, a unit for changing the correction speed, a display unit and n control channels, the first input of each of the control channels is connected to the corresponding output of the control unit combination, the second input channels kazhdog g of adjusting Cpd nen suitable to the second output of the correction element, and a third input of each of the n channels regu- lation i connected to the output correction unit speed change, the first output of each of Canada are. the control is connected to the second input of the corresponding correction element and the second output of each of the h control channels is connected to the corresponding input of the display unit t 23. However, the known device does not provide sufficient accuracy and speed of convergence in all cases and does not provide the signal-to-noise display. in the communication channel. The purpose of the invention is to increase the correction correction rate and convergence rate. To achieve this goal, the adaptive correction device in the frequency domain, with the characteristics display, contains a comb filter, each of ъ 7 outputs of which are connected to the input of the corresponding correction element, the first outputs of odd correction elements are connected to the inputs of the first adder, block of the tuning combination, a block for changing the correction speed, a display unit and n control-regulating channels, first in: the course of each of the control channels is connected to the corresponding output of the block tuning combination, the second input of each of the control channels n is connected to the second output of the corresponding correction element, and the third input of each of the ri control channels is connected to the output of the correction speed change control unit, the first output of each game control channel is connected to the second input of the corresponding correction element , and the second output of the escaping from the n control channels - to the corresponding input of the display unit, the decisive block and the second and third adders are introduced, and the inputs of the second adder are connected to moves correction even elements and a third adder inputs - outputs of the first and second adders, a third adder output is connected to the input of decision block, block inputs vdeleni tuning combinations and correction speed change unit are combined and connected to the output deciding unit, an output of the first summatora-. connected to the second input of the correction rate change block, each of the n control channels completed in the form of a series-connected subtractor and a counter, the first input of the subtractor is the first input of the control channel, the second input of the subtractor is the second input of the control channel, the clock input of the counter is the third input the control channel, and the block for changing the correction rate contains a series-connected reader and counter, the first output of which is the output of the block for changing the speed of correction ii, noise indicator, the input of which is connected to a second output counter, and a delay element input prichem.pervy subtractor is correcting the first input of the speed change unit and to the second input vychi3.

The connector is connected to the output of the delay element, the input of which is the second input of the block for changing the correction rate.

The drawing shows a structural electrical circuit of the proposed device /

The device contains comb filter 1, n correction elements 2, first, second and third adders 3-5, decisive block 6, block 7 indica, block 8 of the tuning combination, h of adjustment channels 9, each of which contains subtractor 10 and counter 11, a correction rate change unit 12, consisting of an emitter 13, a counter 14, a noise indicator 15 and a delay element 16.

The device works as follows

The demodulated signal is fed to a comb filter 1, which, in the presence of a quadrature component of the signal, can include a Hilbert converter, for example, when a signal for one reference point is taken from each unit interval. If two or more reference signals are taken from each unit interval, then the Hilbert converter is not required, since the separation of the signal into the in-phase and quadrature components can be performed using a comb filter 1, with decimation of the count signals at the output of the comb filter 1 made for example, in the form of a fast Fourier transform (FFT) unit.

Comb filter 1 There is no conversion of the time signal to the frequency domain. The signal from the output of the comb filter of each sample in the frequency domain together with the signals of the corresponding window from the memory of the comb filter goes to the corresponding element 2, 2 ,,, ,, 21 ,. correction where it is corrected in accordance with the resulting frequency distortions in the communication channel. The second input of each correction element 2 receives an error signal from the corresponding control channel 9. The differential signal from the subtractor 10 of the control channel 9 is formed as a result of comparing the signals with

09917-4

output of the correction element 2 and the reference signal in the form of the corresponding spectral components from block 8 in the alignment of the training combination, which may

enter the corresponding shift register and the decoder, if this block is made in the form of a memory block, using the decisive block 6 from block 8

10 can be submitted to the subtractor ;: 10 only the corresponding signals of a large magnitude (for example, spectral components are more common, having a value of at least 50% of the maximum value), which increases the noise immunity. With a multilevel signal, block 8 is expediently implemented by analogy with comb filter 1, but with limiters at the outputs,

20 because if, in this case, block 8 is executed in the form of a memory, the memory will be required more.

When entering from the decision block 6 on block 8 of the next signal

25 solutions from block 8, the separated values of the spectral components of the reference signal (training combinations) are received, respectively, by their subtractors 10 corresponding to their 1H

30 channels 9 adjustment. To the second input of the subtractor 10, the signal Y, n is fed from the second output of the correction element 2, more precisely from the output of the multiplier of the correction element through the equalizing delay.

Directly from the outputs of the multipliers of the correction elements 2, the signal goes to the first and second adders 3 and 4 as inverse FFT

40 (OBPF), In certain cases, for example, at low noise of a communication channel, ordinary, digital (or analog) satellites can serve as adders 3-5. If the outputs

45 adders 3 and 4 are missing digital-to-analog converters (D / A converters), then the signals directly from adders 3 and 4 in the form of OBPF are sent to decisive block 6, which is

The SP case is performed in digital form. In certain cases, the comb filter 1 is expediently executed in the form of two FFT blocks (one for Accounting samples and the other for odd ones), which allows

55

Raise correction rate,

The device must include a clock synchronization unit. And the reference signal has connections with blocks and cxefibi elements (indicated connections are shown), From the output of the first adder 3, the value of the output signal with noises through the element 16. The delay is fed to the input of the subtractor 13 of the block 12 for changing the correction rate. The other input of the subtractor 13 receives the decision signal from the decision block 6 (or the c-block 8, where the exact value of the decision signals can also be stored). At the output of the subtractor 13 of the block 12, we have the values of the noise of the communication channel. Using the counters 11 of the adjustment channels 9 and the counter 14 of the block 12, the correction rate is varied depending on the amount of noise in the communication channel; For this, the noise signal from the output of the subtractor 13 through the counter 14 of the block 12 is fed to the clock inputs of the counters 11 of the control channels 9. With large noise, the correction rate decreases, however, the accuracy of the correction increases compared to if the correction rate does not change with a change in the magnitude of the noise. From the output of the counter 14 of the block 12, the magnitude of the noise is fed to the input of the indicator 15, which displays the noise value in the communication channel. From the counters 11 of the control channel 9, the signals are also fed to the input of the frequency characteristics indication unit 7, which displays the frequency characteristics of the communication channels zi The highest correction rate is obtained if the signals of all n points of reference (for example, for data transmission, it is advisable to take n 128) to be removed from each unit interval. However, in many cases it is advisable to take only a part of the signal of reference points from a given unit interval, i.e. distribute 11 128 reference point signals to 32.64 or 128 unit intervals — 4.2 or 1 reference point for each unit interval. This allows many times to reduce the speed of the computing device, i.e. reduce the number of operations per unit of time. Nevertheless, the correction rate remains higher than the correction rate in the known correctors operating in the time-variable region. If from the output of the comb filter 1, for example, on the FFT unit, the signal is fed to the input of the Yvzi channel, and from the output of the communication channel, the signal is fed to the correcting elements 2, 2 ,. . ., 2, then in some cases (for example, in radio channels), noise immunity can be further improved. Then, demodulation (depending on the conditions) is advisable to be carried out before the decision block in the demodulator or in correction elements 2.2, ..., 2. Thus, the introduction of two additional adders and a decision block into the device, as well as the proposed implementation of the adjustment channels and the correction speed variation block with noise indication, improve the correction accuracy and convergence rate, as well as obtain information on noise in the communication channel.

Claims (1)

, ADAPTIVE CORRECTION DEVICE IN THE FREQUENCY AREA WITH CHARACTERISTICS DISPLAY, containing a comb filter, each of the h outputs of which is connected to the input of the corresponding correction element, the first outputs of the odd correction elements are connected to the inputs of the first adder, unit for highlighting the adjustment combination, block for changing the correction speed display unit and η control channels, the first input of each of the n control channels is connected to the corresponding output of the tuning combination unit, the second input of each of η ka control signals is connected to the second output of the corresponding correction element, and the third input of each of the η control channels is connected to the output of the correction speed change unit, the first output of each of the η control channels being connected to the second input of the corresponding correction element, and the second output of each of the control channels to the corresponding input of the display unit,