• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.4
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• pp.117-125
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• 2014

In this paper, a novel hardware architecture of the LT codec is presented where non-BP based decoding algorithm is applied. Novel LT codec architecture is designed with an efficient degree distribution unit using Verilog HDL. To perform permutation operation, different initial valued or time shifted counters have been used to get pretty well permutations and an effect of randomness. The codec will take 128 bits as input and produce 256 encoded output bits. The simulation results show expected performances as the implemented distribution and the original distribution are pretty same. The proposed LT codec takes 257.5 cycle counts and $2.575{\mu}s$ for encoding and decoding instead of 5,204,861 minimum cycle counts and 4.43s of the design mentioned in the previous works where iterative soft BP decoding was used in ASIC and ASIP implementation of the LT codec.

• The Magazine of the IEIE
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• v.12 no.4
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• pp.32-37
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• 1985

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.6
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• pp.59-66
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• 2018

In this paper, we experimented how long distance voice communication is possible After implemented PTT(Push to talk) Bi-directional radio using open source project Codec 2, which is a low speed voice codec for digital amateur radio and 900MHz FSK transceiver. In case of a general digital radio, the AMBE+2 codec, which is regarded as an industry standard in terms of performance, is expensive and has the monopoly of technology. Using the 400MHz band in terms of frequency, narrow bandwidth of DMR(12.5kHz) and DPMR(6.25kHz) is used, so the data rate is low. In the 900MHz bandwidth can be extended, which is advantageous in terms of data transmission. As a result of the voice quality and distance field test, we could find that the communication takes place within about 500m. In this paper, only voice communication is reviewed. if a review of data transmission such as a simple image is added, this solution can be used in various fields as a low cost IOT radio.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.3A
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• pp.360-367
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• 2006

In this paper, we designed a digital codec of an RFID tag for EPC global generation 2 class 1. There are a large number of studies on RRD standard and anti-collision algorithm but few studies on the design of digital parts of the RFID tag itself. For this reason, we studied and designed the digital codec hardware for EPC global generation 2 class 1 tag. The purpose of this paper is not to improve former studies but to present the hardware architecture, an estimation of hardware size and power consumption of digital part of the RFID tag. Results are synthesized using Synopsys with a 0.35um standard cell library. The hardware size is estimated to be 111640 equivalent inverters and dynamic power is estimated to be 10.4uW. It can be improved through full-custom design, but we designed using a standard cell library because it is faster and more efficient in the verification and the estimation of the design.

• ETRI Journal
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• v.27 no.6
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• pp.818-821
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• 2005

Recently, MPEG has opened activity to standardize scene representation for lightweight applications such as in mobile phones. The standard is named lightweight applications scene representation (LASeR) and can be applied to improve and make efficient rich media applications and services on mobile devices. In this standard, we proposed an efficient type codec for point data to maximize the bit efficiency of LASeR. In this paper, we describe the new method and the test results of the proposed scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.2
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• pp.326-332
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• 1996

In this paper, a method to design the sending loudness rating(SLR) is proposed and the desirable transmission characteristics are considered in order to specify the transmission quality, based on the loudness ratings, for the digital telephone system that is a terminal for digital speech communication. To specify the desirable SLR for digital telephone system, the subjective test defining the preferred range of inout level for CODEC was performed. From the test results, it was identified that the optimal input level for CODEC is -15dB and the range not to cause the quantization noise and the distortion of CODEC fall within -12dB and -18dB.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.10A
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• pp.1015-1022
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• 2007

In this paper, dual-band digital codec for UHF(Ultra High Frequency) and MW(Micro Wave) is proposed for an RFID reader system. Most RFID systems have been supported only one protocol. But, There are many protocols of each bandwidth. Especially, UHF bandwidth which is widely used on the globe consists of A,B,C type, and more standards will be established. Recently, Since an interest about mobile RFID system is increasing, the RFID system with more than one protocol will be need. Therefore, this paper suggests a dual-band digital codec with UHF and MW bands for an RFID reader system. Standards used in this system are 18000-6C and 18000-4 standards. The digital codec is synthesize by the Quartus II compiler. Target device is EPC20Q240C8 which is family of CycloneII. Main Clock is 19.2MHz and elements of FPGA which is used for the system is 18,752.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.466-469
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• 2002

Using intelligent information contained within the speech to identify the specific hidden data in the watermarked multimedia data is considered to be an efficient method to achieve the speech digital watermarking. This paper presents the performance comparison between various types of speech codec in order to determine an appropriate one to be used in digital watermarking applications. In the experiments, the speech signal encoded by four different types of speech codec, namely CELP, GSM, SBC and G.723.1codecs is embedded into a grayscale image, and theirs performance in term of speech recognition are compared. The method for embedding the speech signal into the host data is borrowed from a watermarking method based on the zerotrees of wavelet packet coefficients. To evaluate efficiency of the speech codec used in watermarking applications, the speech signal after being extracted from the attacked watermarked image will be played back to the listeners, and then be justified whether its content is intelligible or not.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1984.04a
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• pp.9-12
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• 1984

A digital TV CODEC has been implemented. This CODEC uses a pulse code modulation with a resolution of 9 bits per sample and generates digital ouput at the rate of 90.194Mb/s. In this system, we aadopted a horizontal blanking control scheme to meet the contraint of 90.194Mb/s transmission rete, conswequently ontaining data compression of 9.4%, our system's performances have been measured. Its SNR

• Journal of Broadcast Engineering
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• v.6 no.1
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• pp.66-71
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• 2001

This paper Introduces an implementation of MPEG-2 AAC codec system for digital audio broadcasting. This system consists of the encoder and the decoder. This system includes MPEG-2 system multiplexing and demultiplexing modules for Interfacing to the ETRI-DAB system. Four DSPs are adopted for the encoder and three DSPs for 7he decoder. Each DSP Processes system control. 1/0 control, audio signal processing. multiplexing and demultiplexing. This Paper also discusses some near future estimations relaxed to the DAB system and it\`s services. Currently a stereo audio codec is available but multi-channel audio codec and MPEG-4 audio cosec wall be also Implemented.