SU951725A1 - Device for intercharacter distortion adaptive correction - Google Patents

Description

(54) DEVICE FOR ADAPTIVE CORRECTION OF INTERIM-VOLUME DISTORTIONS

one

The invention relates to communication technology and can be used to correct intersampling distortions in modulated signals received by two demodulators.

A device for adaptive intersymbol distortion correction is known, containing serially connected analog-to-digital converter, a memory unit and an arithmetic unit, outputting polarities and signs of the amplitude deviation of the modulated signal from the nominal value of which is connected to another input of the memory unit whose synchronization input is connected to the output of the program block, the control input of which is connected to another Output of the analog-digital transformer, the synchronization inputs of the arithmetic unit and the memory block coeff of the transfer clients, whose output is connected to another input of the arithmetic unit, another output of the memory block is connected to another input of the coefficient memory block through the correlation block

transmission, and another output of the arithmetic unit 1; the output of the device whose inputs are the input of an analog-digital converter and another input of the program block JflJ However, the known device has a low accuracy of adaptive correction.

The purpose of the invention is to increase the accuracy of adaptive correction by eliminating false adjustments of coefficients.

10 transfer.

This goal is achieved by the fact that the device for adaptive correction of intersymbol distortions, containing serially connected analog digital converter, memory block and arithmetic unit, field output and the signs of the amplitude deviation of the modulated signal from the nominal of which is connected to another input of the block

20 memory, the synchronization input of which is connected to the output of the program block, the control input of which is connected to another output of the analog-digital converter, the synchronization inputs of the arithmetic block and the block of the memory of transmission coefficients whose output is connected to another input of the arithmetic block, another output of the memory block They are connected to the input of the correlation unit, and the other output of the arithmetic unit is the output of the device, whose inputs are the input of the analog-digital converter and another input of the software the block, the additional block of memory and the control block are entered, while the output of the correlation block is connected via the control block to another input of the transmission coefficient memory block, the other output of the program block is connected via an additional memory block whose input is connected to the additional output of the arithmetic block , to another input of the control unit. The drawing shows a block diagram of the proposed device. The device for adaptive intersymbol distortion correction comprises an analog-digital converter 1, memory block 2, program block 3, correlation block 4, arithmetic block 5, block 6 for transmission gains, control block 6, additional memory block 8. The device works as follows. QYQ Q Analog signals from (- and. Of the receiver demodulators (not shown) go to the analog-digital converter 1, where these signals are gated at the reference times, memorized and stored amplitudes of the received voltages of samples and sample conversion c) bit code numbers. The process is transformed AND takes place, which first converts the signal a B from the output of the first (in-phase) demodulator, and then the signal Q5 from the output of the second (quadrature) demodulator of the receiver ;: B. the same order etc writing to memory block 2 of two K-digit samples of the result of the conversion is made. Memory block 2 from the output of arithmetic unit 5 also records polarity data of modulated signals a and a on device codes (SgHO and) and signals SQUe, showing the sign of the amplitude deviation of the amplitude of the corrected modulated signals al and a from the nominal. Control signals for changing the ratio of 4. transmitting the controller of the torch taps are output in accordance with the following algorithm: the common-mode interference compensation Rf J - 6 MaJ®s aJ®s§ e | C.1) i е-.5 ag © s§ ao © eg (i; Approx. Compensation of the quadrature mei influence i s§rHa | s c | 0 © sg.MeS Cz) C4; Oi a and dgu а is the sign of the projection of signals subjected to a pacing effect on the coherent lobbies R and Q. respectively; . gHCI M is the sign of the projection of the signals that create the moving effects on the coherent oscillations R and Q, respectively; Bee and hee is the sign of the projection of the deviation of the amplitudes of the signals a from the nominal value relative to coherent oscillations R and Q, respectively. According to the commands of program block 3 and in accordance with the selected algorithm of the device operation, correlation unit 4 generates signals about the change of the transfer coefficient of the corresponding tap of the device, which, in the form of U NR, has the first TI number stored in the block 6 of the transfer coefficient memory. In each cycle of operation of software block 3, from blocks 2 and 6 to the multiplication block (not shown) of arithmetic block 5, two AND-bit code numbers are received, corresponding to the modules and polarity of the sample codes and transmission coefficient for the corresponding controller retraction device. Other than first in the arithmetic unit 5 comes the code

 signal dt, and then the signal sampling code from 1 (l multiplied by the same coefficient of the transmission coefficient of the controller of the corresponding tap of the device. Received products 5

two pairs of numbers are written by commands from {program block 3 to one of two adders (not shown) of arithmetic block 5, in order to sum the products separately O for signal samples d and a.

In the next cycle of operation of the program block 3, from the blocks 2 and 6 of the memory, the code numbers corresponding to the operation-15 of the multiplication of signals for the next tap of the device arrive at the inputs of the arithmetic unit 5. The resulting products are algebraically summed in the corresponding adders of the arithmetic unit 5 with the numbers obtained in the 20 preceding cycle of operation of the program unit 3 for the preceding tap of the device. This process continues until the sums of the arithmetic unit 5 contain the sums 25 resulting from the summation of the products of the sampling codes and transmission coefficients for all the taps of the device.

In the proposed device signals 30 0 | and a9 can coincide with one of the coherent oscillations. In this case, if the projection of the signal, for example, a9 on the coherent oscillation Q, is zero, then the signal SgKi O will be false, and, therefore, the result of calculation by the expression (2) 5QH 1l is also false. Similarly, an incorrect result of determining the signal tl - takes place for this case and by expression (C) .40

Thus, in order to eliminate the formation of spurious signals SQIrh and sOMh about a change in the transmission coefficients of the controllers of the respective taps of the device, it is necessary to use the control prohibition signals for direct or cross-linking in the corresponding taps, i.e. eliminate the possibility of false adjustment for cases where the projections of the signals a and Ct are zero. These control signals (SgnZ .. I9Ots2.) Are formed in the arithmetic unit 5 and fed to the additional, memory unit 8, which is used to combine these signals in time with the signals Sgna, Sgnaf,, 607) At the required moments: nt: s control signals Zf and SQfHZ

from the output of the additional memory block 8 goes to the control block 7 and prohibits the output from the output of the correlation block 4 or Sg nlllJ about the direction of change of the transfer coefficients of the device tap controllers to the input of the transfer ratio memory block 6.

In the process of setting up the device, in block 6 of the memory of transmission coefficients, such code numbers of transmission coefficients are recorded for tap controllers, at which the magnitude of intersymbol distortion is minimal.

Claims (1)

1. US patent No. 3633105, l. 325-42, 197O (prototype).