JPS6111008B2 - - Google Patents

Description

Detailed Description of the Invention The present invention comprises at least one differential capacitor, at least one coil, at least one resistor, and a differential transformer, and a line placed at a reference potential is connected between an input terminal and an output terminal. The present invention relates to an adjustable attenuation equalizer configured as a four-terminal network with direct feedthroughs.

The attenuation equalizer configured as described above can be adjusted continuously in a non-contact and stepless manner, and can be used, for example, in a carrier frequency system. These equalizers produce an attenuation change with a positive or negative polarity with respect to the fundamental attenuation at a settable frequency, so that the course of the attenuation characteristic curve changes in the simplest case to the frequency. It shows dependent resonance curve-like characteristics. Such an attenuation equalizer is known, for example, from German patent no. Become. Other known circuits, e.g. German Published Application No. 2512459
Other known circuits, such as those described in U.S. Pat. No. 2,512,805 and U.S. Pat. In practice it is necessary to operate such a circuit between finitely large operating resistances, where the input parallel transformer, for example, the transformation to low frequencies, is controlled by a finitely large parallel inductance, f= This is because an attenuation pole occurs when the value is 0. Furthermore, the differential capacitor - all parallel impedances and parasitic elements occurring in the intermediate position, such as winding capacitances, occur on the input side and therefore cannot be compensated very broadband.

SUMMARY OF THE INVENTION An object of the present invention is to provide a contactless adjustable attenuation equalizer circuit in which the transmission frequency range is not limited as much as possible and compensation for parasitic elements can be performed over a wide band.

In order to solve this problem, according to the invention, in the equalizer of the type mentioned at the beginning, a differential transformer is provided in the series branch of the four-terminal network, and the stator of the differential capacitor is connected in parallel on the input side or on the output side. Set in the branch,
The rotor of the differential capacitor is connected via a coil or directly to a tap of a differential transformer, and a resistor is provided between another tap and the through line.

Furthermore, according to the present invention, the line is provided with at least one differential capacitor, at least one coil, and at least one resistor, as well as a differential transformer, and is placed at a reference potential.
In an adjustable attenuation equalizer configured as a 4-terminal network with a direct feed-through connection from the input terminal to the output terminal, the differential transformer is connected in series branch of the 4-terminal network. the stator of the differential capacitor is provided in the input or output parallel branch, the rotor of the differential capacitor is connected via a coil or directly to the tap of the differential transformer; A resistor having an infinite size is provided between the line and the through line.

Next, the present invention will be explained using illustrated embodiments.

In the circuit configuration in the form of a four-terminal network shown in FIG. 1, one input terminal and one output terminal are directly connected through a line 1. This line can be placed at a reference potential, for example as shown in FIG. 1 at ground potential. Terminals not placed at the reference potential are shown as input terminal E and output terminal A. A differential transformer 2 having a total number of turns W is provided in the series branch of the above circuit configuration. The first partial coil used for impedance conversion has a number of turns W ₁ , the second partial coil used for basic attenuation adjustment has a number of turns W ₂ , and the remaining coil between the above two partial coils or between both taps has a number of turns W 1 . The two partial coils have a number of turns W−W ₁ −W ₂ . A differential capacitor 3 is provided in the parallel branch on the input side,
It consists of two stators 4 and a rotor 6. The stator 4 is connected to the input terminal, and the stator 5 is connected to the through line 1. A coil L ₀ is connected between the rotor 6 and the first tap W ₁ of the differential transformer 2.
and a resistor _R0 . However, inductance L ₀ and resistance
It is not necessary to insert and connect R ₀ ,
For example, the impedance value may be set to zero. When the inductance L ₀ takes a value of 0, the rise or fall of the slope of the attenuation characteristic curve can be adjusted with respect to the basic attenuation. A resistor R ₁ is provided between the tap W ₂ of the differential transformer and the through line 1 .

In the circuit configuration shown in FIG. 1, first, power is supplied to the circuit from a voltage source U ₀ having an internal resistance R _E =0 on the input side, and a resistor R _A is activated on the output side A to obtain a voltage attenuation amount a _U =l _o | This is to consider U ₀ /U _A |. On the output side A, there is also an internal resistor R _{A
It is} supplied _from a current _{source I 0} with
) can also be considered. In other words, in the circuit configuration shown in FIG. 1, the differential capacitor 3 does not necessarily need to be provided in the input side parallel branch, but may be provided in the output side parallel branch, for example, it may be provided between the terminal A and the line 1. It's okay. On the other hand, it is also possible to interchange the voltage source (current source) and the terminating impedance, which is immediately clear from the illustrations in FIGS. 2 and 3 for the extreme values. It is also possible to terminate both sides of the circuit with resistors of the same or different values and consider the amount of operational attenuation. What this fundamentally differs from the voltage or current decay function is an additional zero and an additional pole in the negative real axis of the p-plane, which provide a tilt position that essentially compensates for the fundamental decay. It means being born.

FIG. 1 shows the basic variation of the attenuation a depending on the frequency f, in which case the parameter values α=1, α
Two limiting cases of the =0 differential capacitor condition are shown. The basic attenuation is designated by a ₀ and the attenuation changes to be achieved are designated by Δa ₊ and Δa ₋ . At the capacitor 3, the capacitance value C·α or C(1−α) for the stator 4 or 5 is shown, so that for the parameter value α=1, the rotor 6 is completely opposed to the stator 4. , while for parameter value α=0, the rotor 6 completely faces the stator 5.

Figures 2 and 3 show two limiting cases α=
1, the equalizer circuit of FIG. 1 and the associated attenuation characteristic curve for α=0; In that case, for the sake of clarity, the circuit in Figure 1 has two tap points W ₁ and W _2.
coincide (overlap) at the center, that is, the number of turns W ₁ =
W ₂ =W/2. This special case can be fully applied in practice, and the differential transformer 2
The advantage is that you only need to pull out one tap from the source. As is clear from FIG. 2, the capacitance C of the differential capacitor is connected to the input terminal E, while in the case of FIG. 3, the capacitance C is connected to the through line 1.

As is clear from Fig. 2, when the differential capacitor adjustment α = 1 in the circuit of Fig. 1, there is a positive attenuation change Δa ₊
occurs, which takes its maximum value when the angular frequency ω ₀ =√1 _{0 0} . The basic attenuation amount a ₀ is determined by the ratio of the resistance R ₁ and the terminal impedance R _A , the magnitude is determined by the resistance ratios R ₀ /R _A and R ₁ /R _A , and L ₀ /R ² _A C ₀ and 2 The width of the slope of the damping characteristic curve is determined by the two resistance ratios. The limits of these three defining factors can be freely chosen. R ₀ > R ₁
Alternatively, depending on whether R ₀ <R ₁ is chosen, the equalizer four-terminal network has a minimum phase amount or has an all-pass characteristic. When R ₀ =R ₁ , the amplitude or magnitude of the attenuation change is Δa ₊ (ω ₀ )=∞.

FIG. 3 shows the negative attenuation change Δa ₋ under differential capacitor adjustment α=0. The above impedance relationship also determines its size and width. Since this circuit always has the minimum phase amount,
When the differential capacitor rotates between the end positions α=1 and α=0, the transition from a positive attenuation change to a negative attenuation change occurs by a monotonous decrease only because R ₀ >
Only in the case of R ₁ . If R ₀ <R ₁ , the amplitude or magnitude of the positive attenuation change initially increases up to ∞ and only then decreases. In this case, it is not necessary to switch over a large range of α values, ie a corresponding fixed capacitor can be connected in parallel between stator 5 and rotor 6.

When using various transformation ratios _in the differential transformer 2, as shown in _FIG . For example, it can be designed to be monolithic or more advantageously available. It is clear from Fig. 1 that the circuit has a large broadband property, which means that even under the finite inductance of the differential transformer 2, a constant attenuation a ₀ can be maintained up to the frequency α = 0 in the case of feed-through connection. It is from.

FIG. 4 shows an equalizer circuit arrangement which can produce a so-called "swelling of the attenuation characteristic curve" in the case of multiple frequencies. By way of example, via a series-connected differential transformer 2, six series circuits are connected, each with an inductance L ₀ 〓, a differential capacitor C ₀ 〓, and up to three resistors R ₀ 〓 or R ₂ to _{R 13} . Six series circuits are formed. A plurality of impedance circuits each consisting of a differential capacitor and a coil, e.g. L ₀₁ , C ₀₁ ; L ₀₄ , C ₀₄ and optionally three resistors, e.g. R ₀₁ , R ₂ , R ₃ , are connected to the differential transformer 2. Can be connected to different taps. As is clear from this, parasitic disturbances such as ground capacitance and impedance disturbances that are inevitable when operating with finitely large termination resistors or impedances R _E and R _A are introduced uniformly at the intermediate position of the differential capacitor, and the output side E and A, thereby reducing their harmful effects.

The circuit in FIG. 4 is a development of the circuit in FIG. 1, and parts with the same functions are given the same reference symbols in the circuit in FIG.
The explanation given regarding FIG. 3 applies equally.

In FIG. 4, the impedance circuits connected to the taps of the differential transformer 2 are marked with continuous index symbols. Furthermore, resistors R2 to R13 can additionally be connected between the stator, the respective differential capacitor C ₀₁ to C ₀₆ and the respective connection point E' to A' to 1. As mentioned above, the advantage of the embodiment of FIG. 4 is that each impedance two-terminal circuit is arbitrarily distributed between the input side and the output side on the stator side of the differential capacitor.

None of the comparable types of equalizer circuits known in the art have equal bandwidths at the two extreme changes Δa ₊ and Δa _- .

Another significant advantage of the circuit of FIG. Δa ₊ and Δa _-
The main advantage is that the bandwidths of the two can be mutually adapted. This important characteristic can, of course, be transferred to the circuits of FIGS. 1 and 5 by correspondingly additional taps in the differential transformer 2.

In some cases, as shown in Figure 4,
Further impedances Z _KE and Z _KA can be connected for resistance compensation in the input and/or output parallel branches. It is also possible to use a pure resistor or a two-terminal network consisting of a coil and a resistor for this purpose.

FIG. 5 shows another embodiment of the invention. 6 shows the circuit of FIG. 5 and its associated attenuation characteristic curve for the adjustment parameter α=0 of the differential capacitor, and FIG. 7 shows the circuit of FIG. 5 and its associated attenuation characteristic curve for the adjustment parameter α=1 of the differential capacitor. Show a curve. In the circuit of FIG. 5, parts having the same function are indicated by the same reference symbols as in FIG. However, the difference from the circuit of FIG. 1 is that a resistor R' ₁ is connected in parallel to the differential transformer 2 in a series branch. The resistor R ₁ provided in the parallel branch does not necessarily have to be inserted and connected, and can have a resistance value of ∞. The course of the damping characteristic curves in FIGS. 6 and 7 is also schematically illustrated for α=0 and α=1.

FIG. 6 shows the extreme value change Δa ₊ of the circuit of FIG.
As is clear from the figure, the change appears as α=
0 and α=1 as in FIG.
Not against. As shown in Fig. 7, the attenuation change Δa _- appears for α=1, and
Since α must not be 1, the relationship is opposite to that of the circuit shown in FIG.

[Brief explanation of the drawing]

Figure 1 shows the basic circuit diagram of the equalizer and its associated attenuation characteristic curve, and Figure 2 shows the adjustment parameter α = 1 of the differential capacitor and the turns ratio W ₁ = of the differential transformer.
Figure 1 shows the equalizer circuit diagram and the associated attenuation characteristic curve for W ₂ = W/2, and Figure 3 shows the adjustment parameter α = 0 of the differential capacitor and the turns ratio of the differential transformer W ₁ = W. The equalizer circuit diagram and the associated attenuation characteristic curve diagram in Figure 1 for ₂ = W/2, Figure 4 is 1
A circuit diagram of an equalizer capable of producing a large number of attenuation changes for one basic attenuation a ₀ ; FIG. 5 is a circuit diagram of an embodiment of the present invention and its associated attenuation characteristic curve diagram; FIG. Differential capacitor adjustment parameter α
FIG. 5 shows the circuit diagram and the associated damping characteristic curve for the differential capacitor adjustment parameter α=0, and FIG. 7 shows the circuit diagram of FIG. 2... Differential transformer, 3... Differential capacitor,
4, 5...Stator, 6...Rotor, _L0 ...Coil, A...Output terminal, E...Input terminal, _W1 ,
W ₂ ...Tap.

Claims (1)

[Claims] 1. A system comprising at least one differential capacitor, at least one coil, and at least one resistor, as well as a differential transformer, where a line placed at a reference potential is directly connected between an input terminal and an output terminal. In an adjustable attenuation equalizer configured as a four-terminal network with feed-through connection, a differential transformer 2 is provided in the series branches E, A of the four-terminal network, and the differential capacitor 3 is The stators 4 and 5 are provided in parallel branches on the input side or the output side, and the rotor 6 of the differential capacitor is connected to the coil.
4, characterized in that it is connected to the tap W ₁ of the differential transformer 2 via L ₀ or directly, and furthermore a resistor R ₁ is provided between another tap W ₂ and the through line 1.
Adjustable attenuation equalizer configured as a terminal network. 2. The equalizer according to claim 1, wherein the two taps W ₁ and W ₂ overlap. 3. The equalizer according to claim 1, wherein the two taps W ₁ and W ₂ have the same number of turns. 4. Equalizer according to claim 1, characterized in that a resistor R ₀ is additionally provided in the rotor branch 6 of the differential capacitor 3. 5 Input side E and output side A themselves are connected to differential transformer 2
2. An equalizer according to claim 1, wherein the equalizer is adapted to be connected to a tap. 6. Claim 1, wherein separate impedances (Z _KE , Z _{KA )} are provided in the input side and/or output side parallel branch, and the impedance is constituted by a resistor or a series connection of a resistor and a coil.
Equalizer described in section. 7 Claims 1 to 6 above, in which another resistor R′ ₁ is connected in parallel to the differential transformer 2.
The equalizer according to any one of the terms up to the terms.