136 research outputs found

    Jitter reduction techniques for digital audio.

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    by Tsang Yick Man, Steven.Thesis (M.Phil.)--Chinese University of Hong Kong, 1997.Includes bibliographical references (leaves 94-99).ABSTRACT --- p.iACKNOWLEDGMENT --- p.iiLIST OF GLOSSARY --- p.iiiChapter 1 --- INTRODUCTION --- p.1Chapter 1.1 --- What is the jitter ? --- p.3Chapter 2 --- WHY DOES JITTER OCCUR IN DIGITAL AUDIO ? --- p.4Chapter 2.1 --- Poorly-designed Phase Locked Loop ( PLL ) --- p.4Chapter 2.1.1 --- Digital data problem --- p.7Chapter 2.2 --- Sampling jitter or clock jitter ( Δti) --- p.9Chapter 2.3 --- Waveform distortion --- p.12Chapter 2.4 --- Logic induced jitter --- p.17Chapter 2.4.1 --- Digital noise mechanisms --- p.20Chapter 2.4.2 --- Different types of D-type flop-flip chips are linked below for ease of comparison --- p.21Chapter 2.4.3 --- Ground bounce --- p.22Chapter 2.5 --- Power supply high frequency noise --- p.23Chapter 2.6 --- Interface Jitter --- p.25Chapter 2.7 --- Cross-talk --- p.28Chapter 2.8 --- Inter-Symbol-Interference (ISI) --- p.28Chapter 2.9 --- Baseline wander --- p.29Chapter 2.10 --- Noise jitter --- p.30Chapter 2.11 --- FIFO jitter reduction chips --- p.31Chapter 3 --- JITTER REDUCTION TECHNIQUES --- p.33Chapter 3.1 --- Why using two-stage phase-locked loop (PLL ) ?Chapter 3.1.1 --- The PLL circuit components --- p.35Chapter 3.1.2 --- The PLL timing specifications --- p.36Chapter 3.2 --- Analog phase-locked loop (APLL ) circuit usedin second stage --- p.38Chapter 3.3 --- All digital phase-locked loop (ADPLL ) circuit used in second stage --- p.40Chapter 3.4 --- ADPLL design --- p.42Chapter 3.4.1 --- "Different of K counter value of ADPLL are listed for comparison with M=512, N=256, Kd=2" --- p.46Chapter 3.4.2 --- Computer simulated results and experimental results of the ADPLL --- p.47Chapter 3.4.3 --- PLL design notes --- p.58Chapter 3.5 --- Different of the all digital Phase-Locked Loop (ADPLL ) and the analogue Phase-Locked Loop (APLL ) are listed for comparison --- p.65Chapter 3.6 --- Discrete transistor oscillator --- p.68Chapter 3.7 --- Discrete transistor oscillator circuit operation --- p.69Chapter 3.8 --- The advantage and disadvantage of using external discrete oscillator --- p.71Chapter 3.9 --- Background of using high-precision oscillators --- p.72Chapter 3.9.1 --- The temperature compensated crystal circuit operation --- p.73Chapter 3.9.2 --- The temperature compensated circuit design notes --- p.75Chapter 3.10 --- The discrete voltage reference circuit operation --- p.76Chapter 3.10.1 --- Comparing the different types of Op-amps that can be used as a voltage comparator --- p.79Chapter 3.10.2 --- Precaution of separate CMOS chips Vdd and Vcc --- p.80Chapter 3.11 --- Board level jitter reduction method --- p.81Chapter 3.12 --- Digital audio interface chips --- p.82Chapter 3.12.1 --- Different brand of the digital interface receiver (DIR) chips and clock modular are listed for comparison --- p.84Chapter 4. --- APPLICATION CIRCUIT BLOCK DIAGRAMS OF JITTER REDUCTION AND CLOCK RECOVERY --- p.85Chapter 5 --- CONCLUSIONS --- p.90Chapter 5.1 --- Summary of the research --- p.90Chapter 5.2 --- Suggestions for further development --- p.92Chapter 5.3 --- Instrument listing that used in this thesis --- p.93Chapter 6 --- REFERENCES --- p.94Chapter 7 --- APPENDICES --- p.100Chapter 7.1.1 --- Phase instability in frequency dividersChapter 7.1.2 --- The effect of clock tree on Tskew on ASIC chipChapter 7.1.3 --- Digital audio transmission----Why jitter is important?Chapter 7.1.4 --- Overview of digital audio interface data structuresChapter 7.1.5 --- Typical frequency Vs temperature variations curve of Quartz crystalsChapter 7.2 --- IC specification used in these research projec

    A development study for a short range, low capacity digital microwave link

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    Includes bibliographical references.A specific request for development of a short-range, low capacity digital microwave transmission system has been received from the South African Dept. Posts and Telecommunications. The aim of this project is to initiate development work by determining the optimum system configuration and modulation technique to meet the design specifications. In addition, it is proposed to develop and construct an I.F. modulator/demodulator module using which simulation tests chosen modulation application may be performed in order to assess the scheme's feasibi1ity in this specific application

    Wavelength tunable transmitters for future reconfigurable agile optical networks

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    Wavelength tuneable transmission is a requirement for future reconfigurable agile optical networks as it enables cost efficient bandwidth distribution and a greater degree of transparency. This thesis focuses on the development and characterisation of wavelength tuneable transmitters for the core, metro and access based WDM networks. The wavelength tuneable RZ transmitter is a fundamental component for the core network as the RZ coding scheme is favoured over the conventional NRZ format as the line rate increases. The combination of a widely tuneable SG DBR laser and an EAM is a propitious technique employed to generate wavelength tuneable pulses at high repetition rates (40 GHz). As the EAM is inherently wavelength dependant an accurate characterisation of the generated pulses is carried out using the linear spectrogram measurement technique. Performance issues associated with the transmitter are investigated by employing the generated pulses in a 1500 km 42.7 Gb/s circulating loop system. It is demonstrated that non-optimisation of the EAM drive conditions at each operating wavelength can lead to a 33 % degradation in system performance. To achieve consistent operation over a wide waveband the drive conditions of the EAM must be altered at each operating wavelength. The metro network spans relatively small distances in comparison to the core and therefore must utilise more cost efficient solutions to transmit data, while also maintaining high reconfigurable functionality. Due to the shorter transmission distances, directly modulated sources can be utilised, as less precise wavelength and chirp control can be tolerated. Therefore a gain-switched FP laser provides an ideal source for wavelength tuneable pulse generation at high data rates (10 Gb/s). A self-seeding scheme that generates single mode pulses with high SMSR (> 30 dB) and small pulse duration is demonstrated. A FBG with a very large group delay disperses the generated pulses and subsequently uses this CW like signal to re-inject the laser diode negating the need to tune the repetition rate for optimum gain-switching operation. The access network provides the last communication link between the customer’s premises and the first switching node in the network. FTTH systems should take advantage of directly modulated sources; therefore the direct modulation of a SG DBR tuneable laser is investigated. Although a directly modulated TL is ideal for reconfigurable access based networks, the modulation itself leads to a drift in operating frequency which may result in cross channel interference in a WDM network. This effect is investigated and also a possible solution to compensate the frequency drift through simultaneous modulation of the lasers phase section is examined

    Design and implementation of a frequency synthesizer for an IEEE 802.15.4/Zigbee transceiver

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    The frequency synthesizer, which performs the main role of carrier generation for the down-conversion/up-conversion operations, is a key building block in radio transceiver front-ends. The design of a synthesizer for a 2.4 GHz IEEE 802.15.4/Zigbee transceiver forms the core of this work. This thesis provides a step-by-step procedure for the design of a frequency synthesizer in a transceiver environment, from the mapping of standard-specifications to its integrated circuit implementation in a CMOS technology. The results show that careful system level planning leads to high-performance realizations of the synthesizer. A strategy of using different supply voltages to enhance the performance of each building block is discussed. A section is presented on layout and board level issues, especially for radio-frequency systems, and their effect on synthesizer performance. The synthesizer consumes 15.5 mW and meets the specifications of the 2.4 GHz IEEE 802.15.4/Zigbee standard. It is capable of 5 GHz operation with a VCO sensitivity of 135 MHz/V and a tuning range of 700 MHz. It can be seen that the adopted methodology can be used for the design of high-performance frequency synthesizers for any narrow-band wireless standard

    An embedded tester core for mixed-signal System-on-Chip circuits

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    The Telecommunications and Data Acquisition Report

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    This quarterly publication (July-Sept. 1986) provides archival reports on developments in programs managed by JPL's Office of Telecommunications and Data Acquisition (TDA). In space communications, radio navigation, radio science, and ground-based radio astronomy, it reports on activities of the Deep Space Network (DSN) and its associated Ground Communications Facility (GCF) in planning, in supporting research and technology, in implementation, and in operations. This work is performed for NASA's Office of Space Tracking and Data Systems (OSTDS). In geodynamics, the publication reports on the application of radio interferometry at microwave frequencies for geodynamic measurements. In the search for extraterrestrial intelligence (SETI), it reports on implementation and operations for searching the microwave spectrum. The latter two programs are performed for NASA's Office of Space Science and Applications (OSSA)

    Signal constellation and carrier recovery technique for voice-band modems

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    Frequency Synthesis in Wireless and Wireline Systems

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    First, a frequency synthesizer for IEEE 802.15.4 / ZigBee transceiver applications that employs dynamic True Single Phase Clocking (TSPC) circuits in its frequency dividers is presented and through the analysis and measurement results of this synthesizer, the need for low power circuit techniques in frequency dividers is discussed. Next, Differential Cascode Voltage-Switch-Logic (DCVSL) based delay cells are explored for implementing radio-frequency (RF) frequency dividers of low power frequency synthesizers. DCVSL ip- ops offer small input and clock capacitance which makes the power consumption of these circuits and their driving stages, very low. We perform a delay analysis of DCVSL circuits and propose a closed-form delay model that predicts the speed of DCVSL circuits with 8 percent worst case accuracy. The proposed delay model also demonstrates that DCVSL circuits suffer from a large low-to-high propagation delay ( PLH) which limits their speed and results in asymmetrical output waveforms. Our proposed enhanced DCVSL, which we call DCVSL-R, solves this delay bottleneck, reducing PLH and achieving faster operation. We implement two ring-oscillator-based voltage controlled oscillators (VCOs) in 0.13 mu m technology with DCVSL and DCVSL-R delay cells. In measurements, for the same oscillation frequency (2.4GHz) and same phase noise (-113dBc/Hz at 10MHz), DCVSL-R VCO consumes 30 percent less power than the DCVSL VCO. We also use the proposed DCVSL-R circuit to implement the 2.4GHz dual-modulus prescaler of a low power frequency synthesizer in 0.18 mu m technology. In measurements, the synthesizer exhibits -135dBc/Hz phase noise at 10MHz offset and 58 mu m settling time with 8.3mW power consumption, only 1.07mWof which is consumed by the dual modulus prescaler and the buffer that drives it. When compared to other dual modulus prescalers with similar division ratios and operating frequencies in literature, DCVSL-R dual modulus prescaler demonstrates the lowest power consumption. An all digital phase locked loop (ADPLL) that operates for a wide range of frequencies to serve as a multi-protocol compatible PLL for microprocessor and serial link applications, is presented. The proposed ADPLL is truly digital and is implemented in a standard complementary metal-oxide-semiconductor (CMOS) technology without any analog/RF or non-scalable components. It addresses the challenges that come along with continuous wide range of operation such as stability and phase frequency detection for a large frequency error range. A proposed multi-bit bidirectional smart shifter serves as the digitally controlled oscillator (DCO) control and tunes the DCO frequency by turning on/off inverter units in a large row/column matrix that constitute the ring oscillator. The smart shifter block is completely digital, consisting of standard cell logic gates, and is capable of tracking the row/column unit availability of the DCO and shifting multiple bits per single update cycle. This enables fast frequency acquisition times without necessitating dual loop fi lter or gear shifting mechanisms. The proposed ADPLL loop architecture does not employ costly, cumbersome DACs or binary to thermometer converters and minimizes loop filter and DCO control complexity. The wide range ADPLL is implemented in 90nm digital CMOS technology and has a 9-bit TDC, the output of which is processed by a 10-bit digital loop filter and a 5-bit smart shifter. In measurements, the synthesizer achieves 2.5GHz-7.3GHz operation while consuming 10mW/GHz power, with an active area of 0.23 mm2

    Design and Control of Power Converters 2019

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    In this book, 20 papers focused on different fields of power electronics are gathered. Approximately half of the papers are focused on different control issues and techniques, ranging from the computer-aided design of digital compensators to more specific approaches such as fuzzy or sliding control techniques. The rest of the papers are focused on the design of novel topologies. The fields in which these controls and topologies are applied are varied: MMCs, photovoltaic systems, supercapacitors and traction systems, LEDs, wireless power transfer, etc
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