SU1800641A1 - Temporal-position discrete signal modulation - Google Patents

Description

The invention relates to radio engineering and can be used to generate discrete signals modeled in a temporary position.

The aim of the invention is to increase the noise immunity of the output signals by reducing the amplitude of the side peaks of their autocorrelation functions.

In FIG. 1 shows a structural diagram of the proposed modulator; in FIG. 2 is a timing diagram explaining its operation.

The modulator contains a negative voltage source 1, an integrator 2, a comparison unit 3, a quantizer 4, a storage unit 5, a clock generator 6, a first frequency divider 7, an adder 8, a key 9, a second frequency divider 10, a Walsh function generator 11, a rectangular generator 12 oscillations, counter 13, switch 14, multiplier 15.

The modulator works as follows.

At the initial time, the voltage at the output of the quantizer 4 is zero, therefore, at the output of the storage unit 5, it is also equal to zero. At the initial time, the voltage at the output of the integrator 2 is zero. Since the inputs of the comparison unit 3 receive the same voltage, equal to zero, an impulse is generated at the output of the comparison unit 3, which sets the integrator 2 and the storage unit 5 to the initial state. The counter 13 is set to zero. The input modulating signal (Fig. 2 a) is input to the quantizer 4, which periodically reads the values of the input signal at time instants 0, Θ, 2 Θ ... and quantizes them. The number of quantization levels is equal to the number of elements of the Walsh functions (for the case under consideration 2 = 8) (Fig. 2, b). The resulting voltage is stored for certain periods of time in the storage unit 5 (Fig. 2 c). At the output of the integrator 2, a positive sawtooth voltage is obtained (Fig. 2 g). The voltage comparison unit 3 generates a pulse at that moment in time when the sawtooth voltage reaches the voltage value at the output of the storage unit 5 (Fig. 2 e). This pulse initializes the circuit of the storage unit 5 and the integrator 2. At the output of the storage unit 5, positive pulses are obtained, the duration of which is proportional to the value of the quantized voltage, and the amplitude is equal to the value of the quantized voltage (Fig. 2 c). ___

When these pulses arrive at the first (control) input of the key 9, the key turns out to be open, and the pulses from the clock generator 6 (Fig. 2 e) are at the output of the key 9 (Fig, 2 h).

The frequency divider 7 forms from the pulse train from the output of the clock generator 6 a pulse train having a much longer period (Fig. 2, g). This sequence of pulses goes through the adder 8 to the clock input of the Walsh function generator 11, generating a specific Walsh function, for example, Wai (3 0).

The pulses from the output of the key 9 through the adder 8 are added to the pulses from the output of the frequency divider 7 immediately after time instants 0, Θ 2 Θ, ... Since the pulse period from the output of the key 8 is much less than the period of pulses from the output of the frequency divider 7, then at the output of the generator 11 Walsh functions formed Walsh function, modulated in phase. Moreover, the phase shift is proportional to the value of the quantized voltage of the input signal received at the output of quantizer 4. For example, if the value of the quantized voltage is 0, then the phase shift is 6¾. If the value of the quantized voltage is 1, then the phase shift is carried out by one element of the Walsh function. If the value of the quantized voltage is 2, then the phase shift is carried out by two elements of the Walsh function, etc. (Fig. 2, k).

The frequency divider 10 forms from the pulse train from the output of the frequency divider 7 pulses that trigger the quantizer 4 circuit at time instants 0, Θ, 2 Θ, ... (Fig. 2 k). The same pulses arrive at the second input of the start of integration of the integrator 2 and start it up, as well as at the second input of setting the counter 13 to zero and reset it to zero.

The pulse sequence fed to the input of the generator 11 of the Walsh functions is also fed to the inputs of the generator 12 of square waves and to the input of the counter 13. Thus, when the first 2 ^P ' ¹ pulses are received from the output of the adder 8, the output of the counter .13 generates 0, when the following 2 ^P ' ¹ pulses at the output of the counter is formed 1, then until the next moment ty at the output of the counter 13 is formed 0 (Fig. 2 about).

The switch 14 is designed so that when it arrives at its second (control) input 0, a signal is generated at its output at the first (information) input, and when it arrives at its control input 1, a signal is generated at its output at its third ( informational) input.

Therefore, when the first 2 ^P ' ¹ pulses arrive from the output of the adder 8 after time instants 0, Θ, 2 Θ ... at the output of the switch 14, a signal is generated from the output of the square-wave oscillator 12 (Fig. 2 m), when the next 2 ⁿ¹ pulses from the output of the adder 8 at the output of the switch 14 generates a signal from the output of the generator 12 of rectangular waves (Fig. 2 m), upon receipt of the next 2p-1 pulses from the output of the adder 8 at the output of the switch 14, a signal is generated from the output of the source 1 of negative voltage (Fig. 2 n), then until the onset of the next time moment fy at the output of the switch 14, a signal is formed again from the output of the square-wave oscillator 12 (Fig. 2 m). The signal at the output of the switch 14 has the form shown in FIG. 2 p).

The signal from the output of the switch 14 is fed to the input of the multiplier 15 and is multiplied by the Walsh function. At the output of the multiplier 15 a signal is generated modulated by the temporary position (Fig. 2 p).

The pulse repetition period from the output of the generator 6 clock pulses can be chosen so small compared with the duration of the elements of the Walsh functions that short elements (Fig. 2 m, n, p) can be neglected (in Fig. 2 they are shown only to explain the mechanism of the phase shift Walsh functions and phase shift of the output signal).

Claims (1)

Claim A temporal position discrete signal modulator comprising a quantizer, a storage unit, a key, an adder, and a Walsh function generator, the first quantizer input being a modulator input, the output of the storage unit connected to the first input of the comparison unit, the second input of which is connected to the output of the integrator, the first the input of which is connected to the output of the negative voltage source, and the output of the comparison unit is connected to the second inputs of the storage unit and the generator, the second key input is connected with the output of the clock pulse generator and the input of the first frequency divider, the output of which is connected to the second input of the adder and the input of the second frequency divider, the output of which is connected to the installed quantizer input, characterized in that, in order to increase the noise immunity of the output signals by reducing the amplitude of the side peaks of their autocorrelation functions, a square wave generator, a counter, a commutator and a multiplier are introduced, the output of the adder being connected to the input of the square wave generator and to the first the counter, whose outputs are connected respectively to the first and second inputs of the switch, the third input of which is connected to the output of the negative voltage source, the output of the Walsh function generator is connected to the first input of the multiplier, the second input of which is connected to the output of the switch, the output of the multiplier is the output of the modulator, the output of the second the frequency divider is connected to the second input of the counter and the third input of the integrator. _____________________ & ________________________: ________ δΐ— ~~ __ — __ — ___ i_____________ / ³ illllll ί IIII IIII if 11Я111И11ΠΙΠΙ llHIIIIH Illi 111IIIHIIIШIIΗI II I! ΠΙΙΙΙΙΙ111 111 I! eleven! III111II1111 III I Illi 111111 J L I I I ... ,, 1 ...... l I ------ 1 ------ 11 ________________________________________________1111_________________________________________________________________________ Mil I I I I I I I I Illi I______L_J______I______I______II Λ1 _______________________________ II, ΜιΙ (3.8> - '/ β) ψ Wal (3.lk-3 / e) j Γ ~~~ Ί Γί · Γ ~ Ί I Ί ^d 2 n l ......... ------- γςζ .........:. —J Figure 2