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1.
Relationship between ADC performance and requirements of digital-IF receiver for WCDMA base-station 总被引:2,自引:0,他引:2
Hae-Moon Seo Chang-Gene Woo Pyung Choi 《Vehicular Technology, IEEE Transactions on》2003,52(5):1398-1408
The recent rapid development of digital wireless systems has led to the need for multistandard, multichannel radiofrequency (RF) transceivers. The paper presents the relationship between the performance of a bandpass-sampling analog-to-digital converter (ADC) and the requirements of a digital intermediate-frequency receiver for a wideband code-division multiple-access (WCDMA) base-station. As such, the ADC signal-to-noise ratio (SNR), the derivation of the receiver sensitivity using the SNR/spurious free dynamic range (SFDR) of the ADC, the effect of the ADC clock jitter and receiver linearity, plus the relationship between the receiver IF and the ADC sampling frequency are all analyzed. As a result, when a WCDMA base-station receiver has a data rate of 12.2 kbps, bit error rate (BER) of 0.001, and channel index, k, of 5 (sampling frequency of 122.88 MHz and IF of 92.16 MHz), the performance of a bandpass-sampling ADC was analytically determined to require a resolution of 14 bits or more, SNR of 66.6 dB or more, SFDR of 86.5 dBc or more, and total jitter of 0.2 ps or less, including internal ADC jitters and clock jitters. 相似文献
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孔径抖动对中频采样系统信噪比影响的研究 总被引:12,自引:0,他引:12
孔径抖动对中频(或射频)带通采样系统信噪比的影响非常严重.理论上,尽管相同带宽的中频信号和基带信号可以用相同的频率进行采样,但中频采样受孔径抖动等因素的影响更大,其采样技术要求也更高.如果在中频采样系统中解决不好孔径抖动问题,很可能根本采集不到正确的信号.本文通过分析孔径抖动产生的原因,孔径抖动与ADC (模数转换器)的信噪比以及与被采样信号上限频率之间的关系,找出了由孔径抖动决定的被采样信号的上限频率与ADC模拟带宽之间存在差距的原因,并发现了过采样率与处理增益及孔径抖动之间的关系.最后,介绍了几项减小孔径抖动的具体措施. 相似文献
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This paper describes a fully integrated digital-spread spectrum transceiver chip fabricated through MOSIS in 1.2 μm CMOS. It includes a baseband spread spectrum transmitter and a coherent intermediate frequency (IF) receiver consisting of a Costas loop, an acquisition loop for the pseudo-noise (PN) sequence, and a clock recovery loop with a 406.4 MHz onchip numerically controlled oscillator (NCO). The transceiver is capable of operating at a maximum IF sampling rate of 50.8 MS/s and a maximum chip rate of 12.7 R Mchips/s (Mcps) with selectable data rates of 100, 200, 400, and 800 kbps. At the maximum operating speed of 50.8 R MS/s, it dissipates 1.1 W. In an additive white Gaussian noise channel the IF receiver achieves a receiver output SNR within 1 dB of theory and can acquire code with a wide range of input SNR from -17 dB to over 30 dB. The transceiver chip has been interfaced to an RF up/down converter to demonstrate a wireless voice/data/video link operating in the 902-928 MHz band 相似文献
4.
A wide bandwidth continuous time sigma delta analog-to-digital conversion is implemented in 130?nm process. The circuit is targeted for wide bandwidth applications such as video or wireless base-stations. The third-order continuous time sigma delta modulator comprises a third-order RC operational-amplifier-based loop filter and 3-bit internal quantizer operated at 512?MHz clock frequency. To reduce the clock jitter sensitivity, nonreturn-to-zero DAC pulse shaping is used. The excess loop delay is set to half the sampling period of the quantizer, and the degradation of modulator stability due to excess loop delay is avoided with this architecture. The sigma delta ADC achieves a 60?dB SNR and a 59.3?dB signal-to-noise-plus-distortion ratio over a 16?MHz signal band at an oversampling ratio of 16. The power consumption of the continuous time sigma delta modulator is 22 mW from the 1.2?V supply. 相似文献
5.
《Solid-State Circuits, IEEE Journal of》2006,41(8):1846-1855
This paper describes a 14-bit, 125 MS/s IF/RF sampling pipelined A/D converter (ADC) that is implemented in a 0.35$muhbox m$ BiCMOS process. The ADC has a sample-and-hold circuit that is integrated in the first pipeline stage, which removes the need for a dedicated sample-and-hold amplifier (i.e., “SHA-less”). It also has a sampling buffer that is turned off during the hold clock phases to save power. To accurately estimate and minimize the clock jitter, a new jitter simulation technique was used whose results were verified on silicon. The measured silicon results indicate the highest published IF sampling performance to date and prove the viability of the “SHA-less” architecture for IF/RF sampling ADCs. The ADC is calibration-free and achieves a DNL of less than 0.2 LSB and INL of 0.8 LSB. The SNR is 75 dB below Nyquist, and stays above 71 dB up to 500 MHz. The low-frequency SFDR is about 100 dB, and stays above 90 dB up to about 300 MHz. This is also the first ADC to achieve 14-bit level performance for input signal frequencies up to 500 MHz and to have a total RMS jitter of only 50 fs. 相似文献
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主要介绍了一种适用于225—512MHz的宽带数字中频AGC接收机的设计,该接收机的信号带宽是5MHz,OFDM调制。通过对宽带信号接收机的需求进行分析,详细阐述了AGC电路及控制方案的逐步实现过程。 相似文献
10.
Mitteregger G. Ebner C. Mechnig S. Blon T. Holuigue C. Romani E. 《Solid-State Circuits, IEEE Journal of》2006,41(12):2641-2649
A wide bandwidth continuous-time sigma-delta ADC, operating between 20 and 40 MS/s output data rate, is implemented in 130-nm CMOS. The circuit is targeted for applications that demand high bandwidth, high resolution, and low power, such as wireless and wireline communications, medical imaging, video, and instrumentation. The third-order continuous-time SigmaDelta modulator comprises a third-order RC operational-amplifier-based loop filter and 4-bit internal quantizer operating at 640 MHz. A 400-fs rms jitter LC PLL with 450-kHz bandwidth is integrated, generating the low-jitter clock for the jitter-sensitive continuous-time SigmaDelta ADC from a single-ended input clock between 13.5 and 40 MHz. To reduce clock jitter sensitivity, nonreturn-to-zero (NRZ) DAC pulse shaping is used. The excess loop delay is set to half the sampling period of the quantizer and the degradation of modulator stability due to excess loop delay is avoided with a new architecture. The SigmaDelta ADC achieves 76-dB SNR, -78-dB THD, and a 74-dB SNDR or 12 ENOB over a 20-MHz signal band at an OSR of 16. The power consumption of the CT SigmaDelta modulator itself is 20 mW and in total the ADC dissipates 58 mW from the 1.2-V supply 相似文献
11.
In this work, we investigate differentially encoded blind transceiver design in low signal‐to‐noise ratio (SNR) regimes for orthogonal frequency‐division multiplexing (OFDM) signaling. Owing to the fact that acquisition of channel state information is not viable for short coherence times or in low SNR regimes, we propose a time‐spread frequency‐encoded method under OFDM modulation. The repetition (spreading) of differentially encoded symbols allows us to achieve a target energy per bit to noise ratio and higher diversity. Based on the channel order, we optimize subcarrier assignment for spreading (along time) to achieve frequency diversity of an OFDM modulated signal. We present the performance of our proposed transceiver design and investigate the impact of Doppler frequency on the performance of the proposed differentially encoded transceiver design. To further improve reliability of the decoded data, we employ capacity‐achieving low‐density parity‐check forward error correction encoding to the information bits. 相似文献
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Chung B.-Y. Chien C. Samueli H. Jain R. 《Selected Areas in Communications, IEEE Journal on》1993,11(7):1096-1107
A VLSI architecture for an all-digital binary phase shift keying (BPSK) direct-sequence (DS) spread spectrum (SS) intermediate frequency (IF) receiver is presented, and an in-depth performance analysis is given. The all-digital architecture incorporates a Costas loop for carrier recovery and a delay-locked loop for clock recovery. For the pseudorandom noise (PN) acquisition block, a robust energy detection scheme is proposed to reduce false PN locks over a broad range of signal-to-noise ratios. The proposed architecture is intended for use in the 902-928 MHz unlicensed spread spectrum radio band. A 100 kbs information rate and a 12.7 Mchips/second PN code rate are assumed. The IF center frequency is 12.7 MHz and the IF sampling rate is 50.8 Msamples/second, which is the Nyquist rate for the 25.4 MHz bandwidth signal. Finite wordlength effects have been simulated to optimize the architecture, thereby minimizing the chip area, and results of the finite wordlength simulations demonstrate that the chip architecture achieves a bit error rate performance within 1 dB of theory in an additive white Gaussian noise channel 相似文献
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A 16-bit 65-MS/s 3.3-V pipeline ADC core in SiGe BiCMOS with 78-dB SNR and 180-fs jitter 总被引:1,自引:0,他引:1
The analog-to-digital converter presented in this work demonstrates the efficiency of the straight 2.5 bit-per-stage approach for the implementation of pipelined switched-capacitor architectures targeting up to 16-bit resolution and 65-MS/s sampling rate. The test chip has been fabricated in a 45-GHz f/sub T/, 0.4-/spl mu/m 3.3-V SiGe BiCMOS process that makes it suitable for integration with an RF front-end toward an antenna-to-DSP communication processor. Performance of 78.3 dBFS SNR, 88dBc SFDR at 65 MS/s, 1 MHz input is obtained without trimming or calibration, dissipating 970 mW total with external references. Since the 4 V/sub p-p/ signal range chosen for high SNR could lead to distortion in the Sample/Hold and the pipelined quantizer with only 3.3-V supply, a fast and accurate SPICE simulation technique for INL investigation is described that enabled detailed diagnosis of potential nonlinearity sources. Theoretical analysis and practical implementation of the clock circuit are also discussed allowing the design of a CMOS-based clock featuring 180-fs jitter, which preserves high SNR against input frequency: state-of-the-art 73.5dBFS have been observed at 150 MHz input, popular intermediate frequency (IF) for single-heterodyne BTS receivers. Finally, the figures of merit encompassing power, effective resolution, and speed rank the dynamic performance of the ADC core among the best in its class. 相似文献
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The design and experimental results of a 2.7 V 50 MHz switched-capacitor DS modulator in a 0.35 μm BiCMOS process are presented. The circuit is targeted for the IF section of a radio receiver in a GSM cellular phone. It combines frequency downconversion with analogue to digital conversion by directly sampling an input signal from an IF of 50 MHz. The measured peak signal-to-noise ratio for a 100 kHz bandwidth is 81 dB with a 53 MHz blocking signal and the measured IIP3 for IF input is +36.9 dBV 相似文献
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This paper presents a general‐purpose design scheme of a filter bank (FB)–based radio frequency (RF) transceiver that operates across the entire ultra‐high frequency (UHF) TV band from 470 MHz to 698 MHz and complies with the TV white space (TVWS) regulatory requirements. To this end, an intermediate frequency (IF) band‐pass filter (BPF) with a sharp skirt characteristic is considered as a solution for handling the incoming signals from a baseband modem. Specifically, an FB‐based BPF structure with four ceramic resonator filters that effectively rejects unwanted signals is proposed to extract a desired signal in the TV band. Achievable data rates of a cognitive radio system (CRS) employing the proposed FB‐based RF transceiver at the application layer are investigated in both wired and wireless environments. The service coverage of the CRS network is measured according to several modulation and coding schemes (MCSs) of the CRS. The results show that the coverage of a wireless network in a nearly open area can be extended by more than 9.3 km in the TVWS. Experimental results also confirm that the proposed FB‐based RF transceiver is adequate for utilization in TVWS applications. 相似文献
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采样时钟偏差对OFDM系统性能的影响 总被引:1,自引:0,他引:1
针对采样时钟同步偏差对正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)系统的影响,建立了数学模型,分别就采样定时偏差和采样频率偏差的影响进行详细分析;经过仿真,从星座图、误码率(Bit—Error—Rate,BER)及信噪比(Signal—to—Noise Ratio,SNR)损失等角度对采样频率偏差的影响做了揭示和验证。结果表明,采样频率偏差会引起信号幅度衰减和子载波间干扰(Inter—Carrier Interference,ICI),导致系统信噪比性能下降;这种影响与子载波位置有关,还会随着OFDM符号数的增多而加剧。 相似文献
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设计了中物院太赫兹科研装置超导加速器低电平控制系统的射频前端部分,采用了信号源8663A与直接信号发生器板卡AD9858结合的方案,产生射频前端所需的30.72 MHz中频信号和1330.72 MHz本振信号。采用AD9510时钟板产生ADC和DAC采样所需的频率122.88 MHz和245.76 MHz,采样信号时间抖动仅为4 ps,由此引起的幅值采样误差和相位采样误差分别为±0.04%和±0.025%,符合设计要求。 相似文献
19.
传统的PLL(Phase Locked Loop)电路受限于环路参数的选定,其相位噪声与抖动特性已经难以满足大阵列、高精度TDC(Time-to-Digital Converter)的应用需求.本文致力于PLL环路带宽的优化选取,采取TSMC 0.35μm CMOS工艺实现了一款应用于TDC的具有低抖动、低噪声特性的锁相环(Phase Locked Loop,PLL)电路,芯片面积约为0.745mm×0.368mm.实际测试结果表明,在外部信号源输入15.625MHz时钟信号的条件下,PLL输出频率可锁定在250.0007MHz,频率偏差为0.7kHz,输出时钟占空比为51.59%,相位噪声为114.66dBc/Hz@1MHz,均方根抖动为4.3ps,峰峰值抖动为32.2ps.锁相环的相位噪声显著降低,输出时钟的抖动特性明显优化,可满足高精度阵列TDC的应用需要. 相似文献
20.
Arkesteijn V.J. Klumperink E.A.M. Nauta B. 《Circuits and Systems II: Express Briefs, IEEE Transactions on》2006,53(2):90-94
The effective number of bits of an analog-to-digital converter (ADC) is not only limited by the quantization step inaccuracy but also by sampling time uncertainty. According to a commonly used model, the error caused by timing jitter, integrated over the whole bandwidth, should not be bigger than the quantization noise, for a full swing input signals at the maximum input frequency. This results in unfeasible phase noise requirements for the sampling clock in software radio receivers with direct RF sampling. However, for a radio receiver not the total integrated error is relevant, but only the error signal in the channel bandwidth. This paper explores the clock jitter requirements for a software radio application, using a more realistic model and taking into account the power spectrum of both the input signal and the spectrum of the sampling clock jitter. Using this model, we show that the clock jitter requirements are very similar to reciprocal mixing requirements of superheterodyne receivers. 相似文献