Devices and methods for signal coupling

Abstract

Coupling device (120), comprising: a coupling element (20; 37; 70) for sending a first signal and a second signal from a coupling circuit part (10; 25), a first coupling element (21; 38; 71) for receiving the first signal from the output coupling element (20; 37; 70), suppressing the second signal, and a second coupling element (22; 310; 72) different from the first coupling element (21; 38; 71) for receiving the second signal from the output coupling element (20; 37; 70), wherein the first signal is suppressed, wherein the coupling device is configured to couple the output coupling element (20; 37; 70) to the first coupling element (21; 38; 71) predominantly via a magnetic field and to couple the output coupling element (20; 37; 70) to the second coupling element (22; 310; 72) predominantly via an electric field.

Description

TECHNICAL AREA

[0001] The present application relates to methods and devices for signal coupling, i.e., for coupling signals, for example, from one circuit part to another. In particular, the present application relates to signal coupling of high-frequency signals, for example, with a frequency above 1 GHz. BACKGROUND

[0002] In many applications, it is necessary to provide signals, especially high-frequency signals, generated or processed in one circuit section, to another section of the circuit for further use. For example, in some applications, signals generated by an oscillator such as a voltage-controlled oscillator (VCO) must be fed to a frequency divider network, a transmitting circuit, or a receiving circuit; signals from a frequency doubler must be fed to other circuit sections; or part of the output of a transmitting circuit must be fed to a diagnostic circuit such as a power detector for testing purposes.

[0003] When extracting signals from one circuit and coupling them into another, it is often desirable or necessary to minimize the impact on the function of the circuit section from which the signal (or signals) is extracted (hereinafter also referred to as the extracting circuit section). In particular, for many applications, it is desirable that such signal extraction places the lowest possible load on the extracting circuit section. This is especially critical in many applications where high frequencies, such as millimeter waves (in the range above 10 GHz, for example), are used. A voltage-controlled oscillator using a resonator tank serves as an example. If a load is directly connected to nodes of the resonator tank, this loads the resonator tank and affects the phase noise.

[0004] From DE 10 2014 103 344 A1, a coupler with a primary coil and a secondary coil is known. The primary coil comprises a first end coupled to a first contact terminal, a second end coupled to a second contact terminal, and a first center tap coupled to a reference node. With this coupler, a desired signal can be transmitted, while electrostatic discharges are shunted to ground via the center tap and thus suppressed during transmission.

[0005] DE 10 2014 203 228 A1 discloses a directional coupler, and DE 10 2014 114 200 A1 discloses a high-frequency coupler.

[0006] Furthermore, in some applications it is desirable not only to extract a signal at a single frequency, but to extract signals of different frequencies separately from a single circuit. An example is the extraction of a higher harmonic of the fundamental frequency of an oscillator. For instance, if a voltage-controlled oscillator operates at a fundamental frequency of 30 GHz, a second harmonic at 60 GHz may be present at some nodes in certain implementations. In some oscillator configurations, such as a so-called push-push configuration, the fundamental signal (e.g., 30 GHz) is then fed to a frequency divider chain, and the second harmonic (e.g., 60 GHz) is fed to a receiver or transmitter. Two frequencies can also occur simultaneously in frequency doublers, circulators, or duplexers.

[0007] Traditionally, such coupling of multiple signals at different frequencies is achieved through direct coupling, using smaller transistors, for example, to reduce the load and thus minimize (parasitic) load capacitance. However, this can still lead to degradation of the circuit from which the signal is extracted. Furthermore, such approaches can introduce additional parasitic effects. Finally, miniaturizing structures like transistors also has its limitations.

[0008] It is therefore a task to provide improved devices and methods for signal coupling. SUMMARY

[0009] In this regard, methods and devices as defined in the independent claims are provided. The dependent claims define further embodiments.

[0010] The above summary provides only a brief overview and should not be interpreted as restrictive. BRIEF DESCRIPTION OF THE FIGURES Fig. Figure 1 is a schematic representation of a device according to an exemplary embodiment. Fig. Figure 2 is a block diagram of a device according to an exemplary embodiment. Fig. Figure 3 is a circuit diagram of a device according to an exemplary embodiment. Fig. Figures 4-6 are different illustrations to explain the functionality of exemplary embodiments. Fig. Figures 7A-7C show perspective views of a device according to an exemplary embodiment. Fig. 8A and Fig. Figure 8B shows circuits that serve as a basis for simulations. Fig. Figure 9 shows results of simulations based on the circuits of the Fig. 8A and Fig. 8B. Fig. Figure 10 shows a circuit as a basis for simulations. Fig. 11A and Fig. 11B show results of simulations based on the circuit of the Fig. 10. Fig. Figures 12-19 show circuits according to various embodiments. Fig. Figure 20 shows a flowchart to illustrate a procedure according to an exemplary embodiment. DETAILED DESCRIPTION

[0011] The following section explains various exemplary embodiments in more detail with reference to the accompanying drawings. These exemplary embodiments serve only for illustration and are not to be interpreted as restrictive. Thus, a description of an exemplary embodiment with a large number of features should not be interpreted as meaning that all of these features are necessary for implementation. Rather, in other exemplary embodiments, some of the depicted features or components may be omitted and / or replaced by alternative features or components. Furthermore, in addition to the depicted and described features or components, further features or components, such as features or components of conventional high-frequency circuits, may be provided.

[0012] Variations and modifications described for one embodiment may also be applicable to other embodiments. Features or components from different embodiments can also be combined to create further embodiments.

[0013] In the described embodiments, direct connections, i.e., connections without intervening elements (for example, by simple conductor tracks), can also be replaced by indirect connections, i.e., connections with one or more additional intervening elements, and vice versa, as long as the basic function of the connection, for example, to transmit a certain signal, to effect a certain control, or to transmit a certain type of information, is essentially retained.

[0014] In various embodiments, different coupling mechanisms are used to couple two signals of different frequencies from one circuit section to another. In some embodiments, the coupling occurs under galvanic isolation, i.e., without a resistive connection. In other embodiments, only a single coupling element is provided on the output circuit section.

[0015] In some embodiments, a first signal is coupled out by means of inductive coupling, i.e., coupling via a magnetic field, and a second signal is coupled out by means of capacitive coupling, i.e., based on an electric field. This is shown schematically in Fig. Figure 1 illustrates this. On the side of a coupling circuit section 10, a first and a second signal with different frequencies f1 and f2 are present. Using a coupling device 11, the first signal with frequency f1 is coupled to a first circuit section 12 via magnetic coupling (H-field coupling), and the second signal with frequency f2 is coupled to a second circuit section 13 via coupling using the electric field (E-field coupling). It should be noted that "magnetic field" and "electric field" refer to the predominant, i.e., dominant, coupling mechanisms (magnetic induction and coupling predominantly by E-field, e.g., by charge induction (also known as electrostatic induction), similar to the signal transmission of AC signals via a capacitor), which does not mean that the other field is entirely absent. The couplings will be explained in more detail later.

[0016] Due to the different types of coupling, in some embodiments the second signal with frequency f2 is suppressed in the first circuit part 12, and the first signal with frequency f1 is suppressed in the second circuit part 13.

[0017] To implement such couplings, in some embodiments the first signal is coupled as a differential signal and the second signal as a single-pole signal to the first and second circuit sections, respectively. The terms "common mode signals" and "single-pole signal" are used essentially synonymously in the following. For this purpose, for example, a single coil can be provided on the side of the output circuit section 10. This will be explained in more detail later.

[0018] Fig. Figure 2 schematically shows a device according to an exemplary embodiment.

[0019] In the exemplary embodiment of the Fig. 2. A first signal and a second signal, having different frequencies, are fed to a single transmitting element 20 on the side of a coupling circuit section 25. The first signal can be a differential signal and the second signal a single-pole or common-mode signal. The transmitting element 20 can, for example, be a first coil. The first signal is then received by a first receiving element 21, as indicated by arrow 23, for further use in a first circuit section 26. The second signal is suppressed in the coupling path 23. The first receiving element 21 can, for example, be a differential coil to receive the first signal as a differential signal.

[0020] The second signal is transmitted via a coupling path 24 to a second receiving element 22, which can be a single-pole receiving element, for example a "closed" coil, as will be explained in more detail later. The differential first signal is suppressed at the coupling path 24. In this way, the second signal is fed to a second circuit section 27.

[0021] By using a differential signal and a single-pole signal (common-mode signal), a single transmitting element is sufficient for coupling. This reduces the required chip area in some implementations.

[0022] Fig. Figure 3 shows a circuit diagram of an exemplary embodiment to illustrate basic techniques used in some embodiments. The exemplary embodiment of Fig. 3 comprises a coupling device 33. The coupling device 33 comprises a transmitting coil 37 for coupling signals from a coupling circuit part, a first receiving coil 38 and a second receiving coil 310.

[0023] The transmitting coil 37 receives a first signal with a first amplitude V at inputs Inp, Inn. in1 and a first frequency f1 and a second signal with an amplitude V in2 and fed to a second frequency f2. Signal generators 34 are shown schematically for generating the signals. As will be explained later, the signal generators 34 can, for example, include oscillator circuits, frequency divider circuits or multiplier circuits, but are not limited to these.

[0024] The first and second signals are represented in the diagram of the Fig. 3 the inputs Inp, Inn via source impedances 35, 36 with resistance values ​​R ssupplied. The source impedances 35, 36 represent, in the model shown, impedances of circuits that serve to generate the first and second signals, e.g. oscillator circuits.

[0025] As in Fig. As illustrated in Figure 3, the first signal is a differential signal, which is fed to source impedance 35 with a phase angle of 0° and to source impedance 36 with a phase angle of 180°, resulting in a differential signal. The second signal, however, is a common-mode signal, in which the components fed to resistor 35 and resistor 36 have the same phase angle. In other words, the same signal is fed to both terminals of the transmitting coil 37 for the second signal. Diagram 30 schematically shows a spectrum of the input power for the transmitting coil 37 versus frequency, whereby, in the example shown, significant components are only present at frequencies f1 and f2. Both signals are fed to the transmitting coil 37 with similar power.

[0026] The first receiving coil 38 has two terminals, which are coupled to corresponding terminals of a load 39. The signal coupled into the first receiving coil 38 can then be tapped at the load 39. Due to the differential design with two terminals, the first signal is coupled in at frequency f1, while the second signal is suppressed at frequency f2. This is a coupling by magnetic induction, as already described with reference to the Fig. 1. This is briefly explained and will be further elaborated later. The second receiving coil 310 has interconnected terminals, both of which are connected to the first terminal of a load 311, while the second terminal of the load 311 is connected to ground. A signal coupled into the second receiving coil 310 can be tapped at the load 311. Due to the single-pole design, essentially only the second signal at frequency f2 is received, while the first signal at frequency f1 is suppressed.

[0027] This is shown schematically in diagrams 31 and 32. Diagram 31 shows the power P. out, which is coupled into the first receiving coil 38. Schematically, a signal is essentially only received at frequency f1. Diagram 32 shows the corresponding setup for the second receiving coil 310. Here, a signal is essentially only received at the second frequency f2, while the signal at the first frequency f1 is suppressed.

[0028] As mentioned earlier, the use of a single transmitting coil 37 allows the coupling device 33 to be built compactly, eliminating the need for completely separate components for the two couplings. Furthermore, the coupling is implemented with galvanic isolation, i.e., without a direct resistive connection. This reduces the load on the coupling circuit section and thus impairs its operation less. In some embodiments, for example, a fundamental frequency and a higher harmonic can be coupled out, such as in a voltage-controlled oscillator where a second harmonic can be coupled out without requiring an additional current source to ground. Corresponding embodiments will be explained in more detail later.

[0029] Now, with reference to the Fig. 4-6 the functioning of the circuits shown, in particular the circuit of the Fig. 3, with different coupling types (coupling via magnetic field and coupling via electric field) explained in more detail.

[0030] The Fig. Figure 4 explains a typical inductive coupling between two coils 40, 41, which in the case of Fig. 3, for example, correspond to the first coil 37 and the second coil 38. In the Fig. Figure 4 represents a magnetic flux through the second coil 41, which is characterized by a magnetic field B1 generated by a current i1 from the first coil 40. This leads to an induced voltage v. 21 in the second coil 41. The magnetic flux through the first coil 40 or through the second coil is the integral of the magnetic field B1 over the cross-sectional area of ​​the coil.

[0031] A corresponding induction can also occur from the second coil 41 to the first coil 40. This corresponds to the conventional magnetic induction between two coils and is therefore not explained in detail. As can be seen from the Fig. As can be seen in Figure 4, a differential signal connection is required for this induction at both the first coil 40 and the second coil 41, so that, for example, a first signal can be transmitted by induction from the transmitting coil 37 to the first receiving coil 38. Fig. 3 can be coupled in.

[0032] The Fig. Figure 5 shows a corresponding situation for single-pole signals (common-mode signals) in which a voltage is applied to both terminals of the first coil, corresponding to the application of the second signal with frequency f2 to the transmitting coil 37 of the Fig. 3. Accordingly, a voltage is tapped from the second coil. Here, the coils act as the plates of a capacitor 52, as in Fig. Figure 5 illustrates this. Reference symbols 50 and 51 denote a first circuit part that generates a signal to be extracted, and a second circuit part that receives the signal, respectively.

[0033] Thus, by means of the Fig. 4 and Fig. Figure 5 illustrates how differential signals were transmitted via magnetic induction and common-mode signals (single-pole signals) were transmitted via an electric field.

[0034] This will be explained in more detail mathematically below.

[0035] The following section describes the mathematical and network-theoretical background for an idealized case with reference to the Fig. 6A and Fig. Section 6B is explained. First, with reference to the Fig. Figure 6A illustrates the case of a single-pole coupled receiving coil with an inductance L2 to a transmitting coil L1. The differential signal +v1e is applied to terminals 1 and 2 of coil L1. jω1t , -v1 jω1t, where j is the imaginary unit, v1 the amplitude of the first signal, t the time, and ω1 the angular frequency of the first signal. A common-mode signal, v2e, is applied to both terminals. jω2t supplied, where t is time, j is the imaginary unit, ω2 is the angular frequency of the second signal, and v2 is the amplitude of the second signal. C denotes capacitive couplings between the coils.

[0036] The following analysis uses the so-called modified nodal analysis (MNA). Here, x = A -1 · z, where A is a matrix describing the coupling between nodes, x is a matrix containing unknown quantities (especially the voltages and currents coupled in on the receiver side), and z is a matrix containing the sources (i.e., the signals coupled into the transmitting coil).

[0037] In the case of differential excitation (first signal) in Fig. 6A The above equation can be written as follows: x_=[1jωL1(1−k2)+jωC−1jωL1(1−k2)−jωC10−1jωL1(1−k2)1jωL1(1−k2)+jωC−jωC01−jωC−jωC1RL001000001000]−1⋅[000v 1ejω1t−v1ejω1t]=[v1ejω1t−v1ejω1t0v1ejω1t(CL1k2ω2−CL1ω2+2)jωL1(1−k2)−v1ejω1t(CL1k2ω2−CL1ω2+2)jωL1(1−k2)]

[0038] As can be seen, at node 3 in Fig. 6A (third line of the vector x) generates a 0, i.e. the differential input does not contribute a signal in the single-pole output shown.

[0039] In the case of common-mode excitation (second signal of the Fig. 6A) results in the following equation. x_=[1jωL1(1−k2)+jωC−1jωL1(1−k2)−jωC10−1jωL1(1−k2)1jωL1(1−k2)+jωC−jωC01−jωC−jωC1RL00100000100 0]−1⋅[000v2ejω2tv2ejω2t]=[v2ejω2t−v2ejω2t2(jωRLC)v2ejω2t−Cω(2CRω+j)v2ejω2t−Cω(2CRω+j)v2ejω2t]

[0040] Here, at output node 3, a signal corresponding to the second signal v2e is generated. jω2t, which is attenuated by an RC filter.

[0041] Next, with reference to Fig. Section 6B explains the case of differential coupling at the second coil at output nodes 2 and 3. Otherwise, the Fig. 6B of the Fig. 6A.

[0042] First, the transmission of the first signal, i.e., a differential input signal with a differential output, is explained. This results in the following equation. x_=[1jωL1(1−k2)+jωC−kjωL1L2(1−k2)−jωCkjωL1L2(1−k2)−1jωL1(1−k2)10−kjωL1L2(1−k2)−jωC1jωL2(1−k2)+jωC+1RL−1jωL 2(1−k2)−1RLkjωL1L2(1−k2)00kjωL1L2(1−k2)−1jωL2(1−k2)−1RL1jωL2(1−k2)+jωC+1RL−kjωL1L2(1−k2)−jωC00−1jωL1(1−k2) kjωL1L2(1−k2)−kjωL1L2(1−k2)−jωC1jωL1(1−k2)+jωC0110000 0000100]−1⋅[000v1ejω1t−v1ejω1t]=[v1ejω1tv1ejω1tRω(CLω k2+2k−CLω)CLR2kω2−j2Lk2ω−CLRω2+j2Lω+2R−v1ejω1tRω(CLωk2+2k−CLω)CLR2kω2−j2Lk2ω−CLRω2+j2Lω+2R−v1ejω1tI(1)I(2)]

[0043] If the signal is then differentially tapped at nodes 2 and 3, the resulting output signal is... Vout=V2−V3=2⋅v1ejω1tRω(CLωk2+2k−CLω)CLRk2ω2−j2Lk2ω−CLRω2+j2Lω+2R i.e. the first signal with an attenuation which depends on the capacitances, inductances and resistances.

[0044] In the case of common-mode excitation (second signal of the Fig. 6B) and differential sampling, however, results x_=[1jωL1(1−k2)+jωC−kjωL1L2(1−k2)−jωCkjωL1L2(1−k2)−1jωL1(1−k2)10−kjωL1L2(1−k2)−jωC 1jωL2(1−k2)+jωC+1RL−1jωL2(1−k2)−1RLkjωL1L2(1−k2)00kjωL1L2(1−k2)−1jωL2(1−k2)−1RL1jω L2(1−k2)+jωC+1RL−kjωL1L2(1−k2)−jωC00−1jωL1(1−k2)kjωL1L2(1−k2)−kjωL1L2(1−k2)−jωC1jω L1(1−k2)+jωC01100000000100]−1⋅[000v1ejω1t−v1ejω1t]=[v1ejω1tv1ejω1tv1ejω1tv1ejω1t00]

[0045] The differential output signal at nodes 2 and 3 is then as follows: Vout=V2−V3=0 0, so that no signal is transmitted here.

[0046] Thus, the above explanations also demonstrate, from a mathematical network-theoretical perspective, that signal separation through the various coupling mechanisms is possible. It should be noted, however, that in practice, due to asymmetries, small portions of the second signal can still be differentially coupled with the first signal, or parts of the first signal can be coupled in the same mode with the second signal. In other words, various effects can prevent 100% signal separation. For many applications, however, the signal separation is sufficient.

[0047] Next, with reference to the Fig. Section 7 explains one possible implementation for a coupling device. This section shows that... Fig. 7A a top view of the coupling device which Fig. 7B a view from an underside of the coupling device and the Fig. 7C highlights a part of the device. The terms "top view" and "bottom view" are used for convenience only, and the device shown can be used in any orientation.

[0048] The device of Fig. 7 includes a transmitting coil 70, also referred to as the main coil, which is, for example, coil 37 of the Fig. 3. In the case shown, the transmitting coil 70 has a single turn. A first signal, for example, is applied to the terminals of the coil 70 as a differential signal, and a second signal is applied as a common-mode signal.

[0049] Furthermore, the device includes the Fig. 7 a first receiving coil 71 and a second receiving coil 72, each also having one turn and the same coil shape as the transmitting coil 70, and arranged stacked as shown. The coils themselves can be formed, for example, by metallic conductors and separated from each other by non-conductive dielectric material, such as silicon dioxide or silicon nitride.

[0050] The first receiving coil 71 has two connections, as shown, to allow for differential tapping as discussed above. The second receiving coil 72 has only a single connection, as shown, and can therefore be used, for example, as the second receiving coil 310 of the Fig. 3 is used and essentially acts as a capacitor plate as explained. It should be noted that the coil order shown is only an example, and the coils can also be arranged in a different order, for example, the transmitting coil 70 between the receiving coils 71 and 72. Furthermore, the shape of the coils can also differ from that shown. Additional coils, such as a second transmitting coil or further receiving coils, may also be provided. With a device as shown in Fig. As shown in Figure 7, a compact implementation is possible. However, other implementations are also possible.

[0051] To demonstrate how it works, we will now refer to the Fig. 8-11 Simulation results are discussed. It should be noted that these simulation results serve only as further illustration and that, depending on the implementation, results and signals in real circuits may differ.

[0052] The Fig. 8A and Fig. Figure 8B shows diagrams of circuits that were used for the simulation. The diagrams show... Fig. 8A the case of a differentially supplied signal, and the Fig. 8B the case of a single-pole signal, which is characterized by a phase difference of 180 in the Fig. 8A or 0 in Fig. 8B is expressed. With 80, the simulated coupling device, for example according to the Fig. 7, designated. The various resistance values ​​and frequency values ​​which are in the Fig. 8A and Fig. The values ​​shown in section 8B are merely a simulation example for further illustration, and the values ​​used may differ depending on the application. Accordingly, the results may also differ, and the simulations presented are for illustrative purposes only.

[0053] The Fig. Figure 9 shows simulation results for the circuits of the Fig. 8A and Fig. 8B for various cases. This includes... Fig. 9 shows the attenuation in decibels as a function of frequency. Curve 90 shows the differential output signal in the case of the Fig. 8A, i.e., with a differential input signal. As can be seen, there is only a small attenuation here (less than -4 dB). Curve 92 shows the common-mode output of the Fig. 8A. Here, relatively high attenuation prevails, which even at a high frequency of 100 GHz is in the range of -19 to -20 dB. In the case of the Fig. 8A therefore transmits the differential signal to the differential output, but not to a common-mode output.

[0054] Curves 91 and 93 show corresponding cases for the Fig. 8B. Curve 91 shows the differentially tapped output signal in the case of common-mode excitation. Depending on the frequency, attenuations in the range of -40 to -110 dB occur. Only slight attenuations are observed for the common-mode output. Thus, the common-mode signal is transmitted here, while there is hardly any crosstalk to the differential output.

[0055] In the simulation results shown, the crosstalk of the common-mode input signal to the differential output is lower than the crosstalk of the differential input signal to the common-mode output. This is explained with reference to the Fig. 10 and Fig. 11 illustrated by another simulation. Fig. Figure 10 shows a circuit underlying the simulation, where 100 is a coupling device such as the coupling device of the Fig. The number 7 is indicated. As example signals, a 30 GHz signal was used as a differential signal and a 60 GHz signal (for example, the second harmonic) as a common-mode signal. Again, all numerical values ​​given are for illustrative purposes only.

[0056] The Fig. Figure 11A shows the signal components at the differential output (corresponding, for example, to coil 38 of the Fig. 8 or the receiving coil 71 of the Fig. 7), and Fig. Figure 11B shows the relative signal strengths at the single-pole output (for example, via coil 310 of the Fig. 3 or coil 72 of the Fig. 7). As can be seen, at the differential output ( Fig. 11A) The common-mode signal is suppressed (by approximately -50 dB), while the differential signal is suppressed at the common-mode output (albeit to a lesser extent, by approximately -14 dB). This signal separation is sufficient for many applications.

[0057] In the following, various devices will be discussed as application examples of the coupling devices according to the invention. The coupling devices can be implemented in detail as discussed above, for example as in Fig. The examples shown in Figure 7 are not limited to these. Furthermore, the application examples presented are not to be interpreted as restrictive, and coupling devices according to the exemplary embodiments can also be used in other applications.

[0058] The Fig. Figure 12 shows a circuit in which an embodiment of a coupling device 120 serves to extract signals from a push-push voltage-controlled oscillator 126. In the illustrated example, the voltage-controlled oscillator 126 is equipped with two cross-coupled NMOS transistors and two variable capacitors, to which a tuning voltage V is applied. Tune is supplied, implemented.

[0059] The device 120 comprises a transmitting coil 123, which is coupled to the oscillator 126 such that it receives a fundamental signal of the oscillator with a frequency f0 as a differential signal and a harmonic with a frequency 2f0 as a common-mode signal. Furthermore, the device 120 comprises a first receiving coil 121 for transmitting the differential signal with frequency f0 and a second coil 122, the ends of which are connected together, for receiving the common-mode signal with frequency 2f0. The transmitting coil 123 and the receiving coils 121 and 122 operate as described above, for example, as described with reference to the Fig. 3 explained, and can, for example, be like in Fig. The implementation shown in Figure 7 is not limited to this. A first (differential) buffer 124 is coupled to the first receiving coil 121, and an output signal V is then generated via this buffer. outThe signal is output at frequency f0. A second (in this case single-pole) buffer 125 is connected to the second receiving coil 122 to generate a signal V. out to output at a frequency of 2f0.

[0060] In this way, both the signal with frequency f0 and the harmonic with frequency 2f0 can be coupled out in a non-invasive manner, so that the operation of the oscillator is hardly or not at all disturbed.

[0061] The oscillator 126 shown is only an example, and various variations and modifications are possible. Some of these are discussed in the following figures. To avoid repetition, corresponding elements have the same reference symbols and are not explained again.

[0062] In Fig. Oscillator 130 is coupled to coupling device 120. Oscillator 130 is based on cross-coupled PMOS transistors instead of the NMOS transistors of the Fig. 12. Otherwise, the device functions as described. Fig. 13 essentially the device of the Fig. 12.

[0063] Another variant is in Fig. Figure 14 shows an oscillator 140 connected to the coupling device 120. The construction of the oscillator 140 largely corresponds to the construction of the oscillator 126. Fig. 12. In contrast to this, however, oscillator 140 uses cross-coupled bipolar transistors instead of the NMOS transistors of the Fig. 12 implemented.

[0064] Another embodiment is shown in Fig. 15 shown. In the embodiment of the Fig. 15 comprises an oscillator 150 coupled to the coupling device 120, which is constructed from a pair of cross-coupled PMOS transistors and a pair of cross-coupled NMOS transistors (so-called "current reusing" oscillator). The oscillator of the Fig. 15 is thus, as it were, a combination of the oscillators of the Fig. 12 and Fig. 13. In some embodiments, the use of two pairs of cross-coupled oscillators can reduce phase noise.

[0065] Another embodiment is shown in Fig. 16 shown. In the embodiment of the Fig. 16 comprises an oscillator arrangement comprising a first oscillator core 165 with NMOS transistor and a second oscillator core 166 also with NMOS transistors, the cores each essentially corresponding to the oscillator 126 of the Fig. 12 correspond. A coupling device 160 of the Fig. Accordingly, coupling device 16 comprises a first transmitting coil 163 and a second transmitting coil 164. Like coupling device 120, coupling device 160 further comprises a first receiving coil, which operates differentially and is coupled to the first buffer 124, and a second receiving coil 162, which operates unipolar and is coupled to the second buffer 125. Apart from the presence of two transmitting coils, coupling device 160 corresponds to coupling device 120 and operates similarly to it and can be implemented accordingly. For example, the additional transmitting coil can be provided by another coil in the stack of the Fig. 7. The coupling of the oscillator cores 165, 166 is achieved via the magnetic field of the transmitting coils 163, 164, so that the oscillators oscillate in phase and at the same frequency. It should also be noted that more than two cores can be provided.

[0066] Other types of oscillators can also be used. Fig. 17 is represented as oscillator 170, a so-called Colpitts VCO, which in turn is coupled to the coupling device 120. The Colpitts VCO 170 of the Fig. 17 is implemented using NMOS transistors. Fig. Figure 18, in contrast, shows an implementation of a Colpitts VCO 180 based on bipolar transistors, specifically heterojunction bipolar transistors (HBTs). Apart from the different transistor types, the circuit corresponds to the Fig. 18 of those who Fig. 17.

[0067] The application of coupling devices as described is not limited to oscillator circuits. As a further example, the Fig. 19 a frequency multiplier 190, in which a frequency of a differential signal Vinp, Vinn, is multiplied. Here too, a fundamental signal at frequency f0 as a differential signal and a harmonic at frequency 2f0 (frequency-multiplied signal) as a common-mode signal are supplied to the transmitting coil 123 of the coupling device 120, which can then be received separately by the receiving coils 121, 122 as described.

[0068] Thus, coupling devices according to the exemplary embodiments can generally be used to separately couple out signals of different frequencies.

[0069] In Fig. Figure 20 shows a flowchart illustrating a process according to an exemplary embodiment. While the Fig. Figure 20 is presented as a sequence of processes; however, the sequence shown should not be interpreted as restrictive. In particular, some of the processes can also occur simultaneously in different parts of a circuit.

[0070] The procedure of Fig. 20 can be achieved by means of the with reference to the Fig. The devices discussed in sections 1-19 are, however, not limited to them. Modifications and alterations made with reference to the Fig. 1-19 discussed, also refer to the procedure of Fig. 20 applicable.

[0071] At 200 in Fig.In section 20, a first signal and a second signal are transmitted via a transmitting coil, specifically coupled from a coupling circuit section. The first and second signals have different frequencies. For example, the second signal can be a higher harmonic of the first signal, or vice versa. The first signal can be fed to the transmitting coil as a differential signal, and the second signal as a common-mode signal.

[0072] In apparatus 201, the first signal is received at a differential receiving coil, and in apparatus 202, the second signal is received at a single-pole receiving coil (i.e., a receiving coil whose ends are connected), with the other signal being suppressed in each case. In this way, two different signals can be efficiently coupled.

[0073] As already emphasized, the above examples serve only to illustrate the point and are not to be interpreted as restrictive.

Claims

[1] Coupling device (120), comprising: a coupling element (20; 37; 70) for sending a first signal and a second signal from a coupling circuit part (10; 25), a first coupling element (21; 38; 71) for receiving the first signal from the output coupling element (20; 37; 70), suppressing the second signal, and a second coupling element (22; 310; 72) different from the first coupling element (21; 38; 71) for receiving the second signal from the output coupling element (20; 37; 70), wherein the first signal is suppressed, wherein the coupling device is configured to couple the output coupling element (20; 37; 70) to the first coupling element (21; 38; 71) predominantly via a magnetic field and to couple the output coupling element (20; 37; 70) to the second coupling element (22; 310; 72) predominantly via an electric field. [2] Coupling device (120) according to claim 1, wherein the first signal can be supplied to the coupling element (20; 37; 70) as a differential signal and the second signal as a common-mode signal, wherein the first signal can be tapped as a differential signal at the first coupling element (21; 38; 71), and the second signal can be tapped as a common-mode signal at the second coupling element (22; 310; 72). [3] Coupling device (120) according to claim 1 or 2, wherein the coupling element comprises a coil (37; 70), wherein the first coupling element comprises a coil (38; 71) with differential connections, and wherein the third coupling element comprises a coil (310; 72) whose connections are connected to each other. [4] Coupling device (120), comprising: a transmitting coil (37; 70) with a differential connection, a first receiving coil (38; 71) with a differential connection, and a second receiving coil (310; 72) different from the first receiving coil (38; 71), the ends of which are short-circuited to form a single-pole connection. [5] Coupling device according to claim 4, wherein the transmitting coil (70), the first receiving coil (71) and the second receiving coil (72) each comprise only one turn. [6] Coupling device according to claim 4 or 5, wherein the transmitting coil (70), the first receiving coil (71) and the second receiving coil (72) are arranged as a coil stack. [7] Circuit, comprising: a coupling device (120) according to one of claims 1-6, a first circuit section (25) for generating a first signal and a second signal, a second circuit part (26) for receiving the first signal from the first circuit part via the coupling device, wherein the second signal is suppressed, and a third circuit part (27) for receiving the second signal from the first circuit part via the coupling device, wherein the first signal is suppressed. [8] Circuit according to claim 7, wherein the second circuit part comprises a first buffer (124) with a differential input which is coupled to the coupling device (120). [9] Circuit according to claim 7 or 8, wherein the third circuit part comprises a second buffer (125) with a single-pole input which is coupled to the coupling device (120). [10] Circuit according to one of claims 7-9, wherein the first circuit part (25) is configured to supply the coupling device with the first signal as a differential signal and the second signal as a common-mode signal. [11] Circuit according to one of claims 7-10, wherein the first circuit part (25) is configured to generate the second signal as a harmonic of the first signal. [12] Circuit according to one of claims 7-11 wherein the first circuit part (25) comprises an oscillator (126; 130; 140; 150; 165) with cross-coupled transistors or a Colpitts oscillator (170; 186). [13] Circuit according to one of claims 7-12, wherein the first circuit part comprises a frequency multiplier (190) or a frequency divider. [14] Procedures, including: Sending a first signal and a second signal by means of a transmitting coil (37; 70), wherein the first signal is supplied to the transmitting coil (37; 70) as a differential signal and the second signal is supplied to the transmitting coil as a common-mode signal, Receiving the first signal at a differential first receiving coil (38; 71), and Receiving the second signal at a second receiving coil (310; 72), whose terminals are short-circuited. [15] Method according to claim 14, further comprising generating the first signal and the second signal by means of an oscillator circuit (126; 130; 140; 150; 165; 170; 186). [16] Method according to claim 14 or 15, wherein the first signal has a different frequency than the second signal. [17] Method according to one of claims 14-16, wherein the transmitting coil (37; 70), the first receiving coil (38; 71) and the second receiving coil (310; 72) form a coupling device according to one of claims 1-6. [18] Method according to any one of claims 14-17, wherein the method is carried out using a circuit according to any one of claims 7-13.

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