DE1762089C - Circuit arrangement for regenerating pulses of different polarity - Google Patents

Description

Frequently, impulses are transmitted on a transmission. route or by storing on an information carrier and resampling in their form and., amplitude changed in such a way that they cannot be processed further immediately , but can be processed further. must be converted into pulses of a defined shape and amplitude. Special difficulties then arise. if the pulses have different polarity. then be the case when on a magnet! positive and neg: jti \ e Recliteekimpulse are generated, the polarity of which should be used for each control of a course. During the playback, the playback head differentiates the Rf ·, corner pulse and delivers two consecutive pulses of different polarity in a known manner, for example when playing a positive Ret hi. ^ Pulse first a positive and then a negative pulse. Most of the pulses are free of direct current potential and referenced to ground. The evaluation of these signals is even more difficult because interference signals are superimposed.

The object of the invention is to provide a circuit arrangement with the deformed differentiated signals cn new signal is formed, which is the occurrence of an original Characterizes square wave signal and its polarity. The invention is based on the knowledge that the polarity of the original square wave signal can then be recognized if a certain Edge of the deformed pulse, e.g. B. the first or the last edge, i ur evaluation is used. The first pulse edge is expediently used and an arrangement is used which is based on this flank addresses, the other flanks against it disregarded.

The practical realization of this knowledge and the solution of the task described above are equipped with a circuit arrangement for regenerating pulses of different polarity achieved, which is characterized by the fact that the pulses to be regenerated parallel two monostable Flip-flops are supplied, one of which when a positive is supplied and the other when Supplying a negative pulse switches to the unstable state and its time constants become larger than the duration of the supplied pulses, and that one trigger is blocked when the other is in the unstable state.

For safe control of the monostable multivibrators, a pulse shaper stage is connected upstream of each of them, those assigned to the other pulse shaper stage depending on the switching status monostable tipping stage is open or locked. Each pulse detector stage expediently contains a transistor in emitter circuit, the base bias of which depends on the switching state of the respective mono-

stable tipping stage is derived. So that the circuit arrangement does not respond to interference pulses, the pulse shaping stages are blocked in the idle state in such a way that a pulse exceeds a certain level must if he is to make the pulse shaping stage respond. On the other hand, it is that of the others left .-: pulse shaper stage downstream flip-flop stage in the unstable State, so is controlled by this, the reverse voltage increased so far that pulses

half supply — gu hrcndc ^ Lu tu ng / _ür description of the l-unkumd, _S ^ aluint vu.rd taken that initially both K u are stable state around Ma _fe nOk j ·, signal is sampled which origin, »., , positive Rechieckimpu s ™ - f- ■ "'"' ■ this signal "ill at the Ausfuhrungsbe s, u ■ · used first flank. d, e is positive at the assumed momentum. The P ^OMmt ''"·>''! F '~"' S

p pulse positive i P! f _r .,

on the level of the useful signal, the pulse shaper stage io anyway in the Spcrr / ustand located lransisto
ih h nodi further in the locked state. Against us

Transistor 7v, w> m blocking state in the luu

daIi on his m.i,

no longer respond.

The known circuits with two transistors can be used as monostable multivibrators. The two flip-flops are expediently constructed in the same way with the same time constants. They only differ in the conductivity type of the transistors used, so that one trigger stage is switched on by positive and the other by negative pulses. Ai. «- h The transistors Min of various conductivity types used in Lku pulse shaping stages are useful. The output pulses of the monostable multivibrator can be used to control a bistable multivibrator to generate a binary signal.

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On the basis of the drawing, in which the circuit diagram 25 flip-flops, Afühi k

State switched so _

a negative impulse arises. This negative ii: is attached to the RC -Cilied C,. R, diiterui / .ieri. mii positive part of the differentiated signal wnu m-> nostabik flip-flop with Ue 11 lr.msisorv · and T. switched to the unstable /.usiand. ., the KoIIcM.> ipoien: .al of the transistor / · the Hjsis bias voltage of the I d;: H this tab in the blocking / u and the negative slope of the sarmsimpuls .. · -, the ImpiiKlormerstule not to speak. Dk- pulse duration of the monosu, '

also

increases and with it
sistors / 's ,, so
controlled wiu!

the

an exemplary embodiment is shown, the invention and other advantages and Supplements described and explained in more detail.

From the winding 1 of a magnetic head, the signal passes via a transformer U to a VoV amplifier 2, in which the necessary equalization of the frequency response is carried out and, if necessary, an interference signal of a certain frequency is suppressed. The circuit arrangement proper for regenerating the pulses scanned by the magnetic head is connected to the preamplifier. It essentially consists of two trigger stages with the transistors Ts ₁ . and Ts. or 7v "and Ts ₁₀ , each of which is preceded by a pulse shaper stage with the transistor Ts ₅ or Ti ₈ . In the stable state of the monostable multivibrators, the transistors Ts ₁ and Ts ₁₀ flow current, while the transistors Ts ₆ and Ts _{11 are} blocked. From the collector voltage of the transistor Ts. The id Ilfi 7

the essentially sun of the capacitor C _i; and the b / w. of the capacitor C - and

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35

constant

Standes «, resistance R _{1 is} determined. is chosen so that, lunger than you · duration of the l.mgaiuis impulse. It is ensured that each pulse only triggers one of the two Mppsu to switch over. So that the at the collector of the 1 rans.stor. Occurring negative pulse the pulse shape . - _{,, with the transistor / v K} does not switch, is in -. from the collector of the transistor / λ . ζί r liasiselect .. .. of the transistor 7λ, leading line a 1 ·. coupling diode D, switched. With the /.unu. tilting the monostable tilting column decreases the voltage at the collector of the transistor Is .

In the chosen embodiment, the output pulses of the monostable multivibrator have the following: T d T iti Plantat Dies ·.

Resistance K ₁ , of the differentiated

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Basic preload only. ·? of the pulse shaper _{transistor 7.s 8} 45 transistors Ts ₁ . and Ts. positive Polantat.
and from the Koflektorsspannung of the transistor Ts ₁₀ pulses are differentiated, namely with a: the base bias of the pulse shaper transistor time constant, which is derived essentially by the drolie Ts. In the stable state of the flip-flops of a capacitor C _H and a
is "the base bias is set to be determined by. The negative part
Flare pulses of smaller amplitude not opened 50 Signal is suppressed by means of a diode />.. However, when a useful signal arrives, the positive part passes through a resistor R _H and which has a larger amplitude, switched through d CA n dn one

will. The conductivity type of the transistors of the one trigger stage and the pulse shaper stage connected upstream of it is different from that of the other flip-flop and the other pulse shaper stage. It is

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therefore possible to feed the entire circuit arrangement with a common supply voltage Un. Half the supply voltage is then applied to each trigger stage.

The output pulses of the preamplifier 2 are fed via a capacitor C ₁ or C _{1 to} the base electrodes of the pulse shaping transistors Ts _R and Ts _s 1. Via a further condenser Ail fi di a capacitor C ₁₁ , to the output, to which a bistable multivibrator is connected can be, which is switched by this pulse.

If a pulse occurs at the output of the preamplifier, the first edge of which is negative, then the monostable multivibrator with i T d T hltet s that

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gate C, the output pulses arrive at a die

speaking pp

the transistors Ts, _t and Ti _1n switched over, so that the Impi'lsformertransistor Tr is blocked. The output pulses are differentiated, the positive part of the differentiated signal is cut off by means of a diode D. and the negative part is given to the output via a resistor R- and capacitor 10, where it switches back the possibly connected bistable multivibrator.

1 sheet of drawings

Claims (9)

Patent claims: 1. A circuit arrangement for regenerating pulses of different polarity, characterized in that two monostable multivibrators (Ti ₀ , Ti ₇ and Ts ₉ , Ts ₁₀ ) are provided, one of which (Ts _B , Ts ₁ ) when a positive is supplied and the one others (T ¹ J ₉ , Ts ₁₀ ) with i »supply of a negative pulse switches to the unstable state and whose time constants are greater than the duration of the supplied pulses, and that each trigger stage is blocked when the other is in the unstable state . 2. Be it arrangement according to claim 1, characterized in that the monostable flip-flops are each preceded by a 'mpulsformerstufe (Tj. Or 7 "j _n ), which is opened or blocked depending on the switching state t'er the other pulse shaper associated monostable flip-flop . 3. Circuit arrangement according to claim 1 or 2, characterized in that each pulse shaping device has _{a transistor (Ti 5 or TjJ} in F.mitl.-r., circuit whose base bias is derived from the switching state of the respective other pulse shaper stage (Tj ₈ or Ti ₅ ) downstream of the monostable multivibrator (Ts ₉ , Ts ₁₀ or Ts, .. Ts ₇ ). 4. Circuit arrangement according to claim 2 or 3, characterized in that the pulse shaper stages (Ts ₅ , Ts ₁₁ ) are blocked in the idle state and that the blocking voltage is increased when the monostable multivibrator connected downstream of the other pulse shaper stage is in the unstable state. 5. Circuit arrangement according to claim 4, characterized in that each monostable multivibrator contains two transistors (Ts _R , Ts ₁ or Ts ₉ , Ts ₁₁₁ ) and that the conductivity type of the transistors of the one trigger stage is different from that of the transistors of the other trigger stage. 6. Circuit arrangement according to one of claims 3 to 5, characterized in that the transistors (Ti ,, Ti ₈ ) of the pulse shaper stages have opposite conductivity types. 7. Circuit arrangement according to one of claims 3 to 6, characterized in that the transistors (Ti ₅ , Tj ₈ ) of the pulse shaper stages and the transistors (Tj ₀ , Tj ₇ or Tj ₉ , Tj _1c ) of the respective downstream monostable flip-flops have the same conductivity type to have. 8. Circuit arrangement according to claim 7, characterized in that the first transistor operating in the emitter circuit (Tj ₀ or Ti _n ) of the monostable flip-flops is blocked in the stable state and the second transistor operating in the emitter circuit (Tj ₇ or Ts ₁₁₁ ) is opened and that the base of the transistor [Ts _H or Tj ₅ ) of the pulse shaper stage connected upstream of the other flip-flop is connected to the collector of the transistor (Tj ₇ or Tj _10). 9. The circuit arrangement according to claim 8, characterized in that in each case a forward ge m in the (/ λ Ti ₇ or ₁₀₎ from the collector of the second Kippstufentransistors -to base of Impulsformerstufentransistors <Is _H or Tv) leading lines pol te Entkopplungsd.ode :. '), or £> ._,) is done.