DD250616A1 - CIRCUIT ARRANGEMENT FOR MONITORING IMPULSE CONSEQUENCES - Google Patents

Abstract

The circuit arrangement serves to monitor the pulse train of two symmetrical, square-wave signals of the same frequency which are phase-shifted by 90. Known circuit arrangements of this type work with the evaluation of the input signals and their complement signals. For this purpose, a relatively high circuit complexity is required. This drawback is overcome by connecting the quadrature input signals to the inputs of a first comparator circuit, and the output of this comparator circuit to the input of a second comparator circuit constructed of CMOS circuit structures, directly timed to the associated comparator input Integrator is supplied, wherein the output signal of the second comparator circuit forms the input signal of a Impulsverlaengerungsstufe whose output signal represents the output signal of the inventive circuit arrangement. For the realization of the comparator circuits, antivalence or equivalent circuits are used. Fig. 1

Description

For this 2 pages drawings

Field of application of the invention

The invention describes a circuit arrangement which uses the transhipment of a capacitor in conjunction with comparator circuits and a pulse extension stage for monitoring the pulse train of two mutually phase-shifted by 90 °, symmetrical, rectangular signals of the same frequency.

Characteristic of the known technical solutions

In international specialist literature such as

- Journal "Electronic Design" 29 (1981) H.17, pages 158 and 160;

- Journal "Radio" 56 (1980) H.3, page 35;

circuit arrangements are described, which adheres to the disadvantage, when using two such circuits for monitoring two mutually phase-shifted by 90 °, symmetrical, rectangular signals of the same frequency, the first pulse edge during the transition from static to dynamic state of the input signals not to capture.

In DD-PS 95875 a method for digital frequency multiplication is described, which is when using two such circuits and appropriate dimensioning of monostable multivibrators for monitoring the pulse train of two mutually phase-shifted by 90 °, symmetrical, rectangular signals of the same frequency, is suitable. However, this method has the disadvantage of a high circuit complexity, due to the evaluation of the input signals and their complement signals.

Object of the invention

It should reduce the circuit complexity and eliminate the mentioned disadvantages, thereby making circuit arrangements of this kind more economical.

Explanation of the essence of the invention

The object of the invention is to provide a circuit arrangement for monitoring pulse sequences, which is capable of reducing the effort, in particular passive, tolerance-sensitive electronic components in a pulse sequence of two mutually phase-shifted by 90 °, symmetrical, rectangular signals of the same frequency to respond each pulse edge within the pulse train and to operate independently of the direction of the phase shift of the two input signals.

The invention is based on the idea that a comparator whose input signals represent two mutually phase-shifted, symmetrical, rectangular signals of the same frequency, an output signal with twice the frequency compared to the input signals, the duty cycle of the output signal of the phase shift of the input signals is dependent.

The object of the invention is achieved in that the two phase-shifted by 90 ° input signals to the inputs of a first comparator circuit are supplied, the output of a signal with twice the frequency compared to the input signals, at a duty ratio of 1: 1 delivers.

This signal is fed to the input of a second comparator circuit directly and the associated comparison input via an integrator delayed in time. The output of the second comparator circuit thus provides pulses with a, depending on the time constant of the integrator pulse duration _A , at four times the frequency compared to the two phase-shifted by 90 ° input signals of the circuit arrangement according to the invention. The output signal of the second comparator circuit forms the input signal of a pulse extension stage whose output is the output of

inventive circuit arrangement represents. If _A m _ax <t _A2 , then the time T _{Amax is covered} by the output pulse duration t _{A2 of} the pulse extension stage and thus the dynamic state of the two input signals of the inventive circuit arrangement phase-shifted by 90 ° is detected.

To implement the comparator circuits CMOS circuit structures are used, which allow it due to their high-impedance inputs allow the integrator high impedance to reduce the burden of the first comparator circuit and optionally dispense with a decoupling stage. Will t _A1 < T _Arn | _{n is} selected, then the same conditions for the detection of the LH and the HL edge of the output signal of the first comparator circuit are created when using CMOS circuit structures in which U _s = U _B / 2 applies. For Us = U _B / 2, U ₅ = U _E h, U _E l = OV, at t _A i < -T _Amin and neglecting all the switching times of the second comparator circuit:

t _A1 = C χ R χ In 2 t _A1 = 0.7 x C x R

embodiment

Reference to an embodiment of the invention will be explained in more detail.

1 shows a circuit diagram of the circuit arrangement according to the invention, FIG. 2 shows the action plan of the circuit arrangement according to FIG. 1

According to FIG. 1, the input signals Ei and E2, which are phase-shifted by 90 °, are connected to the inputs of the equivalent circuit 4. The output of the equivalent circuit 5 directly and with the associated comparison input 2 via an integrator R ₁ ; Ci connected. The output of the equivalent circuit 5 forms the input signal 3 of the pulse extension stage 6 whose output represents the output A of the circuit arrangement according to the invention. Fig. 2 illustrates that, regardless of the direction of the phase shift between the Eingangsignale.E! and E ₂ each pulse edge of the input signals E ₁ and E ₂ at the input 3 of the pulse extension stage 6 causes a pulse whose pulse length t _A1 of the time constant of the integrator R ₁ ; C _{1 is} dependent. The output signal of the pulse extension stage 6, in compliance with the conditions T _{Ama! (} <T _A2 gives information about the static or dynamic state of the input signals E ₁ and E ₂ .

Claims (2)

1. Circuit arrangement for monitoring the pulse train of two mutually phase-shifted by 90 °, symmetrical rectangular input signals of the same frequency, which operates independently of the direction of the phase shift between the input signals, characterized in that the phase-shifted by 90 ° input signals (Ei, E ₂ ) with the Inputs of a comparator circuit (4) are connected, and that the output signal of the comparator circuit (4) the input (1) of a comparator circuit (5), which is composed of CMOS circuit structures, directly and the associated comparison input (2) via an integrator (R ₁ , Ci), wherein the output signal (3) of the comparator circuit (5) forms the input signal of a pulse extension stage (6) whose output signal represents the output signal of the circuit arrangement according to the invention. 2. Circuit arrangement according to item 1, characterized in that for the realization of the comparator circuits antivalence or equivalent circuits are used.