Method for generating a frequency-modulated transmission signal for a transmitter, computer program product, computer-readable storage medium, transmitter and detection device

Abstract

Method for generating a frequency-modulated transmit signal (8) for a transmitting device (5) of a detection device (2) for transmitting the frequency-modulated transmit signal (8) into an environment (3) of the detection device (2), comprising the steps: - Generating a frequency comb (11) using an optical mode-locked source (10) of the transmitting device (5); - Filtering of at least one frequency line (12) in the generated frequency comb (11) by means of a first optical filter device (13) of the transmitting device (5); and - Generating the frequency-modulated transmit signal (8) by means of a photodiode (14) of the transmitting device (5) as a function of the filtered frequency comb (15), wherein the frequency-modulated transmit signal (8) is generated proportionally to the frequency difference to the filtered frequency line (12), wherein at least two frequency lines (12) are brought closer together by means of an optical dispersive element (18) of the transmitting device (5) or at least two frequency lines (12) are pulled further apart by means of an optical dispersive element (18) of the transmitting device (5), wherein the dispersive element (18) is arranged in the beam path after the first optical filter device (13) or the dispersive element (18) is arranged in the beam path before the first optical filter device (13).

Description

[0001] The invention relates to a method for generating a frequency-modulated transmission signal for a transmitter of a detection device for transmitting the signal into an environment of the detection device. The invention further relates to a corresponding computer program, a corresponding computer-readable storage medium, a corresponding transmitter, and a corresponding detection device.

[0002] Radar sensor devices for motor vehicles are already known from the automotive industry. In particular, such radar sensor devices are used in, for example, partially autonomous vehicles, but especially in fully autonomous vehicles. However, to enable such automated driving, reliable environmental perception is essential. This involves capturing the surroundings using sensors such as radar, lidar, and cameras. A comprehensive 360-degree three-dimensional capture of the environment is particularly important, enabling the detection of all static and dynamic objects. Lidar plays a crucial role in redundant, robust environmental perception, as this sensor type can precisely measure distances and also be used for classification. However, these lidar sensors are expensive and complex to design.In particular, 360-degree three-dimensional environmental sensing is problematic, as it either requires many smaller individual sensors, which typically operate with numerous individual light sources and detector elements, or large lidar sensors. Furthermore, lidar sensors are susceptible to weather conditions such as rain, fog, or direct sunlight.

[0003] Radar sensors and radar sensor devices are also well-established in automotive engineering and deliver reliable and fail-safe data in all weather conditions. Even poor visibility conditions such as rain, fog, snow, dust, or darkness hardly affect their detection reliability.

[0004] However, according to the current state of the art, the resolution is limited; in particular, commercially available radar systems only offer a resolution of approximately 7 degrees. To meet the requirements for increased automation in automotive engineering with safe driving functions, the radar sensor device is intended to deliver three-dimensional images with a high resolution in the range of 0.1 degrees and below, with high insensitivity to interference from its environment. This is not achievable with conventional radar technology according to the current state of the art, as the resolution of such systems is too low.

[0005] Furthermore, photonic radar sensor devices are already known that achieve an increase in resolution by cointegrating electronic and photonic components into a single semiconductor point. Tracking of an FMCW signal, as well as all signal processing and evaluation, is performed by a central station. Each transmitting and receiving module features an electronically and photonically cointegrated chip, a so-called Epic chip. Silicon photonics technology is used for the cointegration. This enables the monolithic integration of photonic components, high-frequency electronics, and digital electronics together on a single chip. The technical innovation of such a system lies in the signal transmission of gigahertz signals using the optical carrier signal in the terahertz frequency range.A central station, which can also be described as a central electronic computing unit, generates an optical carrier frequency in terahertz. The signal to be transmitted is modulated onto this carrier frequency with one-eighth of the radar frequency and sent to the antenna chips via optical phase correction. On these chips, the signal undergoes an eightfold frequency amplification, enabling the radar radiation to be emitted. Signal detection occurs in reverse. All data is processed at the central station. However, such an implementation is very complex in terms of gigahertz electronics at the chip level. In particular, the frequency quadrupling that takes place on the chip after detection by a photodiode is technically challenging and requires significant effort in generating a gigahertz signal with a high signal-to-noise ratio and minimal jitter. Therefore, the gigahertz signal must undergo further complex stabilization steps.Furthermore, gigahertz electronics are expensive. High power requirements are also placed on the optical substrate, particularly a laser, as significant optical power is needed to generate a highly precise gigahertz signal. This makes a single-phase ring topology for a radar array with many distributed radar semiconductor chips difficult to implement. In particular, two different photonic semiconductor chips are still required for each transmit and receive channel, leading to further cost increases.

[0006] As previously described, photonic radar systems and lidar systems based on frequency-modulated continuous waves (FMCW) are known from the prior art. These systems can be designed, for example, as frequency-modulated continuous wave radar or frequency-modulated continuous wave lidar.

[0007] These systems require optical frequency-modulated continuous wave signals for operation. These are often generated using a continuous wave (CW) laser and a subsequent intensity modulator, for example a Mach Zehnder modulator, which is driven by an electrical signal. Any phase shifts are directly translated into the optical signal. These shifts can cause problems in signal processing.

[0008] This problem can be addressed, for example, by using optical mode-coupled sources, such as a Kerr resonator or mode-locked lasers (MLL - multi-line lasers). The output signal of these sources is already phase-stabilized. However, Kerr oscillators, which are particularly easy to integrate, deliver very little power. In contrast, MLLs, which were previously difficult to integrate, deliver high power, but also radiate increased thermal energy.

[0009] In particular, when using Kerr oscillators as a pulse source, both oscillators are already pumped with an optical FMCW signal. Furthermore, it is known that the pulse source is used to compensate for the nonlinearity of an existing FMCW laser signal.

[0010] A disadvantage of these known systems is that they require pre-existing FMCW laser signals. Furthermore, thermal stabilization of these systems is difficult, as the two optical rings, for example, must be thermally coupled. It is also known that the pulse sources are not used to stabilize the FMCW ramp, but rather for an advantageous method of signal localization. Additionally, it is known, for example, in photonic radar systems, that the optical signal must be converted into an electrical signal. This is usually done using a photodiode. However, due to the lack of two-sideband modulation, the photodiode cannot generate any time-varying signal.

[0011] WO 2022 / 157191 A1 relates to a radar sensor device for a motor vehicle comprising at least one central electronic computing unit designed to generate an electrical control signal for a transmitter, a laser device which generates an optical transmission signal for transmission to the transmitter depending on the electrical control signal, a transformer device comprising at least one first optical ring resonator which generates a pulse train depending on the optical transmission signal, wherein the transformer device is designed to generate an electrical output signal depending on the pulse train, a transmitter device designed to transmit the electrical output signal, and a receiver device for receiving an electrical receive signal for transmission to the central electronic computing unit.

[0012] JP 2019 039972 A describes the generation of a signal, such as a microwave and a millimeter wave, with suppressed phase noise, in a frequency-variable state, without the specific requirement of a stable optical frequency comb reference light source.

[0013] CN 114 36 19 31 A discloses a very low-noise electro-optic frequency comb generating device, comprising: an optical frequency comb module for generating an optical frequency comb; the continuous laser module is used to output a reference laser with a stable frequency and a continuous laser for electro-optic modulation; a feedback module for locking the optical frequency comb to the reference laser and for locking the continuous laser to the optical frequency comb; the microwave frequency generation module is used to receive the optical frequency comb and to convert the optical frequency comb into a microwave signal; and the electro-optic modulation module is used to receive the microwave signal to perform electro-optic modulation on the continuous laser to generate an electro-optic frequency comb.

[0014] CN 1 08 919 244 A discloses a microwave photon full-band radar detection method. The microwave photon full-band radar detection method comprises the steps of performing suppression carrier single-sideband modulation on an optical carrier at a frequency of fL using an intermediate frequency chirp signal to obtain a linear frequency-swapped first-order optical sideband signal; selecting a single-comb signal from optical frequency-comb signals with a frequency distribution fOC=fL+ / -Nfc to combine beams with the linear frequency-swapped first-order optical sideband signal, where N=0, 1, 2, 3...L, and L is a positive integer; the received combined optical beam signal is converted into an electrical signal, and the electrical signal is transmitted to a target as a radar detection signal; and the combined optical beam signal is taken as an optical reference signal, an electrical signal reflected from the target is subjected to optical domain frequency conversion and tilt processing to obtain an intermediate frequency signal carrying target information, and the target information is extracted from the intermediate frequency signal.

[0015] CN 1 15 184 943 A discloses a terahertz radar detection method and system based on photon technology, and the method comprises the following steps: selection of two comb teeth by a wavelength selection module, splitting one comb tooth into an upper path and a lower path, enabling a baseband signal to suppress the one-sided carrier modulation of the upper path of the optical comb teeth, and obtaining an optical sweep frequency signal; then the optical signal is meshed with the other comb of the optical frequency comb to form a composite optical signal;Part of the composite optical signal is converted into a terahertz signal by a photoelectric detector and then radiated into a target environment; a receiving unit receives a target echo signal and then performs a down-conversion through a harmonic mixer to obtain a baseband echo signal; and the baseband echo signal modulates a lower comb tooth to obtain a received optical signal;The optical receive signal and the other part of the composite optical signal are sent to a coherent receiver module to achieve coherent reception. An intermediate frequency signal carrying target information is obtained, and the acquisition target information can be extracted by an algorithm. Photon generation and coherent real-time reception of terahertz radar signals are achieved through the same reference source, the synchronous optical frequency comb, and the harmonic mixer. The parameters of the radar system are flexible and adjustable, and the anti-interference capability is high.

[0016] Reference is also made to the printed document CN 1 11 190 160 A.

[0017] The object of the present invention is to provide a method, a corresponding computer program product, a corresponding computer-readable storage medium, a corresponding transmitting device and a corresponding detection device, by means of which a frequency-modulated continuous wave signal can advantageously be generated.

[0018] This problem is solved by a method, a corresponding computer program product, a corresponding computer-readable storage medium, a corresponding transmitting device, and a corresponding detection device according to the independent claims. Advantageous embodiments are specified in the dependent claims.

[0019] One aspect of the invention relates to a method for generating a frequency-modulated transmit signal for a transmitter of a detection device for transmitting the signal into the vicinity of the detection device. A frequency comb is generated by means of an optical mode-locked source of the transmitter. At least one frequency line in the generated frequency comb is filtered by means of a first optical filter of the transmitter. A frequency-modulated transmit signal is generated by means of a photodiode of the transmitter as a function of the filtered frequency comb, wherein the transmit signal is generated proportionally to the frequency difference with respect to the filtered frequency line.

[0020] In particular, an optical bandpass filter is proposed which filters out at least one frequency line, and especially a finite number of frequency lines, from the frequency comb, whereby the frequency-modulated transmitted signal is then generated based on the filtered frequency comb. The frequency-modulated transmitted signal is, in particular, a frequency-modulated continuous wave (FMCW) signal.

[0021] In particular, the detection device can be designed for a so-called continuous-wave radar, especially a frequency-modulated continuous-wave radar, as well as for a frequency-modulated continuous-wave lidar. For distance measurement, sawtooth or triangular waveforms are typically used. In the embodiment of the continuous-wave radar, this can be a radar system that differs from a pulse radar in that the transmitting device operates continuously during the measurement process. Specifically, the transmitted frequency is modulated in the continuous-wave radar. Based on the continuous-wave radar, for example, a non-contact speed measurement based on the Doppler effect or a motion detector can be used.Continuous-wave radar systems can be used, for example, for distance or altitude measurement, or as short-range navigation radars on ships or boats. The frequency-modulated transmission signal is therefore a periodically frequency-modulated signal, enabling highly accurate measurements that are essentially linear over time. However, its use as a continuous-wave radar is just one of several applications. The transmitter can also be used for radio-based communication, for example.

[0022] In particular, the optical mode-locked source is designed to generate the frequency comb, from which a finite number of frequency lines are filtered out and the selected lines are separated. The photodiode then generates the signal to be emitted based on the filtered signal, which is proportional to the frequency difference of the selected lines.

[0023] In particular, any modulation, such as a frequency-modulated ramp, can be generated using an optical mode-locked source. Due to its generation method, this signal is already phase-stabilized.

[0024] In contrast to the prior art, for example, no separate laser device is required to generate the frequency-modulated signal, as only lines from a mode-locked source are needed. Therefore, the system does not require thermal stabilization. Furthermore, the proposed method allows for the generation of a time-varying signal within the photodiode. This makes it possible, for example, to implement a photonic radar.

[0025] It should be noted in particular that the proposed detection device is not only suitable for use in automotive engineering, but also, for example, in corresponding production facilities for monitoring a manufacturing process. In particular, in addition to the radar system, a radio system or, more generally, a communication device for wireless communication based on the generated transmission signal can also be provided.

[0026] In a first alternative, it can be provided that at least two frequency lines are brought closer together by means of an optical dispersive element in the transmitting device. In particular, depending on the repetition frequency of the optically modulated source, the selected lines can thus be brought closer together using the optional dispersive optical element. The decomposition of light into its wavelength components is called dispersion. An element with this property is called a dispersive element. This makes it possible to generate different frequency-modulated transmission signals.

[0027] A second alternative approach involves using an optical dispersive element in the transmitter to further separate at least two frequency lines. Specifically, depending on the repetition frequency of the optically modulated source, the selected lines can be separated using the optional dispersive optical element. This allows for the generation of different frequency-modulated transmission signals.

[0028] In one alternative approach, the dispersive element is positioned in the beam path after the optical filter. This allows the dispersive element to reliably further separate or converge the frequency lines based on the already filtered signal, thereby improving the generation of the transmitted signal.

[0029] A second alternative involves placing the dispersive element in the beam path upstream of the optical filter device. This means the frequency comb is already compressed or stretched by the dispersive element, thus improving the filtering process.

[0030] According to an advantageous embodiment, at least a second optical filter device is provided, wherein at least one further frequency line is filtered by means of the second optical filter device. In particular, these signals can then be combined again and transmitted together to the photodiode. Based on the different frequencies, the frequency-modulated transmit signal can again be reliably generated by the photodiode.

[0031] Furthermore, it has proven advantageous if at least one additional frequency line is filtered by means of the first optical filter device. In particular, it is thus provided that at least two frequency lines, and especially more than two frequency lines, for example three or more frequency lines, are filtered out by means of the single optical filter device. This makes it possible to reliably generate the frequency-modulated transmit signal using the photodiode with a single optical filter device.

[0032] It is further advantageous to generate a frequency ramp as the frequency-modulated transmission signal. The frequency ramp is, in particular, an essentially triangular transmission signal. For example, descending or ascending frequency ramps can be generated. With an ascending frequency ramp, the frequency of the transmitted signal increases over time. With a descending frequency ramp, the frequency decreases over time. Thus, the proposed method can be advantageously used, for example, in continuous-wave radar or continuous-wave lidar.

[0033] According to an advantageous embodiment, heterodyne detection is performed in the photodiode. Heterodyne detection is a signal processing method used to detect waves of unknown frequency by mixing them with waves of a reference frequency. In particular, this allows for reliable analysis of the corresponding signals. Alternatively, homodyne detection can be performed. This method detects the modulation of an oscillation by mixing it with a nearly identical reference frequency. Thus, different detection methods are available.

[0034] Furthermore, it has proven advantageous to provide the detection device as a photonic radar or lidar device. Alternatively or additionally, the detection device can also be used for a communication device, such as a radio device. Thus, the method / transmitting device is highly flexible and usable in different situations, depending on the required transmission signals. Here and in the following, a radio signal can be understood as electromagnetic waves whose frequencies are less than or equal to 3 THz and which propagate through space without artificial guidance. Corresponding frequency ranges for the radio signal can be low-frequency waves, radio waves, or microwaves. For example, the frequency of the electromagnetic waves can lie between 3 Hz and 3 THz, in particular between 100 MHz and 100 GHz.A well-known type of lidar system is the so-called laser scanner, in which a laser beam is deflected by means of a light deflection device, allowing for various deflection angles of the laser beam. The light deflection device can, for example, contain a rotatably mounted mirror. Alternatively, the light deflection device can have a mirror element with a tiltable and / or swiveling surface. The mirror element can, for example, be designed as a microelectromechanical system (MEMS). In the environment, the emitted laser beams can be partially reflected, and the reflected portions can then strike the laser scanner, in particular the light deflection device, which can direct them onto a detector unit of the laser scanner. Each optical detector of the detector unit generates a corresponding detector signal based on the portions detected by the respective optical detector.Based on the spatial arrangement of the respective detector, together with the current position of the light deflection device, in particular its rotational or tilting and / or swiveling position, the direction of incidence of the detected reflected components can be determined. An evaluation unit can also, for example, perform a time-of-flight measurement to determine the radial distance of the reflecting object. Alternatively or additionally, a method can be used to determine the distance by evaluating the phase difference between emitted and detected light.

[0035] Other types of lidar systems are flash lidar systems. These are non-scanning systems that do not require such a light deflection arrangement. Instead, the laser light generated by the light source is scattered by an optical element, so that it is emitted in a single flash over a wide angle. This results in high flexibility and versatility of the method and the transmitter.

[0036] The presented method is, in particular, a computer-implemented method. Therefore, a further aspect of the invention relates to a computer program product with program code means which, when the program code means are executed by the electronic computing device, cause it to carry out a method according to the preceding aspect.

[0037] A further aspect of the invention relates to a computer-readable storage medium containing at least one computer program product according to the preceding aspect.

[0038] The invention further relates to a transmitter for a detection device for generating a frequency-modulated transmission signal for sending the transmission signal to an environment of the detection device, comprising at least one optical mode-locked source, a first optical filter device, and a photodiode, wherein the transmitter is configured to carry out a method according to the preceding aspect. In particular, the method is carried out by means of the transmitter.

[0039] For example, the transmitting device also has an electronic computing device to generate the frequency comb or to adjust the filter device accordingly.

[0040] A computing unit / electronic computing device can be understood, in particular, as a data processing device containing a processing circuit. The computing unit can therefore process data to perform arithmetic operations. This may also include operations to perform indexed access to a data structure, such as a lookup table (LUT).

[0041] The computing unit may, in particular, contain one or more computers, one or more microcontrollers, and / or one or more integrated circuits, for example, one or more application-specific integrated circuits (ASICs), one or more field-programmable gate arrays (FPGAs), and / or one or more systems on a chip (SoCs). The computing unit may also contain one or more processors, for example, one or more microprocessors, one or more central processing units (CPUs), one or more graphics processing units (GPUs), and / or one or more signal processors, in particular one or more digital signal processors (DSPs). The computing unit may also include a physical or virtual array of computers or other units of the aforementioned type.

[0042] In various embodiments, the computing unit includes one or more hardware and / or software interfaces and / or one or more storage units.

[0043] A storage unit can be volatile data storage, for example as dynamic random access memory (DRAM) or static random access memory (SRAM), or as non-volatile data storage, for example as read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory or flash EEPROM, ferroelectric random access memory (FRAM), or magnetoresistive random access memory.It can be designed as MRAM (magnetoresistive random access memory) or as phase-change random access memory, PCRAM (phase-change random access memory).

[0044] The invention also relates to a detection device with at least one transmitting device according to the preceding aspect.

[0045] A further aspect of the invention relates to a motor vehicle with a detection device according to the preceding aspect. The motor vehicle can, for example, be designed as an at least partially electrically powered vehicle or as a fully electric vehicle. Furthermore, the motor vehicle can be designed as an at least partially autonomous vehicle or as a fully autonomous vehicle.

[0046] For use cases or application situations that may arise during the procedure and are not explicitly described here, it may be provided that, according to the procedure, an error message and / or a request for user feedback is issued and / or a default setting and / or a predetermined initial state is set.

[0047] The invention also includes further developments of the transmitting device according to the invention, which have features already described in connection with the further developments of the method according to the invention. For this reason, the corresponding further developments of the transmitting device according to the invention are not described again here.

[0048] For example, the detection device can be configured for a vehicle guidance system. Therefore, one aspect also concerns an electronic vehicle guidance system with a corresponding detection device. An electronic vehicle guidance system can be understood as an electronic system designed to guide a vehicle fully automatically or autonomously, in particular without requiring any intervention by a driver. The vehicle automatically performs all necessary functions, such as steering, braking, and / or acceleration maneuvers, monitoring and recording road traffic, and responding accordingly. In particular, the electronic vehicle guidance system can implement a fully automatic or fully autonomous driving mode of the motor vehicle according to Level 5 of the classification according to SAE J3016.An electronic vehicle guidance system can also be understood as an advanced driver assistance system (ADAS), which supports the driver during partially automated or semi-autonomous driving. Specifically, the electronic vehicle guidance system can implement a partially automated or semi-autonomous driving mode according to levels 1 to 4 of the SAE J3016 classification. Here and in the following, "SAE J3016" refers to the corresponding standard in its April 2021 version.

[0049] At least partially automated vehicle control can therefore include driving the vehicle in accordance with a fully automated or fully autonomous driving mode of Level 5 according to SAE J3016. At least partially automated vehicle control can also include driving the vehicle in accordance with a partially automated or semi-autonomous driving mode according to Levels 1 to 4 of SAE J3016.

[0050] Further features of the invention will become apparent from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown in the figures, may be encompassed by the invention not only in the combinations specified, but also in other combinations. In particular, the invention may also encompass embodiments and combinations of features that do not have all the features of an originally formulated claim. Furthermore, the invention may encompass embodiments and combinations of features that go beyond or deviate from the combinations of features set out in the cross-references to the claims.

[0051] The invention also includes combinations of the features of the described embodiments.

[0052] The following describes exemplary embodiments of the invention. This is illustrated by: Fig. 1 a schematic top view of an embodiment of a motor vehicle with an embodiment of a detection device with an embodiment of a transmitting device; Fig. 2 a schematic block diagram according to an embodiment of the transmitting device; and Fig. 3. A further schematic block diagram according to one embodiment of the transmitting device.

[0053] The embodiments described below are preferred embodiments of the invention. In these embodiments, the described components each represent individual features of the invention that can be considered independently of one another. Each of these features further develops the invention independently and can therefore be considered part of the invention individually or in a combination other than that shown. Furthermore, the described embodiments can also be supplemented by other features of the invention already described.

[0054] In the figures, functionally identical elements are each provided with the same reference symbols.

[0055] Fig. Figure 1 shows a schematic top view of an embodiment of a motor vehicle 1. The motor vehicle 1 can be configured as an at least partially electrically powered motor vehicle 1 or as a fully electrically powered motor vehicle 1. In particular, the motor vehicle 1 can also be configured as an at least partially assisted-drive motor vehicle 1 or as a fully assisted-drive motor vehicle 1. The motor vehicle 1 has at least one detection device 2. The detection device 2 is configured, in particular, for detecting or capturing an environment 3. In the present embodiment, an object 4 is located in the environment 3.The detection device 2 has a transmitter 5, a receiver 6 and an electronic computing device 7, which can be used, for example, to evaluate a transmitted signal 8 in relation to a received signal 9, which in the present embodiment was reflected at the object 4.

[0056] The detection device 2 can preferably be configured as a radar device. Alternatively or additionally, the detection device 2 can also be configured as a lidar device.

[0057] Alternatively or additionally, the presented method can essentially also be designed for radio-based communication.

[0058] The Fig. Figure 1 shows in particular the transmitted signal 8, which can also be referred to as a frequency-modulated transmitted signal 8. As already mentioned, the frequency-modulated transmitted signal 8 is reflected by the object 4 and received as a received signal 9 by the receiving device 6. Based, for example, on corresponding phase differences or the like, both a distance and, for example, the velocity of the object 4 can be detected based on a Doppler effect.

[0059] Fig. Figure 2 shows a schematic block diagram according to an embodiment of the transmitter 5. The transmitter 5 is designed, in particular, to generate the frequency-modulated transmit signal 8 and to transmit the transmit signal 8 into the environment 3. A frequency comb 11 is generated by means of an optical mode-locked source 10. A frequency line 12 in the generated frequency comb 11 is filtered by means of a first optical filter device 13 of the transmitter 5. The frequency-modulated transmit signal 8 is generated by means of a photodiode 14 as a function of the filtered frequency comb 11, wherein the frequency-modulated transmit signal 8 is proportional to the frequency difference with respect to the filtered frequency line 12.

[0060] The presented embodiment shows in particular that a second optical filter device 16 can be provided, wherein at least one further frequency line 17 can be filtered by means of the second optical filter device 16.

[0061] Furthermore, it has been shown that, for example, by means of the first optical filter device 13 as well as in the present case by means of the second optical filter device 16, at least one further frequency line 12, 17 is filtered.

[0062] It is further shown that, in particular, the adjustment of the first optical filter device 13 and / or the second optical filter device 16 can be carried out via the electronic computing device 7. This adjustment can also be referred to as tuning. The electronic computing device can, for example, also be coupled to the optical mode-locked source 10 to generate the frequency comb 11.

[0063] Furthermore, the Fig. 2, that by means of an optical dispersive element 18 of the transmitting device 5 at least two frequency lines 12, 17 can be brought closer together or at least two frequency lines 12, 17 can be pulled further apart by means of the optical dispersive element 18.

[0064] In the present embodiment, it is shown in particular that the dispersive element 18 is arranged in the beam path after the first optical filter device 13 and / or the second optical filter device 16.

[0065] Fig. Figure 3 shows another schematic embodiment of the transmitting device 7. In the present embodiment, compared to the Fig. 2 in particular amended such that the dispersive element 18 is arranged in the beam path in front of the first optical filter device 13 and / or the second optical filter device 16.

[0066] It may also be provided that a frequency ramp is generated as the frequency-modulated transmit signal 8. Furthermore, it may be provided that the photodiode 14 is configured specifically for heterodyne detection. Alternatively or additionally, the photodiode 14 may also be configured for homodyne detection.

[0067] In particular, it can thus be provided that the optical mode-locked source 10 generates the frequency comb 11. From this frequency comb 11, a finite number of frequency lines 12, 17 can be filtered out and the selected lines separated accordingly. Depending on the repetition frequency of the optical mode-locked source 10, the selected frequency lines 12, 17 can be brought closer together or further apart by means of the optional dispersive element 18. The transmit signal 8 is then generated in the photodiode 14, which is proportional to the frequency difference of the selected lines.

[0068] In particular, the presented transmitter 5 can generate any modulation, for example an FMCW ramp, using the optical mode-locked source 10. The FMCW ramp is specifically a frequency-modulated continuous wave ramp. Due to its generation method, this signal is phase-stabilized and therefore very advantageous, especially for use in motor vehicles 1.

[0069] Overall, the Fig. 1 to 3 a system for generating frequency-modulated signals using the frequency comb 11. Reference symbol list 1 motor vehicle 2 Detection device 3 Environment 4 objects 5 Transmitter 6 Receiving equipment 7 electronic computing device 8. Transmit signal 9 Received signal 10 optical mode-locked source 11 Frequency comb 12 Frequency line 13 first optical filter device 14 Photodiode 15 filtered frequency comb 16 second optical filter device 17 more frequency lines 18 dispersive element

Claims

[1] Method for generating a frequency-modulated transmit signal (8) for a transmitting device (5) of a detection device (2) for transmitting the frequency-modulated transmit signal (8) into an environment (3) of the detection device (2), comprising the steps: - Generating a frequency comb (11) using an optical mode-locked source (10) of the transmitting device (5); - Filtering of at least one frequency line (12) in the generated frequency comb (11) by means of a first optical filter device (13) of the transmitting device (5); and - Generating the frequency-modulated transmit signal (8) by means of a photodiode (14) of the transmitting device (5) as a function of the filtered frequency comb (15), wherein the frequency-modulated transmit signal (8) is generated proportionally to the frequency difference to the filtered frequency line (12), wherein at least two frequency lines (12) are brought closer together by means of an optical dispersive element (18) of the transmitting device (5) or at least two frequency lines (12) are pulled further apart by means of an optical dispersive element (18) of the transmitting device (5), wherein the dispersive element (18) is arranged in the beam path after the first optical filter device (13) or the dispersive element (18) is arranged in the beam path before the first optical filter device (13). [2] Method according to claim 1, characterized by, that at least a second optical filter device (16) is provided, wherein at least one further frequency line (17) is filtered by means of the second optical filter device (16). [3] Method according to claim 1 or 2, characterized by , that at least one further frequency line (17) is filtered by means of the first optical filter device (13). [4] Method according to any one of the preceding claims, characterized by , that a frequency ramp is generated as a frequency-modulated transmit signal (8). [5] Method according to any one of the preceding claims, characterized by , that heterodyne detection is carried out in the photodiode (14). [6] Method according to any one of the preceding claims, characterized by , that the detection device (2) is provided as a photonic radar device or as a lidar device. [7] Method according to any one of the preceding claims, characterized by, that the detection device (2) is provided for a motor vehicle (1) and / or for a production plant. [8] Computer program product comprising program code means which cause an electronic computing device (7) to perform a method according to any one of claims 1 to 7 when the program code means are executed by the electronic computing device (7). [9] Computer-readable storage medium comprising at least one computer program product according to claim 8. [10] Transmitter device (5) for a detection device (2) for generating a frequency-modulated transmit signal (8) for transmitting the frequency-modulated transmit signal (8) into an environment (3) of the detection device (2), comprising at least one optical mode-locked source (10), a first optical filter device (13) and a photodiode (14), wherein the transmitter device (5) is configured for carrying out a method according to one of claims 1 to 7. [11] Detection device (2) comprising at least one transmitting device (5) according to claim 10 and a receiving device (6).

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