Integrity testing of mixed analog-digital systems

Abstract

The present disclosure provides for integrity testing of mixed analog-digital systems. An apparatus (120) for checking the integrity of digital transmission of analog output (114) for a system (104). Transient errors of the analog output (114) can be checked that can be attributed to digital transmission paths embedded within a vehicle system (104). Test signals are introduced into the digital transmission (112) that can be reassembled from the analog path (118) of the analog output (110) and if not, allow the test apparatus (120) to pinpoint errors that occur due to the digital path and not due to the analog output. In this way, debugging of the system (104) becomes easier; gaining confidence in the reliability of mixed analog-digital systems becomes less difficult and less time consuming.

Description

Technical Field

[0001] This disclosure relates to integrity testing of hybrid analog-digital systems. Background Technology

[0002] Some vehicle systems (e.g., warning systems, infotainment systems, user interface devices) generate information for output to acoustic components. Digitized audio information propagates along digital transmissions within these systems to ultimately output as an analog signal or sound. These digital transmissions can encounter faults or introduce transient errors that may propagate intermittently or unpredictably. Errors can be caused by a variety of issues and, when present in the audio output, can be unpleasant and impact driving safety if they cause distraction or mask other concurrent warnings (e.g., ringtones or announcements). Integrity checks can be performed to examine whether purely digital transmission paths are causing errors in the output. However, these techniques may not be suitable for checking hybrid systems with both digital and analog transmission paths, or they may be too expensive or time-consuming for many verification tasks. Days of computer simulation and months or years of real-world road driving are unacceptable methods for verifying the integrity of the output of a hybrid digital-analog system. Summary of the Invention

[0003] This overview introduces simplified concepts related to integrity testing of hybrid analog-digital systems, as further described in the detailed description and conveyed by the accompanying drawings. In one example, at least one processor of the device is configured to check the integrity of digital transmissions for the analog output of the system and output an indication of whether any errors have been introduced into the digital path of the digital transmissions, opposite to the analog path of the analog outputs. To check integrity, a test signal is estimated from a first test signal generator (TSG), such as a pseudo-random number generator (PRNG), of the system or device under test. The test signal is injected into the digital transmissions output on the analog path of the analog outputs. Then, in the absence of a direct access path to the digital transmissions, a second TSG is used to estimate the test signal, which depends on the same test signal generation function as the first TSG. However, the second TSG is compensated for by the linear transfer function of the combined digital path of the digital transmissions and the analog path of the analog outputs. The determination of whether the estimated test signal can be identified from the analog path of the analog outputs enables at least one processor to determine whether the digital path of the digital transmissions is error-free. It can output an indication of whether any errors (including transient or static, such as malfunctions) have been introduced by the digital path of digital transmission. This indication can be used downstream by a warning system, infotainment system, vehicle controller, or other actor of the vehicle, who may perform instructions or actions based on the digital transmission that may have been compromised.

[0004] This overview is not intended to identify the essential features of the claimed subject matter, nor is it intended to determine the scope of the claimed subject matter. Although primarily described in the context of integrity testing for hybrid analog-digital systems in vehicles, the techniques for integrity testing of hybrid analog-digital systems as described herein can be applied to other applications where signal integrity and reliability are as important as processing speed, such as computer technology, information technology, communication and mobility technology, industrial technology, manufacturing technology, power generation technology, other vehicles including aircraft and ships, and other systems. Attached Figure Description

[0005] This document describes in detail one or more aspects of integrity testing for hybrid analog-digital systems with reference to the accompanying drawings, wherein the same reference numerals are used throughout the drawings to denote similar components, and are briefly described below:

[0006] Figure 1 A conceptual diagram illustrating an environment for a vehicle system configured to perform integrity testing on a hybrid analog-digital system, according to the technology of this disclosure.

[0007] Figure 2 A conceptual diagram of a vehicle system configured to perform integrity testing on a hybrid analog-digital system, according to the technology of this disclosure, is illustrated.

[0008] Figure 3 A flowchart illustrating a process for performing integrity testing on a hybrid analog-digital system according to the technology of this disclosure is provided.

[0009] Figure 4 A conceptual diagram illustrating an example data flow for integrity testing of a hybrid analog-digital system, according to the technology of this disclosure, is shown.

[0010] Figure 5 A conceptual diagram illustrating an example data flow for integrity testing of a hybrid analog-digital system, according to the technology of this disclosure, is shown. Detailed Implementation

[0011] introduction

[0012] Vehicle systems are equipped with sophisticated computer systems that make driving easier and more enjoyable; ensuring the reliability of their functions is crucial. Digital audio information can be transmitted from the analog output as analog signals or sounds in these systems. Driving warnings, ringtones, announcements, telephone calls, entertainment content, etc., are examples of information digitally transmitted before being converted and output on the analog path. These digital transmissions can introduce transient errors into the information, which may propagate intermittently or unpredictably. Transient errors are observable in audio signals because audio jumps or pops / cracks may be caused by errors in the sequence of digitized information received at the analog output, or may occur due to unexplained spurious signals or repeated reads from the buffer. Errors in the audio output can be unpleasant for the driver of a car; furthermore, if the error causes a loud sound or disrupts other simultaneous warnings (e.g., ringtones or announcements), the error can affect driving safety. This is particularly important in autonomous vehicles configured to instruct the operator when the driver wants to regain manual control. For example, not hearing an audible instruction may cause the autonomous vehicle to pull over as a safety precaution.

[0013] Evaluating long-term performance through physical testing is an expensive and time-consuming process. It may require days of computer simulations and months or years of real-world in-vehicle testing to complete the checks and verifications with sufficient confidence before releasing it to a product. Some existing techniques for checking the quality of audio output during a vehicle's testing or engineering development cycle typically involve checking six major parameters: level, frequency response, total harmonic distortion (THD), phase, crosstalk, and signal-to-noise ratio (SNR). Each of these checks carries the risk of missing transient errors and therefore not being addressed during development and testing. Even if some of these existing checks pass, vehicle systems remain susceptible to transient errors that have never been observed before, potentially ruining the audio for the vehicle's end-user.

[0014] Other methods for testing the continuous, error-free propagation of digital transmissions are known from telecommunications, involving sending a test signal and comparing it upon reception. A pseudo-random bit sequence (PRBS) generated by a PRNG is typically used as the test signal. Performing this test in an end-to-end digital system can identify transient errors. However, these techniques are not suitable for large, distributed systems where the digital transmission path is inaccessible. While such tests will detect the described transient errors, they are practically unsuitable because, unlike in telecommunications, digital transmissions are generally not easily accessible except in some dedicated systems. Thus, in hybrid digital-analog systems distributed across different parts of a vehicle, existing techniques are unsuitable for checking for transient errors in digital transmissions or due to analog paths in analog outputs. Existing integrity checks of digital systems are useless for hybrid digital-analog systems and may not be suitable as a substitute for long-term onboard reliability testing. Furthermore, the described techniques enable the identification of transient errors that occur intermittently over time in the analog output, as well as static errors or faults that continuously recur over time in the analog output.

[0015] Example Environment

[0016] Figure 1 A conceptual diagram of an environment 100 configured to perform integrity testing on a hybrid analog-digital system according to the technology of this disclosure is illustrated. In environment 100, a vehicle 102 is shown integrated with a vehicle system 104. The vehicle 102 can be any other application for a hybrid digital-analog system. Non-vehicle components (e.g., computers, servers, media players, audio devices) may also include hybrid digital-analog systems, such as vehicle system 104, but for purposes other than vehicle use. Therefore, the technology of this disclosure can be applied to other computer systems in other contexts.

[0017] Vehicle system 104 represents any hybrid digital-analog system in which transient errors can propagate to the analog output via digital transmission. Vehicle system 104 can be implemented on a single computer card, as a single processing unit, as a system-on-a-chip, or as any other suitable architecture. It is generally referred to herein as an audio system; other types of systems may benefit from the described techniques. These techniques can be used to examine any application in which the propagation path includes both digital and analog forms. Vehicle system 104 includes a device under test 106 and a test device 120.

[0018] The device under test 106 can be any component or element of the vehicle system 104 that transmits digital data for output using an analog device. The device under test 106 has an analog output 110 configured to receive digital transmission 112 via analog path 118 and generate an analog response 114. The device under test 106 may include a digital transmission source (e.g., an audio decoder, audio codec) that decompresses digital audio data and then sends uncompressed digital data as digital transmission 112 to the analog output 110 (e.g., a speaker device, microphone), from which it is converted into an analog signal (e.g., sound).

[0019] Although shown as part of the same vehicle system 104 as the device under test 106, the test device 120 may reside on different hardware or be external to the vehicle 102. The test device 120 is configured to check the integrity of digital transmissions from the device under test 106 without any intrusive probing or processing of the digital transmissions 112 themselves. The test device 120 is configured to check the integrity of the digital transmissions 112 based on information obtained via the analog outputs 110 of the vehicle system 104 itself. The test device 120 may have interfaces within the vehicle 102 (e.g., sound card inputs to the analog outputs 110 or other speakers or microphones of the vehicle system 104) and may perform integrity checks from a remote workstation that performs the functions of the test device 120 from outside the vehicle 102.

[0020] In some examples, the test device 120 is configured to check the integrity of the digital transmission 112 while the vehicle system 104 is operational and in use. This is partly because there is no direct probing of the digital transmission 112. For example, the vehicle's onboard controller can initiate the integrity check via a software routine by invoking the test device 120 embedded in the vehicle 102. Still in some examples, the test device 120 is additionally or alternatively configured to check integrity when the vehicle system is not operational, under maintenance, or parked. Development and engineering become easier because the digital transmission 112 can be checked automatically without the need for expensive test bench or road testing to check the performance of the vehicle system 104 under a seemingly infinite set of environmental conditions. Furthermore, mechanical workstations, charging stations, filling pumps, or other vehicle-external devices can alternatively utilize a remote terminal connection to the test device 120 to initiate similar integrity checks.

[0021] To enable integrity checks using test apparatus 120, the device under test 106 includes a test signal generator (TSG) 108-1. The TSG 108-1 can be a PRNG or other test sequence generator that reliably produces the same, consistent test signal, and in the case of PRBS, has a pattern that appears noisy or random. During digital transmission 112, the TSG 108-1 injects the test signal (e.g., PRBS) into digital transmission 112 for output by analog output 110. The source of digital transmission 112 can include the TSG 108-1, or the TSG 108-1 can have an input to a digital path to digital transmission 112 to inject the test signal within digital transmission 112 without requiring any modification to the audio decoder or other source.

[0022] Test apparatus 120 includes a corresponding TSG 108-2 that uses the same test signal generation function as TSG 108-1 or has access to it. For example, if TSG 108-1 is a PRNG, then TSG 108-2 is also a PRNG with the same polynomial or randomization algorithm as PRNG 108-1. Given the same input parameters, this allows TSG 108-2 to reproduce the same test signal generated by TSG 108-1. Matching TSG 108-1 and TSG 108-2 enables non-intrusive testing of digital transmission 112 by analyzing only the analog output 110.

[0023] Instead of performing extensive physical tests or obtaining unusable results through the application of purely digital testing techniques, the test module 122 of the test apparatus 120 examines the analog output 110 for errors 116 (e.g., transient errors, static errors) attributable to digital transmission 112 or any other digital transmission that may occur anywhere within the device under test 106. The test module 122 uses the output from TSG 108-2 as the initial test signal to estimate the test signal generated by TSG 108-1. However, the test module 122 also compensates for the test signal estimate using the linear transfer function of the digital path of digital transmission 112 and the analog path of analog output 110. Thus, the test module 122 compensates the estimated test signal for the linear transfer function between digital transmission 112 and analog path 118. The estimated test signal can be compared with the analog response 114 to determine whether the digital transmission 112 is free of transient errors, based on whether the test signal estimated with TSG 108-2 can be identified from the analog response 114 (analog signal, based on the audio signal of digital transmission 112) on the analog path 118 of the analog output 110.

[0024] Based on whether the measured signal corresponds to a compensated, estimated test signal (e.g., within an acceptable tolerance range), test module 122 can determine whether digital transmission 112 has propagated an error or is functioning as intended. Therefore, if the estimated test signal cannot be identified, the result of this check is that it can pinpoint the time when an error occurs due to digital transmission 112. This can aid in debugging and engineering to obtain confidence that no errors have occurred due to analog output 110.

[0025] Indications regarding whether any errors have been introduced in digital transmission can be reported as Indication 124, for example, graphically, audibly, or via log (e.g., as Indication 124-1, Indication 124-2…Indication 124-n). If an error is observed, Test Module 122 can output Indication 124-2. Otherwise, if no error is detected, Test Module 122 can output Indications 124-1 through 124-n to indicate that Vehicle System 104 is functioning as expected.

[0026] This makes the installation of the commissioning vehicle system 104 easier, and therefore less time-consuming and more cost-effective. Furthermore, achieving reliability for the hybrid analog-to-digital transmission system becomes less difficult, and once reliability is achieved, it can be verified with a higher degree of confidence.

[0027] Example architecture of the test device

[0028] Figure 2 A conceptual diagram of a vehicle system 200 configured to perform integrity testing on a hybrid analog-digital system according to the technology of this disclosure is illustrated. Vehicle system 200 is an example of vehicle system 104. It includes a device under test 106-1 and a test device 120-1.

[0029] The device under test 106-1 includes a source 212 for a digital transmission 112. Source 212 generates digital information received by analog output 110 to elicit an analog response 114, or sound. Source 212 may include a decoder 214 configured to convert compressed digital information into uncompressed audio information suitable for playback from analog output 110. Decoder 214 may include a TSG 108-1, shown as PRNG 108-1, and may be a separate component of source 212. PRNG 108-1 is configured to inject a test signal into the digital transmission 112 output by decoder 214. That is, PRNG 108-1 and decoder 214 are also configured to inject the test signal along with the uncompressed audio information into the digital transmission.

[0030] Test apparatus 120-1 includes a processor 202 and a computer-readable storage medium (CRM) 204 storing instructions that, when executed by the processor 202, implement functions associated with test module 122, TSG 108-2 (which is referred to as PRNG 108-2), test interface 206, transfer function estimator 208, and folding block 210. The processor 202 can be any processing device, processing unit, controller, or other computer. The CRM 204 can be any type of computer storage suitable for maintaining instructions executable by the processor 202 to implement the functions of test apparatus 120-1.

[0031] Test interface 206 receives analog response 114 (e.g., a signal in the air) from analog path 118. Test interface 206 may be a sound card input to test device 120, which may receive output from analog output 110 (or other speakers of vehicle system 104), or in some cases, may rely on microphone input to test interface 106. In this way, test device 120-1 does not need to directly probe device under test 106, and therefore does not affect digital transmission 112; this indirect inspection increases the confidence that digital transmission 112, rather than other content, is the focus of integrity checking.

[0032] PRNG 108-2 is associated with transfer function estimator 208 and folded block 210. These three logic blocks or cells use PRNG 108-2 to measure the linear transfer function of the digital path of digital transmission 112 and the analog path 118 of analog output 110.

[0033] The transfer function estimator 208 obtains the test signal estimated by the PRNG 108-2. The transfer function estimator 208 then determines the linear transfer function of the combined digital transmission 112 and analog path 118. This linear transfer function is calculated by the transfer function estimator 208 using a cross-correlation function to estimate the phase correlation between the source of the digital transmission 112 (e.g., decoder 214) and the first PRNG 108-1. The cross-correlation can be set based on predetermined measurements of the device under test 106-1.

[0034] Folding block 210 configures processor 202 to estimate the test signal by compensating PRNG 108-2 with linear transfer functions for the combined digital and analog paths by folding the impulse response with a second PRNG. Folding block 210 also obtains the test signal estimated by PRNG 108-2, and the phase correlation calculated by transfer function estimator 208. Based on these inputs, folding block 210 obtains an impulse response 114 of analog output 110 associated with the test signal estimated by transfer function estimator 208 and PRNG 108-2.

[0035] Thus, test module 122 can obtain the actual position in the time series of digital transmission 112, at which point it obtains a measurement of the analog response 114 of the analog output 110 from analog path 118. Test module 122 obtains the measured analog response and compares it with the test signal estimated by folding block 210 to determine whether an error has occurred in digital transmission 112 itself.

[0036] For example, when loaded from CRM 204 and executed by processor 202, test module 122 can compare the measured response of the analog output obtained from test interface 206 with the test signal estimated by fold block 210 to determine whether the estimated test signal is identifiable from the analog path. When the estimated test signal is approximately identifiable from the measured response, test module 122 determines that the digital path of digital transmission 112 is error-free (the error includes transient or static errors).

[0037] In practice, the test signal injected by PRNG 108-1 meets the signal tolerance level, ensuring that the estimated test signal, which can be identified in digital transmission 112, also appears in the measured response. Since less accurate modeling may not address additional crosstalk affecting the analog response 114, the signal tolerance level needs to be changed (e.g., increased or decreased) to accommodate variations in the vehicle system 104, the unit under test 106, and the components used to implement the test apparatus 120.

[0038] When the estimated test signal cannot be identified from the measured response, test module 122 determines that there is an error in the digital path of digital transmission 112. Any significant fault in digital transmission 112, such as bit errors of higher value bits or dropped frames or dropped buffers, causes this significant distortion in the analog response, making these significant errors detectable in addition to transient errors.

[0039] Thus, the test device 120 provides a non-intrusive way to check the integrity of the hybrid analog-to-digital transmission system. The vehicle 102 may include the test device 120 within the vehicle system 104, or may interface with the test device 120, which may be performed outside the vehicle 102 (e.g., at a workstation in a garage during engineering or testing).

[0040] Exemplary processing

[0041] Figure 3 A flowchart illustrating a process 300 for performing integrity testing on a hybrid analog-digital system according to the technology of this disclosure is provided. Process 300 can be performed by test apparatus 120, unit under test 106, or a combination of both. Depending on the application, the steps of process 300 can be repeated, rearranged, omitted, or otherwise modified. For ease of description, in... Figure 1 Processing 300 is performed within the context of the element.

[0042] At 302, the integrity of the digital transmissions used for the analog outputs of the vehicle system is checked. For example, the test module 122 of the test apparatus 120 obtains an analog response 114 from the analog path 118 of the analog output 110 to check the integrity of the digital transmissions 112 that occur within the device under test 106.

[0043] At 304, the test signal generated from the first TSG is injected into the digital transmission to the analog output. For example, the PRNG108-1 inputs the test signal into the digital transmission 112 that is sent to the analog output 110.

[0044] At 306, a second TSG, which relies on the same test signal generation function as the first TSG, is used to estimate the test signal generated by the first TSG. For example, PRNG 108-2 is a mirror component of PRNG 108-1 and is capable of reproducing the same test signal injected into digital transmission 112 by PRNG 108-1 by performing the same polynomial as PRNG 108-1.

[0045] At 308, the test signal estimated by the second TSG is compensated using a linear transfer function calculated for the digital path of the digital transmission and the analog path of the analog output. For example, test module 122 determines the linear transfer function by estimating the phase correlation between the source of digital transmission 112 (e.g., the audio decoder of the device under test 106) and the first TSG using a cross-correlation function. Based on the phase correlation, test module 122 can obtain the impulse response of analog output 110 associated with the estimated test signal. In other words, given the known relationship (linear transfer function) between the source and analog output 110, test module 122 can determine more accurately how the test signal might appear if there are no errors when the test signal is measured from analog response 114.

[0046] At 310, it is determined whether the estimated test signal can be identified from the analog output. For example, test module 122 can cross-correlate the estimated test signal with analog output 110 to determine the actual position in the time series of digital transmission 112, at which the measured response from analog output 110 of analog path 118 is obtained. Then, by comparing the measured response of analog output 110 with the estimated test signal, test module 122 can determine that the digital path of digital transmission is error-free when the estimated test signal can be approximately identified from the measured response (see the "Yes" branch of 310), and that the digital path of digital transmission 112 is error-prone when the estimated test signal cannot be identified from the measured response (see the "No" branch of 310).

[0047] If no error is identified, then at 316, an indication is output that no error was introduced in the digital path. For example, test module 122 can enable test device 120 to output a graphical user interface that provides confidence in digital transmission 112.

[0048] Otherwise, if an error is identified, then at 312, it is determined that the digital path introduced the error. At 314, an indication of the digital path introduced the error is output. For example, test module 122 can cause test device 120 to output a graphical user interface that provides an indication of which digital path of vehicle system 104 contains an error or introduces an error in digital transmission 112.

[0049] Example applications for testing equipment

[0050] Figure 4 A conceptual diagram of an example data flow 400 for integrity testing using a hybrid analog-digital system, according to the technology of this disclosure, is illustrated. Figure 4 The application of test apparatus 120 is shown, which can be easily connected to the device under test 106-2 to verify that there are no intermittent digital faults in digital transmission 112.

[0051] A media player or a dedicated test mode player plays the test signal (e.g., a PRNG mode with a given polynomial). The digital transmission mechanism transmits this data in real time to the processing stage executed by the sound processor via the device under test 106-2.

[0052] In the processing stage (e.g., the equalizer), the sound processor sets the audio data to neutral tuning during testing. Another delivery system feeds the audio data to the digital-to-analog converter and amplifier in real time.

[0053] The digital-to-analog converter transforms the digital transmission 112 and the embedded test signal into an analog signal or analog response 114. According to the principles of digital-to-analog conversion theory, the analog response 114 is modified by a linear time-invariant transfer function, which is neither specified nor known for the test apparatus 120.

[0054] The test system receives the analog response 114 via an analog-to-digital converter (e.g., the sound card input of test system 120) to digitize the audio signal 114 for error assessment. At test module 122, signal modification of the test signal, estimated using a linear transfer function, occurs. Test module 122 provides a means to characterize and compensate for the linear transfer function without directly accessing the test signal injected by device under test 106.

[0055] Other applications of testing equipment

[0056] Figure 5A conceptual diagram of an example data flow 500 for integrity testing using a hybrid analog-digital system, according to the technology of this disclosure, is illustrated. Figure 5 The application of test apparatus 120 is illustrated, which can be connected to device under test 106-3 to verify the absence of transient errors or other sporadic digital faults in digital transmission 112. Typically, since the test signal is neutral noise, a subset of bits, such as the four most significant bits of the PRNG, can be used to replace the actual four least significant bits of the music channel, and analog sampling feedback from the outward channel can test the presence of this PRNG portion.

[0057] The media player plays entertainment audio content, such as music. The warning ringtone player plays warning messages, but the lower bits are replaced by a PRNG with a specific polynomial. Since the PRNG will acoustically produce sound like white noise and only uses the lower bits, it can be injected into the ringtone as a virtually inaudible noise base.

[0058] Remove the least significant bit from the playing music to make room for the test mode. Both music and ringtones can be added to an audio signal, and the unchanged PRNG sequence can be in the lower bits.

[0059] The transmission mechanism delivers the data to the processing level in real time via a computer system. Another transmission system delivers the audio data to the audio codec in real time.

[0060] At this point, the signal can be tapped at path 118 and provided to test module 122 to confirm fault-free ringtone playback. This is accomplished by test module 122 removing all high-order bits carrying the mixture of music and ringtone, and extracting only the test pattern (PRNG) and using it in test module 122 to evaluate whether digital transmission 112 is error-free. Linear transfer function compensation is performed to compensate for the filter and volume settings of the processing stage (e.g., equalizer).

[0061] Consider the example of adding a loud clicking sound when a vehicle's lane departure warning identifies that the vehicle is drifting at the lane boundary. Such a sound would alert the driver to the fact that the wheels are on uneven ground, much like encountering gravel beside the road. This is a good way to warn the driver without interrupting all other music. This warning needs to be well-monitored so that a safety state can be triggered if its playback fails, for example, using a simple warning sound generator on a separate speaker. The proposed technique is similar to injecting a watermark with the acoustic properties of white noise into the desired sound, and the presence of the watermark can be easily tested to check for errors that are too infrequent to be noticeable in testing.

[0062] Additional examples

[0063] Example 1. A method comprising the steps of: checking the integrity of a digital transmission for an analog output of a system; and outputting an indication of whether any errors have been introduced due to the digital path of the digital transmission, wherein the step of checking the integrity of the digital transmission comprises: using a second test signal generator (TSG) to estimate a test signal generated from a first TSG of the system and injected into the digital transmission to be included in the analog output, the first TSG and the second TSG depending on the same test signal generation function and compensating for the linear transfer function of the combined digital path and the analog path of the analog output; and determining whether the estimated test signal can be identified from the analog path of the analog output to determine whether the digital path of the digital transmission is error-free.

[0064] Example 2. According to the method of Example 1, wherein determining whether the estimated test signal can be identified from the analog path includes: cross-correlating the estimated test signal with the analog output to determine the actual position in the time series of the digital transmission, obtaining a measured response of the analog output from the analog path at the actual position; comparing the measured response of the analog output with the estimated test signal; determining that the digital path of the digital transmission is error-free when the estimated test signal can be approximately identified from the measured response; and determining that the digital path of the digital transmission is error-free when the estimated test signal cannot be identified from the measured response.

[0065] Example 3. The method according to Example 2, wherein the first TSG includes a first pseudo-random number generator (PRNG), and the test signal includes a first pseudo-random number injected by the first PRNG at least above a signal tolerance level, such that the estimated test signal can be identified in the measured response, and the second TSG includes a second PRNG that depends on the same polynomial function as the first PRNG.

[0066] Example 4. The method according to any other example further includes: determining the linear transfer function of the combined digital path and the analog path by: estimating the phase correlation between the source of the digital transmission and the first TSG using a cross-correlation function; and obtaining, based on the phase correlation, the impulse response of the analog output associated with the estimated test signal.

[0067] Example 5. According to the method of Example 4, estimating the test signal by compensating the second TSG for the linear transfer function of the combined digital path and the analog path includes folding the impulse response with the second TSG.

[0068] Example 6. The method according to Example 4 or 5, wherein the test signal is injected into the digital path of the digital transmission by the source or the first TSG.

[0069] Example 7. The method according to any one of Examples 4 to 6, wherein the source is separate from the first TSG.

[0070] Example 8. The method according to any one of Examples 4 to 6, wherein the source includes the first TSG.

[0071] Example 9. The method according to any one of Examples 4 to 8, wherein the source includes an audio decoder configured to output uncompressed audio information to the digital transmission.

[0072] Example 10. The method according to Example 9, wherein the source further includes the first TSG, and the audio decoder is further configured to inject the test signal together with the uncompressed audio information into the digital transmission.

[0073] Example 11. The method according to any of the preceding examples, wherein the error includes (i) a transient error that occurs intermittently in the analog output over time.

[0074] Example 12. The method according to any of the preceding examples, wherein the error includes a fault that continues to reproduce in the analog output over time.

[0075] Example 13. The method according to any of the preceding examples, wherein the analog output includes a speaker device, and the analog path includes an audio signal based on the digital transmission sent to the sound card input of the test device.

[0076] Example 14. The method according to any of the preceding examples, wherein the system includes a vehicle system mounted on a vehicle, the means being separate from the vehicle, and the at least one processor is configured to check the integrity during operation and use of the vehicle system.

[0077] Example 15. The method according to any of the preceding examples, wherein the system includes a vehicle system mounted on a vehicle, the device is separate from the vehicle, and the at least one processor is configured to remotely check the integrity when the vehicle system is not in operation, is under maintenance, or is parked.

[0078] Example 16. The method according to any of the preceding examples, wherein the apparatus includes the system.

[0079] Example 17. A computer-readable medium comprising instructions that, when executed, cause computer hardware components of a vehicle system to perform the method according to any of the preceding examples.

[0080] Example 18. A computer-readable medium according to Example 17, wherein the vehicle system includes the computer hardware component, the vehicle system and the computer hardware component are part of the vehicle, and the computer hardware component is configured to check the integrity when the vehicle system is in operation and use.

[0081] Example 19. A computer-readable medium according to Example 17, wherein the vehicle system is part of the vehicle, the computer hardware component is separate from the vehicle and the vehicle system, and the computer hardware component is configured to check the integrity when the vehicle is not in operation, is in maintenance mode, is unoccupied, or is parked.

[0082] Example 20. An apparatus comprising at least one processor configured to perform the method according to any of the preceding examples.

[0083] Example 21. A system comprising means for performing the method according to any of the preceding examples.

[0084] Example 22. A system comprising: a device under test, the device under test including: an analog output; a digital path to the analog output; a source configured to generate a digital transmission for the analog output on the digital path; and a first test signal generator configured to inject a test signal into the digital path of the digital transmission; and a test device including: a second TSG, the second TSG depending on the same test signal generation function as the first TSG; and at least one processor configured to examine the digital path of the device under test by: estimating the test signal generated from the first TSG using the second TSG; compensating the estimated test signal for a linear transfer function of the combined digital path and the analog path of the analog output; determining whether the estimated test signal is identifiable from the analog path of the analog output to determine whether the digital path of the digital transmission is error-free; and outputting an indication of whether any errors have been introduced due to the digital path of the digital transmission.

[0085] While various embodiments of the present disclosure have been described in the foregoing description and illustrated in the accompanying drawings, it should be understood that the present disclosure is not limited thereto, but can be implemented in various ways within the scope of the appended claims. It will be apparent from the foregoing description that various changes can be made without departing from the scope of the claims. Problems associated with the digital transmission of information may arise in systems other than automobiles, trucks, and vehicle systems. Therefore, although described as a means to improve the safety and reliability of vehicle systems, the techniques described above can be applied to other systems that will benefit from rapid integrity checks of the digital transmission of information.

[0086] The use of “or” and grammatically related terms indicates a non-exclusive substitution without limitation unless the context clearly indicates otherwise. As used herein, the phrase referring to “at least one” in a list of items means any combination of those items, including single members. As an example, “at least one of the following: a, b, or c” is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination of multiples of the same element (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and cc, or any other order of a, b, and c).

Claims

1. An apparatus for checking the integrity of digital transmission of analog outputs for a system, wherein, The system includes a first test signal generator, which is configured to generate a test signal using a test signal generation function and to inject the test signal into the digital transmission for inclusion in the analog output. The apparatus includes: A second test signal generator, which uses the same test signal generation function as the first test signal generator; and At least one processor is configured to check the integrity of the digital transmission and output an indication of whether any errors have been introduced due to the digital path of the digital transmission by the following processing: The test signal is estimated using the second test signal generator, and the estimated test signal is compensated for by the linear transfer function of the combined digital path and the analog path of the analog output. Determine whether the estimated test signal can be identified from the analog path of the analog output in order to determine whether the digital path of the digital transmission is error-free.

2. The apparatus of claim 1, wherein, The at least one processor is configured to determine whether the estimated test signal can be identified from the analog path through the following processes: The estimated test signal is cross-correlated with the analog output to determine the actual position in the time series of the digital transmission, at which the measured response of the analog output from the analog path is obtained; The measured response of the simulated output is compared with the estimated test signal; When the estimated test signal can be approximately identified from the measured response, it is determined that the digital path of the digital transmission is error-free. and When the estimated test signal cannot be identified from the measured response, it is determined that there is an error in the digital path of the digital transmission.

3. The apparatus of claim 2, wherein, The first test signal generator includes a first pseudo-random number generator, and the test signal includes a first pseudo-random number injected by the first pseudo-random number generator at least above a signal tolerance level, such that the estimated test signal can be identified in the measured response, and the second test signal generator includes a second pseudo-random number generator, which depends on the same polynomial function as the first pseudo-random number generator.

4. The apparatus of any one of claims 1 to 3, wherein, The at least one processor is further configured to: The linear transfer function of the combined digital path and analog path is determined by the following process: The phase correlation between the source of the digital transmission and the first test signal generator is estimated using a cross-correlation function; and The impulse response of the analog output, associated with the estimated test signal, is obtained based on the phase correlation.

5. The apparatus of claim 4, wherein, The at least one processor is further configured to estimate the test signal by compensating the second test signal generator with the linear transfer function of the combined digital path and the analog path by folding the impulse response with the second test signal generator.

6. The apparatus of claim 4, wherein, The test signal is injected into the digital path of the digital transmission by the source or the first test signal generator.

7. The apparatus of claim 4, wherein, The source is separate from the first test signal generator.

8. The apparatus of claim 4, wherein, The source includes the first test signal generator.

9. The apparatus of claim 4, wherein, The source includes an audio decoder configured to output uncompressed audio information to the digital transmission.

10. The apparatus of claim 9, wherein, The source also includes the first test signal generator, and the audio decoder is further configured to inject the test signal along with the uncompressed audio information into the digital transmission.

11. The apparatus of claim 1, wherein, The error includes at least one of (i) a transient error and (ii) a fault, wherein the transient error occurs intermittently in the analog output over time and the fault continues to recur in the analog output over time.

12. The apparatus of claim 1, wherein, The analog output includes a microphone or speaker device, and the analog path includes an audio signal based on the digital transmission.

13. The apparatus of claim 1, wherein, The system includes a vehicle system mounted on a vehicle, the device being separate from the vehicle, and the at least one processor being configured to check the integrity during operation and use of the vehicle system.

14. The apparatus of claim 1, wherein, The system includes a vehicle system mounted on a vehicle, the device being separate from the vehicle, and the at least one processor being configured to remotely check the integrity when the vehicle system is not in operation, is under maintenance, or is parked.

15. The apparatus of claim 1, wherein, The device includes the system.

16. A computer-readable medium comprising instructions that, when executed, cause computer hardware components of a vehicle system to: Check the integrity of the digital transmission, which is used for the analog output of the vehicle system; and The output indicates whether any errors were introduced due to the digital path of the digital transmission. wherein, When executed, the instruction causes the computer hardware components to check the integrity of the digital transmission through the following processes: The second test signal generator estimates the test signal generated by the first test signal generator of the vehicle system using a test signal generation function and injected into the digital transmission to be included in the analog output, and compensates for the linear transfer function of the combined digital path and the analog path of the analog output, wherein the second test signal generator uses the same test signal generation function as the first test signal generator. and Determine whether the estimated test signal can be identified from the analog path of the analog output in order to determine whether the digital path of the digital transmission is error-free.

17. The computer readable medium of claim 16, wherein, The vehicle system includes the computer hardware component, the vehicle system and the computer hardware component are part of the vehicle, and the computer hardware component is configured to check the integrity when the vehicle system is in operation and use.

18. The computer readable medium of claim 16, wherein, The vehicle system is part of the vehicle, the computer hardware component is separate from the vehicle and the vehicle system, and the computer hardware component is configured to check the integrity when the vehicle is not in operation, is in maintenance mode, is not occupied, or is parked.

19. A method for checking the integrity of digital transmissions for analog outputs of a system, the method comprising the steps of: The second test signal generator estimates the test signal generated by the first test signal generator of the system using a test signal generation function and injected into the digital transmission to be included in the analog output, and compensates for the linear transfer function of the combined digital path of the digital transmission and the analog path of the analog output. The second test signal generator uses the same test signal generation function as the first test signal generator. Determine whether the estimated test signal can be identified from the analog path of the analog output, in order to determine whether the digital path of the digital transmission is error-free; and Output an indication of whether any errors were introduced due to the digital path of the digital transmission.

20. A system comprising a device under test and a measuring device, The device under test includes: Simulated output; The digital path to the analog output; Source, the source being configured to generate digital transmissions for the analog output on the digital path; as well as A first test signal generator is configured to generate a test signal using a test signal generation function and inject the test signal into the digital path of the digital transmission. The testing apparatus includes: A second test signal generator, which depends on the same test signal generation function as the first test signal generator; and At least one processor is configured to check the integrity of the digital path of the device under test by performing the following processes: The test signal generated from the first test signal generator is estimated using the second test signal generator. The estimated test signal is compensated by the linear transfer function of the combined digital path and the analog path of the analog output; Determine whether the estimated test signal can be identified from the analog path of the analog output to determine whether the digital path of the digital transmission is error-free; and The output indicates whether any errors were introduced due to the digital path of the digital transmission.

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