Riding the wind of rebirth

"The first one is a streaming media codec chip. The design code is MMD1370, which is the abbreviation of Multi Mediea Decoder Clip. 1370 represents the number of modification iterations from design to finalization."

"Depending on the design requirements, this chip needs to have several features."

“The first is multi-format support. In addition to decoding traditional AAC, WAV, and FLAC formats, we also need to be able to decode audio files in MP3 format and WMP format. This multi-format support allows users to play audio files in different formats more flexibly. , to meet the diverse needs of users.”

"This is the world's first multi-format decoding chip, and according to the design concept in the requirement document, we designed an external storage interface for the chip, which can cooperate with EEPROM to realize the addition and upgrade of the protocol. In other words, it can be used in the future Decode more formats of audio files without changing hardware devices.”

“The second feature of this chip is its efficient decoding capability: its built-in algorithm can quickly and accurately decode audio files in the aforementioned multiple formats, allowing users to quickly convert files into playable audio streams and obtain fast and smooth audio playback experience.”

"The third point is high-quality audio restoration. The chip can restore high-quality audio through advanced audio decoding algorithms and technologies. It can eliminate or reduce the audio loss caused by the compression format to the greatest extent, providing a nearly lossless sound quality experience. For low-end High-quality audio files with a higher compression ratio can be restored to be more realistic, delicate and full of details, which can improve the user experience."

"The fourth point is effect processing and enhancement. The chip integrates an effects processor, which can perform basic equalization, enhancement, surround and other effects processing on the audio. Users can adjust the tone, volume, bass and other parameters of the audio according to personal preferences."

"Because the requirement document also mentioned that it should be as portable as possible, this chip also needs two designs. One is low energy consumption. To make the device perform well in terms of power consumption, energy needs to be effectively managed from all aspects; the other is anti-interference. It can effectively shield the effects of electromagnetic interference, environmental noise, etc. on audio signals, allowing the device to play stably in complex environments and provide clear and pure sound quality."

"In order to better meet the above requirements, in addition to designing MMD1370 as the benchmark decoding chip, we also designed a digital-to-analog conversion chip DAC3533 to cooperate with it."

"DAC is the abbreviation of digital audio compiler?" Zhou Zhi asked.

"Yes, if MMD1370 is responsible for interpretation, DAC3533 is responsible for processing, rendering and effect processing the digital audio stream interpreted by MMD1370, which can improve the immersion and entertainment of the audio."

"Actually, we are not the first to create DAC chips. Starting from Philips' TDA1547 in 1955, we later moved on to AD's AD43, CL's CS179xx, TI's PCM90x, ESS's ES90xx, ES179xxPRO and DSDx. There are many chips."

"But our DAC3533 uses the latest industry achievement authorized by AXA Patent Warehouse - the Sigma-Delta framework. The DAC3533 produced using multi-bit Sigma-Delta modulators has a larger dynamic range than the current mainstream DAC chips. , smaller noise and distortion ratio, lower CMOS circuit cost, and it is easier to add other processing functions on the chip.”

"We are confident that this chip will become a mainstream chip in the high-end audio market."

"You can't be blindly confident." Zhou Zhi said with a smile: "According to the tracking of the Intellectual Property Department of AXA Fund, a new technology is about to mature, that is, 'field programmable gate array' and 'complex programmable logic device' Two technologies.”

"Of course, these two technologies are actually just reflections of the rewritable technology in the field of DAC chips. They are actually very similar to our idea of ​​reserving an EEPROM interface for the MMD1370, but it is obvious that they are still ahead of us. "

"Yes, but I heard that AXA is in contact with Altera? Altera is a company with quite a lot of FPGA and CPLD patents." Liao Hongxing said.

FPGA and CPLD are the abbreviations of the two programmable technologies mentioned earlier. These are two technologies that have not yet been transformed, but only represent the future direction. “We are in contact.” Zhou Zhi nodded: “AXA has a plan to acquire Altera, because Altera not only has cutting-edge technology, but is also very strong in traditional DAC chip technology.”

"But these are things in the future, let's talk about the present."

The technology of audio decoding also involves all aspects. In addition to the core decoding chip and digital-to-analog conversion chip, there is also a digital audio receiving chip.

The modules involved also include digital audio receiving modules, independent modulation and independent digital-to-analog conversion modules, on-chip solutions, etc.

Key technologies include parallel bits, modulation sampling, digital filtering, noise shaping, dynamic component adaptation, asynchronous sampling rate conversion, phase-locked loop, time base jitter elimination, low-level cascade modulation, noise shaping, sampling rate multiplier, advanced Segmented DAC, data weighted averaging, gain correction, distortion compensation, baseline reference voltage correction, current output, low output impedance, differential complementary output, external digital filtering, low-noise linear power supply, etc. There are a lot of technologies, really all of them To put it into detail, I couldn't leave this room for three days and three nights that week.

Fortunately, Liao Hongxing and Xu Wangting did not hesitate, and quickly concluded: "MMD1370 and DAC3533, the performance of these two chips has exceeded that of AKM's new chip, which currently has the most pins, the most expensive price, and the highest dynamic range in the industry. The flagship AK2388 is equipped with SPDIF and EEPROM interfaces and has the ability to decode multiple encoding formats, so its comprehensive performance indicators should be the best in the world."

"In addition, the DAC3533 is an eight-bit four-channel DAC that uses double-rate sampling, reaching 128fs, which is twice as precise as the DSD64 clock used in all current DAC chips, and its performance has been greatly improved."

"That is to say, the superposition performance of our two chips has exceeded the resolution capability of AK2388?" Zhou Zhi asked.

Liao Hongxing smiled confidently: "It's too much."

"AK2388, how much is it selling for now?"

"Current DAC chips, depending on their performance, sell for between eight dollars and twenty-eight dollars. AK2388 is the flagship product, currently priced at twenty-four dollars."

"This is only the price of the DAC chip," Xu Wangting added: "It does not include the price of the decoding chip and the receiving chip."

"Do we have a receiving chip?" Zhou Zhi asked: "If we add a receiving chip, will we have complete independent research and development of the player?"

"The receiving chip is not among our public relations priorities." Xu Wangting said: "I use Sony's RSS2000 for the engineering machine. Because of our group's relationship with NEC, Japanese chips are easier to obtain."

"If our two chips are mass-produced, how much will the price be?" Zhou Zhi was secretly happy. At 28 US dollars for a chip, AKM received a lot of money.

"We can now control the cost to 908 yuan per piece. If we bring in all the th and th factories and expand the production capacity and reduce it to yuan per piece, there shouldn't be a big problem." Hu Changfeng smiled with satisfaction: " Elbow, the mess of Project should be considered alive."