WO2015049307A1

WO2015049307A1 - Apparatus for providing a signal

Info

Publication number: WO2015049307A1
Application number: PCT/EP2014/071074
Authority: WO
Inventors: Jan Sundermeyer; Norbert Weber
Original assignee: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority date: 2013-10-02
Filing date: 2014-10-01
Publication date: 2015-04-09
Also published as: DE102013220108A1

Abstract

Embodiments of the present invention provide an apparatus for providing a signal. The apparatus has a first device having a plurality of switchable signal sources and a second device having a plurality of switchable signal sources. In this case, a change in an output signal from the first device by the smallest possible level step at at least one output signal level requires switching by at least two of the switchable signal sources, while a change in an output signal from the second device by the smallest possible level step requires switching by no more than one switchable signal source. In this case, the apparatus is designed to provide the signal on the basis of the output signal from the first device and the output signal from the second device.

Description

Device for providing a signal Description

Embodiments of the present invention relate to an apparatus for providing a signal. Further embodiments relate to a system with a distortion and at least one device for providing a signal, wherein at least one output driver of the distortion is set based on the signal provided by the at least one device. Further embodiments relate to a method for operating a device for providing a signal. Some embodiments relate to an extended digital-to-analog converter for transmission level control during operation.

Rapid data transmission (of, for example, more than 500 Mbits per second) from a transmitter to a receiver via a cable requires an equalizer at the transmitter and receiver because a signal transmitted over the cable is distorted by frequency dependent channel attenuation of the cable. If there is communication from the receiver to the transmitter and the channel is not fixed, the characteristics of the transmitter must be adjusted during data transmission.

To compensate for the data channel, predistorters are often used in the transmitter. The adjustment of the transmission characteristic usually takes place during the establishment of the data connection or during interim calibration cycles. The predistorter itself can be constructed as a FIR filter, in which the scaled basic signal is retransmitted and added to the original signal.

1 shows a schematic block diagram of an FIR predistorter 10. As can be seen in FIG. 1, the FIR predistorter (FIR filter) 10 can be implemented by operating n output drivers 12 ₀ to 12 _{n-1 in} parallel and Output driver i (ie [0 ... n-1]) is operated with a signal delayed by i clock periods, where n is a natural number. For this purpose, the FIR predistorter 10 may comprise n-1 delay elements 14, 14 to 14 _n-1 , which are connected starting from a first delay element 1 i, which is connected to an input 16 of the FIR predistorter 10 and at the input 16 of the FIR predistorter. Predistorter 10 applied input signal delayed by one clock period, a delay form a chain of events and delay the input signal in each case by an additional clock period. The 0th output driver 12 ₀ is connected directly to the input 16 of the FIR predistorter 10, while the remaining n-1 output drivers 12i to 12 _{n-1 are} connected to the corresponding n-1 delay elements 1 i to 14 _n-1 . All n-output drivers 12 ₀ to 12 _n .i have an individually adjustable output level g, so that the combination of the output levels, eg via the n-1 summers 2d to 20 _n .i, determines the characteristics of the FIR predistorter 10.

For adjusting the output level of the output drivers 12 _\ are driven normally each provided with a digital-to-analog converter (engl, digital-to-analog converter, DAC) to 12 _n-1. If, during operation, the output levels of the individual output drivers 12 ₀ to 12 _n- i are to be adapted, a disturbance that arises for the output level when switching the respective digital-to-analog converter may not be too large, since otherwise errors in the data transmission arise.

Two basic structures lend themselves to controlling this output level. On the one hand, a current source can be controlled directly via a reference signal, which can be freed of interference by low-pass filtering. On the other hand, the output level can be set via switchable current sources, which inevitably leads to interference when switching to a new level, which directly leads to disturbances in the output signal which is provided at the output 18 of the FIR predistorter 10.

A digital-to-analog converter for level control for an FIR output driver 10 is usually constructed in a binary-coded manner in order to minimize the complexity of wiring and layout. In some cases, higher-order bits of the digital-to-analog converter are thermometer-coded to reduce switching effects, but it is usually not possible to completely thermometer-encode the complete digital-to-analog converter (eg 8-bit) since the number of elements to be connected then it gets very big. 2 shows a schematic block diagram of a digital-to-analog converter 30, which is realized by means of switchable current sources 32 ₀ to 32 ₈ . As can be seen in FIG. 2, an example of a level control for an FIR output driver 12 ₀ to 12 _{n-1 is} a digital-to-analog converter 30 with 8-bit resolution. The 4 higher-order bits (engl, most significant bits, MSB) of the 8 bits can be implemented as a thermometer-coded digital-to-analog converter to monotone the digital-to-analog converter 30 while the 4 less significant bits (LSB) of the 8 bits can be realized as a binary-coded digital-to-analog converter.

Most transistors switch between the 16 ^χ n + 15 and 16 ^χ (n + 1) values (ne [0..14]) as the target value increases. If the value of the digital-to-analog converter 30 is increased from 15 to 16, then 31 elements simultaneously switch (16 are activated and 15 are deactivated) whose disturbances due to different switching times during activation and deactivation can not be compensated, and so on generate relatively large disturbance at the output. In the worst case, the activation and deactivation takes place staggered, so that the level is temporarily set to 31 or to 0, as shown in FIG.

FIG. 3 shows in a diagram 40 curves of a setpoint level 42 and an actual level 44 during a switching operation of the nominal level value, plotted over time.

This means that the data communication must be interrupted if the characteristic of the predistorter is changed in the transmitter, since even short disturbances due to the fast data transmission already lead to noticeable interference signals at the receiver and errors in the data transmission.

Alternatively, the transmission level of the individual FIR output drivers 12 ₀ to 12 _{n-1 can be} controlled via a filtered reference signal, but this is disadvantageous with respect to the reproducibility of the set level in various chips due to series variability. The present invention is therefore based on the object to provide a concept which allows a reproducible change in the transmission level during operation without interrupting the data transmission.

This object is achieved by a device for providing a signal according to claim 1, a system according to claim 15, a device for providing a signal according to claim 17, a method for operating a device for providing a signal according to claim 18 and a computer program according to claim 19 Embodiments of the present invention provide an apparatus for providing a signal. The device has a first device with a plurality of switchable signal sources and a second device with a plurality of switchable signal sources. In this case, changing an output signal of the first device by a smallest possible level step in at least one output signal level requires switching of at least two of the switchable signal sources, while a change of an output signal of the second device by a smallest possible level step requires switching of at most one switchable signal source. The apparatus is configured to provide the signal based on the output of the first device and the output of the second device. The present invention is based on the idea that a low-noise adaptation of a level of a signal in at least one limited level range can be realized by the second device having a plurality of switchable signal sources. The second device is configured such that a change of the output signal of the second device by a smallest possible level step requires switching of at most one switchable signal source, whereby a simultaneous switching of a plurality of switchable signal sources, as conventionally for changing the signal by a smallest possible level step at least one output signal level level is required, and the concomitant pronounced noise is avoided.

Further embodiments provide a system with a distortion having a plurality of output drivers, and at least one device for providing a signal. The device has a first device with a plurality of switchable signal sources and a second device with a plurality of switchable signal sources, wherein a change of an output signal of the first device by a smallest possible level step at at least one output signal level step switching at least two of the switchable signal sources wherein changing an output signal of the second device by a smallest possible level step requires switching at most one switchable signal source, and wherein the device is configured to provide the signal based on the output signal of the first device and the output signal of the second device. The system is configured to drive an output driver of the plurality of output drivers based on the provided signal of the device.

Further embodiments provide an apparatus for providing a signal. The device has a first signal provider with a plurality of switchable Signal sources for providing a first signal component and a second signal provider with a plurality of switchable signal sources for providing a second signal component. The first signal provider is designed in such a way that a change of the first signal component provided by the first signal provider by a smallest signal step associated with the first signal provider results in a simultaneous switching of a plurality of switchable signal sources of the first signal provider, at least in one case. The second signal provider is designed in such a way that the plurality of switchable signal sources of the second signal provider can each be switched between two level values which differ by the smallest level step assigned to the first signal provider.

Further embodiments provide a method for operating a device for providing a signal. The device has a first device with a plurality of switchable signal sources and a second device with a plurality of switchable signal sources. A change of an output signal of the first device by a smallest possible level step in at least one output signal level requires switching of at least two of the switchable signal sources, wherein a change of an output signal of the second device by a smallest possible level step requires switching of at most one switchable signal source. The method includes providing the signal based on the output of the first device and the output of the second device.

Embodiments of the present invention will be explained with reference to the accompanying drawings. Show it:

Fig. 1 is a schematic block diagram of an FIR predistorter;

Fig. 2 is a schematic block diagram of a digital-to-analog converter implemented by means of switchable current sources;

FIG. 3 is a graph showing progressions of a desired level and an actual level during a switching operation of the desired level value, in each case plotted over time; FIG.

4 is a schematic block diagram of an apparatus for providing a signal according to an embodiment of the present invention; 5 is a schematic block diagram of an apparatus for providing a signal according to an embodiment of the present invention;

6 is a schematic block diagram of a system according to an embodiment; and

7 shows a flow chart of a method for operating a device for providing a signal, according to an exemplary embodiment of the present invention.

In the following description of the embodiments of the invention, the same or equivalent elements are provided with the same reference numerals in the figures, so that their description in the different embodiments is interchangeable.

4 shows a schematic block diagram of a device 50 for providing a signal 52 according to an embodiment of the present invention. The device 50 has a first device 54 with a plurality of switchable signal sources 56 ₀ to 56 _k and a second device 58 with a plurality of switchable signal sources 60 ₀ to 60 | on. A change of an output signal 62 of the first device 54 by a smallest possible level step requires at least one output signal level step to switch at least two switchable signal sources of the switchable signal sources 56 ₀ to 56 _k . A change of an output signal 64 of the second device 58 by a smallest possible level step requires switching of at most one switchable signal source of the switchable signal sources 60 ₀ to 60 I. The device 50 is configured to provide the signal 52 based on the output 62 of the first device 54 and the output 64 of the second device 58.

In embodiments, the first device 54 may have up to k + 1 switchable signal sources 56 ₀ to 56 _k , where k is a natural number greater than or equal to one, k> 1. Further, the second device 58 may have up to 1 + 1 switchable signal sources 60 ₀ to 60 | where I is a natural number greater than or equal to one, I s 1.

The switchable signal sources 56 ₀ to 56 _{k of} the first device 54 and the switchable signal sources 60 ₀ to 60 _{t of} the second device 58 may be connected to an output node 51 of the device 50. The device 50 may be configured to provide the signal 52 at the output node 51. Furthermore, the switchable signal sources 56 ₀ to 56 _{k of} the first device 54 and the switchable signal sources 60 ₀ to 60 | the second device 58 may be connected in parallel, for example between the output node 51 and a reference potential node or reference potential connection 53.

The switchable signal sources 60 ₀ to 60 | The second means 58 may be configured to provide (in an on state) output signal portions of equal levels. For example, the switchable signal sources 60 ₀ to 60 | The second device 58 may be switchable current sources, which are designed to supply (in a switched-on state) currents with the same current intensities I.

In this case, the plurality of switchable signal sources 60 ₀ to 60 | The second device 58 can be driven based on lower-order bits of a bit sequence for controlling the device 50. The lower order bits of the bit string for driving the device 50 based on which the plurality of switchable signal sources 60 ₀ to 60 | the second device 58 can be thermometer-coded.

The plurality of switchable signal sources 56 ₀ to 56 _{k of} the first device 54 may be divided into a first group of switchable signal sources and a second group of switchable signal sources.

The first group of switchable signal sources of the plurality of switchable signal sources 56 ₀ to 56 _{k of} the first means 54 may be configured to provide (in a switched-on state) output signal portions of different levels. For example, the switchable signal sources 56 ₀ to 56 _{k of} the first device 54 may be switchable current sources, wherein the first group of switchable current sources may be configured to provide (in an on state) currents of different current levels. The different current strengths of the switchable current sources can be staggered, for example, according to powers of two, such as I, 21, 41, 81 and 161.

In this case, the first group of switchable signal sources of the plurality of switchable signal sources 56 ₀ to 56 _{k of} the first device 54 can be driven based on further low-order bits of the bit sequence for driving the device 50, wherein the other low-order bits can be binary-coded The second group of switchable signal sources of the plurality of switchable signal sources 56 ₀ to 56 _{k of} the first device 54 may be configured to provide (in an on state) equal-level output signal portions. As already mentioned, the switchable signal sources 56 ₀ to 56 _{k of} the first device 54 can be, for example, switchable current sources, wherein the second group of switchable current sources can be designed to deliver currents with the same current intensities (in a switched-on state).

In this case, the second group of switchable signal sources of the plurality of switchable signal sources 56 ₀ to 56 _{k of} the first device 54 can be driven based on higher-order bits of the bit sequence for driving the device 50, wherein the higher-order bits can be thermometer-coded.

As can be seen in FIG. 4, the switchable signal sources 56 ₀ to 56 _{k of} the first device 54 can each be connected in series by a (constant) electrical signal source 57 ₀ to 57 _k (eg current source or voltage source) and an electrical switching element 59 ₀ to 59 _k (eg semiconductor switches, such as bipolar transistor, field effect transistor, etc.) can be realized. Accordingly, the switchable signal sources 60 ₀ to 60 | the second device 58 in each case by a series circuit of a (constant) electrical signal source 61 ₀ to 61 _k (eg current source or voltage source) and an electrical switching element 63 ₀ to 63 _k (eg semiconductor switches, such as bipolar transistor, field effect transistor, etc.) can be realized ,

In embodiments, the device 50 may be configured to turn on a predetermined number of switchable signal sources of the plurality of switchable signal sources 60 ₀ to 60, the second device 58 in a preset mode, and to adjust the signal 52 to a desired level in the default mode, in that, taking into account the number of switched switchable signal sources of the second device 58, a combination of switchable signal sources of the plurality of switchable signal sources 56 ₀ to 56 _{k of} the first device 54, which approximates the nominal level of the signal 52, is switched on.

The device 50 may be configured to switch on half of the plurality of switchable signal sources 60 ₀ to 60 of the second device 58 in the default mode. Further, the device 50 may be configured to track an actual level of the signal 52 to a desired level in a fine adjustment mode by adjusting a number of switched switchable signal sources of the plurality of switchable signal sources 60 ₀ to 60 of the second device 58.

For example, the device may be configured to adjust the number of switched switchable signal sources in the fine adjustment mode by switching on or off at most one switchable signal source of the plurality of switchable signal sources 60 ₀ to 60 i of the second device 58 per switching cycle.

Furthermore, the device 50 may be configured to dispense with switching the plurality of switchable signal sources 56 ₀ to 56 _{k of} the first device 54 in the fine adjustment mode. 5 shows a schematic block diagram of an apparatus 50 for providing a signal 52 according to an embodiment of the present invention. In order to avoid large disturbances when switching many switching elements (eg switchable current sources or switchable voltage sources), the conventional digital-to-analog converter 54 further switchable signal sources (eg lower-order bit elements (LSB elements)) 60 ₀ to 60 | added as operating correction. In the default mode (eg at the start time) one half of the additional 1 + 1 switchable signal sources (eg additional elements) 60 ₀ to 60 can be activated. Further, in the default mode (eg, in an initial phase), the digital-to-analog converter 54 may be set to an optimum value. In the fine adjustment mode (eg during operation) it is now possible to correct the level by ± (1 + 1) / 2. During a correction, a maximum of one switchable signal source of the switchable signal sources (eg a lower-order bit element) switches 60 ₀ to 60 | the second device 58 and generates accordingly little interference. The number of additional switchable signal sources (eg lower-order bit elements) 60 ₀ to 60 depends on the expected amount of correction during operation. If the value can fluctuate by ± I, 2 switchable signal sources (eg lower-order bit elements) must be provided. The device 50 for providing a signal 52 has the advantage that the device (digital-to-analog converter) 50 has the same dynamic range as previous ones Circuits, that the extra space and circuit complexity are minimal, and that in operation, the signal (eg, digital-to-analog converter value) 52 can be easily adjusted without generating large disturbances of the signal during switching.

6 shows a schematic block diagram of a system 80 according to one embodiment of the present invention. The system includes a warper 10 having a plurality of output drivers 12 ₀ to 12 _n-1 and at least one device 50 ₀ for providing a signal. The system 80 is configured such that one output driver of the plurality of output drivers 12 ₀ to 12 _{n is driven} based on the provided signal of the device 50 ₀ .

As can be seen in FIG. 6, the system 80 may include a plurality of the devices 50 ₀ to 50 _n-1 for providing signals, the system 80 being configured such that each output driver of the plurality of output drivers 12 is ₀ to 12 _n- i is driven based on the provided signal of a device of the plurality of devices 50 ₀ to 50 _n- i.

7 shows a flowchart of a method 90 for operating a device 50 for providing a signal 52, according to an embodiment of the present invention. The device 50 has a first device 54 with a plurality of switchable signal sources 56 ₀ to 56 _k and a second device 58 with a plurality of switchable signal sources 60 ₀ to 60 | wherein a change of an output signal 62 of the first device 54 by a smallest possible level step at at least one output signal level stage requires switching of at least two of the switchable signal sources 56 ₀ to 56 _k , and wherein a change of an output signal 64 of the second device 58 by a smallest possible level step a switching of at most one switchable signal source 60 ₀ to 60 | requires. The method 90 includes providing 92 the signal 52 based on the output 62 of the first device 54 and the output 64 of the second device 58.

Embodiments of the present invention provide a specially adapted digital-to-analog converter 50 which allows the level of the FIR output driver 12 ₀ to 12 _n to be adapted during operation without imposing significant interference on the transmission signal. Embodiments of the device 50 for providing the signal 52 are characterized in that the transmission power can be controlled directly, eg the additionally necessary registers are visible to a user. In a closed system, indications of the disturbance when switching the transmission power can be detected by measurements with, for example, an oscilloscope, since there is a small area in which only minor disturbances occur when switching, while clearly higher switching disturbances are visible outside this range.

Although some aspects have been described in the context of a device, it will be understood that these aspects also constitute a description of the corresponding method, so that a block or a component of a device is also to be understood as a corresponding method step or as a feature of a method step. Similarly, aspects described in connection with or as a method step also represent a description of a corresponding block or detail or feature of a corresponding device. Some or all of the method steps may be performed by a hardware device (or using a hardware device). Apparatus), such as a microprocessor, a programmable computer or an electronic circuit. In some embodiments, some or more of the most important method steps may be performed by such an apparatus.

Depending on particular implementation requirements, embodiments of the invention may be implemented in hardware or in software. The implementation may be performed using a digital storage medium, such as a floppy disk, a DVD, a Blu-ray Disc, a CD, a ROM, a PROM, an EPROM, an EEPROM or FLASH memory, a hard disk, or other magnetic disk or optical memory are stored on the electronically readable control signals, which can cooperate with a programmable computer system or cooperate such that the respective method is performed. Therefore, the digital storage medium can be computer readable.

Thus, some embodiments according to the invention include a data carrier having electronically readable control signals capable of interacting with a programmable computer system to perform one of the methods described herein. In general, embodiments of the present invention may be implemented as a computer program product having a program code, wherein the program code is operable to perform one of the methods when the computer program product runs on a computer.

The program code can also be stored, for example, on a machine-readable carrier.

Other embodiments include the computer program for performing any of the methods described herein, wherein the computer program is stored on a machine-readable medium. In other words, an embodiment of the method according to the invention is thus a computer program which has a program code for performing one of the methods described herein when the computer program runs on a computer.

A further embodiment of the inventive method is thus a data carrier (or a digital storage medium or a computer-readable medium) on which the computer program is recorded for carrying out one of the methods described herein.

A further embodiment of the method according to the invention is thus a data stream or a sequence of signals, which represent the computer program for performing one of the methods described herein. The data stream or the sequence of signals may be configured, for example, to be transferred via a data communication connection, for example via the Internet.

Another embodiment includes a processing device, such as a computer or programmable logic device, configured or adapted to perform any of the methods described herein.

Another embodiment includes a computer on which the computer program is installed to perform one of the methods described herein. A further embodiment according to the invention comprises a device or a system which is designed to use a computer program for carrying out least one of the methods described herein to a receiver. The transmission can be done for example electronically or optically. The receiver may be, for example, a computer, a mobile device, a storage device or a similar device. For example, the device or system may include a file server for transmitting the computer program to the recipient.

In some embodiments, a programmable logic device (eg, a field programmable gate array, an FPGA) may be used to perform some or all of the functionality of the methods described herein. In some embodiments, a field programmable gate array may cooperate with a microprocessor to perform one of the methods described herein. In general, in some embodiments, the methods are performed by any hardware device. This may be a universal hardware such as a computer processor (CPU) or hardware specific to the process, such as an ASIC.

The embodiments described above are merely illustrative of the principles of the present invention. It will be understood that modifications and variations of the arrangements and details described herein will be apparent to others of ordinary skill in the art. Therefore, it is intended that the invention be limited only by the scope of the appended claims and not by the specific details presented in the description and explanation of the embodiments herein.

Claims

Patent claims

1 . Device (50) for providing a signal (52), with the following features: a first device (54) with a plurality of switchable signal sources (56 _0:56 _k ); and a second device (58) with a plurality of switchable signal sources (60 ₀ :60i); wherein a change in an output signal (62) of the first device (54) by the smallest possible level step at at least one output signal level requires switching of at least two of the switchable signal sources (56o: _56k ); wherein a change in an output signal (64) of the second device (58) by the smallest possible level step requires switching of at most one switchable signal source (60o'.60|); and wherein the device (50) is configured to provide the signal (52) based on the output signal (62) of the first device (54) and the output signal (64) of the second device (58).

2. Device (50) according to claim 1, wherein the device (50) is designed to switch on a predetermined number of switchable signal sources of the plurality of switchable signal sources (60 ₀ :60|) of the second device (58) in a presetting mode, and in order to set the signal (52) to a target level in the presetting mode by taking into account the number of switched-on switchable signal sources of the plurality of switchable signal sources (60 ₀ :60|) of the second device. Device (58) a combination of switchable signal sources of the plurality of switchable signal sources (56 _0:56 _k ) of the first device (54) which approximates the target level of the signal (52) is switched on.

The device (50) according to claim 2, wherein the device (50) is designed to switch on half of the plurality of switchable signal sources (60 ₀ :60|) of the second device (58) in the preset mode.

Device (50) according to one of claims 1 to 3, wherein the device (50) is designed to track an actual level of the signal (52) to a target level in a fine adjustment mode by a number of switched-on switchable signal sources of the plurality of switchable signal sources (60o :60i) of the second device (58) is adapted.

Device (50) according to claim 4, wherein the device (50) is designed to adapt the number of switched-on switchable signal sources of the plurality of switchable signal sources (60o:60i) of the second device (58) in the fine adjustment mode by having at most one switchable signal source per switching cycle Signal source of the plurality of switchable signal sources (60o:60i) of the second device (58) is switched on or off.

Device (50) according to claim 4 or 5, wherein the device (50) is designed to dispense with switching of the plurality of switchable signal sources (56 _0:56 _k ) of the first device (54) in the fine adjustment mode.

7. Device (50) according to one of claims 1 to 6, wherein the plurality of switchable signal sources (60 ₀ :60|) of the second device (58) supply output signal components with the same levels.

8. Device (50) according to one of claims 1 to 7, wherein at least a portion of the switchable signal sources of the plurality of switchable signal sources Sources (56 _0:56 _k ) of the first device (54) deliver output signal components with different levels.

9. Device (50) according to one of claims 1 to 8, wherein the plurality of switchable signal sources (60 ₀ :60|) of the second device (58) are controlled based on lower-order bits of a bit sequence for controlling the device (50).

10. Device (50) according to claim 9, wherein the lower-order bits of the bit sequence for controlling the device (50) are thermometer-coded based on which the plurality of switchable signal sources (60o:60i) of the second device (58) are controlled.

1 1. Device (50) according to claim 9 or 10, wherein only a portion of the plurality of switchable signal sources (56o:56 _k ) of the first device (54) is controlled based on higher-value bits of the bit sequence for controlling the device (50), where the more significant bits are thermometer coded.

12. Device (50) according to one of claims 9 to 1 1, wherein at least two switchable signal sources of the plurality of switchable signal sources (56o:56 _k ) of the first device (54) based on further lower-order bits of the bit sequence for controlling the device (50 ) are controlled, with the other lower-order bits being binary coded.

13. Device (50) according to one of claims 1 to 12, wherein the plurality of switchable signal sources (56 _0:56 _k ) of the first device (54) are connected in parallel to one another, and / or wherein the plurality of switchable signal sources (60 ₀ :60|) of the second device (58) are connected in parallel to one another.

14. Device (50) according to one of claims 1 to 13, wherein the plurality of switchable signal sources (56 _0:56 _k ) of the first device (54) are switched are bare current sources, and/or wherein the plurality of switchable signal sources (60 ₀ :60|) of the second device (58) are switchable current sources.

15. System (80), with the following features: a distorter (10) with a plurality of output drivers (12 _0:12 _n- i); and at least one device (50o:50 _n -i) for providing a signal according to one of claims 1 to 14; wherein the system (80) is configured such that an output driver of the plurality of output drivers (12 _0:12 _n -i) is driven based on the provided signal of the device ( ₅₀ 0:50 _n- i).

16. The system (80) of claim 15, wherein the system (80) comprises a plurality of devices (50o:50 _n- i) for providing signals, the system (80) being configured such that each output driver of the plurality of Output drivers (12 _0:12 _n- i) are driven based on the signal provided by a device of the plurality of devices ( ₅₀ 0:50 _n- i).

17. Device (50) for providing a signal (52), with the following features: a first signal provider (54) with a plurality of switchable signal sources (56 _0:56 _k ) for providing a first signal component (62); and a second signal provider (58) with a plurality of switchable signal sources (60 ₀ :60|) for providing a second signal component (64); wherein the first signal provider (54) is designed such that a change in the first signal component (62) provided by the first signal provider (54) by a smallest level step assigned to the first signal provider (54) results in simultaneous switching of a plurality, at least in one case of switchable signal sources (56o:56 _k ) of the first signal provider (54); and wherein the second signal provider (58) is designed such that the plurality of switchable signal sources (60o:60i) of the second signal provider (58) each differ between two level values that differ by the smallest level step assigned to the first signal provider (54). , can be switched.

18. Method (90) for operating a device (50) for providing a signal (52), the device (50) having a first device (54) with a plurality of switchable signal sources (56o: _56k ) and a second device ( 58) with a plurality of switchable signal sources (60o ^' .60|), wherein a change in an output signal (62) of the first device (54) by the smallest possible level step at at least one output signal level results in switching of at least two of the switchable signal sources (56o: 56 _k ), and wherein a change in an output signal of the second device (58) by the smallest possible level step requires switching of at most one switchable signal source (60 ₀ :60|), the method (90) comprising:

Providing (90) the signal (52) based on the output signal (62) of the first device (54) and the output signal (64) of the second device (58).

19. Computer program with a program code for carrying out the method according to claim 18, if the computer program runs on a computer.