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RNC55H3831FSRSL_Vishay Dale_Through Hole Resistors

来源:LM317 Electronics Components编辑:Injectorall时间:2021-06-15 13:53:01

First, automotive OEMs have been running into bottlenecks due to the data uploads of hundreds of MB up to several GB of data into vehicles using end-of-production-line programming in order to program software into modules on CAN, MOST, and FlexRay networks. In essence, the industry is seeing the need for the performance of a high-speed router in the vehicle. In order to implement this upload more efficiently, and cut time and costs, there is a movement towards Ethernel—a logical choice for diagnostics; is capable of high-speed data transfer; the hardware is inexpensive; and there is an enormous amount of software applications that are available.

This research work deals with the implementation and characterization of a real-time 2D correlator based on a DSP. Two image resolutions were tested, 256×256 and 512×512. The system can yield 12 fps and only 2 fps, respectively. A basic pattern recognition system implemented with the correlator, has shown a slight lower performance of 10 and 1.5 fps respectively, mainly due to the additional processing besides correlation.

We idetified some limitations on the use of DSPs for digital image processing. DSPs are very well suited for basic image processing operations, such as binarization or spatial filtering, and they take advantage of software and hardware resources. However, the architecture of the DSP used in this implementation does not allow a peak performance when operations such as 2D filtering in frequency domain or 2D correlation are performed.

RNC55H3831FSRSL_Vishay Dale_Through Hole Resistors

The implementation of the pattern recognition system allowed us to compare four filter designs that guarantee rotation-invariant results for correlation. Particularly, phase-derived CHFs achieved the best results when we measured probability of detection. Future work will be focused on including invariance to small perspective variations generated when the target is far away from the vertical axis of the camera. Also, a superior resistance to noise presence and changes in illumination will improve the performance of the system.

Henry Arguello Fuentes is associated in the Department of Electrical, Electronic and Telecommunications at the UIS. He received his B.S and M.S. degrees in 2000 and 2003, respectively, in electrical engineering from the same department.

References

RNC55H3831FSRSL_Vishay Dale_Through Hole Resistors

Few audio standards have had the impact of MP3. But there’s more to audio codecs than just MP3. 3GPP audio standard format families, AAC and AMR, are the commercial powerhouses that are early in their market acceptance. There is no doubt that the 3GPP codecs will become commercially critical technology. To gain an overview understanding of the underlying technology, we’ll start with MP3 – the predecessor to AAC

MPEG-1 (MP3) MP3 stands for MPEG-1 Audio Layer III. Although it has become ubiquitous as an audio codec, it is not really separate from the MPEG-1 video encoding format. The strength of MP3, apart from being an international standard, is its relatively high degree of compression in comparison to a straight digitized music track. MP3 is a lossy data compression method in which compressing a file and then decompressing it creates a file that in general will be different to the original. MP3 relies on the fact that the human brain can not discern all of the data in a loss-free signal, thus MP3 is adequate to store good quality audio in small files. MP3 uses psychoacoustics to determine which data can be eliminated without affecting the quality of the audio heard by listeners.

RNC55H3831FSRSL_Vishay Dale_Through Hole Resistors

MP3 bit rates range from 8 kbps to 320 kbps. During the early stage of MP3 acceptance as a stand-alone audio codec, most of the audio files were encoded using a 128 kbps bit rate which remains the most popular bit rate in the world. Based on subjective listening tests, a slightly higher bit rate, like 192 kbps or 256 kbps, improves the audio quality so that it is comparable to CD quality. MP3’s primary weakness is at lower bit rates such as 64kbps where high frequency components are lacking. The problem with MP3 takes place at lower bit rates of 64 kbps and below, because the codec drops out the high frequency components.

MP3PRO MP3PRO was designed to address some of the problems associated with MP3 files. MP3 PRO improves the sound quality of MP3 at low bit rates by employing a codec that restores some of the high frequency components. The extended codec technology uses Spectral Band Replication” (SBR). SBR generates the high frequency components of an audio signal in an efficient fashion. The MP3 PRO audio format has two components, the MP3 part for the low frequencies and the SBR or PRO” part for the high frequencies. The low frequency band information is encoded into a normal MP3 stream. This permits the encoder to band limit the audio signal while achieving an improved low band encoding. The codec is also compatible with existing MP3 players. The high frequency band information is encoded into a part of the MP3 stream typically normally ignored by existing MP3 decoders.

Too few coldstart attempts. Ideally, one coldstart attempt should start up a FlexRay network. Unfortunately, there are a number of factors that can distort the sync frame sent to the leading coldstarter, forcing another coldstart attempt. The user can configure the number of allowed coldstart attempts, so be sure to configure enough to cover any expected disturbances.

Too long or too short TSS. The Transmission Start Sequence (TSS) is transmitted ahead of any frame to activate star couplers and receivers. The TSS length is checked during reception, and if it’s too long or too short, the frame is invalidated. The TSS can be shortened or enlarged by star couplers and receiver asymmetries, and the FlexRay protocol specification gives formulas and ranges for sufficient TSS length according to the topology.

To avoid invalid frames, the TSS inside the transmitter should be configured to satisfy the given protocol rules. If the TSS length can be configured independently inside the transmitter and the receiver, such as in Freescale’s MFR4200, the first production FlexRay controller, the receiver should be configured to accept a TSS that is at least one bit longer than that configured by the transmitter.

Incorrect header CRC. Even if the header cycle redundancy code (CRC) is not calculated correctly, the transmitting node still sends its frames. Header CRCs are not checked in the transmitter or during transmission, but they are checked in the receiver during reception, at which point a faulty header CRC will be discarded. A configuration tool will prevent faulty header CRCs.

FlexRay is a complex, sophisticated protocol, and starting up a network requires thought and precision. However, using the right tools, following step-by-step procedures and avoiding some common mistakes can go a long way toward successful implementation, regardless of the application.

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