Generator orthogonal functions

 

(57) Abstract:

Generator orthogonal functions applies to automatics and computer engineering and can be used to create a generator equipment multi-channel communication systems. The purpose of the invention is the increased robustness of the generated signal by reducing the amplitude of the side peaks of the autocorrelation functions of these signals. Generator orthogonal functions contains the oscillator, the power generation of the Walsh function, 2nswitches (2n- the number of generated signals) and the limiter level signals. 6 Il.

The invention relates to automation and computer engineering and can be used to create a generator equipment multi-channel communication systems.

Known generator of the Walsh function, containing the master oscillator and the power generation of the Walsh function.

However, the signals generated by the function generator Walsh, have low immunity, because they have poor correlation properties - amplitude lateral peaks of the autocorrelation functions of these signals are close to one.

The aim of the invention is to increase the noise immunity generated

In Fig. 1 shows a block diagram of the generator of orthogonal functions; Fig. 2 is a timing diagram illustrating the process of forming the proposed function generator (6,), Fig. 3 is a timing diagram of the functions generated by the prototype of Fig. 4 - autocorrelation function of the signals generated by the prototype of Fig. 5 is a timing diagram of the functions generated by the proposed generator of Fig. 6 - the autocorrelation function of a signal generated by the proposed generator.

Generator orthogonal functions contains the master oscillator 1, block 2 formation of the Walsh function, the switches 3 and the stopper 4 level signals.

The generator of orthogonal functions is as follows.

Upon receipt of the pulses output from the oscillator 1 to the clock input of block 2 of the formation of the Walsh function at the outputs of block 2 are formed functions Walsh, coming to the information inputs of the respective switches 3. On the third output unit 2 the formation of the Walsh function is formed by the function Wal (2, ) (Walsh functions at the outputs of block 2 are sorted by the number of snakeprint), which is fed to the input of limiter 4-level signals. It can be implemented as a diode so, commutation 3.

Thus, if the period of the Walsh function, generated by unit 2, denoted by T, to the control inputs of switches 3 during the time [0,T/4] "1" comes, in the course of time ] T/4, 3T/4[ - "0" during time [3T/4, T] is "1". Switches 3 are conventional two-input switches, the outputs of which are formed from the signal of the first information input of the switch, if the control input goes to "1" and the outputs of which are formed from the signal of the second information input of the switch, if the control input signal "0" (see fundamentals of discrete ACS technology and communications./Edited Grinenko, F., L.: WIKI, 1980, S. 354, Fig. 11.3). As a result, in the course of time [0,T/4] on the outputs of the switches 3 are formed signals on their first informational inputs, over time ]T/4, 3T/4[ on the outputs of the switches 3 are formed signals on their second information inputs over time [3T/4, T] from the outputs of the switches 3 are formed signals on their first informational inputs.

In Fig. 2 shows a temporary state of the output of oscillator 1 (a), (seventh unit output 2 formation of the Walsh function, which is formed by the function Wal (6, ) (b), the second o the Finance of the Walsh function, which is formed by the function Wal (2,) (g), output limiter 4-level signals (d), the output of the seventh switch, which is formed by the function C (6,) (e).

In Fig. 5 presents orthogonal functions generated by the proposed generator.

The orthogonality of the functions generated by the proposed generator, you can verify by multiplying any generated signals and integrating the result of multiplying the time So it is Known that the autocorrelation function of the signal S(t) is determined by the expression

R() = S(t)S(t-)dt,

(1) where is the magnitude of the time difference signal. From the expression (1) shows that R() characterizes the degree of connection (correlation) of the signal S(t) with its copy shifted by the value on the time axis. Function =0 reaches its maximum when any signal is perfectly correlated with itself. If this

R(0) = S2(t)dt=E, i.e., the maximum value of the autocorrelation function is equal to the signal energy (Gonorovski I. C., Radio circuits and signals. - M.: Soviet radio, 1971, S. 68).

For the case of signals, normalized by the energy given E = 1, the autocorrelation function FM PSS consists of a Central peak with an amplitude of 1, is hosted on the interval (-o,o), lichnye values, but the signals with good correlation properties they are small, i.e., substantially smaller than the amplitude of the Central peak, is equal to I (Varakin L. E. communication Systems with noise-like signals. - M.: Radio and communication, 1985, S. 30). Signals with lower amplitude side peaks of the ACF are more robust.

Values of the side peaks of the autocorrelation function, which is usually smaller than the main, depend on the actual code sequence (in our case the signal generator output orthogonal functions) and are a consequence of partial correlation code sequence with the same code sequence shifted in time. If you experience these side peaks of the correlation function the ability of the receiver system (communication system that uses signals of a particular class) to establish a reliable synchronization worse, because in this case he must distinguish between the main and lateral peaks of the correlation function (Dixon R. K. Broadband system. - M.: Communication, 1979, S. 67).

The autocorrelation function is of greatest interest when selecting a code sequence to obtain the lowest probability of establishing a false synchronization (Dikso the spine (signal) characterizes the measure of distinctiveness (PR), defined as the difference of values of the autocorrelation function corresponding to the main and lateral peaks. Obviously the greater the PR, the better the code sequence (Dixon R. K. Broadband system. - M.: Communication, 1979, 65 C., and S. 66, Fig. 3.11).

Using EDCM was synthesized signal generated by the proposed generator orthogonal functions having much better compared to analogue and prototype of the autocorrelation function and indicators of distinctness, increasing the immunity generated signals.

The use of the invention allows to create generating equipment multi-channel communication systems, providing the formation of orthogonal functions with a higher noise immunity than analog and prototype through improved correlation properties of the signal by reducing the amplitude of the side peaks of the autocorrelation functions of these signals.

GENERATOR ORTHOGONAL FUNCTIONS, containing the master oscillator and the power generation of the Walsh function, and the output of the master oscillator is connected to a clock input of the processing unit of the Walsh function, characterized in that it wnen with the third output of the processing unit of the Walsh function, and the output - control inputs of all of the switches, the I-th and (2n+ 1 =i)-th outputs (i = ) block the formation of the Walsh function are connected respectively with the first and second information inputs of the i-th switch, the outputs of the switches are the outputs of the generator.

 

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