DD276574A1 - METHOD AND CIRCUIT ARRANGEMENT FOR GENERATING BINARY PSEUDOSTOCHASTIC IMPULSE SUCCESS - Google Patents

Abstract

The inventive circuit arrangement is used with an appropriate setting for the generation of voltage pulses of selectable constant amplitude, wherein Tastverhaeltnis and pulse width vary pseudo-stochastically in areas whose limits are easy to dimension. Thus, it is suitable for the simulation of interference signals (random telegraph waves), for the analysis of messaging, measurement and control systems - especially for the verification of information channels. In particular, it is suitable for the simulation of stochastically interfered binary signals and jitter effects. The object of the invention is a circuit arrangement and a method for generating bivalent pulse sequences pseudo-stochastically fluctuating pulse width and fluctuating Tastverhaeltnis that are particularly suitable for the simulation of frequency-distorted Binaerfolgen. According to the invention, the object is achieved in that a simple arrangement of inverting trigger, capacitor and two resistors of suitable interconnection is disturbed by suitable coupling in of a periodic control voltage. In contrast to conventional methods, the period of the pseudo-stochastic fluctuations does not depend on the complexity of the component. The invention can be seen in FIG. Fig. 1

Description

the output voltage; it can be calculated from C, Ra, the trigger output levels and its switching thresholds. The control voltage disturbs the vibration of the multivibrator; If this voltage acts in a concomitant manner, ie it accelerates the transhipment of the capacitance during the dynamically stable state, then its duration shortens to T _{m! n} , with opposite effect it increases to T _m , ". Both parameters can be calculated in simple cases, but always determined experimentally; in addition to the characteristics of the multivibrator, they depend on the coupling resistance Re and the amplitude of the control voltage. The choice of the frequency f _{E of} the control voltage now has a decisive influence on the behavior of the circuit. If the frequency of the control voltage is close to the natural frequency of the multivibrator, ie if

T _mi "a (2 · ft)" ¹ s T _m "(D.

is true, it comes to the synchronization, the multivibrator then oscillates with the frequency of the control voltage, and Eq. (1) determines the catch and hold area for it. Also around the odd multiples and parts of the natural frequency of the multivibrator are such synchronization ranges.

The frequency control voltage must be selected so that synchronization does not occur. It can be experimentally and by Poincaro analysis? show that arise pseudo-stochastic binary signals with very long periods, especially in the vicinity of irrational frequency ratios of natural vibration and control signal at the output of the circuit.

embodiment The invention sol! be explained on an embodiment; to show in the affiliation to drawing 1 shows a suitable circuit according to the invention, 2: the idealized transfer characteristic of the inverting trigger, FIG. 3 shows a realization which approximates the ideal properties of the trigger with an operational amplifier (Ra

einb'.zogen, Ri = R ₂ · Uss / (Ucc - Uss)

 4: characteristic voltage curves.

For the sake of simplification, it is assumed that the trigger has no input current and has symmetrical threshold voltages Us, -Us and output levels Ucc, -Ucc. In the first place, Eig E is open. Then the capacitor is charged via Ra against the respectively lying at the trigger output voltage U _A = Ucc or U _A = -Ucc until the capacitor voltage and) reaches the threshold U ₅ and -U $, the trigger switches and dei re-charge Condenser causes. The pulse width of the square-wave voltage results accordingly

Ucc + Ua T = C * H »* lri -, (2)

υcc ~ u $

ie the natural frequency is f _o = (2 · Τ) ~ '.

Suppose that at terminal E there is a periodic disturbance voltage Uc; their levels should also Ucc ^ur * d -Ucc se ^! n; the duty ratio is sti one and for the pulse width T _t 2 T. T has the input voltage Ue during the whole time rather capacitor charge the same value wio Ua (eg Ucc). so the trigger threshold Us already after the time

, R_c. * _ RA _{t ln} ^ü «! .. Us me \ 'R- f R ₄ n-- - lic' * ³ '

in the case of fully opposite action (R. B. Ua = Ucc. Ue - -U _C c) only after a duration T, c *? «-'--.? * * in -? - l .- ^,

its I IXA Ua "Ut

(4)

rc

R _C

reached.

Is dio frequency of the input voltage is set so that Tc> T _mt, is considered, part T _n remains of each control pulse which affects a temporal section of the nächston Umladophase. 4 illustrates this by way of example, wherein in the following calculation, the profile of the trigger input _voltage U _{tT is assumed to} be piecewise linear. This is a good approximation if only a fraction of the operating voltage is set as the trigger threshold. Thus, the maximum relative deviation from the exact exponential curve at U _s / Ucc = 0.25 is only 10%.

It will be seen that any phase shift T _n , between a UA edge and jar next Uc edge (see Fig. 4), depends only on the previous shift T _n and on whether Ue and Ua are equal during T _n · Or contrary. It also shows that each phase shift T _n unambiguously results in an associated pulse width T _{n of} the output signal Ua. With the abbreviations and definitions

»0 -" ce ♦- * ~ - _n " (5)

Π-,

I'm just when

Irit (-), k = J

T (i1 if ι unhappy

[-1 if Ug and U ^ in opposite directions during t ^ Tm "x + Tnii". "ThiÄx ~ Trvu'h

ti if Uf and Ua in the same direction during 1 "n. ,,

(8,9)

J (10,11)

The global behavior of the embodiment for arbitrary times and arbitrary frequency ratios f _E / t ₀ = T / T _{E can be described} as a two-dimensional discrete function (T _n ♦ t, C _n ♦ i) = fi (T _n , C _n ) and T _n = fj (T _n , C _n ) boron:

^C K (12),

wonnT _n ST _G ι.

^r ""<W in

if T ₀ , T _n <T ₀ :,

(14)

if T _n a T ₀₂ .

The boundaries T ₀₁ ,] are after each sign change from c "according to Gin. (10), (11) to be changed. This equation system can be conveniently implemented as an algorithm, so that dependencies of the period and the Impulsbreito value stores can be calculated from the frequency ratio. It turns out that the impulse Fluctuations are always periodic, but that in the case of irratic frequency ratios, in the vicinity of which rational numbers coincide

large denominator and counter are very long periods are adjustable within which the pulse width varies stochastically.

Claims (3)

1. A method for generating binary pseudo-stochastic pulse trains, characterized in that the circuit arrangement is set so that when open input at the trigger output (A) produces square wave pulses of their natural frequency, the duty cycle of the rectangular pulses is determined by the trigger thresholds, the frequency of the periodic control voltage such Deviating from the natural frequency and the ratio of the resistance (R _E ) to the resistance (R _A ) is chosen so large that the circuit is excited to square waves pseudo-stochastically disturbed pulse width. 2. The method according to claim 1, characterized in that the characteristics of the generated signal can be adjusted by changing the circuit parameters and / or changing the frequency of the control voltage relative to the natural frequency of the circuit arrangement. 3. Circuit arrangement for generating binary pseudo-stochastic pulse sequences, characterized in that the circuit arrangement of an inverting T'igger, two resistors (R _E , Ra) and a capacitor (C), the trigger output (A) via a series circuit consisting of the Resistor (Ra) and the capacitor (C) is connected to ground, the trigger input (E,) is connected to the non-ground terminal of the capacitor (C), the resistor (R _A ) and the resistor (Re) and at the other terminal of the resistor (Re), the input of the circuit, a periodic control voltage is applied. For this 1 page drawings Field of application of the invention The erfhidungsgemäße circuit arrangement is used with an appropriate setting for the generation of Spannungsinipulsen selectable constant amplitude, duty cycle and pulse width pseudo-stochastically fluctuate in areas whose limits are easy to dimension. Thus, it is suitable for the simulation of interference signals (random telegraph waves), for the analysis of messaging, measurement and control systems - especially for the verification of information channels - suitable. In particular, it is suitable for the simulation of stochastically disturbed binary signals and jitter effects. Characteristic of the known technical solutions The most well-known digital circuit arrangement for generating binary pseudo-stochastic signals consists of a feedback chain of shift registers whose N individual elements provide the maximum number of 2 ^N - 1 combinations (Maximelfolgo) with suitable execution of the feedback, so that the largest possible period TV.-, = (2 ^N - il / fT.sult. The effort occurs as a logarithmic with the period duriFinger.A .: Algebraic Structures in Information Processing, Verlag Technik, Berlin 1987). In the international patent literature there are several hundred suggestions on how the available finite state space can be modeled or enlarged by suitable transformations. Modern methods are based on storing the state values in a read / write memory and using the shift register signal only as an initial for varied readout, wherein the address was previously processed on a wide variety of AM (eg DE-AS 253/167, DE -PS 3129911, DE-OS 2850240, JP 57-201939). A disadvantage of all dieson variants is that the given by the basic idea ratio of effort and period length can not be exceeded. Object of the invention With the invention, the aim is to obtain a simple circuit for generating Psoudozufallsimpulsfolgen, boi the period does not depend on the component cost. Explanation of the essence of the invention The object of the invention is to generate pseudo-stochastic pulse sequences with adjustable constant amplitude and within long periods of randomly varying pulse width and fluctuating duty cycle. According to the invention the object is achieved in that a simple circuit arrangement, consisting of an inverting trigger, two resistors and oinem capacitor, wherein the trigger output via the series circuit of a resistor Ra and the capacitor C is grounded and the Triggeroingang with the not ground ' lying terminal of the capacitor and the two resistors Re is connected to the other terminal, a periodic control voltage is applied, is dimensioned so that the arrangement operates without this Stoust voltage as a multivibrator and rectangular sequences with a natural frequency f ₀ = 1 / (2 · T) T generated is the duration of ainos dynamic stable state