RU1790041C - Device for transmission of multifrequency signals - Google Patents

Abstract

The device contains 1 code sequence forming unit (1), 1 control unit (2), 1 complex signal former (3), N multipliers (4,5), 1 adder (6). 1 low pass filter (7), 1 spectrum conversion unit (8). 1 synchronization unit (4) and 1 radio transmitting unit (10). 1-4-6-7-8-10, 1-5-6, 1-2-3-4. 3-5, 2-9-10, 2-1. 5 ill.

Description

The invention relates to telecommunications.

The purpose of the invention is to improve noise immunity.

In FIG. 1 shows a structural electrical diagram of the proposed device; in FIG. 2 is a block diagram of a code sequence generating unit; in FIG. 3 is a diagram of a control unit; in FIG. 5 is a diagram of a spectrum conversion unit.

The device comprises a code sequence generating unit 1, a control unit 2, a complex signal generator 3. pulses, multipliers 4, 5, adder 6, low-pass filter 7, spectrum conversion unit 8, synchronization unit 9, radio-transmitting unit 10.

Block 1 contains a generator 11, an analog-to-digital converter (ADC) 12, a counter 13, a demultiplexer 14, OR elements 15, 16, buffer registers 17-20, multiplexers 21, 22, a matching block 23, a count: chic 24.

The control unit 2 comprises a random number generator 25, a trigger 26, a frequency divider 27, a pulse shaper 28, a coincidence unit 29, a frequency divider 30, a shift register 31, an element. OR 32, a coincidence block 33, a generator 34, a clock generator 35, an adder 36 coincidence unit 37, frequency divider 38, inverter 39, driver 3 comprises a demultiplexer 40, coincidence block 41, counter 42, demultiplexer 43, buffer register 44, inverter 45, buffer register 46, inverter 47, generator 48, controllable dividers, frequencies 49 , 50, frequency divider 51, phase shifter l 52, frequency divider 53, phase shifter 54, quadrator 55, multiplier 56, quadrator 57, multiplier 58.

Block 8 comprises an amplifier 59, a spectrum analyzer 60, a control signal driver 61, a tunable filter 62.

The device operates as follows.

The signal from the source goes to the input of the code sequence forming unit, where it is converted to digital form, recorded and presented in the form of pulse packets of a certain duration. The conversion to digital form is carried out using the ADC 12 (Fig. 3) using clock pulses from the generator 11. The first N reports are written to the buffer registers 17 ... 18, the next N samples to the buffer registers 19 ... 20. The recording addresses are formed by the demultiplexer 14 using the counters 13. At the end of the recording of the first N values, they are simultaneously read and the parallel code is converted

in serial using multiplexers 21 ... 22. The pulse duration and duty cycle are determined using a counter 24 and a matching block 23 from the output of block 1, the pulse packets are sent to the N inputs of the N multipliers via N parallel channels. The second inputs of the multipliers receive a signal of the form

N .Sri-1,

G (w) 2) {2 tamin (T0 +

 I

+ vAt) sin (ay + v / cAw) x x (T0 + vAtX2 + yAQ i2 (1)

 Sn-1

 2, cos m (a)) X

V, m 0..

X (TO + vAt) l,

where k is the frequency index; v is a temporary index;

amin - minimum amplitude; T0 is the duration of the time interval;

At-distance between two time elements;

YVK is the law determining the choice of Aad Do) - the interval between adjacent frequencies ;.

S is the number of bursts of pulses; p is the number of pulses in the packet.

Such a signal is generated in block 3. For this, the pulse train from the output of the generator 48 is fed to the inputs of the frequency dividers 49 ... 50 forming a frequency grid. The signals at the output of the dividers are phase-shifted by 90 ° using phase shifters 52, 54, their frequency is changed by the value of m using dividers 51, 53, and a signal is generated with the spectrum corresponding to expression (1) using squares 55, 57 and multipliers 56, 58. The division factors of the dividers 49, 50 do not remain constant, but are randomly changed to improve the noise immunity of the signal. Their values are written from the output of the control unit 2 to the buffer registers 44, 46. To convert the serial code to parallel, a demultiplexer 40, a coincidence block 41, and a counter 42 are used. Recording is made in the intervals between pulses using a demultiplexer 43, reading is performed using inverters 45 , 47.

Using the control unit 2 (Fig. 5), the division factors of the Divisors 49 ... 50 are set and the operation of units 1 and 3 is synchronized. The values of the division coefficients are generated by a random generator, whose number 25 is from a certain interval. N values of them are written into the shift register 3q for 6 write pulses generated using coincidence unit 29, divider 30 w of generator 34. When register 31 is filled with an overflow signal, trigger 26 stops the random number generator 25. The shift register 31 is received read pulses from generator 34 through coincidence unit $ 3 and OR element 32. At the end of readings, trigger 26 generates a signal to start the random number generator. Blocks 27, 28, 37, 38, and 39 are used for synchronization.

.Y -; - v.;,:; ;;; -:,: ;; ,,. . -:; -. : ;;;: -, At the beginning of each cycle of the random number generator, a clock pulse is generated using block 35. It is summed with the signal from the output of the random number generator 25 in adder 36; which allows, through the synchronization unit 9 and the radio transmitting unit 10, to transmit information about the change in the frequencies of the components of the many frequency components of the signal to the receiver ..:; . :: :: / J: l

Promodul iro wa nnne. signals cj of the output of multipliers 4 ... 5 are fed to the N inputs of the adder b. where is the formation of a complex signal. Then, using a filter 7, the signal from the digital form is converted into a set of harmonic components in the spectrum conversion unit (Fig. 4), its energy spectrum is changed according to the expression For Optimal spectral density

1

1

G () ()) ..; h: -: -:; /: p) ....

where A w is the frequency interval;

G (co) is defined by the expression (1).

To this end, the signal is amplified by an amplifier 59, its spectrum is analyzed by a spectrum analyzer 60, and depending on the type of energy spectrum by generating a control signal 61, the characteristic of the tunable filter 62 is changed so that its output has an energy spectrum close to optimal. Expressed by the formula (2) .; ; ,

After that, the generated signal is transmitted to the communication channel using the radar-transmitting unit 10.

. L o rmula and sampling

-; : ./. :. -:. ; . . ; - .-::. .

A device for transmitting multi-frequency signals, comprising a code sequence generating unit, the first input of which is an input of the device, an M-multiplier, the first inputs of which are connected to the outputs of the code sequence generating unit, the second input of which is connected to the first output of the control unit, the second output of which is through the block synchronization is connected to the first input of the radio transmitting unit, the output of which is the output of the device, the outputs of the multipliers are connected to the inputs of the adder, which one with an input low-pass filter, the output of which through the block transform

the spectrum is connected to the second input of the radio-transmitting unit, therefore, in order to increase the noise immunity, a complex signal former is introduced, the inputs of which are connected to the third, fourth, and fifth outputs of the control unit -leni, the input of which is connected to the corresponding output of the block of forming-; and code sequences, the outputs of the former signal generator

co :: dinen with the second inputs of the multipliers. ; , .-. . . :;., ..: V.