Digital Audio Broadcasting Research Articles

Design and implementation of a novel emergency wake-up alert system within a conventional T-DMB service network

Existing emergency alert techniques of terrestrial-digital multimedia broadcasting (T-DMB) and digital audio broadcasting (DAB) can be executed only when the receivers are activated. To overcome the limitation of existing technique, a novel emergency wake-up alert system within a conventional T-DMB service network is proposed. The emergency wake-up alert signal is periodically generated by emergency transmission data unit (ETDU) and then transmitted through the conventional T-DMB/DAB station. After receiving the emergency wake-up alert signal, T-DMB/DAB receiver can be wake-up, activating and result in showing emergency broadcasting contents to people. To obtain frequency efficiency, the emergency wake-up alert signal is overlaid onto the conventional T-DMB frequency band using a direct sequence spread spectrum technique. To assess the performance of the developed ETDU, simple RF transmitter, test receiver and measurement equipment are used. The performance is checked with different values of emergency wake-up alert signal to T-DMB power ratio. The laboratory test results shows that the wake-up alert signal can be transmitted without degrading the existing T-DMB signal quality and can be detected at very low power emergency wakeup alert signal, e.g., as low emergency wake-up alert signal to T-DMB power ratio as -22.2dB.

Digital radio – the fight for diffusion in Germany

Purpose– The diffusion of digital radio has experienced more challenges than for digital TV regarding a digital switchover. The purpose of this paper shows on the specific case of Germany, which difficulties the digital sound broadcasting technology of Digital Audio Broadcasting (DAB) has been facing from several points of view. The difficulties are reviewed and outlined to overcoming different barriers and to facilitating its diffusion.Design/methodology/approach– The paper analyses how the diffusion of digital radio is perceived by industry representatives such as radio consultants and several stakeholders along the value chain of the radio industry. In semi-structured interviews, participants describe and evaluate the challenges for DAB as digital audio broadcasting standard mainly in Germany.Findings– After two decades of deploying digital radio in Germany, its success is still missing. Various very different aspects have prevented the diffusion of the new technology. Among various barriers, the radio industry sees missing benefits, marketing errors and a lack of inter-industrial collaboration as barriers in a retro-perspective.Research limitations/implications– The analysis does not cover other countries, where DAB as standard was introduced. Also other standards for digital radio are not considered.Practical implications– With referring to barriers for digital radio, there is a scope for those countries about to introduce the technology to troubleshoot the failings of overcoming barrier. An idea can emerge, how authorities and industrial stakeholders can help to facilitate the diffusion of digital radio. It also indicates the need of governmental interaction for the coordination of a technology introduction in a network industry.Social implications– The theoretical model, referred to, gives a good overview of potential diffusion barriers as most identified problems for the German case. The model and the illustrated problems of the paper can be used in practice to manage potential diffusion problems during technology introductions.Originality/value– There is a lack of published information about the faced challenges for the diffusion of digital radio. The retro-perspective benefits from the broad experience of participants having observed the challenges of the past decade with DAB in Germany. Additionally, the results are mapped to a theoretical framework with limits for the diffusion of innovation for generalising.

Low-Cost Low-Power ASIC Solution for Both DAB+ and DAB Audio Decoding

DAB+ is the upgraded version of digital audio broadcasting (DAB). DAB and DAB+ coexist in many countries, so receivers are required to be compatible with both standards. In this paper, a solution integrating an MPEG1-LayerII (MP2) decoder and an advanced audio coding (AAC) low-complexity (AAC LC) decoder is proposed to provide basic audio decoding for both DAB and DAB+. It also utilizes simple methods to improve high frequencies and stereo quality instead of complicated spectrum band replication and parametric stereo. A highly integrated low-power audio decoder design compatible with DAB/DAB+ and using a purely ASIC approach is presented. As a result of the system structure optimization and hardware sharing, the audio decoder is fabricated in 1P4M 0.18- μm CMOS technology using only 3.2 mm2 silicon area (including 147 456 bits RAM and 170 496 bits ROM). The power consumption of the audio decoder is 10.4 mW for DAB audio decoding and 8.5 mW for DAB+ audio decoding. Laboratory and field tests show that the function is correct and the audio quality is good for receiving both DAB and DAB+. The audio decoder is thus proven to be a low-cost low-power solution for the two existing DAB standards.

Improving the Reception Performance of Legacy T-DMB/DAB Receivers in a Single-Frequency Network with Delay Diversity

This paper describes a simple delay diversity technique for terrestrial digital multimedia broadcasting (T-DMB) and digital audio broadcasting in a single-frequency network (SFN). For the diversity technique, a delay diversity scheme is adopted. In the delay diversity scheme, a non-delayed signal is transmitted in the first antenna, and delayed versions of the signal are transmitted in each additional antenna. For an SFN environment with multiple transmitters, delay diversity can be executed by controlling the emission times of the transmitters. This SFN delay diversity scheme does not require any hardware changes in either the transmitter or receiver, and perfect backward compatibility can be acquired. To evaluate the performance improvement, laboratory tests are executed with various types of commercial T-DMB receivers as well as a measurement receiver. The improvement in the bit error rate performance is evaluated using a measurement receiver, and an improvement of the threshold of visibility value is evaluated for commercial receivers. Test results show that the T-DMB system can obtain diversity gain using the described technique.

Digital Terrestrial Video Broadcast Interference Suppression in Forward-Looking Ground Penetrating Radar Systems

In this paper we show how radio frequency interference (RFI) generated by digital video broadcasting terrestrial and digital audio broadcasting transmitters can be an important noise source for forward-looking ground penetrating radar (FLGPR) systems. Even in remote locations the average interference power sometimes exceeds ultra-wideband signals by many dB, becoming the limiting factor in the system sensitivity. The overall problem of RFI and its impact in GPR systems is briefly described and several signal processing approaches to removal of RFI are discussed. These include spectral estimation and coherent subtraction algorithms and various filter approaches which have been developed and applied by the research community in similar contexts. We evaluate the performance of these methods by simulating two different scenarios submitted to real RFI acquired with a FLGPR system developed at the Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR), (GER). The effectiveness of these algorithms in removing RFI is presented using some performance indices after suppression.

Area Efficient Fft/Ifft Processor for Wireless Communication

Fast Fourier Transform (FFT) processing is one of the key procedures in popular Orthogonal Frequency Division Multiplexing (OFDM) communication systems. Structured pipeline architectures, low power consumption, high speed and reduced chip area are the main concerns in this VLSI implementation. In this paper, the efficient implementation of FFT/IFFT processor for OFDM applications is presented. The processor can be used in various OFDM-based communication systems, such as worldwide interoperability for Microwave access (Wi-Max), Digital Audio Broadcasting (DAB), Digital Video Broadcasting-Terrestrial (DVBT). We adopt single-path delay feedback architecture. To eliminate the Read Only Memories (ROM’s) used to store the twiddle factors, this proposed architecture applies a reconfigurable complex multiplier to achieve a ROM-less FFT/IFFT processor and to reduce the truncation error we adopt the fixed width modified booth multiplier. The three Processing Elements (PE’s), Delay-Line (DL) buffers are used for computing IFFT. Thus we consume the low power, lower hardware cost, and high efficiency and reduced chip size.

High-Power Wideband $L$-Band Suboptimum Class-E Power Amplifier

This paper presents a high-power high-efficiency wideband suboptimum Class-E RF power amplifier based on a packaged high-power GaN HEMT. It uses a simple double-reactance compensation and impedance transformation load network that includes device intrinsic capacitance, package parasitics, low-loss microstrip transmission lines, and lumped components. This load network makes the GaN HEMT operate in suboptimum Class-E from 900 to 1500 MHz (50% fractional bandwidth at 1200 MHz). The amplifier can operate both in continuous wave and pulsed modes over its full bandwidth without tuning. It delivers up to 180-W output power with up to 85% drain efficiency and PAE=81%. To the best of the authors' knowledge, the amplifier proposed in this work outperforms commercial grade amplifiers that operate in the same frequency band with similar output power levels. Direct applications for this amplifier include mobile satellite communications transmitters, envelope elimination and restoration digital audio broadcasting transmitters, and power stages for primary and secondary RADAR transmitters.

Subjective and objective evaluation of sound quality of radio programs transmitted via Digital Audio Broadcast (DAB+) System

The work presents results of research on the sound quality of different radio programs transmitted via Digital Audio Broadcasting (DAB+). This assessment has been provided with a use of psychoacoustic model as well as standard listening tests, using an Absolute Category Rating (ACR) method of scaling, and Comparison Category Rating (CCR) method. Results have shown that sound quality gets worse when bit-stream is of the lowest values (48 kbit/s or 24 kbit/s). Application of the Spectral Band Replication processor significantly improves the perceived quality, which is satisfying for bit streams higher than 64 kbit/s, particularly for jazz and popular music. The assessment with ACR method (recommended for broadcast by International Telecommunication Union) showed better notes than CCR one. It means that recommended method is less critical. Also results obtained with psychoacoustic model are more similar to obtained with CCR method. The attributes of spatial impression change in different ways. The greatest distortion has been observed for the perspective and spaciousness of sound image, while the sound color as well as localization stability and accuracy of phantom sources remained almost the same.

A SAW-Less First Folded-Conversion Second Down-Conversion Receiver for Multistandard Broadcasting Radio Applications

A surface-acoustic-wave-less first folded-conversion and second down-conversion receiver for the AM/FM/digital radio mondiale (DRM)/digital audio broadcasting (DAB) radio standards is presented. This architecture is more suitable for broadcasting radio with ultra-narrow signal bandwidth since it relaxes the requirement on the local area (LO) generator by decreasing its tuning range. To reduce the blockers and out-of-band (OB) interferers, current amplifying and polyphase filters are introduced simultaneously. An inverter-based switched capacitor array technique is proposed in voltage-controlled oscillator (VCO) design to isolate the noise from the substrate. With a single VCO, the receiver can cover the frequency range from 100 kHz to 1.5 GHz. Without the RF pre-filters, the in-band ${\rm IIP}_{3}$ is 1.5 dBm, and the OB ${\rm IIP}_{3}$ is up to 17.4 dBm. The LO phase noise in the worst case is $-$ 119 dBc/Hz@1 MHz. The chip is fabricated in a 0.18- $\mu{\hbox{m}}$ CMOS technology, and mounted on a QFN package. It consumes only 86.4 mW under 1.8-V supply. To our best knowledge, this is first receiver reported thus far that supports all four AM/FM/DRM/DAB standards.

Complexity reduction for non‐coherent iteratively detected differentially encoded quaternary phase shift keying based on trellis decomposition

AbstractIn this letter, we investigate complexity reduction for non‐coherent iterative detection of differentially encoded quadrature phase shift keying applied to digital audio broadcast receivers. We use 2D blocks in an orthogonal frequency division multiplexing scheme and trellis decomposition to calculate, iteratively, the a posteriori probabilities of the information symbols. Furthermore, the trellis decomposition method allows us to estimate the unknown channel phase efficiently. This phase is related to sub‐trellises of which we can determine the a posteriori probabilities. In our first approach, we investigate a method that is based on finding, at the start of each new iteration, the dominant sub‐trellis first and then do the forward–backward processing for demodulation only in this dominant sub‐trellis. This method reduces the number of multiplications by a factor of 3, the normalizations by a factor 8 and, after five iterations, introducing ≈ 0.05 dB loss in performance on the COST‐207 TU‐6 channel. Our second approach involves choosing the dominant sub‐trellis only once, before starting with the iterations. This results in reducing the number of multiplications and normalizations by a factor of 8 and introduces ≈ 0.5 dB loss in performance. Copyright © 2013 John Wiley & Sons, Ltd.

Adaptive Digital Predistortion for Wideband High Crest Factor Applications Based on the WACP Optimization Objective: An Extended Analysis

This paper provides an extended analysis of the adaptive digital predistortion technique initially proposed and conceptually overviewed in [1]. This digital predistortion technique is suitable for wideband high crest factor applications (digital audio broadcasting, digital video broadcasting-terrestrial & wideband code division multiple access high power transmitters) and overcomes the technical deficiencies of the traditional direct learning method. Specifically, predistortion filter parameter estimation is modeled as a generic mathematical optimization problem instead of a linear regression problem. In addition, the optimization objective is derived in the frequency instead of the time domain. A hybridly pruned Volterra series with memory is used to implement the predistortion filter. Hybrid pruning leads to a small optimization vector space, whilst the predistortion filter memory makes the method well suited to wideband applications. Given that predistortion filter parameter estimation does not rely on known test signals being injected into the transmitter, the method is on-air adaptive. Implementation aspects of the technique not covered in [1], but requiring extended coverage in this paper, include selection of mathematical optimization algorithms, predistortion filter memory estimation, weighted adjacent channel power weighting function application, and on-air adaption performance. Results obtained from actual hardware are presented.

Design and Performance Evaluation of Digital Radio Measurement Test Beds for Laboratory Test: DAB, DAB+, and T-DMB Audio

This paper depicts the digital radio test bed design and performance evaluation for digital audio broadcasting, DAB+, and terrestrial digital multimedia broadcasting audio systems that are representative digital radio broadcasting standards operating in band III (out-of-band). We consider a laboratory trial to measure the performance of each digital radio system. The existing broadcasting measurement systems have some limitations, such as the small number of available measurement items and broadcasting systems. However, the introduced test bed can cover above representative three digital radio systems and measure various performance parameters. This paper minutely describes not only the test bed designs but also various test results according to the measurement items. Therefore, this paper can help select an appropriate digital radio standard.

DRM과 DRM+ 기반의 AM/FM 디지털라디오 활용 연구

In this paper, the possibility and necessity of the digital broadcasting propulsion in AM and FM is presented based on DRM and DRM+ transmission modes, They are the members of series technological family in digital radio development. As the frequency utilization, the application of DRM+ is flexible in any mode such as IN-BAND or OUT-OF-BAND. When the digital audio broadcasting is planned at LOW-VHF bandwidth such as TV channel No.5 and NO.6 being adjacent to FM band and OUT-Of-BAND DRM+ technology is applied, there is no collision and jamming. Particularly, in the IN-BAND Hybrid mode, it is mentioned that there was the difficulty problem for multiple SFN transmitters uses. Not like the IN-BAND mode the OUT-OF-BAND mode lets multiple transmitters, because neighbor transmitters do not interfere each other. Digital transmitter can be combined with the existing FM transmitter. The intensity of power and size of area can be easily determined according to local broadcasters` condition. And the OUT-OF-BAND mode is advantageous for AM/FM integration in digital radio receiver manufacturing, which makes the conversion schedule much shorter.

Modeling and Performance prediction of Eureka-147 OFDM based DAB system

The new digital radio system DAB (Digital Audio Broadcasting), developed within the Eureka 147 project is a very innovative and universal multimedia broadcast system that has the potential to replace existing AM and FM audio broadcast services in many parts of the world in the near future. DAB employs coded OFDM technology that enables it for mobile reception and makes receivers highly robust against channel multipath fading effect. In this paper, we have analyzed the bit error rate (BER) performance of DAB system conforming to the parameters established by the ETSI (EN 300 401) using frequency interleaving and Forward Error Correction (FEC) in different transmission channels. The results shows DAB to be suitable radio broadcasting technology for high performance in mobile environment.

Guest editorial special issue on passive radar (Part I)

Passive radar (passive coherent location, PCL) has been monitored and discussed repeatedly over the last decade by the aerospace and electronic systems community. Within the last few years system concepts, experimental systems, and technology demonstrators have been developed by research institutions, universities, and industry. The use of different types of illuminators, ranging from analogue FM-radio, analogue TV over digital broadcasters like digital audio broadcast (DAB), digital video broadcast-terrestrial (DVB-T) to cell-phone base stations, and WiFi and satellite-borne transmitters has been considered. The different illuminator systems are characterised by individual strengths and weaknesses with respect to radar requirements, and fields of application have been identified for the different sensor types.

A high-speed mixed-signal down-scaling circuit for DAB tuners

A high-speed mixed-signal down-scaling circuit with low power consumption and low phase noise for use in digital audio broadcasting tuners has been realized and characterized. Some new circuit techniques are adopted to improve its performance. A dual-modulus prescaler (DMP) with low phase noise is realized with a kind of improved source-coupled logic (SCL) D-flip-flop (DFF) in the synchronous divider and a kind of improved complementary metal oxide semiconductor master-slave (CMOS MS)-DFF in the asynchronous divider. A new more accurate wire-load model is used to realize the pulse-swallow counter (PS counter). Fabricated in a 0.18-μm CMOS process, the total chip size is 0.6 × 0.2 mm2. The DMP in the proposed down-scaling circuit exhibits a low phase noise of −118.2 dBc/Hz at 10 kHz off the carrier frequency. At a supply voltage of 1.8 V, the power consumption of the down-scaling circuit's core part is only 2.7 mW.

방송 수신 소프트웨어의 사용자 요구 품질 향상이 가능한 예외상황 테스트케이스 자동생성 기법

소프트웨어 생성 주기 동안에 품질을 제어할 수 있는 매우 중요한 영역 중의 하나로 소프트웨어 테스트 방안을 들 수 있다. 일반적으로 소프트웨어 테스트케이스는 사용자 요구에 대한 이해를 기반으로 생성되지만, 사용자가 요구하는 수준의 품질을 충족시킬 수 있는 측정 가능한 테스트케이스를 생성하는 일은 결코 쉬운 일이 아니다. 특히 비기능적 요소나 예외상황에 대한 테스트 케이스 생성은 테스터의 경험에 많이 의존하기 때문에 매우 어려운 부분이다. 본 논문에서는 이러한 문제를 해결하기위한 방안으로 방송 수신 소프트웨어의 품질 측정 시 예외상황에서 발생 가능한 테스트케이스를 자동으로 생성할 수 있는 기법을 제안한다. 제안된 기법의 우수성을 검증하기 위해 상용 방송 수신 소프트웨어를 이용하여 기존 기법과의 비교 테스트를 수행하였다. 모의실험을 통해 본 논문에서 제안한 기법을 적용하여 다양한 예외상황에서 자동 생성된 테스트케이스를 수행한 결과로 기존 기법을 적용한 경우와 비교하여 7.08%의 결함을 더 발견할 수 있었다. Testing is an important part of quality control in the software life cycle. One of the most important issues in the software testing is to generate the appropriate test cases. Generally, the software can be tested based on product understanding. However, it is not easy to create test cases that can ensure the quality of the software according to the clients' request. Especially, it is difficult to create test cases for abnormal or exceptional situations. In this paper, we present a novel approach to generate exceptional test cases at the design level of UML model. Furthermore, we describe the results of actual experiment where DAB(Digital Audio Broadcasting) parsing program is tested with previous method and also with the proposed method. The results implies that our proposed method of generating test cases for exceptional situations detect more faults than that of previous method by 7.08%.

Optimization and Hardware Implementation of the AAC Inverse Quantization Algorithm for Portable DAB plus Receivers

DAB+ is the upgraded version of DAB (Digital Audio Broadcasting) by replacing the formerly adopted MPEG1-Layer2 audio standard with HE-AAC V2 (High Efficient Advanced Audio Coding, Version 2) standard to increase the spectrum efficiency and the robustness of the receipt audio quality. Portable DAB+ receivers require low power consumption AAC decoder, which in return requires the optimizations of the decode algorithm to reduce the complexity and circuit area. In this paper, we focus on the optimization of the inverse quantization block, which occupies about 5-11% computations of the AAC decoder. The algorithm was simplified according to the statistical result of numerous quantized spectrum samples of the DAB+ programs. The hardware architecture of the simplified algorithm was proposed and verified on FPGA to receive DAB+ programs in real time. The circuit consumes only 45 Logic Elements and 2304 ROM bits. The audio quality is good and the difference is nearly imperceptible comparing to the original algorithm.

Minimization of Ici Using Ofdm Techniques

Orthogonal Frequency Division Multiplexing (OFDM) is an emerging broadband multicarrier modulation technique developed into a popular scheme for wideband digital communication, whether wireless or wired used in applications such as Digital Television, audio broadcasting, wireless networking and broadband internet access.OFDM has a well known limitation that is very sensitive to frequency error between transmitter and receiver local oscillator. This frequency offset results in Intercarrier Interference. In this paper, Inter Carrier Interference self cancellation scheme is studied for combating the effect of Inter Carrier Interference self. It shows that OFDM system with Intercarrier Interference self cancellation scheme perform much better than standard system.

Transmission Interferences Level Measurement for Digital Audiobroadcasting Signals Transmitted on Hybrid Mode

Una de las estrategias mas importantes para impulsar la introduccion de la radiodifusion digital en estaciones comerciales se basa en el uso de la actual infraestructura de transmision analogica para enviar senales tanto analogicas como digitales a traves de un mismo medio y rango de frecuencias, utilizando un adecuado esquema de modulacion. Este de transmision, denominado modo hibrido, se basa en el uso de las frecuencias de guarda entre frecuencias activas de transmision analogica para el envio de senales digitales. Sin embargo, cuando las estaciones transmisoras utilizan frecuencias adyacentes con guardas de proteccion minimas entre ellas, la informacion digital puede estar sujeta a una fuerte interferencia. En este trabajo se analiza el comportamiento de los estandares AM In Band–On channel (AM IBOC) y Digital Radio Mondiale (DRM) transmitiendo en hibrido desde frecuencias adyacentes, se realiza una simulacion para calcular el nivel de interferencia y se detallan las implicaciones del fenomeno y sus posibles soluciones, tomando como ejemplo el caso de tres estaciones comerciales de la Ciudad de Mexico.