RU2295195C1 - Digital device for data transfer and protection in communication lines - Google Patents

Abstract

FIELD: digital communications engineering.

SUBSTANCE: proposed device has data input unit as well as clock sync pulse shaper, input data encoding, modulation signal selecting, control signal shaping, initial phase selecting, and modulation signal frequency selecting units integrated into microprocessor set, multichannel digital pulse generator, modulation units made in the form of multichannel digital partial-frequency orthogonal signal generator, multiplexer, adder, matched infinite impulse response filter quasi-optimal with respect to speed, two delay units, reset unit, digital-to-analog converter, amplifier, and matching unit with communication channel, as well as relevant interconnections between them.

EFFECT: enhanced data transfer speed over communication channel.

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Description

The invention relates to communication technology and technology.

Known, for example, devices for the simultaneous use of communication channels in the transmission of audio information and the transmission of telemechanical information, for example in electrical communication channels [1. "Theoretical Foundations of Information Technology" F.E. Temnikov, V.A. Afonin, V.I. Dmitriev. - M .: Energy, 1979, S. 315-330].

The need to simultaneously generate several harmonic oscillations of different frequencies associated with internal coherence with the phase of oscillations of a common reference source arises, for example, when creating communication systems based on ultra-wideband signals, when relaying several frequency bands, etc. [2. "Synthesizers of frequencies and signals" L.A. Belov. - M .: SAYNS-PRESS, 2002, p.70-71]. However, the simultaneous amplification of several quasi-harmonic oscillations can lead to crosstalk due to the appearance of peak instantaneous values. Depending on the choice of the values of the channel frequencies and their initial phases, periodic changes in the envelope may occur in the total signal, even if the channel signals do not have amplitude modulation. In digital communication channels, including radio channels, the correlation separation method is widely used. For example, in digital devices with frequency and phase separation, a carrier with the functions COS kwt and SIN kwt is used.

Closest to the proposed solution is a device [3. RF patent 2132593 "Multichannel device for transmitting speech signals", N 04 B 3/00, H 04 J 3/00, 05/13/98], containing an information input unit, a clock synchronizer, a modulation signal selection block, a control signal shaper, blocks modulation, adder, first and second delay units, a reset unit, the first output of the first delay unit connected to the input of the second delay unit, and the second output with the input of the reset unit, amplifier and matching unit with the communication channel. The number of modulation units and the number of amplifiers in it is equal to the number of channels.

The disadvantages of this device include low noise immunity to external noise in the communication channel, and especially to intersymbol interference. This leads to irrational use of the frequency range of tones of the switched communication channel, which can be hybrid, for example, a radio extension plus a public telephone network. A multi-frequency broadband signal passing through switched analog communication channels is distorted, since different frequency components are delayed for different times, depending on the parameters of the switched communication channel and the frequency of the signal under study. Technical implementation is complicated by a high noise level with an undefined distribution law and non-stationary parameters of information transmission channels in communication technology and technology. Therefore, for the transmission and noise-free reception and protection of information in the tonal frequency range in real time, it is necessary to apply adaptive digital filters that are optimal in noise immunity.

The present invention is directed to increasing the transmission speed of information in a communication channel in the tonal frequency range by using multi-frequency orthogonal partial frequency signals with a reduced peak factor. The technical result achieved in solving this problem is the optimal use of a switched communication channel at the physical level.

This is achieved by the fact that in a known device containing an information input unit, a clock generator, a modulation signal selection unit, a control signal generator, modulation units, an adder, a first and second delay unit, a reset unit, the first output of the first delay unit is connected to the input the second delay unit, and the second output with the input of the reset unit, an amplifier and a matching unit with a communication channel, input information coding units, initial phase selection, and modulation signal frequency selection are introduced c, a multi-channel digital pulse generator, a multiplexer, a quasi-optimal digital matched IIR filter and a digital-to-analog converter, modulation blocks are made in the form of a digital multi-channel generator of orthogonal partial frequency signals, and a clock generator, input information encoding block, modulation signal selection block, block forming control signals, a block for selecting the initial phases and a block for selecting the frequency of modulation signals are combined into a microprocessor a complete set, wherein the information input of the input information encoding block is connected to the output of the information input block, and the output is with the first input of the modulation signal selection block, the first output of which is connected to the initial phase selection block, the output of which is connected to the corresponding inputs of the multi-channel digital pulse generator, and the second the output of the modulation signal selection block - with the input of the modulation signal frequency selection block, N outputs of which are connected to the corresponding control inputs of the digital multi-channel of a partial frequency orthogonal signal generator, the exciting inputs of which are connected to the corresponding N outputs of a multi-channel digital pulse generator, and 2N of the digital multi-channel partial frequency orthogonal signal generator is connected to the corresponding inputs of the adder via a multiplexer, the output of the adder is connected to a quasi-optimal matched digital IIR information input filter, the output of which through a series-connected digital-to-analogue conversion The atelier, amplifier, and matching unit are connected to the communication channel, the first, second, and fourth control inputs of the quasi-optimal matched digital IIR filter being connected through the driver to the corresponding outputs of the modulation signal selection block, the third and fifth control inputs are connected to the corresponding outputs of the block reset, and the synchronization inputs of all blocks and the microprocessor set are connected to the corresponding outputs of the clock generator. The preferred embodiment also consists in the fact that the multi-channel generator of orthogonal partial frequency signals contains N adaptive resonant narrow-band digital filters, each of which is made in the form of a first arithmetic multiplier connected in series in parallel code, the first input of which is connected to the corresponding output of the multi-channel digital pulse generator, arithmetic adder-subtractor and two digital integrators, the first of which consists of sequentially connected the second arithmetic multiplier and the first arithmetic accumulator-accumulator, and the second digital integrator - from a series of the third arithmetic multiplier and the second arithmetic accumulator-accumulator, the output of the second digital integrator connected to the second input of the arithmetic adder-subtractor and at the same time is the first output of the filter, the output the first digital integrator is the second output of the filter, the second input of the first arithmetic multiplier and the combined second inputs s second and third arithmetic multipliers coupled to corresponding control outputs of the selection frequency modulation block signals, and the reset inputs of digital integrators connected to respective outputs of the microprocessor package. It is also proposed to perform a quasi-optimal matched-speed IIR digital filter containing the first arithmetic multiplier connected in series in parallel code, the first input of which is the filter information input, the first arithmetic adder-subtractor and two digital integrators, the first of which consists of a second arithmetic multiplier and the first arithmetic accumulator adder, and the second digital integrator - from the third in series about an arithmetic multiplier and a second arithmetic accumulator-adder, and the output of the second integrator through the first input of the second arithmetic adder-subtractor connected to the second input of the first arithmetic adder-subtracter, and the output of the first integrator through the buffer register connected to the second input of the second arithmetic adder-subtractor, the second the input of the first arithmetic multiplier is the first control input of the filter, the second inputs of the second and third multipliers are the second control input filter house, the second control inputs of the first and second arithmetic adders drives are connected to respective outputs of the reset unit, and an output buffer register simultaneously the filter output and is connected to the data input of the digital to analog converter.

Figure 1 shows a diagram of the proposed digital device for transmitting and protecting information in communication networks;

figure 2 - execution diagram of a multi-channel generator of orthogonal signals of partial frequencies;

figure 3 is a diagram of a quasi-optimal performance matched digital IIR filter.

The proposed device (see Fig. 1) contains an information input unit 1 combined in a microprocessor set 2, a clock synchronizer 3, a digital input information encoding unit 4, a modulation signal selection block 5, a control signal shaper 6, an initial phase selection block 7, and a block frequency selection modulation signals 8, a multi-channel digital pulse generator 9, a digital multi-channel generator of orthogonal partial frequency signals 10, a multiplexer 11 and an arithmetic adder 12, quasi-optimal in terms of speed, a digital matched IIR filter 13, a first delay unit 14 and a second delay unit 15, a reset unit 16, a digital-to-analog converter (DAC) 17, an amplifier 18, and a matching unit with a communication channel 19.

A preferred embodiment of a single channel digital multi-channel orthogonal partial frequency signal generator in the form of an adaptive resonant narrow-band digital filter is shown in FIG. 2. This digital filter contains a first arithmetic multiplier 20, an arithmetic adder-subtractor 21, a first digital integrator 22 and a second digital integrator 23, a second arithmetic multiplier 24 and a first arithmetic adder 25, a third arithmetic multiplier 26 and a second arithmetic adder 27.

Quasi-optimal matched digital IIR filter (see FIG. 3) contains the first arithmetic multiplier 28, the first arithmetic adder-subtractor 29, the first digital integrator 30 and the second digital integrator 31, the second multiplier 32 and the first arithmetic adder 33 an arithmetic multiplier 34 and a second arithmetic adder-accumulator 35, a buffer register 36 and a second arithmetic adder-subtracter 37.

A digital device for transmitting and protecting information in communication networks works as follows. Figure 1 shows a diagram of a signal transmitter with time-pulse modulation. Digital input information (for example, audio information or analog signals from telemetry sensors after analog-to-digital conversion (ADC) in real time, voice mail with buffer memory, text information recorded in digital form, etc.) through the information input unit 1 in a parallel code enters the microprocessor set 2. The input of information is synchronized by a precision clock generator 3, the first output connected to the control input of the digital block of encoders Nia input data 4 which, in accordance with the code table of input data symbols and signal frequencies in the switched communication channel, for example, in the tone frequencies, selects time-variant impulse transmitter modulation. The information output of the digital input information encoding unit 4 is connected to the modulation signal selection block 5, which first and second real-time information outputs controls the initial phase selection block 7 and the modulation signal frequency selection block 8. The clock synchronization of these blocks is carried out by the control signal generator 6, which is connected to a precision clock driver 3. To increase the accuracy of coherent formation of multi-frequency signals, partial x frequencies in the tonal frequency range, it is necessary to use a frequency divider in the driver of control signals (for example, 100 MHz / 10 MHz / 1 MHz / 100 kHz / 10 kHz), and the lower limit of 10 kHz can be used for ADCs when entering information in real time. The synthesis of multi-frequency orthogonal partial frequency signals is performed using a multi-channel digital pulse generator 9 and a digital multi-channel generator of orthogonal partial frequency signals with a higher frequency (for example, two orders of magnitude higher, 1 MHz). This can significantly improve the accuracy of approximation of harmonic signals at the output of a digital multi-channel generator of orthogonal partial frequency signals, which is made in the form of N parallel adaptive digital resonant narrow-band filters (see figure 2). The main advantages of this version of the synthesis of orthogonal harmonic signals using a generating dynamic system described by a second-order differential equation include:

- the ability to adaptively control in digital form one-by-one defined parameters “amplitude”, “phase” and “frequency”;

- the minimum number of arithmetic operations that must be performed on each clock cycle in the pipelined mode of digital signal processing;

- the speed of changing and tuning parameters, such as frequency.

In order to transmit and receive multi-frequency signals with a reduced peak factor, one should select the nominal frequency values F _n and the grid spacing d F _ij so that the ratio of any of the grid frequencies to the step size is not a small integer. The possibility of using an uneven frequency grid simplifies the solution to this problem. It is necessary to choose such a distribution of the initial phases over the channels so that for the repetition period [1 / d F _ij ] never simultaneously all the vectors of the partial channels have the same angular coefficients. As an initial approximation to the optimal distribution, one can choose the quadratic proportionality of the initial phases to the partial frequencies of the channels (the envelope of the LFM signal with such a phase spectrum is constant). The initial phases with a high degree of coherence under zero initial conditions are provided by a multi-channel digital pulse generator 9 for each of N partial frequencies. So, for example, the relative error in setting the nominal frequency values in accordance with the requirements of a uniformly temperamental system should be no more than 10 ^-3 in the frequency range of the order of an octave. A quantitative estimate of the permissible frequency instability of the generator of orthogonal harmonic signals is usually called the value of the parasitic frequency deviation for a time of the order of 1 s (lower frequency F _H = 1 Hz, upper frequency F _B > 1 MHz). An example is a synthesizer of a stable frequency grid based on an analog chip ADF4113 by Analog Devices, which operates on a single-ring PLL with a fractional frequency divider with a variable division ratio (DPCD). The process of switching to another grid frequency takes no more than 200 μs. The spectral density of phase noise at the output is not more than 89 dBc / Hz, the discrete components of the MSS are not more than 70 dB. The proposed device allows you to complete the transition to another partial frequency in almost two cycles of the clock shaper 3 (for example, 2 × 10 ^-8 s). The error in setting the initial phases (for example, in the range of one octave from 2000 Hz to 4000 Hz) will not exceed 0.01 degrees. Frequency modulation is noise-resistant, since distortion during the transmission of information in the communication channel and the presence of industrial interference is mainly affected by the signal amplitude, not the frequency. The signal spectrum necessary for this type of modulation can be significantly narrower than the entire bandwidth of the communication channel.

The effective duration of the generated orthogonal harmonic signals at the output of the digital multi-channel generator 10 is precisely controlled by the multi-channel digital pulse generator 9 and the corresponding control signal from the output of the driver of the control signals 6. The continuously generated 2N signals through the multiplexer 11 are fed to the corresponding inputs of the arithmetic adder 12. The total multi-frequency signal of limited duration in parallel code from the output of the arithmetic adder 12 in real m the time scale is fed to the information input of a digitally matched IIR filter 13, which is quasi-optimal in speed, a detailed diagram of the technical implementation of which is shown in FIG. 3. This digital IIR filter, adaptively tuned to the frequency band and controlled by the corresponding signals from the modulation signal selection block 5 through the control signal generator 6 included in the microprocessor set 2, optimally filters the multi-frequency signal before applying it to the information input of the DAC 17, with additional gating the effective duration of the information transmission frame is carried out by the first 14 and second 15 delay units, the outputs of which are connected through a reset unit 16 to the corresponding mi control inputs digital matched IIR filter (see figure 3). Next, the multi-frequency signal through the amplifier 18 and the matching unit with the communication channel 19 enters the communication channel in the form of a limited-duration real-time information frame, which is transmitted to the recipient of information and decoded.

An important characteristic of a multi-frequency signal is the coefficient of its peak factor k _p = P _max / P _cf , where P _max is the peak vibrational power, and P _cp is the average power of the total oscillation. Experimental verification of the layout of the proposed digital information transfer device with moderate performance requirements for the microprocessor set showed a decrease by an order of magnitude of the peak factor with optimal initial phasing. For comparison, we can cite the known results of the transmission and identification of tone dialing signals (DTMF): 0, 1 ... 9, *, #, A, B, C, D (the so-called code "2 of 6"); the minimum generation time and adequate identification of a single tone is 32 ms. The proposed device allows you to generate and accordingly identify on the receiving side 10 individual tones in one octave of the tonal frequency range for a shorter time interval, for example 10 ms.

Claims (3)

1. A digital device for transmitting and protecting information in communication networks, comprising an information input unit, a clock synchronizer, a modulation signal selection unit, a control signal generator, modulation units, an adder, a first and second delay unit, a reset unit, and a first output of the first unit the delay is connected to the input of the second delay unit, and the second output to the input of the reset unit, the amplifier and the matching unit to the communication channel, characterized in that it contains blocks for encoding input information, select phase and frequency selection of modulation signals, a multi-channel digital pulse generator, a multiplexer, a quasi-optimal digitally matched IIR filter and a digital-to-analog converter, modulation blocks are made in the form of a digital multi-channel generator of orthogonal partial frequency signals, and a clock generator, an input information encoding unit, modulation signal selection block, control signal generation block, initial phase selection block and frequency selection block m modulation signals are combined into a microprocessor set, the information input of the input information coding block connected to the output of the information input block, and the output to the first input of the modulation signal selection block, the first output of which is connected to the initial phase selection block, the output of which is connected to the corresponding inputs of the multi-channel generator digital pulses, and the second output of the modulation signal selection block - with the input of the modulation signal frequency selection block, N outputs of which are connected to the control inputs of a digital multichannel orthogonal partial frequency signal generator, the exciting inputs of which are connected to the corresponding N outputs of the multichannel digital pulse generator, and 2N outputs of a digital multichannel orthogonal partial frequency signal generator are connected to the corresponding inputs of the adder via a multiplexer, the output of the adder is connected to a quasi-optimal information input performance of an agreed-upon digital IIR filter, whose output through the last the digitally-analog converter, amplifier, and matching unit are connected to the communication channel, the first, second, and fourth control inputs of a quasi-optimal matched digital IIR filter connected through a driver of control signals to the corresponding outputs of the modulation signal selection block, the third and fifth control inputs are connected to the corresponding outputs of the reset unit, and the synchronization inputs of all units and the microprocessor set are connected to the corresponding Exit serial clock generator. 2. A digital device for transmitting and protecting information in communication networks according to claim 1, characterized in that the multi-channel generator of orthogonal signals of partial frequencies contains N adaptive resonant narrow-band digital filters, each of which is made in the form of a first arithmetic multiplier connected in parallel in parallel code, the first input of which is connected to the corresponding output of a multi-channel digital pulse generator, an arithmetic adder-subtractor and two digital integrators, the first of which of the second consists of a third arithmetic multiplier and a first arithmetic accumulator-accumulator, and a second digital integrator of a third arithmetic multiplier and a second arithmetic accumulator-sequentially connected, the output of the second digital integrator connected to the second input of the arithmetic adder-subtractor and simultaneously being the first filter output, the output of the first digital integrator is the second output of the filter, the second input of the first arithmetic mind the cutter and the combined second inputs of the second and third arithmetic multipliers are connected to the corresponding control outputs of the modulation signal frequency selection unit, and the reset inputs of the digital integrators are connected to the corresponding outputs of the microprocessor set. 3. A digital device for transmitting and protecting information in communication networks according to claim 1, characterized in that the matched quasi-optimal speed IIR digital filter contains a first arithmetic multiplier connected in parallel in code, the first input of which is a filter information input, the first arithmetic adder a subtractor and two digital integrators, the first of which consists of a second arithmetic multiplier and a first arithmetic accumulator-accumulator connected in series, and the second the second digital integrator is from the third arithmetic multiplier and the second arithmetic accumulator-accumulator connected in series, the output of the second integrator through the first input of the second arithmetic adder-subtractor connected to the second input of the first arithmetic adder-subtracter, and the output of the first integrator through the buffer register connected to the second input the second arithmetic adder-subtractor, the second input of the first arithmetic multiplier is the first control input of the filter, the second input The second and third multipliers are the second control input of the filter, the second control inputs of the first and second arithmetic accumulators are connected to the corresponding outputs of the reset unit, and the output of the buffer register is simultaneously the output of the filter and connected to the information input of the digital-to-analog converter.

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