DE1813452A1 - Variable system equalizer - Google Patents

Description

Variable system equalizer.

The invention particularly relates to a variable system equalizer for broadband transmission paths.

As is well known, this is the case on transmission paths through the transmission medium attenuated signal through amplifier devices back to the original or raised to another desired level value. As a result of the incomplete agreement the gain with the attenuation as a function of the frequency errors occur on the amplitude frequency response, which is balanced out after a certain section length if the transmission quality is not impaired in an impermissible manner target.

In order to compensate for these distortions, as is well known, the above-mentioned System, additional or magistral equalizers are used.

The previously known equalizers can be divided into the following groups: 1. Search equalizer The distortions occurring on the transmission path are with Pogelsicht devices fixed and by a variable equalizer (search equalizer) with a limited number of links (bridged T links or base links) compensated. The one that is actually built into the system and cannot be changed afterwards - The equalizer is manufactured according to the building regulations assigned to each switch position.

Disadvantages of these equalizers are: a) high basic attenuation, b) none Subsequent uninterrupted equalization possible, c) commissioning is about the period between the detection of the equalizer data and the bus delivery of the equalizer is delayed.

2. Cosine or echo equalizer With the cosine or echo equalizer, For the undelayed signal the same amplitude is given via delay elements and the polarity variable signals are added.

This results - caused by the phase differences between the delayed and the undelayed signal - an almost cosine-shaped curve the amplitude-frequency characteristic By superimposing several, different delayed signals can occur according to the principle of Fourier analysis Distortions are compensated.

Disadvantages of these equalizers are: a) very large basic attenuation, b) large expenditure on delay elements, c) for setting the equalizer during A computer is required for operation.

3. Equalizer according to Oswald This is essentially about a bridged T-link, longitudinal and transverse branches are via a transformer and a X link coupled; potentiometers are used to change the amplitude.

Disadvantages of these equalizers are: a) high basic attenuation b) high number of components 4. An equalizer with decoupled parallel circuits Bei has already been proposed This equalizer is frequency-dependent at parallel crets according to the voltage divider principle preferred signals tapped and via a potentiometer in a bridge circuit in phase or out of phase with the one damped by an ohmic voltage divider Signal added, the parallel circuits are against each other via high-ohmic resistances decoupled. The equalization effect takes place in the range around the resonance frequency.

Disadvantages of these equalizers are: a) The basic attenuation is very large.

It is therefore the purpose of the invention to extend the known above Corrector eliminates inherent defects.

The object of the invention is to develop a variable system equalizer, which operates at discrete frequencies, i.e. without interrupting operations, with sewer leakage measuring devices can be adjusted and with only low basic attenuation and relatively low technical Effort in a transmission system as a result of not being completely in agreement the gain with the attenuation depending on the frequency occurring errors compensates again in the amplitude frequency response.

This object is achieved according to the invention in that two decoupler circuits an input decoupler and an output decoupler, connected by two wires are, where the connection is in one branch, the main branch, direct or Uber there is an attenuator, the connection in the other branch, the secondary branch, on the other hand only via a network consisting of series or parallel connected relative simply built up from a coil, a capacitor and a voltage divider Parallel circles, the resonance frequencies of which are staggered in an advantageous manner, that the lowest frequency below and the highest above the transmission range and a further resistor and an impedance converter connected in series will be produced. The coils of the circles have each stel windings, with each the first windings are connected in series and in both circuit variants the relevant winding of the last circuit is connected to ground, while the winding the first coil is connected to the input decoupler. With series connection as the base circle from the second winding of the respective coil, the capacitor and the voltage divider, which is built in parallel with parallel circuits, is the wiper of the voltage divider Each circuit on the one hand via a further resistor with the center of the coil winding of its own circle and, on the other hand, directly with the Middle of the coil connected to the second winding of the next circle. Also is the center tap of the second winding of the coil of the last circuit at the cash register placed while the wiper of the potentiometer of the first circle next to the connection via the additional resistance to the center tap of the second winding of the coil this circuit is directly connected to the impedance converter. With parallel connection the one as the base circle from the second Winding of the respective coil, parallel circuits built up parallel to the capacitor and the voltage divider the center taps of the second windings of the coils are individually on Ground, while the wipers of the voltage divider each over the additional Resistance are led to a common line and this common line connected directly to the impedance converter.

For a better understanding oei the invention on the basis of two exemplary embodiments explained in more detail.

The associated figures show in detail: Fig. 1: The basic circuit of the variable Systementzer rers Fig. 2a: the special design of the parallel circuit network, Parallel circuits connected in series Fig. 2b: the special design of the parallel circuit network, Parallel circuits connected in parallel.

As shown in FIG. 1, the equalizer consists of two decoupling circuits, the input decoupler EE and the output decoupler Ea, which are two-wire together are connected, the connection in one branch, the main branch a directly exists, while the connection in the other branch, the secondary branch b, is only via dae Network N and the series-connected impedance converter W is established. The network N consists, as FIGS. 2a and 2b show, of those in series or parallel circuits 1 to n, the. relatively simple as a base circle only from the coil L, the capacitor C and the voltage divider R1, e.g. a potentiometer or a step resistor, and the additional resistor in each case R2.

The coils L of the circles each have two windings, with the Circuit variants the first windings are connected in series and the relevant Winding of the last circle n is placed at the cash register, while the winding of the first Coil with the Input decoupler EE is connected. With series connection the als- base circle from the second winding of the respective coil L, the capacitor C and the voltage divider R1 built up parallel circuits 1 to n is the slider S of the voltage divider R1 of each circuit on the one hand via a resistor R2 the center of the second winding of the coil of its own circle and, on the other hand, directly connected to the center tap of the second winding of the coil of the next circuit. In addition, the center tap of the second winding is the coil of the last circuit n is connected to ground, while the wiper S of the potentiometer E1 of the first circle 1 next to the connection via the resistor R2 to the center tap of the second winding the coil of this circuit is directly connected to the impedance converter W.

When connected in parallel, the base circle from the second winding the respective coil L, the capacitor C and the voltage divider R! built up Parallel circles are the center taps of the second windings of the coils individually connected to ground, while the wiper S of the voltage divider R1 each are led via the resistor R2 to a common line and this common Line is directly connected to the impedance converter W.

The resonance frequencies of the parallel circles 1 to n are more advantageous Way staggered so that the lowest frequency is below and the highest frequency is above the transmission range to an almost constant in the entire useful band Input; resistance of the equalizer. The addition or subtraction the signal components of the main branch a and the secondary branch b results in the desired Equalization effect.

Because of its relatively simple technical structure and because of its The equalizer can be easily adjusted for broadband transmission paths use very economically.

Claims (4)

Claims 1.) Variable system equalizer, especially for broadband transmission paths, characterized in that two decoupler circuits, one input decoupler (EE) and an output decoupler (EA), two-wire connected to each other, wherein the Connection in one branch, the main branch (a), directly or via an attenuator exists, the connection in the other branch, the secondary branch (b), on the other hand only via a network (N), consisting of series or parallel connected relatively simple built up only from a coil (L), a capacitor (C) and a voltage divider (R1) Parallel circles (1 to n) whose resonance frequencies are advantageously staggered in this way are that the lowest frequency below and the highest frequency above the transmission range and a further resistor (R2) and one connected in series Impedance converter (W) is made. 2. Equalizer according to claim 1, characterized in that the coils of the circles (1 to n) each have two windings, the first winding are connected in series and the relevant winding of the last circle (s) Ground and the winding of the first circuit (1) with the input decoupler (EE) is connected. 3. Equalizer according to Claims 1 and 2, characterized in that that in the case of the base circle from the second winding of the respective coil (L) the Capacitor (C) and the voltage divider (R1) built-up parallel circuits (1 to n) the wiper (S) of the voltage divider (R1) of each circle on the one hand via a resistor (R2) to the middle of the second winding of the Coil (L) of its own circle and, on the other hand, directly to the center tap of the second winding of the coil of the next circuit and also the center tap the second winding of the coil of the last circle ses (n) connected to ground and the Veil (S) of the potentiometer CR1) of the first circle (1) next to the connection Via the resistor (R2) to the center tap of the second winding of the coil of the own circuit is directly connected to the impedance converter (W). 4. Equalizer according to Claims 1 and 2, characterized in that that in the case of the base circle from the second winding of the respective coil (L) the Capacitor (C) and the voltage divider (R1) built in parallel circuits (1 to n) the center taps of the second windings of the coils (L) each individually Ground and the wiper (S) of the voltage divider (R1) each via a resistor (R2) are led to a common line and this common line directly is connected to the impedance converter (w).