DE4302929C1 - Wide band repeater coil with two coaxial windings - connected in series with same winding sense to connection point forming induction coil output - Google Patents

Abstract

The induction coil has a core (1) on which a first and second two-wire line or coaxial line (W1,W2,W3,W4) are wound. The two-wire or coaxial lines are connected to the same winding sense in series. For the first two-wire line or coaxial line (W1,W2) the first conductor (W1) is connected at one end (1,3) to the repeater coil input (E). The second conductor (W2) is connected at the other end (5,7) to the output (A). The unconnected free ends (3,2,4) are connected directly or via a reactance (C1) to a common base point (M). ADVANTAGE - Has bandwidth of more than 5 frequency decades.

Description

The invention relates to a broadband transmitter.

Broadband transmitters usually consist of waveguides (Wire, ribbon cable, coaxial cable), which together on one Core, e.g. B. a toroidal ferrite core are wound (F. KOVACS, high frequency applications of semiconductor devices, Munich 1977, pages 194 to 197). The cable length determines the characteristic impedance and the upper frequency limit of the Waveguide transmitter. The waveguide transmitter with Ferrite cores work in the lower frequency range magnetic coupling.

As the frequency increases, the permeability of the Ferrite core and the transformer gradually goes into a pure one Waveguide transmitter via; d. H. the coupling only takes place still over waveguide.

A broadband transmitter is known from US Pat. No. 3,731,237 Carries multifilament windings on a toroidal core. Primary and Secondary windings are arranged there separately, to prevent parasitic capacitive couplings under the windings minimize. Are parts of primary and secondary windings connected in parallel and over another winding on one common footpoint switched.

The object of the invention is a broadband transmitter specify the high bandwidth, especially over several Frequency decades, with good impedance matching. This Object is solved by the features of claim 1. In the dependent claims are advantageous refinements shown.  

In broadband transmitters it is known to be unequal To transform external resistances by tapping (DE 30 22 023 A1). However, this will make the loss of the ideal Line relationships accepted. It is also in itself known to match by impedances, e.g. B. capacitors, at the entrance, exit or within a broadband transmitter to be improved (DE 33 29 368 A1, Telefunken Zeitung, Jg. 28, Issue 107, March 1955, pages 5 to 14, especially page 9,  SU 12 77 226 A1), but these realizations do not give Suggestion for a combination in terms of the characteristics of claim 1.

Ein aus Electronics, August 16, 1973, pages 113 to 116, known broadband transmitter in waveguide implementation has a third waveguide that connects to the output is connected, but this waveguide is intended to the impedance transformation ratio at the expense of Increase bandwidth. There is also no galvanic Decoupling between the input and output circuit.

The implementation according to the invention has in particular following advantages:

• - The frequency range of the broadband transmitter is 5.5 Decades without significant disturbance of the impedance conditions and is therefore for digital signals with changing bit rates suitable,
• - the input circuit is from the output circuit - contrary to known Realizations (DE 30 22 023 A1, DE 33 29 368 A1, EP 01 29 464 A1) - galvanically decoupled, especially for use in the input circuit of news devices, the one have specified insulation strength, is advantageous,
• - The impedance matching is in the middle frequency range optimal,
• - By the resonance increase according to the invention in the upper The amplitude range is improved without the frequency range Disrupt conditions in other frequency ranges,
• - The broadband transmitter according to the invention has one wide setting range for a desired Impedance transformation ratio a good matchability,
• - By coupling the second two-wire or Coaxial line across the entire winding is the bandwidth of the Broadband transmitter higher than a broadband transmitter in waveguide implementation with only partial coupling.

Using the drawings, an embodiment of a Broadband transmitter explained in more detail according to the invention. It demonstrate

Fig. 1 is a schematic diagram of a Breitbandübertragers according to the invention,

Fig. 2 shows the amplitude response of a Breitbandübertragers according to the invention,

Fig. 3 is a schematic sketch of a broadband transmitter according to the invention with a ring core.

The wideband transmitter according to Fig. 1 consists of two two-wire conductors which are connected in series and are mutually the same direction wound on a core K. Instead of the two-wire lines, coaxial lines can also be used. All subsequent versions for two-wire lines apply mutatis mutandis to coaxial lines. The first two-wire line consists of the two lines w1 and w2, the second two-wire line consists of the two lines w3 and w4. In the first two-wire line, the first line w1 leads at the first line end to the input E (connection 1 ) of the broadband transmitter. At the second line end of the first two-wire line, the second line w2 is connected to the output A (connection 5 ) of the broadband transmitter. Output A of the broadband transmitter is thus galvanically decoupled from input E. The second two-wire line consists of conductors w3 and w4. The cable w3 is connected via its connecting terminal 8 to the connecting terminal 7 of the connecting cable w1, as is the cable w4 via the connecting terminal 6 to the connecting terminal 5 of the connecting cable w2. The free ends 2 and 3 of the cable runs w2 and w4, which are not yet connected, are connected directly to a common base point M (ground potential) and the free end 4 of the cable run w4 via a reactance in the form of the capacitor C1.

This capacitor C1 forms with the line w4 open two-wire line consisting of w3, w4, one Series resonance circuit.

In the lower frequency range, the coupling between the first two-wire line and the second two-wire line, ie between the conductor lines w1, w2, w3, is magnetic, since the conductor lines are wound on a ferrite pot or toroidal core K of very high permeability. The winding of the conductor line w4 does not work, since this winding with the capacitor C1 represents a series resonance circuit at the upper end of the band. With increasing frequency and decreasing permeability of the core K, the coupling via the conductor tracks w1 to w4 is brought about in its capacity as a waveguide. The transmission ratio (the impedance transformation) of the broadband transmitter is determined in the lower frequency range according to the ratio of the number of turns of w1, or w2, to w3. In the upper frequency range, the transmission ratio is determined by the ratio of the line lengths of the waveguides w1 or w2 and w3 or w4. For a transmission ratio that is the same over the entire frequency range, the number of turns and conductor lengths must be coordinated. If this coordination is not exactly possible due to other specifications, additional reactances at the entrance and exit, here e.g. B. in the form of transverse capacitors C2 and C3, an improvement in the impedance transformation can be brought about. The open line, consisting of w3 and w4, is coupled directly as a winding over the entire core to the line consisting of w1, w2; ie in the embodiment with a ring core ( Fig. 3), both lines are evenly distributed over the entire core circumference. With this arrangement, the coupling is strong and the transmitter bandwidth is very high by preventing stray losses. The already very high bandwidth of the transmitter as a result of this measure can be increased further if, according to the invention, a resonance increase is provided in the upper frequency range of the broadband transmitter.

Such an increase in resonance can be achieved, for example Setting a series resonance of the resonant circuit, existing from the line w4 and the capacitor C1. For this purpose, the capacitor C1 is preferably adjustable educated.

Fig. 2 shows the amplitude response (attenuation a / dB) over the frequency of a broadband transmitter according to the invention. The bandwidth extends over 5.5 decades - 500 Hz to 100 MHz - and is therefore extremely high. This broadband transformer was implemented with an input impedance of 90 ohms and an output impedance of 75 ohms. The first two-wire line was designed with 28 core turns and the second two-wire line with 3 core turns. A common 2R (20 × 7) core was used as the ring core.

FIG. 3 shows the arrangement of the two-wire line on the ring core and its connection according to FIG. 1.

Claims (5)

1. Broadband transmitter with the following features:

• a first and a second two-wire or coaxial line (w1, w2 and w3, w4) are wound on a transformer core (K),
• - The two-wire or coaxial lines are connected in series with the same winding sense,
• - In the first two-wire or coaxial line (w1, w2) is the first conductor line (w1) at one line end ( 1 , 3 ) with the input (E) of the broadband transmitter and the second line line (w2) at the other line end ( 5 , 7 ) connected to the output (A) of the broadband transmitter,
• - The unconnected free ends ( 3 , 2 , 4 ) of the two-wire or coaxial lines are connected directly or via a reactance (C1) to a common base (M).

2. Broadband transmitter according to claim 1, characterized characterized in that that cable run (w4) of the second Two-wire or coaxial line, which to the output (A) of Broadband transmitter performs on a capacitor (C1) the common base point (M) is switched.   3. Broadband transmitter according to claim 1, characterized characterized in that the capacitor (C1) is adjustable that it is together with the conductor track leading to output (A) (w4) the second two-wire or coaxial line Series resonance circuit in the upper frequency range of the Broadband transmitter forms. 4. broadband transmitter according to one of claims 1 to 3, characterized in that between the input (E) and / or Exit (A) of the broadband transmitter and common base (M) reactances (C2, C3) are provided for impedance matching.   5. broadband transmitter according to one of claims 1 to 4, characterized in that the transformer core (K) as Ring core is formed and that both the first and the second two-wire or coaxial line evenly over the whole ring core is distributed.