JPS6137808B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a separator or combiner for signals having significantly different frequencies.

It is well known to use directional couplers for the separation or combination of high frequency signals in the frequency range from several hundred megahertz to about 1 gigahertz.
However, when one of the signals has a frequency of only a few hundred kilohertz, the use of a directional coupler becomes
It is no longer effective because the cut-off damping becomes insufficient and the pass damping becomes high. It is well known that directional couplers do not work satisfactorily at low frequencies. This is because directional couplers produce a high degree of coupling attenuation for low frequencies. Even when coupling low frequencies via coupling splitters or low-pass elements in the signal path for high-frequency signals, a high degree of coupling attenuation occurs for the low-frequency signals, unless a mutual influence of the two signal paths is avoided.

The need for a duplexer to separate signals at significantly different frequency locations is in antenna circuits using transmitter/receiver duplexers as well as in the coupling of relatively low frequency pilot signals to directional radio signals.
It is further known from the art of transmitting digital signals over long distances to transmit digital signals with a bit transmission rate of several hundred megabits per second together with relatively low frequency signals. In this case, the low-frequency signals are used for the transmission of monitoring information, and also the transmission of service channels is possible.

It is therefore an object of the invention to provide a splitter of the type mentioned at the outset, in which signals in the frequency range of several hundred kilohertz and signals in the frequency range of several hundred megahertz to about 1 gigahertz can be coupled in a common signal path. It is an object of the present invention to provide a demultiplexer or combiner that allows output coupling from a common signal path.

This problem is solved by the present invention as follows. That is, a waveguide is provided which is wound around a ferromagnetic core, the first conductor of the waveguide being connected at one end to a common signal path for the signals, and the first conductor of the waveguide being connected to a common signal path for the signals. a first conductor of which at the other end has a relatively high resistance to high frequency signals and a relatively low resistance to low frequency signals compared to the characteristic impedance; and a signal path for high-frequency signals, the other connection of the cable being connected to a reference potential, and the second conductor of the waveguide being connected directly to earth at one end. and is connected at the other end to a reference potential via a capacitor and further directly connected to the signal path for the low frequency signal, and the capacitor, together with the inductance of the waveguide, is connected to a reference potential for the low frequency signal. form a circuit. A particular advantage of the duplexer according to the invention is that it can also be used with broadband high-frequency signals, such as digital signals with bit transmission rates of several hundred megabits per second. Another advantage is that the separator or combiner of the invention is a passive component that does not require additional current consumption, so that its use in e.g. remotely powered devices is easily possible and the parameters of the active component There is no need to compensate for variations in A particular advantage of the splitter or combiner of the invention is that it can be used both to separate signals having significantly different frequencies and to combine them into a common signal path.

Advantageous embodiments of the frequency separator or combiner according to the invention are described in detail in the claims 2 to 12.

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

The duplexer shown in FIG. 1 is used to separate two signals of different frequencies coming from a generator G and reaching the input of the duplexer from this generator via a common line. . The duplexer has a first coaxial line KL1 as a waveguide line. The coaxial line is wrapped around a disk-shaped ferrite in the form of a line reactor. The inner conductor of the coaxial line is connected to the common line or generator G, while the outer conductor is connected directly to a reference potential at any end. Connected to the other end of the inner conductor is a signal path for high-frequency signals, which is schematically illustrated by a first choke L0 and a first load V1. A first capacitor and a first transformer u¨1 are connected to the other free end of the outer conductor of the coaxial line KL1, the other electrode of the capacitor being connected to earth and the transformer is load V2
The actual signal path for a second, low-frequency signal in the form of is connected. Capacitor C1 is
Together with the inductance of the coaxial line KL1, in particular of the outer conductor, they form a parallel resonant circuit, the resonant frequency of which corresponds to the frequency of the low-frequency signal.

This embodiment is a splitter for separating a digital signal having a spectral range of about 5 MHz to 500 MHz and a low frequency telemetry signal having a frequency of about 600 KHz. The internal resistance of the generator G corresponds to the characteristic impedance of approximately 75 Ω of the coaxial line as well as the load V1, and for the different load V2 the first transformer U
1 is provided, and matching of the load V2 with the characteristic impedance is performed by impedance conversion of this transformer. A stub is provided as the station L0, the length of the stub being tuned to the bit repetition frequency of the digital signal, ie to the frequency of the high-frequency signal.

The equivalent circuit shown in FIG. 2 is generated for the high-pass path of the duplexer, which is a frequency separator, shown in FIG. At that time, in the equivalent circuit, the characteristic impedance Z of the common line connected to the generator G is
It is assumed that the characteristic impedance matches the characteristic impedance of the coaxial line KL1. The yoke L0, which corresponds to a stub with shorted ends, exhibits a high impedance in the frequency range of high-frequency signals, but
This impedance is either negligible compared to the impedance of the load V1 or is taken into account in the signal equalization insofar as this load corresponds to the characteristic impedance Z.

Oscillating circuit capacitor C1 for low frequency signals
has a sufficiently low resistance in the frequency range for high-frequency signals, so that the transmission of high-frequency signals through the coaxial line KL1 is not disturbed and the load V2
It has such a high capacitance that even high frequency signal components reaching up to 100 nm are negligible. The inductance L1 of the transformer U1 is then of little concern, as is the transformed impedance ^U2.Z of the low-frequency signal path, ie the impedance of the second load V2.

Figure 3 shows the coaxial line KL acting as a line reactor in another equivalent circuit for the splitter.
An ideal transformer U2 with a transformation ratio of 1:1
and by the lossy inductance L2. The first conductor path for the high-frequency signal with the first load V1 and the transmission line L0 is then connected directly to the primary winding of the second transformer U2 and to the reference potential. 2 of the second transformer U2
The next side corresponds to the outer conductor of the coaxial line KL1, so that the secondary winding of the second transformer and the inductance L2 connected in parallel thereto are connected on one side to a reference potential, On the other hand, they are connected to a load V2 via one electrode of a capacitor C1 and a transformer U1. Line KL1 acts as an inverting transformer for low-frequency signals, with both terminals of the secondary winding of the transformer, i.e. both terminals of the outer conductor of the coaxial line, being replaceable, in which case the phase The inverting circuit is omitted.

From FIG. 3, the equivalent circuit of FIG. 4 results for the low frequency bandpass path of the duplexer. This is because the impedance of the yoke L0 is extremely small for low frequency signals. For low-frequency signals, the connection terminal of the primary winding of transformer U2, which is opposite the generator, is therefore essentially at reference potential. There, the capacitor C1 together with the inductance L2 of the coaxial line KL1 forms an oscillating circuit which is detuned by the inductance of the first transformer U1 and the signal path for the low frequency signal, ie the transformed inductance of the load V2. Sometimes.
In the specific example, the inductance L2 of the coaxial line was about 4 μH, but the inductance can be adjusted within a certain range depending on the disc-shaped core used, which allows compensation for the effects of other inductances. become. In this case, a so-called semi-rigid cable with a characteristic impedance of 75Ω is used as the coaxial line, and the loads V1 and V
The impedance of each of the two was 75Ω.

For splitters used for high-frequency signals with frequencies below 200 MHz, it is advantageous to use parallel two-wire lines or lines consisting of twisted wires as waveguides.

For relatively high requirements imposed on the decoupling of the two signal paths, capacitor C1 can additionally be formed as a high-order low-pass filter or bandstop filter using a further coil and capacitor.

FIG. 5 shows the inventive combiner used as a transmit combiner, ie a combiner for two signals. A high-frequency digital signal is generated by the generator G1, and the signal is sent to one connection terminal of the chain yoke L3 and to the inner conductor of the second coaxial line KL2. A stub with a short-circuited end for the high-frequency signal is used as the yoke L3, the other connecting terminal of the yoke being again connected to a reference potential.

A relatively low frequency signal is generated by the generator G2, which signal is coupled via a third transformer U3 to the outer conductor of the second coaxial line KL2. One end of the outer conductor of the second coaxial line KL2 is connected to a reference potential, and the other end is connected to ground via a capacitor C2, while the other end of the inner conductor , a common signal path for high-frequency and low-frequency signals is connected, illustrated by a load V. The design of the combiner in FIG. 5 corresponds completely to the design of the separator in FIG. Furthermore, since the same signals as in FIG. 1 are used, the circuit constants of the individual elements of the duplexer of FIG. 1 are also equal to the circuit constants of the individual elements of the duplexer of FIG. 5.

[Brief explanation of the drawing]

FIG. 1 is a schematic circuit diagram of one embodiment of the duplexer of the present invention configured as a separation duplexer, and FIG. 2 is an equivalent circuit for the high-pass path of the duplexer of FIG.
Fig. 3 is another equivalent circuit of the duplexer shown in Fig. 1, Fig. 4 is an equivalent circuit for the low frequency bandpass path of the duplexer shown in Fig. 1, and Fig. 5 is an equivalent circuit of the duplexer shown in Fig. 1. 1 is a schematic circuit diagram of an embodiment of a duplexer according to the present invention. G...Signal generator, KL1, KL2...Coaxial line, L0, L1, L2, L3...Chiyoke, C
1, C2...Capacitor, U1, U2...Transformer, V1, V2...Load, Z...Characteristic impedance

Claims (1)

[Claims] 1. A waveguide is provided which is wound around a ferromagnetic core, and a first conductor of the waveguide is connected at one end to a common signal path for signals. In addition, the first conductor of the waveguide has a relatively high resistance to high frequency signals and a relatively low resistance to low frequency signals compared to the characteristic impedance at the other end. One connection part of the chain yoke, which is a resistor, is connected to a signal path for a high-frequency signal, and the other connection part of the tyoke is connected to a reference potential, and the second conductor of the waveguide line is connected to one side. is directly connected to earth at one end and connected to a reference potential via a capacitor at the other end and directly connected to the signal path for the low frequency signal, said capacitor being connected to the waveguide line. A separator or combiner for signals having significantly different frequencies, characterized in that it forms a parallel resonant circuit for low frequency signals with an inductance of . 2. The separator or coupler according to claim 1, wherein a transformer is inserted in the connection line between the second conductor of the waveguide and the signal path for the low frequency signal. 3. Claim No. 3, wherein the waveguide line is a coaxial line, and the inner conductor of the coaxial line represents a first conductor of the waveguide line, and the outer conductor of the coaxial line represents a second conductor of the waveguide line. The separator or combiner according to item 1. 4. The separator or coupler according to claim 1, wherein a parallel two-wire line is provided as the waveguide line. 5. The separator or coupler according to claim 1, wherein a line made of twisted wires is provided as the waveguide line. 6. The separator or combiner according to claim 1, wherein a signal source is connected to the common signal path and a load is connected to the separated signal path. 7. The separator or combiner according to claim 1, wherein a load is connected to the common signal path, and a signal source is connected to each of the separated signal paths. 8. The separator or coupler according to claim 1, wherein a stub tuned to the frequency of the high-frequency signal is provided as the chain. 9. The separator or combiner according to claim 1, wherein a high-pass filter for high-frequency signals is additionally formed on the chain yoke. 10. The separator or combiner according to claim 1, wherein a relatively high-order bandpass filter for high-frequency signals is additionally formed on the chain. 11 Claim 1 in which a low-pass filter for low-frequency signals is additionally formed on the capacitor.
Separator or combiner as described in Section. 12. The separator or coupler according to claim 1, wherein the waveguide is wound around a disc-shaped core made of ferrite material.