DE2051683B2 - Passive amplitude limiter - Google Patents

Description

2 OSl 683

In FIG. 3, the output level P _{A is} plotted as a function of the input level P _E at approximately 1 kHz for a nominal level P _n.

F i g. 4 shows the noise _{voltage I7 G} emitted at the relative level - 2Np with a 25 Hz ringing voltage Ό% on a two-wire line. The transistor limiter according to the invention initially shows a falling noise voltage U _R above the starter insert. The increase in the noise voltage U _a with a higher ringing voltage U _{R is} due to the fact that the upstream fork transformer is already heavily overdriven at this voltage Limiter accordingly emits more and more needle pulses per unit of time.

For this purpose 2 sheets of drawings

Claims (2)

Two transistors of the same type are provided, the patent applications of which are connected in anti-parallel at the input of a four-pole attenuation known per se 1. Passive amplitude limiter with two are and their collectors at the output of the damping-like transistors, thereby identified 5 fungsvxerpo s each with the Langsghed of Damp that the base-emitter lines are connected to the four-pole connection, at the input of which the input (El, E2) one to known damping base of the respective transistor is connected.
five-pole four-pole (D) are connected in antiparallel and it is advantageous to use the collector at the output (A1, A2) of the four-pole attenuation limiter in outgoing four-pole attenuation (D), each with the series io wire lines in the low-frequency and service line element of the four-pole attenuation (D ) are connected, end circuits of telephone systems, msbesonan whose input (El, EZ) the base of the respective carrier frequency, radio relay or pulse code transistor (D 1, D 2) is connected to modulatioris multiplex systems. 2. Amplitude limiter according to claim 1, it is advantageous that m the known end characterizes by its use in disconnected 15 mostly already ^ a of long-distance line is provided, which can be included in the speech transmission systems according to the invention, in particular carrier amplitude limiters,
gerfrequency, directional radio or pulse code modulas with the amplitude limiter according to the invention multiplex systems. ao you get a circuit that is at the input of the Attenuation quadrupole acts like a diode limiter, but also during the control of the base-emitter paths of the transistors of the output passage of the attenuator through the collectors 35 is attenuated. That means the output voltage becomes smaller as soon as the input voltage decreases The invention relates to a passive amplitude base-emitter threshold which transistors exceeds, limiter with two similar transistors. With very high sinusoidal input voltages In low-frequency or service line end switches, the output voltage only consists of very Dependent on telephone transmission systems there are in 30 narrow pulses at the beginning and end of each sine general in the outgoing four-wire line half-wave. Amplitude limiter is provided, which is based on an exemplary embodiment, the Voltage peaks resulting from two-wire line, as explained in more detail below.
Call tension and crackling, to the permissible maxi- The F i g. 1 shows a passive according to the invention limit malvalues. Thereby, an amplitude limiter connected downstream 35 letes with a terminal attenuation D multiplex system, such as carrier frequency, target and two transistors Tl and 7. * 2 The inputs of the radio or pulse code modulation system are protected against overload with El and E 2, the outputs with Al loads. The previously designated for this purpose and A 2. applied diode limiter or limiter amplifier The amplitude limiter according to the invention works have the disadvantage that the output amplitude of 40 at the input E1, E2 through the base-emitter path at the beginning of the limit use with increasing one of the two transistors T1 and Γ 2 rises like a diode output voltage by several dB. Des limiter, but in which additionally at each half-half the limiting insert must wave wide of the training, the-emitter threshold voltage of the base of the "expensive limit the subsequent four-wire line Lie transistors Tl and T 2 exceeds, called the output. A further disadvantage lies in the fact that the output 45 of the quadrupole D attenuation is short-circuited. Dagangsspannung of the limiter is the more a by results at the output A 1, A 2, a chip-square-wave voltage approaches, the larger the input nungsverlam C _A over time t as 2 voltage is shown in Fig.. If one leads this tension over a represented .si. Filters, for example a low-pass filter, then result in In FIG. 1- inclines the curve α the limited carrion Because of the delay time distortions at the filter output 50 output spar ^ ns U _A , if the input EMF can only be output voltage peaks that are considerably above the limit threshold level c, c ' , limiter output voltage. At higher input voltages, such as 25 Hz This also applies to the one from the magazine "The Rufspannungen, the short circuit at the output Post Office Electrical Engineers'Journal", Vol. 62, A 1, A 2 , so that, like Part. 4, January 1970, S. 213 to 217, known Be 55 curve b shows, at each zero crossing only limiters, in which the base-emitter paths of two receives a positive or negative pulse, the larger the input voltage, the smaller the transistors connected in series are arranged between the two-wire line, wäh- is. This means that the output amplitude U _A rend the interconnected collectors on the one hand no longer per se from the limitation onwards and the interconnected bases on the other hand each increase to 60 and the output power increases as a supply voltage increases. The input voltage requirement drops significantly,
additional supply voltages means a Die F i g. 3 and 4 show one due to another disadvantage. Measurement results obtained comparison between the The object of the invention is to provide an amplitude mode of action of a known diode limiter denbegrenzer a soldering device that avoids these disadvantages and the transistor limiter according to the invention, solution to be specified. The diode limiter is a dashed and the With a passive amplitude transistor limiter, this task becomes a solid curve the limiter according to the invention solved in that assigned.